Case 1

Frontal and lateral radiographs of the skull are provided. Many students of radiology in the present day are not familiar with the range of normal skull images and may find it difficult to make a precise interpretation. In this case there are two obvious observations. One is the configuration of the skull which has an increased height (acrocephaly or turrycephaly). The second observation is the increased accentuation of the skull markings. A 'silver beaten' or 'copper beaten' appearance is present. If you carefully notice, you will see that sutures are not visible. Combination of coronal and sagittal sutural premature closure results in the acrocephaly configuration. Often the condition is associated with a syndrome. Most frequently encountered entity is Crouzen syndrome. Many other anomalies may coexist along with the facial dysmorphism. Hence patients has to be viewed in totality.

CT examination is extremely important in this condition not only for confirming the sutural fusion but also to assess the extent of malformation. What is your observation on the CT images? The striking observation is that the anterior part of the facial structures are poorly developed with very shallow orbits. These patients may come with the popping eyeballs due to dislocation from the sockets so it is extremely important information for craniofacial surgeon to quantify this 'shallow orbit' configuration. Pre-op CT is an important element in the planning for and the follow-up of patients after reconstructive surgery

Case 2

These set of patient have presented with an acute neurological condition. Axial non-contrast CT images are provided.

I am not trying to question or underestimate expertise or the imaging experience of the viewer. No harm in visiting the basics, which are often taken for granted. Examples (a) as you are very familiar, shows an epidural haematoma. Biconvex, next to the bone with a sharp medial margin, can be seen in association with a bony injury or injury to the adjacent vessels, like middle meningeal artery. This condition is one of the important neurosurgical emergency. Example (b) Here haematoma is present in a crescentic shape, shows some heterogeneity in the density, associated with massive mass-effect and compartmental herniation. This is a presentation of an acute subdural haematoma.  Often imaging under estimates the size of haematoma.  Image (c) demonstrate subarachnoid and intraventricular blood. Essentially CSF spaces instead of being hypodense become hyperdense. In the ventricles bleeding may be seen tracking along with the choroid plexus. This is appearance of subarachnoid blood, along with trauma, bleeding vascular malformation and aneurysms  contributed to this appearance. The last one is a parenchymal haemorrhage, mostly located in the ganglionic area with early leak into the ventricles. Hypertensive bleeds belong  to this category, ultimately open into the ventricular system.

Case 3

Skull radiograph of a 4-month-old child is presented. Any observations and conclusions on these radiographs?

It should be obvious that there is increase in the density at the parietal region. The increased density appears to be on the left side in the frontal radiograph, and some element of bone thickening is also suspected. The image below looks little softer though, and is intended to show the soft tissue element and bone thickening. This is a case of an organized Cephalohematoma. In the past it used to be more common due to forceps delivery and subsequent mechanical trauma. The blood clot is Initially radiolucent and subsequently gets organized and calcified.

Case 4

Flexion and extension radiograph of a middle-aged patient is provided. Range of movement and alignment obviously appear normal. Intervertebral discs are well preserved. There are no prevertebral soft tissue abnormality. What is the abnormality? If you look carefully in the upper cervical region there is increased bone density posteriorly along the vertebral bodies. This needs further scrutiny. CT examination of the same region is provided subsequently. Findings are obvious on the CT examination where there is complete ossification of posterior longitudinal ligament. This is not a part of ankylosing spondylitis as rest of the supportive findings are missing. Another condition which can cause this appearance is diffuse idiopathic skeletal hyperostosis. Also note that the spinal canal is narrowed and this observation is not well appreciated on the plain radiography.

Case 5

This patient is an adult female with the recurrent headache. Contrast-enhanced CT images are provided for evaluation. There is not much of a diagnostic problem in identifying the abnormality which is presented as a enhancing mass in the sellar and suprasellar region. Sella is not enlarged. Intrasellar and suprasellar components of  the lesion appear somewhat confluent. Differential diagnoses for such a condition are many, and may be different in different age groups. In the adult age group, a sellar mass with suprasellar extension is likely a pituitary adenoma, prolactinoma. Occacional cranio-pharyngioma menifest in the late age group. Another, relatively uncommon, interesting lesion which can present like this is a germinoma arising from the floor of the third ventricle. This patient was a confirmed case of germinoma.

Case 6

This patient is a female with recurrent headache and blurring of vision. Patient had delivered recently. Representative images of the MRI is provided with various sequences. What are your observations and the possible diagnosis? The first set of images are diffusion-weighted images which appear unremarkable. T2-weighted and FLAIR images show hyperintensity in the subcortical occipitoparietal white matter, frontal subcortical white matter and some distributed along the deep central region. There is no mass-effect. Differential diagnosis should include conditions like PRES, encephalitis or acute demyelination. Patient did not have supportive evidence of encephalitis or demyelinating disease. Patient was diagnosed to have PRES.

Case 7

Skull radiographs provided are of the child being evaluated for suspected swelling. Any observations regarding the skull? If you are familiar with the normal structures, identification of a linear radiolucency in the left posterior parietal area is not very difficult to make. So this lucency is likely to be due to a fracture. Complete extent of injury is very important to define, as in such cases bone depression and associated leptomeningeal injury are important information for management. CT examination revealed subtle hyperdensities in the left posterior parietal area, probably due to subdural/subarachnoid hemorrhage. Also there is an extracranial hematoma. Bone windows obviously show fractures, part of which are minimally depressed. Depression more than 5 mm is extremely important as prognostic information regarding management.

Case 8

A child with the global developmental delay. Evaluated with MR examination. This is a textbook case for a student of radiology. Findings are very typical. The midline structure, the corpus callosum is absent and so we do not see the C-shaped band in the sagittal images. Unique appearance of radiating gyri are evident along the medial aspects of the cerebral hemispheres. Also, azygous configuration of the anterior cerebral artery will be visible if you perform the angio series. Lateral ventricles are somewhat parallel in orientation and show prominent medial impressions due to prominent white matter bundles along the medial aspect, the bundle of Probst. There may be varying degree of ventricular dilation. This condition is also associated with midline cysts, cortical heterotopias, posterior fossa  and spinal anomalies.

Case 9

Newborn baby with a large head and multiple anomalies. Neurosonography revealed enlarged lateral ventricles. Patient was evaluated with CT and subsequently with an MR examination.

Observations: 

CT examinations provide an interesting combination of a hugely enlarged supratentorial compartment and hardly visible posterior fossa structures. There is a specific lateral ventricular configuration, colpocephaly. Fourth ventricle and posterior fossa structures are hardly visible. If you note carefully, foramen magnum appears somewhat large. By now the diagnosis should be clear-cut. We are dealing with a possible Arnold-Chiari malformation. Students should go through the whole spectrum of the condition and understand the differences between the described varieties.

In the MR examination, we see a significant discrepancy of ventricular size when compared to CT. Ventricles look much smaller. What is the cause? Your guess may be right. Patient has undergone a V-P shunt. Still you can see somewhat large lateral ventricles with the colpocephaly. Periventricular parenchyma shows T2 hyperintensity, either due to hypo-myelination or trans-ependymal fluid. Posterior fossa structures are tightly packed and also extend to the upper cervical region. Also, there is a 'vermian pseudotumor' projecting through the tentorial hiatus. The final two images of the distal spine shows a lumbar meningocele with a dermal tract. This combination confirms this entity as Chiari type II malformation.

Case 10

64-year-old male presented with seizures progressing to unresponsiveness.

Sample images of the axial and sagittal contrast-enhanced CT are provided. Interpretation of this examination should not be very difficult. We had to differentiate mass lesion versus massive infarct. A simple observation is that the overall shape of the involved structure is maintained. Also undistorted anatomy is obvious as some vessels are visualized within the hypodense area. Patient had a massive basilar artery occlusion with a cerebellar infarct. Herniation of the posterior fossa structures in the cervical region is a potential clinical problem. Generally, dilated lateral ventricles are noted in such instances.

Case 11: Child with an abnormal head configuration.

When a child presents with an abnormal head shape, a tell-tale evidence of sutural abnormality is generally predictable. Simple logic dictates that the outcome of any abnormal sutural fusion leads to a typical and predictable skull configuration. In the present case, the patient has a scapho-cephalic (boat-shaped) head configuration. So we know that the sagittal suture is prematurely fused. Then what is the indication for radiographic examination? You will be surprised to know that this is not done for making a diagnosis, but rather for showing the extent of changes and making a plan for surgical correction if needed. Abnormal configuration precedes the radiological changes. In the initial stages, the changes are present in the fibrous components of the sutures, and hence may not be visible radiographically. When the changes are in the bones, there is obliteration of the sutures, peri-sutural sclerosis, and formation of the ridge along the sutural interface (as shown in this case). Ridge formation is also clearly evident in the axial sections like the hull of a boat.

Case 12: Newborn with a large head and multiple congenital anomalies

CT sections of the brain are provided. Examination demonstrates gross dilatation of lateral ventricles with colpo-cephalic configuration. Third ventricle is also dilated, although relatively less so. Fourth ventricle is small, slit-like and oriented antero-posteriorly. Posterior fossa structures appear somewhat tight. What are the likely possibilities? Do you think this goes with an aqueduct stenosis? Do think this is compatible with Arnold-Chiari malformation? Do you suspect any other congenital anomaly? MRI examination is needed for obtaining further detail.

MR examination of the brain with images in various planes demonstrates hugely dilated lateral ventricles without midline septum. Corpus callosum is developed anteriorly, but not visualized in the posterior part. Any other observations? Posterior fossa structures are in place. No obvious descent of the brainstem. There is evidence of polymicrogyria. This patient has dysplastic corpus callosum, possibly a midline dorsal-third ventricular cyst, hydrocephalus and cortical microgyria (migrational anomalies)

Case 13

Sagittal MR examination with T1 and T2 waiting a provided. You have already seen the intracranial structures and chest and abdomen in the previous illustration. You will notice that there is a dorsolumbar meningocoele with cord tethering. Vertebral anomalies and also confirmed. You will see signal voids in the spinal canal around the neural structures. These are due to dilated epidural veins.

Case 14:  45-year-old male with the neck pain, treated with a procedure.

Lateral views in flexion and extension are provided. Initial radiograph in the preoperative radiograph and a subsequent one, after anterior disc implant. This form of surgical intervention became popular in the late 90s-, inserting a spacer in the involved disc level for degenerative disc disease. This radiograph is just to familiarize the appearance of the procedure on plain radiography and MRI examination. Note is that there is no significant disc/implant bulge into the spinal canal or any signs of cord compression

Case 15

52-year-old male with tinnitus. Investigated with CT examination elsewhere.

Representative MR Images without and with contrast are provided in different sequences. Interpretation of this examination should not be very difficult for those familiar with the skull base anatomy. Abnormality is located in the left jugular fossa in the form of the slightly T2 hyperintense well-defined lesion causing expansion of the jugular fossa. In the provided images no clear-cut salt-and-pepper appearance is noted. There are foci of T1 hyperintensity, could be due to foci of haemorrhage.  However following intravenous contrast there is a homogeneous intense enhancement of the lesion, also showing extension posteriorly into the posterior fossa in the cerebellar medullary region. Differential diagnosis for the mass in the jugular fossa are straightforward, main entities are glomus tumours, cranial nerve schwannoma , meningioma, lymphoma or metastatic disease etc. This was a case of glomus jugulare tumour.

(Prepared in colloboration with Dr Hemanth)

Case 16:  21-year-old male with headache

Representative MR Images of the brain are provided without and with gadolinium contrast. An area of the well-defined lobulated opacity is noted in the suprasellar region, isointense with the cerebral cortex in the T1 and T2 weighted images. Location is just above the sella, extending upwards and elevating the optic chiasma. Extension is preferentially on the right side lying adjacent to the intracranial part of the ICA. There is a homogeneous contrast enhancement following a gadolinium based contrast. What do you think about the localization of the lesion? Well, the Lesion is extra-axial. In this location the differential diagnosis should include Pituitary adenoma, meningioma cranio-pharyngioma and granuloma etc.

(Prepared in colloboration with Dr Hemant

Case 17

20-year-old male patient with a symmetrical weakness in the upper limbs and wasting of the inner muscles

Sagittal MR images of cervical spine in flexion and extension are available with T2 waiting with a single image in the axial plane. Once dynamic images are shown your focus is to see whether there is a possibility of Hirayama disease. Examination may appear normal in the extension. In flexion, however, there is marked reduction in the anterior subarachnoid space, cord lying close to the vertebra. Other occasional observations include adjacent signal changes in the cord , prominent epidural veins in the posterior subarachnoid space and cord atrophy. This patient was diagnosed with Hirayama disease. This condition is supposed to be due to a short dural canal, leading to dynamic cord compression, focal motor amyotrophy on the anterior horns of C7 C8 and T1.

(Prepared in collaboration with Dr. Hemanth)

Case 18

42 year old male with a left hearing loss, investigated for possible posterior fossa lesion.

Plain and contrast-enhanced images are provided in this MR examination. This is one of the very typical locations of a lesion in posterior fossa.(10%) When there is hearing loss and a mass in the region of CP angle, the diagnosis of an acoustic schwannoma is always likely. Other occasional masses in the cerebello-pontine angle include trigeminal /facial schwannomas, meningioma, ependymoma, vascular malformation and metastases. Examination should be of sufficient quality to identify lesions in the internal auditory canal and should be able to demonstrate/identify the nerves in IAC. The contrast examination sometimes is of great value in small lesions as the lesion enhances completely and intensely. Also there may be enhancement of the vestibular nerve more distally into the IAC. Bony changes also should be appreciated in MR, better shown on the CT studies. If the lesion is bilateral, additional signs of NF type II–should be looked for.

(Prepared in collaboration with Dr. Hemanth)

Case 19

7-month-old male child with epilepsy, investigated for a possible intracranial mass.

Plain and contrast enhanced MR images are provided in various planes. Presence of an enhancing mass is clear-cut. The lesion appears to be lobulated, peripherally enhancing and cortical/subcortical location in the high posterior frontal area. There is perilesional oedema and some haemorrhage into the anterior part of the lesion. Mass-effect is moderate. Differential diagnosis is somewhat non-specific. Since this is a young child, differential diagnosis should include gliomas( anaplastic astrocytoma, glioblastoma, oligodendroglioma), metastasis, astroblastoma, PNET tumours etc.. This patient was diagnosed to have an ependymoma on histopathology.

(Prepared in collaboration with Dr. Abhishek)

Case 20

16-year-old female with complex partial seizures.

Multiple coronal images of the temporal region are provided. Obviously we are looking for a possible mesial sclerosis. Accurate positioning and obtaining quality images of the temporal region, with the imaging plane perpendicular to the long axis of the hippocampus are essential. We are basically looking for asymmetry, signal abnormality, signs of atrophy and the occasionally subtle reduction of thickness of hippocampal gyrus and the related structures of the limbic system. All findings may not be seen in a patient. Also sometimes comparison is defective due to bilateral involvement(10%). There are more advanced MR techniques, in the form of Hippocampal volumetry, T2 relaxometry, DWI and spectroscopy. Along with the EEG localization, clinical signs and imaging observation a diagnosis often can be made. This patient had a diagnosis of right mesial temporal sclerosis

(Prepared in collaboration with Dr. Abhishek)

Case 21

3-month-old child investigated for a suspected boggy swelling in the posterior parietal scalp region.

Interpretation of the skull radiograph is a forgotten art. At least major landmarks should be identified on the plain radiography. You should be able to identify the sutures, namely coronal and lambdoid sutures in this view. If one is knowledgeable about the skull development, you will also note open spheno-occipital synchondrosis and Mendosal suture. There is a subtle bony injury involving the posterior part of the parietal bone, seen as an area of radiolucency. Interpretation of this findings is  sometimes complicated by multiple ‘sutural bones’( wormian bones) in the vicinity, hence correlation with an additional, Towne’s view would be helpful.

Case 22: 6-month-old child with seizures and drowsiness.

This is a 6-month-old child with seizures leading to drowsiness. Axial non-contrast CT is provided.

Do you agree with me that this is a non-contrast ready? If you do not agree, you may be in trouble. This patient has extensive thrombosis of the deep venous system and sagittal and straight sinuses. Recent thrombi are hyper dense on CT. The patient’s condition was due to the severe dehydration leading to extensive thrombosis. It is not common to observe thrombosis of the thalamostriate and septal veins.!!! As noted in this case. Parenchymal haemorrhages of venous distribution may be associated, though not present in this case.

Case 23. 9-month-old child with developmental delay.

MR shows the most striking observation, easily detectable. CSF intensity cavity is noted in the left parieto- occipital region, adjacent to the mildly dilated left lateral ventricle. It may be serated from the venricle by a thin membrane or freely communicate with venrticular cavity. You will notice that the overlying cortex is grossly thinned and also significant volume loss is noted in the ipsilateral hemisphere. This is an example of porencephalic cyst, as a result of earlier intraparenchymal haemorrhage. Intracranial haemorrhage was a common complication in the past in preterm babies, when the neonatal services and treatment options were limited.

Case 24: 6-month-old child with seizures. Diagnosed as a metabolic disorder.

MR evaluation of the brain in T1 and T2 axial sequences and a follow-up CT after 18 months is provided.

Neuro metabolic disorders are vast entities, some having specific imaging patterns, others needing a battery of investigations for a specific diagnosis. In this patient the abnormality is seen in both putamina (part of the corpus striatum). There are necrotic areas in both putamina. Additionally a similar cavitary lesion is noted in the white matter of the left frontal lobe. Non- myelination of the rest of white matter could be a normal variant at this age. However follow up non-contrast CT examination at 2 years reveal diffuse white matter hypodensity, subcortical calcification in the right frontal area, calcification in both ganglionic areas and some calcification in the lower base. Patient was diagnosed to have mitochondrial disorder. (MELAS). Radiologists in training can explore this entity and the large number of similar disorders involving the ganglionic area.

Case 25

4 weeks infant with relatively large head. Sonography revealed an abnormality.

MR images with T1 and T2 weighting are provided in various planes.

This is an Aunt Minnie diagnosis. Case illustrates a large Dandy-Walker cyst communicating with the fourth ventricle. Posterior fossa is relatively large, and the brainstem appears hypoplastic. In the supratentorial compartment there is a lateral ventricular dilatation, which appear parallely oriented. You might have noted the agenesis of the corpus callosum. These clusters of observations are fairly common in the developmental CNS disorders

Case 26

3-month-old child brought to the hospital for seizures.

Skull frontal and lateral and CT images are provided. It is very clear that there is a linear radiopaque density, in skull views - could be a pin/needle/wire. This is a FB within the skull. How did it get in to the skull???. CT examination was performed after removal of the object. The findings are obvious: there is hydrocephalus with dilated lateral ventricles, minimal periventricular lucency and there are blood products in the region of anterior interhemispheric and left lateral ventricle. Most intriguing part of the story is that, older brother of this child introduced this needle through the open anterior fontanel !!. A surgeon in the making?? –The history which was obtained in retrospect. Anything can happen in the world of humanity. I was not fortunate to preserve the image of one 70 year old with a larger metallic object in the intracranium (metalic part of a screwdriver). This case was reported by my colleagues.

Case 27

45-year-old male was treated for left parieto-occipital glioma. Follow-up MR study performed at 12 month interval.

Pre-and-post contrast enhanced MR images are provided in different planes. This patient had glioma in the left temporoparietal area. This is a follow-up scan after 12 months following radiation therapy. Now the question is whether there is a recurrence of the lesion or is there any other possibility. Comparison with the previous MR exam is a must before we start interpreting these images. Obviously there is a lobulated ring enhancing lesion without involvement of the corpus callosum or subependymal region of the ventricles. The main concern is whether this observation could be consistent with radiation necrosis. Spectroscopy is of great value in differentiation, showing low choline, creatinine and NAA peaks. (In this patient it was not available). Enhancement pattern is often ringlike sometimes with soap bubble appearance. Perfusion MRI may show low rCBV.  Lesions tend to be hypometabolic on PET scans. Patient had a diagnosis of radiation necrosis on followup.

(Prepared in colloboration with Dr Abhisek)

Case 28

Young male with pain and episode of focal seizures.

MR images in the various pulse sequences and imaging planes are provided. In terms of imaging diagnosis this case probably is not challenging. Identification of the lesion is very simple, seen as an area of oedema surrounding the ring lesion in the high left frontal area. On close up view you will also notice a possible nidus within the ring. There is intense peripheral ring enhancement of the lesion. Diagnosis of cysticercosis is empirically done in endemic areas. Occasionally a diagnostic dilemma can be encountered in differentiating tubercular lesion versus cysticercosis. Classic findings have been described in each category. Neuro cysticercosis tends to be less than 2 cm, on spectroscopy shows multiple amino acid peaks. Scolex can be seen in T2-weighted images. In cases of tuberculosis lesions can be larger, meningitis may be associated, posterior fossa is often the site and the on spectroscopy lipid peaks are generally seen. Diffuse restriction is not a common feature in lesion in cysticercosis.

Case 29

Images of the arterial and venous phase of the vertebral artery are provided. This procedure is done through transfemoral catheterisation using a head hunter configuration catheter. Generally left vertebral artery can be easily cannulated through the left subclavian artery. 6-8 ml, non-ionic contrast is utilized. Presently examination is performed for demonstration of vascular lesions, malformations and suspected aneurysm. Incase of suspected aneurysm, 4-vessel angiogram is done. Cathetarisation of both vertebral artery may be needed. Dural AV fistula is occasional diagnosis which needs combination of the intracranial and extracranial vascular assessment. Vertebral artery has small cervical dural and muscular  branches, posterior inferior cerebellar artery(PICA), anterior inferior cerebellar artery(AICA), superior cerebellar arteries and both posterior cerebral arteries. Smaller branches occasionally seen from the basal artery, directly supplying the pons and medulla. Posterior choroidal artery is also an important branch. Posterior communicating arteries, when patent might pacify anterior circulation. On the venous phase precentral cerebellar vein, inferior vermin vein, superior and inferior cerebellar veins may be seen. Straight sinus may be opacified, subsequently opacifying the transverse and sigmoid sinuses.Case 29

Images of the arterial and venous phase of the vertebral artery are provided. This procedure is done through transfemoral catheterisation using a head hunter configuration catheter. Generally left vertebral artery can be easily cannulated through the left subclavian artery. 6-8 ml, non-ionic contrast is utilized. Presently examination is performed for demonstration of vascular lesions, malformations and suspected aneurysm. Incase of suspected aneurysm, 4-vessel angiogram is done. Cathetarisation of both vertebral artery may be needed. Dural AV fistula is occasional diagnosis which needs combination of the intracranial and extracranial vascular assessment. Vertebral artery has small cervical dural and muscular  branches, posterior inferior cerebellar artery(PICA), anterior inferior cerebellar artery(AICA), superior cerebellar arteries and both posterior cerebral arteries. Smaller branches occasionally seen from the basal artery, directly supplying the pons and medulla. Posterior choroidal artery is also an important branch. Posterior communicating arteries, when patent might pacify anterior circulation. On the venous phase precentral cerebellar vein, inferior vermin vein, superior and inferior cerebellar veins may be seen. Straight sinus may be opacified, subsequently opacifying the transverse and sigmoid sinuses.

Case 31

31-year-old male presenting with bilateral the upper and lower limb weakness. Patient is symptomatic for 2 years with the sudden increase in weakness in the past month.

T1 and T2-weighted MRI images of the cervical spine are provided. There are additional contrast enhanced MR examinations of the lumbar spine.

This is a very interesting clinical and imaging example with complex features. Patient was partly investigated elsewhere, sent for a second opinion. If you look at images of the cervical and lumbar region there are T1 hypo-and hyperintense and T2 hyperintense lesions in the central cord, extending over several vertebral length.Lesions are assiciated with significant focal mass effect.. Part of this abnormality can repreesnt an area of haemorrhage in the central cord/central canal or alternatively lesion can be a large lipomatous tumour. Axial images show the central location of the lesion indicating a possibility of syrinx with hemorrhaghic CSF. In the lumbar region similar observations are present.There is suggestion of T1,T2 hypointense nodule in the distal cord(T12-L1), along with dilated central canal. More interesting observations are noted on the contrast-enhanced MR images of the lumbar region. There is intense enhancement of nodular lesion on the right side of cord at the level of conus, ialong with the syrinx. In this young patients such lesions can occur in patients with hemangioblastomas. Part of the appearance could be due to bleeding in a hemangioblastoma leading to a syrinx with blood products. Additional cause of bleeding may be due a bleed in a vascular as a menifestion of syndrome, and occationally such lesions are incidently noticed in the MR examinations.

Case 32

This 2yr 6 month old child with developmental delay. CT examination of the head was performed at presentation and subsequently followed for next 3 years.

Observations on the scan is straightforward. There is calcification of both ganglionic areas predominantly involving the putamina. There is minimal prominence of extracerebral CSF spaces in the region of the sylvian fissures and interhemispheric fissure. Ganglionic calcification can be associated with the various metabolic disorders like MILAS,MERRF etc. Additionally there are many other conditions with basal ganglia calcification like Farr’s disease, Hyperparathyroidism, pseudohypoparathyroidism,  and idiopathic conditions. In this patient, follow up did not show progression of symptoms. Extent of calcification became more focal and localised. This patient did not have a metabolic disease on screening.

Case 33

40-year-old male with a gait abnormality.

MR images of the brain in various sequences are provided. Diagnosis is not very difficult in this patient as observations are straightforward. Initially in the T2-weighted images you will notice that there is global cerebellar atrophy, characterised by prominent cerebellar foliae and loss of volume in the cerebellum. No specific signal abnormalities noted. There is mild dilatation of lateral ventricles. In the provided sagittal view also noted, apart from small hypoplastic cerebellum ,small midbrain pons and medulla.  This is a case of Olivo-ponto-cerebellar atrophy. Now many posterior fossa neuro-degenerative disease are classified under the Multiple systemic atrophy(MSA)- MSA-C subtype of MSA. Imaging wise many quantitative parameters can be derived on MR data based on the altered size of neural structures. Relative proportions of various structures of brainstem can be documented providing some idea regarding involvement of predominent structure. Some have diagnostic and some have prognostic value. Interested readers are recommended to explore the literature. 

Case 34

Neonate with seizures and microcephaly.

MRI examination of the brain with the varying sequences and imaging planes provided

If you have seen similar cases before, this is an Aunt Minnie diagnosis. Patient has very few cortical gyri, visualised gyri are also somewhat flat and appear thickened in the high parietal convexity region. Fissure are shallow. There is overall hypoplasia of cerebral hemispheres. There is generalised white matter hypodensity. Lateral ventricles have not significantly enlarged and the posterior fossa is normal. Overall findings are compatible with neuronal migrational abnormality like lissencephaly-pachygyria complex  Typically two types are described. 

1. Classical form, seen as lissencephaly in patients having typical presentation of absence of gyri (figure of 8 appearance) to the spectrum of patchygyri. There is association with the band heterotopia. 

2. generally seen in association with syndromes like Walker Walberg syndrome, Fukuyama disease and muscle- eye- brain disease. Morphologically this is associated with cobblestone appearance of the cortex. This is a large topic with varieties of presentations and morphological features. Resident radiologist is recommended to refer more advanced work (Dr. J. Barkovich) for better understanding of the disease spectrum

Case 35

MR images of a 6 month old child is presented. Notice that only some representative images are included for the purpose of the test. Always make sure that you observe the exact sequences presented and support with a logical explanation. In this patient it is obvious that the lateral and third ventricle are enlarged. The fourth ventricle is hardly visualized. Any major difference between pre- and post- contrast examination? Any additional information in the T2 sequence? You should be able to identify an abnormal signal flow void in the posterior third ventricular region and in the straight sinus. So this is a case of an aneurysmal malformation of the vein of Galen. MIP image of the arterial structures are provided. Also note that these images are obtained with an older MR unit, which explains the technical quality and appearance of the images when compared to present quality standards. It is important to note the arterial feeders, size and morphology of the nidus(malformation}, asoociated additional venous abnormalities and  any associated complications.

Case 36

8-month-old patient with seizures.

You are given only T2 and diffusion weighted images. Now that you have seen some samples of CNS images in this web page, you may be able to make the right diagnosis.

I am sure you have noticed the dilated lateral ventricles, abnormal T2 hyperintensities in ganglionic areas and areas of diffusion restriction in the right ganglionic area and splenium of the corpus callosum. I guess you have rightly made the diagnosis of MELAS. This patient has small vessel disease as a part of syndrome, leading to acute ischemia in affected territory. Occipital lobe is frequently involved. Ischemia can extend to the cortex if a larger vessel is involved.

Case 37

An adult female with a severe headache. Had a surgical procedure in the past.

You were provided with Sagittal T2-weighted images and postcontrast images of the anterior skull base.  Any suggestions?

You will notice that sella is enlarged, occupied by CSF spaces– there is extensive manifestation of empty sella. Where is the pituitary gland? How about  the suprasellar structures?  With great imagination you can see infundibulum and the infundibular recess of the third ventricle, extending to the posterior aspect of the sella, findings better appreciated with contrast studies. Pituitary gland is compressed and lying posteriorly. Do you see any abnormality in the nasopharyngeal region?  With this leading information, you should be able to appreciate a small fluid filled outpouching in the region of the nasopharynx. This patient had transsphenoidal surgery and there is a subtle communication between this outpouching and sella, a post-procedural complication–pseudomeningocele. This is an extremely rare complication following transsphenoidal pituitary surgery. Literature has many examples of this entity.

Case 38

This 45 year old patient with headache and a pulsatile swelling in the right temporal area, was investigated with CT and MR.

I was lucky to bump into this case as a consultation case, examination done elsewhere. This is one of the most uncommon conditions I have come across. You will see that there is a focal soft tissue bulge in the scalp on the right side, in line with the superficial temporal artery, which intensely enhances on CT scan confirming that it is a vascular structure. Visualized brain and adjacent bony structures appear normal.

In the MRI examination, the brain appears essentially normal. You will notice that soft tissues visualized on the CT scan represent  superficial temporal artery and branches. Adjacent scalp, bones and intracranial structures are all normal. Striking observations are noted on a MR angiography, there is demonstration of an enlarged, tortuous superficial temporal artery. There are a few enlarged vascular structures in the vicinity in the adjacent scalp. No obvious vascular mass or cluster of vessels or visibly dilated venous structures visualized. So what are the possibilities? Usually arteriovenous malformation of the scalp can be associated with the enlarged feeding superficial temporal artery. Demonstration of a nidus and large venous component, if seen would have been an ideal setting. In this case there is no obvious nidus nor there is evidence of large AV shunting, hence this case could represent partly involuted vascular malformation. Alternatively this may be an isolated arthritis with the aneurysmal dilatation of the superficial temporal artery. In view of the younger age group for the patient a developmental lesion is most likely rather than entities likely giant cell arteritis. I do not have follow-up or any surgical information on this patient. Looks like a candidate for an interventional procedure following good demonstration of the pathology by arteriography.

Case 39

You have MRI images of the brain in the sagittal and coronal planes in a child with the paroxysmal breathing abnormality.

This is an interesting abnormality of the defective development of cerebellar vermis, cerebellum and brainstem. We will notice that the middle cerebellar peduncle is somewhat elongated, vertically oriented with enlarged fourth ventricle. On imaging this orientation gives rise to a molar tooth sign, characteristic sign of the syndrome. You will also notice deformity of the fourth ventricle. There is absence of vermis leading to free communication of the fourth ventricle with the large cisterna magna. Patients with a syndrome have a short life span, can have skeletal and renal anomalies as well. This disorder is categorized as autosomal recessive ciliopathy. Now you have a diagnosis of Joubert syndrome

Case 40

This is a 7 year old child investigated with the CT head due to a history of repeated falling.

Plain and contrast enhanced axial images are provided.  What are your observations? 

Lesion stands out as a hypodense( almost a cystic) well-defined area in the medial cortex of the right frontal lobe. Mass-effect is very little. There is a mild impression on the adjacent lateral ventricle. With these observations. We are Looking for a neoplastic lesion. Appearance could be that of a superficial glioma. Low-grade gliomas can show this typical appearance. We have an MRI examination on this patient. Lesion is T2 bright and shows very low T1 signals. Findings consistent with a low grade glioma. Other low-grade lesions in the brain include, Pilocytic astrocytoma, pleomorphic xanthoastrocytoma, Dysembryoplastic neuroepithelial tumour(DNET) and ganglioglioma.

There are few images with Fibre-tracking(DTI). While assessing eloquent regions of the brain this MR examination is a valuable additional option. Importance of this examination is to see the morphology and location of functional fibres tracts in relation to the mass. In slow growing benign masses, these tracts are sometimes displaced, seen in unexpected locations, although in the vicinity. Knowing this information is helpful to the surgeon while planning excision or deciding the site of biopsy. It may also help planning image guided therapy.

This is a 4-month-old child with the development of delay and hypotonia.

MR examination of the brain is provided.

If you note this patient does not appear to have any significant myelination at all in the supratentorial brain. The corpus callosum is extremely thin. Overall appearance is that there is a lack of myelination of white matter bundles. Extremely tricky situation to assess white matter state in an early infantile age, and under 6 months. Most of the myelination starts appearing in MR studies from the age of 4 month – progresses up to 18 months to have a predictable MR pattern. In this case apart from the suggestion of a non-myelination, there is extreme thinning of corpus callosum .Large group of diseases can produce this appearance. 

1.First group consists of patients who have systemic disease/enzyme defects adversely affecting the neural development- many inborn errors of metabolism, mitochondrial diseases, and amino acid metabolism related clinical syndromes.

2. Second group is syndromes like Down’s syndrome and other syndromes with poor neurodevelopment. 

3. Third category is a white matter hypoplasia group, which are specific disorders of myelination. 

          Differentiation should be made between hypo-myelination, dysmylination or demyelination disorders. This may be very difficult in this age group on imaging but easier when some myelination milestones are demonstrated in an older child.  Typical disorders with poor/hypomyelination or nonmyelination are  Pelizaeus–Merzbacher disease, hypomyelination with congenital cataract, hypomyelination with hypogonadotropic hypogonadism and hypodontia, Pelizaeus–Merzbacher-like disease, infantile GM1 and GM2 gangliosidosis, Salla disease and fucosidosis.

 Obviously defining MRI criterion for a diagnosis of hypomyelination is an unchanged pattern of deficient myelination on two successive MRI scans at least 6 months apart. One of the MRI scans should have been obtained at the age of more than 1 year at the time of initial workup. (Marjan E. Steenweg, Adeline Vanderver et al Brain, Volume 133, Issue 10, October 2010, Pages 2971–2982, https://doi.org/10.1093/brain/awq257),  A large number of disease group is added in hypomyelination syndromes category recently. It is recommended that initial MR examination is evaluated at the age of 1 year for adequate assessment of the status of myelination. This leaves a large gap in the evaluation of infants under 1 year. This case is presented to stimulate the trainee radiologists to revisit process of myelination ,understand myelination sequence, extent, evolution in a normal child so that he can build a suitable base for understanding myelination disorders. Alos familiarise with all sequences suited for evaluation of myelin.

Case 42

One day old neonate with seizures. Child was a product of difficult delivery and had a delayed crying at birth.

I present this case just to familiarize you with the difficulty in interpretation of the examinations in the newborn. Unlike adults it is not always easy to get perfect positioning of the patient in children. especially if the head shape is also abnormal or if there are other circumstantial difficulties in positioning.  Prior to the volumetric scanning, often we were faced with images like this. At the present moment we have solutions of retro reconstruction to optimize positioning. This patient has no intracranial mass. Indeed there are hemorrhagic areas in the left thalamic area and cortex with extensive white matter oedema. Apparent mass-effect is due to positioning artefacts.

Case 43

This is a neonate who was observed to have a soft swelling in the posterior parietal area near midline. MR examination is and MR venography is provided.

This is one such typical lesion, once seen making the diagnosis in the second case may not be difficult. In this instance we are dealing with a case of atretic parietal cephalocele(APC). This is a condition of congenital/genetic origin associated with a small cephalocele or its fibrous remnant, in association with the intracranial vascular and brain anomalies. Our case has many observations. There is a small cystic swelling in the midline(encephalocele) with associated bone defect. Superior sagittal sinus is showing a cleft allowing the fibrous tract and dural communication. There is an associated persistence of a primitive vertical falcine vein. Tentorial hiatus is defective within open top configuration towards the parietal defect. We do not see tectal beaking, an observation in some patients. Additionally we do see somewhat superiorly oriented cerebellar vermis and a large cisterna magna. The patient may present with a range of abnormalities ranging from complete, large cephalocele with sac to a fibrous strand with just a remnant of the cephalocele. Differential diagnosis for local compressible soft tissue swellings can be considered before the imaging studies. Sinus pericranii, sebaceous cyst, dermoid and vascular lesion like a haemangioma merits consideration. Once intracranial observations are made, diagnosis is obvious

Case 44

9-year-old male patient with seizures. Investigated with chest CT scan and MRI.

This is a classic focal disease demonstrated on CT and MR. We are seeing an area of oedema with nodular enhancement following intravenous contrast. There is no significant mass-effect. These findings are obvious on CT scan. Lesion is located in the precentral gyrus. On MR images will see a dural based nodular area of enhancement with necrotic centre. There is subtle enhancement of the dura. This was a single lesion in this patient. Patient was diagnosed with intracranial tuberculoma, responded well to the treatment.

Case 45

46-year-old male with persistent, progressive headache. MR images were performed

There are a series of MRI images provided for review. Those with basic ideas regarding MR interpretation of the brain, will realize that there is a large right temporal mass. A simple description is that there is an area of altered signal in the right temporal fossa with gross mass-effect and compression of adjacent structure.  This is a simple view of an obvious mass. What more interpretation can be done to improve to provide more sensible input for diagnosis and management?

1. There is a mass-effect; there are two components to the mass effect a. on the adjacent anatomical structures like bony structures, orbits, sella which may lead to localising symptoms. b.The second component is a distant mass-effect that occurs indirectly. In this case you are seeing tentorial herniation and compression of the midbrain. Characteristically called the 'uncal herniation'. Midbrain compression can have ipsilateral or contralateral symptoms. Larger lesions close to the convexity will also cause cingulate herniation–trans-falcine herniation . Both forms of herniation is seen in the present case

2. Some useful information can be obtained by the contrast enhancement pattern. It may be uniform, patchy, circumferential and negligible. What pattern of enhancement is seen in our patient? One component is a diffuse generalized and nodular enhancement. There is also an area of focal enhancement at the anterior temporal pole, adjacent to the dura.

3. Any other observations of importance? Is there any invasion of the bony structures? These small observations are often missed. This lesion is causing bone destruction of the sphenoid in the temporal fossa and skull base, showing extension to the infratemporal fossa– a behavior seen in post-operative aggressive gliomas. Such behavior can also be seen after biopsy. 

4. Diffusion-weighted images and perfusion weighted images can add value for providing quantitative information and prognostic elements for management. Diffusion tensor imaging can provide valuable input regarding location of certain important functional fiber pathways. This element of evaluation was not in not performed in this patient. (Study performed before advance technology was prevalent)

5. Spectroscopy can add information regarding specific chemical signatures (amino acids) choline distribution( lesion border mapping) and nectosis( Macromolecule-lipids-lactate)

This patient was diagnosed to have a gliosarcoma.

Case 46

Plain radiography and 3D CT imaging are two important modalities that will help to assess abnormal head shape. There is a clear mathematical model of abnormal sutural fusion and subsequent skull deformation. Fused or fibrosed sutures prevent expansion of bone growth perpendicular to the suture. Hence compensatory development and expansion takes place around the other sutures. Given example shows antero-posterior expansion of the skull, leading to a scaphocephaly configuration. ( Boat-shaped ) This deformity can result from premature fusion of the sagittal suture. The range of abnormalities due to abnormal fusion of various sutures are discussed  elsewhere in greater detail.

Case 47

2-year-old child with regression of developmental milestones.  CT and MR examination are provided. There is a followup study after 2 years.  Striking observation in this patient is a diffuse bilaterally symmetrical hypodensity of white matter on CT. Evaluation of white matter abnormality is an extensive topic. Range of white matter abnormality start from non-myelination, delayed myelination, dysmyelination and focal or global myelin damage. We have series of brain CT examination in a 2-year-old, followed up 2 years later. In this patient there is absence/paucity of myelination of the white matter in the supratentorial and infratentorial brain. Cortex appears spared. Changes are progressive with time, leading to near CSF density/intensity white matter. These changes are classical for a Vanishing white matter disease. This is also called Van der knapp disease. Disease has a genetic basis, shows gradual progression,  ultimately leading to death.

Case 48

Illustration of soft tissue and bone windows of a CT head examination of child is provided. Injury to the skull bones in the child may show some variations, unlike the adult. Rather than a clear-cut fracture, sometimes injury is plastic, just a depression in the bone. This is described as a ping-pong injury. Minor depression is generally harmless. With time there may be remodelling of the bone, restoring normalcy. Depression with fracture, depression of more than 5 mm depth or adjacent brain–dural injury needs prompt attention. Undetected dural tear may lead to growing fracture.

Case 49

Skull frontal and lateral radiographs are provided, in a patient who had a minor trauma. Illustration is meant to show some normal variations. Normal variations may mimic pathology, like fracture or an osteolytic lesion. Linear, branching vascular markings of the anterior branch of middle meningeal artery is the usual culprit. Prominent vascular markings in the skull can be due to arterial or venous origin. Normal arterial markings seen in the skull are due to anterior and posterior branches of the middle meningeal artery/vein. The diplopic venous markings are generally seen in parietal and frontal bones. Classical appearance of a diplopic venous congregation is a spider like or stellar. Occasionally venous lakes in the form of the radiolucent areas are seen, mimiking ostelytic lesion. Occasionally enlarged emissary foramina are noted. Radiolucent areas in the parasagittal location could be due to arachnoid granulations. The present patient shows a prominent frontal venous markings on the right side, ending up back in radiolucent area in the parasagittal location. (? Arachnoid granulation)

Case 51

Frontal and lateral radiograph of the skull is provided in a 2-month-old neonate. In fact more accutate impresion about this condition is better appreciated clinically. Patient has a symmetrical small head. Head circumference is well beyond the lower percentile. Patients tend to have a large face in relation to the small head. Radiographically craniofacial ratio might be altered. Structurally bones remain normal. There is no indication of sutural fusion. A plain radiograph for scrutiny should be made regarding areas of calcification to exclude prenatal infective aetiology.

Case 53

A 12-year-old female presented with clumsy walking and abnormal speech. Pre-and post contrast enhanced MR images are available. Lesion is standing out. What are your considerations? There is an intra-axial mass in the medial left frontal lobe, showing solid and cystic elements. Lesion is moderately circumscribed, showing T2 hyperintensity. It is extending across the midline via corpus callosum. There is subtle peripheral enhancement. What is your first guess? Glioblastoma?? or any other lesion ? This patient had a biopsy of the lesion which revealed a PNET tumour.

Case 54

This case is more like a spot radiograph. There is an abnormal skull shape with macrocephaly and regional occipital craniolacunia. You may be familiar with the lacunar skull( aka  Lukenschdel) . This condition is a defective development of the membranous skull. There is a strong association with the Chiari II malformation. This phenomena is not related to mechanical pressure on the skull bones, rather it is due to membranous skull dysplasia. Our case, which shows a localised form of the disease, is a classical proof. The patient also had hydrocephalus, without Arnold-Chiari malformation.  Patient had abnormal upper limbs, partially appreciated in the chest radiograph.

Case 55

You are provided with the plain CT scan and MRI of the brain in a child who had left sided body weakness.

I do not think you have a great diagnostic challenge here. Subtle hypodensities in the right frontotemporal region are clear cut. Also on MR you will notice that there is sudden cut-off of the right middle cerebral artery with subtle T2 hyperintensities in the involved territory. We do not see obvious collaterals in the region of the circle of Willis. Note there is any signs of a haemorrhage.Diffusion images were not available !! This case opens.up discussion on paediatric stroke. This is a well recognised topic and some degree of overlap with the established sources of information are inevitable. I have summarised some of the contents from radiopaedia. Readers may resource material through the link provided in the main Page

Some of the important causes of paediatric stroke are:

Arterial ischemic stroke:

• Arteriopathies, focal cerebral arteriopathy of childhood, CNS vasculitis (systemic lupus erythematosus), CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy),MELAS (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes)moyamoya disease/syndrome

• Embolic Stroke, main causes are cyanotic heart disease, cardiomyopathies, mitral valve prolapse

• arterial dissection, trauma, fibromuscular dysplasia, syndromic( Marfan syndrome,Ehlers Danlos syndrome, homocystinuria

Infection:  purulent meningitis, varicella zoster (post varicella arteriopathy), tuberculosis

blood disorders: sickle cell disease, polycythemia, protein C deficiency, protein S deficiency

Genetic disorders (e.g. neurofibromatosis type 1 2, ACTA2 mutation,  Fabry disease)

Hemorrhagic stroke:

• a. Vascular lesions, arteriovenous malformation, arteriovenous fistula, aneurysms cavernous malformations, moyamoya

• b. blood disorders: platelet disorders inherited bleeding disorders, anticoagulation,vitamin K deficiency

• c. sickle cell disease

• d. Drugs: amphetamines, cocaine

• f. Venous thrombosis:  malignancy (e.g. acute lymphoblastic leukemia)chemotherapy (e.g. L-asparaginase anemia, dehydration 

Case 56

This patient presented just before the Kuwait invasion. He was an Iraqi student with difficulty in reading and some disability of his movements. This scan was performed in Iraq and was brought for consultation (1989). Despite a product of an earlier generation of scan, information is easily appreciable. You might have, rightly, guessed that this patient has a multifocal white matter disease. Subtle volume loss is present, as the patient is very young. This patient has classical findings of multiple sclerosis.

Case 57

A 3-yr-old child with recurrent chest infection and ataxia.

CT images of the brain and chest are provided. Observation in the CT is straight forward, in the form of cerebellar atrophy. Supratentorial brain is within normal limits Interestingly this patient also has a CT chest, which was performed due to recurrent chest infection. Does this combination ring a bell? This patient has an entity called ataxia telangiectasia syndrome. A–T syndrome is caused by a defect in the ATM gene, which is involved in the recognition and repair of damaged DNA. Children generally manifest early childhood, when they start sitting and walking. Due to altered humeral and cell mediated defects in the immunity, they are prone to sinusitis and recurrent chest infection. Due to defective blood vessels, cutaneous symptoms will appear gradually with time, due to cutaneous and scleral telangiectasia. Patients are having increased incidence of malignancy, particularly lymphomas and leukaemias. 

Case 58 :   SWS

7-month-old child with a facial nevus and seizures. MR examination of the brain is provided. Patient has some classical observation of an established syndrome–Sturge Weber syndrome. I am sure you had noticed right cerebral hemiatrophy with T2 hypointense changes in the cerebral cortex and widening of the extracerebral CSF spaces. Bone thickening is occasionally seen, may be very subtle in our patient. Ventricular dilatation, tram line cortical calcification is also seen in this condition, not evident in our patient. However, in the postcontrast study we see gyriform enhancement involving the right cerebral hemisphere. Changes are more extensive in the frontal lobe, as against a typical posterior distribution. This diagnosis is done clinically by observing the facial nevus in the trigeminal distribution. This entity is described as phakomatosis, occurs sporadically has no specific hereditary predisposition. Pathologically there is a leptomeningeal angiomatosis with a subcortical steal phenomenon leading to cortical ischaemia. On angiography superficial cortical veins are absent leading to abnormal drainage of the deep venous system. Most of the imaging changes are secondary to the ischaemic sequelae and subsequent brain atrophy. 

Roach et al. suggested a classification according to the presence/absence of facial and leptomeningeal angiomas: (Radiopedia)

• type I: represents classic syndrome, with both facial and leptomeningeal angiomas; may have glaucoma

• type II: facial angioma without evidence of intracranial disease; may have glaucoma

• type III: isolated leptomeningeal angioma; usually no glaucoma

Case 61 : Chiari malformation and bone changes.

This is an exercise to revisit the past; Initially to understand the flow of radiological process in a suspected case of ACM. Subsequently to see some image examples. Plain radiography of the skull and spine were performed routinely.

 Skull frontal and lateral radiographs are provided here to start with. You can appreciate a huge calvaria with the relatively radiolucent bones. ( as bones are thin, membraneous). Occasionally you can see cranio-lacunae. You can observe the disproportion between the facial structures and the size of the calvaria – some  measure of quantitative information regarding the extent of hydrocephalus. Regarding the spinal changes, the essential observation are widening of the inter-pediculate distances, compounded by absence of fusion of the spinous processes. Extent of widening is directly proportional to the size of the meningocele. The location of defect can vary from sacrum to the cervicodorsal region. Scalloping of the posterior margin of the vertebra flattening of the pedicles, bifid spines, segmentation anomalies of the vertebra and multiple rib anomalies can be seen. Close review of these images provides you almost all these observations. 

 You have another set of radiographs of the lower extremity. The reason I included this radiograph is due to its significance in patient management. Many patients who had bony injuries, were often undetected in the initial phase. Bone lesions are due to secondary changes like disuse and effects of physiotherapy etc. Generalized bone density is decreased due to deficient osteoid and poor mineralization. Patient frequently have greenstick fractures.(bending rather than a straight fractures). Illustration shows an obvious distal femoral greenstick fracture and a subtle metaphyseal fracture of the upper tibia. As shown in the earlier illustration, abundant callus may be noted at the fracture sites.

Case 60 : Chiari malformation–Presentation

This illustration is intended to give you some idea about dynamic changes noted on the presentation and follow up of patients with Chiari malformation. This patient has a severe descent of the posterior fossa structures with the gross hydrocephalus

Case 61 : ACM Cranial menifestations on follow up

 Case 61 :

In the follow-up after shunt, there is a tendency for signs of over drainage of the lateral ventricles– like development of a subdural hygromas, extreme crowding of cortical sulci, increase the vascularity around the cortical surface and around the tentorial hiatus. You can appreciate the multiple flow voids in the vessels around the collapsed brain cortex. Another common observation in the drained ventricle is the loculation of CSF spaces into multiple pockets. These pockets may or may not communicate, occasionally lead to incomplete drainage. Such observation call for selective shunt placement in sequestrated CSF spaces. Presently enodoscopic surgery uses this information for  tailored treatment.

Case 62 : ACM spinal changes

Spinal changes in the ACM can vary a great deal depending on the location and size of the meningocele. I have mentioned about the changes on the plain radiograph in the earlier passage. The MR appearance also are interesting. The major factor that provides you an idea about the extent of malformation is overall length of the spine which is greatly shortened in severe disease. Spinal curvature tends to be rather straight. Tethered cord, diastematomyelia, syringohydromyelia of the cord features often. The placode, the distal element of the spinal cord shows attachment to the meningeal sac in a diverse way. Large number of patients show enlarged epidural veins as shown in our illustration, showing signal voids. Meningocele morphology can vary from a subtle skin covered closed sac to wide open–ruptured meningeal sac supported by extraneous support devices.

You have an opportunity to see some CT examinations of the lumbar region. CT is not generally indicated to evaluate meningocele. In the examination see the lateral angulated orientation of the pedicles and a large posterior spinous process defect, highly characteristic appearance.

Case 63 :    Chiari malformation–evolution

This illustration is intended to give you some idea about dynamic changes noted on the follow up of patients with Chiari malformation. This patient has a severe descent of the posterior fossa structures with the gross hydrocephalus. This examination was done around 2000 and not many observations were recorded in the literature at that moment about dynamic MR signal changes in the brain. In the initial brain T1-weighted images done at the first week of life this patient showed intense T1 hyperintensity of ganglionic area which extended cranially towards the precentral gyrus. In the follow-up examination however the signal intensities turned out to be normal. The areas are slightly T2 hyperintense. This is probably related to exaggerated myelination process. The second observation of significance is the size and extent of the T1 hyperintensity of the pituitary gland. In the follow-up after shunt, there is a tendency for signs of over drainage of the lateral ventricles– like development of a subdural hygromas, extreme crowding of cortical sulci, increase the vascularity around the cortical surface and around the tentorial hiatus. It can appreciate the multiple flow voids around the collapsed brain cortex. Another common observation in the drained ventricle is the loculation of CSF spaces into multiple pockets. These pockets may or may not communicate, occasionally lead to incomplete drainage. In this patient I saw some additional unusual observation in the form of a focal defect in the corpus callosum at the junction of the genu and body. 

Case 64  

ACM with syrinx. 

This ia part of the illustrated examples of patients with Chiari malformation with some additional observations. This case demonstrates associated syringomyelia. Supratentorial observations are clear cut in the form of hugely dilated lateral ventricles with the colpocephaly. You also notice tightly packed posterior fossa structures with compressed fourth ventricle. Tonsil is extending almost up to lower cervical region!! You also notice enlarged foramen magnum through which part of the cerebellum is descending down. There are two cystic structures in the cervicodorsal region separated by some solid/membranous components. The lower part represents a syrinx. Nature of the upper collection is not very clear, either a loculated pocket of CSF or a complex syrinx. Have a close look at the T1 coronal image, showing tonsils in the lower cervical region!! A very unusual phenomenon. Lower down we can see the extent of syringomyelia in the lower dorsal cord. More distally there is a large meningocele with a tethered distal cord. These cases may not be seen often; however, they broaden your understanding about the disease and likely pathogenesis.

Case 65

There is some amount of overlap in the pathology illustrated in these examples. In this instance I am demonstrating a case of the callosal agenesis in association with a midline cyst. This combination is well established. Depending on the size of the cyst, clinical and imaging presentation may vary. Large cyst is associated with large head with gross hydrocephalus. This combination also may be seen in association with brain parenchymal defects like schizencephaly. Jim Barkovich at all analyzed group of such patients and proposed a morphological classification. Basically, this entity is a heterogeneous group. In the broad group category, Type I - cysts are extensions through the third or the lateral ventricles. Either seen in the association with the high-grade hydrocephalus or in association with diencephalic malformation. Type II - cysts are seen in association with the ACC. Cyst can be loculated. A sub variety of type II cyst is seen in association with the Aicardi syndrome. This system of classification perhaps needs revisiting with increasing case database and advancing knowledge about the condition.

Case 66

This is a week-old neonate investigated for a large head. I do not think this case would challenge you if are aware of this entity. This is an obvious case of Lipoma of corpus callosum in association with partial agenesis. There is associated hydrocephalus. General facts about lipoma corpus callosum are well known. It constitutes 1% of the intracranial tumors, half of them are associated with the brain malformations. Often, they are incidentally detected. Occasionally they present with seizures. Morphologically they may be a nodular or curvilinear.  Nodular variety is more common and tends to enter into the lateral ventricles through the region of tela choroidea. This patient belongs to this category. Curvilinear type usually seen in posterior part of CC, wraps around the splenium of corpus callosum. Resident radiologist may find some interest in the fat related susceptibility artefacts (chemical shift artefacts) shown in the old generation T2/gradient MR images. Curvilinear, Brackett type of thin calcification is a well-known in the radiology literature, aptly illustrated by many examples.

Case 67

This is a child 3 months old with enlarging head size circumference. Patient had surfactant deficiency was on neonatal intensive care management.

In the MR examination of the brain, we notice mild ventricular dilatation. More striking observations is the  symmetrical  extracerebral CSF collections on both sides. Signal intensities of the collection is nearly that of CSF, although slightly heterogenous. Small focal hyperintense foci are noted on the left side probably due to blood products/thrombosed vessels/slow flow in the vessels. Findings could be due to subdural hygroma or chronic SDH. There are also axial CT images of the chest showing ground glass opacities in both lungs, subsegmental atelectasis, slight exaggeration of the interstitial pattern and hypo-aeration – appearances consistent with sequel of surfactant deficiency.

Hygromas are occasionally seen in patients on long-standing respiratory support. Most of the hygromas are considered as a sequel of trauma. In some children hygroma can be idiopathic.  Most of the subdural hygromas are managed conservatively. There are a few differential diagnoses, (1) benign widening of CSF spaces, in which situation collection of fluid is in the subarachnoid spaces, not in the subdural space. (2) Another group of differential diagnosis can be considered if the collection is asymmetric, a context in which an localized lesion like arachnoid cyst can be considered.

Case 68

Child with developmental delay. MRI examination demonstrates gross dilatation of the lateral ventricles with colpocephalic configuration. Third and fourth ventricles are relatively spared.  Is there anything else that attract your attention? I am sure some of you will notice that the ventricular wall is somewhat nodular and irregular, lined by tissues similar to the cerebral cortex – hence we are dealing with a case of cortical heterotopia. This child does not have other additional CNS malformation. Cortical heterotopia is a vast topic, essentially part of the spectrum of  neuronal migrational disorder. 

 Grey matter heterotopias can be divided macroscopically into:

1. Nodular heterotopias

subependymal heterotopia: most common

subcortical heterotopia

2. Diffuse heterotopias

band heterotopia also known as double cortex heterotopia and X-linked lissencephaly (chromosome Xq22.3)

lissencephaly: types 1 and 2

laminar heterotopia (a problematic term variably defined) [ source Radiopedia]

Neuronal migrational disorders are often associated with the other CNS malformation like agenesis of the corpus callosum, Chiari malformations and encephalocele etc.

Case 69 :

15-year-old patient had a lesion in the intracranium since early childhood, operated many times presently having left eye blindness. CT and MR imaging of the brain is provided.

The intention of this illustration is to show the diversity of presentation of a fairly common childhood tumour. CT images at the age of 14 years was performed after ventricular drainage. Examination demonstrates multicystic lesion with,nodular calcification in the suprasellar region. Lower third ventricular outline is obscured. There is a rounded, large calcific density in the left temporal fossa, which appear to be part of the calcifications. There is the lateral ventricular dilatation with predominant left lateral ventricular dilatation. Encephalomalacic changes are noted in the frontal lobe bilaterally, more extensive on the left side. Following contrast there is some amount of wall enhancement of lesions close to the skull base. Most of the cystic components do not enhance. So, we have an intracranial lesion in the suprasellar region with the cystic and calcific components. Findings typical for a craniopharyngioma.

 Now we need to look at the MR images. This may be a good exercise for a trainee radiologist, a lesson in characterizing spin echo signals within a lesion. Initially look at the T2-weighted images, which demonstrate, most of the cysts showing T2 hyperintensity. Not all cystic lesions have the same signals indicating complex contents of the cyst. Calcific lesion in the left temporal fossa is homogeneously hypointense, consistent with a dense calcium. You can see the similar pattern shown in all the other T2-weighted images in different planes. Rest of the findings are as shown with CT observations. Next look at the FLAIR image provided. While most of the cysts show FLAIR hypointensity, there is one which is FLAIR hyperintense. Also, we can appreciate white matter changes in the right frontal lobe part of which appear to be oedema. Ventricular system does not show indirect evidence of pressure as periventricular structures do not show significant hyperintensity. (Subtle changes on the left side). T1-weighted images demonstrate slight T1 hyperintensity in the FLAIR hyperintense lesion. Also, the calcific density shows hyperintense signals indicating an element of bound calcium. Following contrast, peripheral enhancement is noted in some of the cystic areas. And there are post-operative changes in the bones. Looking at the studies, we do see cystic and calcified elements of craniopharyngioma, one locule probably showing blood products. There are secondary brain changes due to ventricular obstruction and results of surgery.

Case 74

This is a 3-day-old neonate, investigated for an intracranial anomaly. There were few illustrations before, showing some of the components of the anomaly seen in this patient. This case shows some classic appearances along with other combinations. Obviously lissencephaly brain-pattern is noted with the hypoplasia of the cerebellum (Type I). Dangling choroid plexus is noted in the bilateral lateral ventricles, and a finding of importance when fetal sonography is performed. Extent of cerebellar-vermian hypoplasia is somewhat atypical. Cerebellum is retracted and seen is a small hump high up in the posterior fossa. Brain stem appears hypoplastic, almost bare in the lower half. Additionally,there is a large posterior fossa cyst with a small outpouching posteriorly. Cyst is freely communicating with the open fourth ventricle, indicating a large Dandy-Walker cyst. If you carefully review the images, you will also notice that corpus callosum is not recognisable and there is a thin walled cyst in the region of the caudothalamic groove. Overall, very complex malformation of organogenesis and neuronal migration.

Case 75

This young, 4-year-old, female presented with incontinence. MR examination was performed to exclude spinal anomalies. Clinically, there were no obvious findings in the lumbosacral region.

What is your impression on the MR images?  Diagnosis is not difficult. You are seeing a low-lying cord lying at S2-3 levels with thickening of the filum which is lying along the posterior aspect of the theca. There is a hydromyelia in the region of conus. Also there is a plaque-like lipoma adherent to the theca from L2 level to the L5 level. On close observation that is a small defect in the spinal process at the S1 level, at which level lipomatous intraspinal component to communicate with the subcutaneous fat. This is a skin covered spinal dysraphism with a lipoma of the distal cord and cord tethering.  This is an extensive topic. Radiology residents are recommended to familiarise themselves with a wide range of possibilities in this context. Some additional illustrations are available in the presentation.

Case 79

19-month-old patient treated with the bilateral VP shunts for congenital hydrocephalus. Chest and abdominal radiograph along with the contrast-enhanced images of the head are provided. Chest radiographs with these shunt tubes are not frequently seen these days. Thanks to the fetal medicine, early detection and management strategy. This examination is intended to give you familiarity with the appearance of VP shunt on chest and abdominal radiographs. Discontinuity in the shunt tube is to be observed; occasionally ectopic location of the distal end of the shunt tube may lead to obstruction. Various ectopic locations, abdominal and thoracic, including location in the breast are described. Abdominal end of the shunt tube may be the cause of obstruction, due to entanglement and adhesions. Intracranially following shunt, drainage pattern is not always predictable. Global drainage, if it takes place, will often cause symmetrical reduction in the ventricle system. Subdural hygromas, occasional hematoma may be the sequelae. Occasionally drainage is asymmetric due to loculation. This will need additional shunt drainage or revisions. Rarely secondary infection and meningitis may be the sequelae of shunting. I guess you have noted asymmetrical drainage as well as the subdural collection in the left frontotemporal regions.

Case 80

This is a patient of 6 years who had minor gait disturbance. Initially he was investigated with a CT scan. 2-sets of examinations of CT are available, one at presentation another one subsequently after external ventricular drainage. Observation on the CT examination is subtle. There is mild ventricular dilatation in the lateral ventricles. Areas of minimal enhancement are observed in the inferior vermis. Incidentally there is minimal increase in the density of the tentorium. Though minimal increase is expected, in this case it appears more evident. CT examination with IV contrast showed very evident enhancement of the tentorium and subtle enhancement of the inferior vermis indicating a possible medulloblastoma with the posterior fossa spread. Patient initially underwent external drainage for decompression.  And subsequently underwent surgical removal of the inferior vermis and adjuvant chemotherapy. Patient remained symptom-free for nearly 3 years and presented with lower limb weakness and inability to walk steadily.

 An MR examination was performed at that stage. This case shows a pattern of the disease spread in cases of medulloblastoma. Our patient showed no significant residual disease in the posterior fossa. Post-operative changes in the form of surgical cavity, gliosis of adjacent cerebellum and post-operative bony changes. But there is an extensive disease process in the cervical dorsal spine in the form of the extensive nodularity and plaque-like enhancement of the posterior theca.  It is important to evaluate the changes in the spinal canal with contrast-enhanced MRI in patients with medulloblastoma at the initial state itself, so that staging is properly performed.  The prognosis is strongly influenced by surgical resection, the presence of CSF metastases at the time of diagnosis, and expression of the c-erbB-2 (HER2/neu) oncogene.

Case 81 :  10-yr-old-male child with headaches.

Case 81.

Patient is a 10-year-old boy with headaches and some non-specific complaints. Patient was initially evaluated with a CT scan.  There are no obvious abnormalities on the CT images. Subsequently an MR examination is performed. MR findings are also somewhat non-specific. There are multifocal subcortical white matter hyperintensities, in the left anterior frontal region, right posterior limb of the internal capsule. Cerebral subcortical lesions show fine micro haemorrhages in the gradient images. There is no mass-effect. Posterior fossa as well as the visualised spinal cord is within normal limits. These appearances pose a challenge for imaging diagnosis. Patient did not have any obvious systemic abnormality. There are a wide range of possibilities based on MR observations; main differential diagnosis include small vessel vasculitis, focal encephalitis, demyelination or demyelination due to conditions like neurofibromatosis. The patient made a spontaneous recovery.

Case 84

This patient is a smart, young girl of 14-years who had occasional headaches. She was doing well in school, was persuaded for the examination by a relative, a neonatologist.  Initial CT examination revealed a hypodense lesion in the superior aspect of the right cerebellum without significant mass-effect or enhancement. To characterize the abnormality further, an MR examination was performed. This MR demonstrates another Aunt Minnie Case. You will notice an abnormality in the superior aspect of the right cerebellum in the form of T1 hypointense and T2 hyperintense legion which shows a linear and lobulated.micorcystic pattern. (Striate pattern) There is no significant mass-effect. The involvement appears to be mostly cortical, retaining some of the intrinsic pattern of cerebellar folia. Do we have the diagnosis?  This is an imaging manifestation of Lhermitte-Duclos disease, also known as dysplastic cerebellar gangliocytoma.

This entity is classified as WHO grade 1 tumour. Histologically it has interesting observations. There is thickening of the outer molecular cell layer, loss of the middle Purkinje cell layer, and infiltration of the inner granular cell layer with dysplastic ganglion cells of various sizes. There appears to be strong genetic basis, PTEN mutations are invariably present in adults, not in the children. There are many associated conditions. (Radiopedia)

• Cowden disease (as part of COLD syndrome, see below)

• disorders of cortical formation

  • megalencephaly

  • grey matter heterotopia

  • polymicrogyria

• polydactyly

• hydromyelia

• macroglossia

• localized gigantism

• leontiasis ossea

Presentations can vary a great deal, some of them manifesting with obstructive symptoms of CSF pathway, requiring surgical management. Small lesions tend to be asymptomatic, very slowly growing.

( Louis DN, Ohgaki H, Wiestler OD et-al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol. 2007;114 (2): 97-109)