Indian Journal of Radiology and Imaging Indian Journal of Radiology and Imaging

: 2006  |  Volume : 16  |  Issue : 4  |  Page : 971--973

Radiological quiz - neuroradiology

S Sharma, M Surya, SGG Kumar, A Negi, N Agarwal 
 1007, Basant Vihar, Kasumpti, Shimla-171009 (H.P), India

Correspondence Address:
S Sharma
1007, Basant Vihar, Kasumpti, Shimla-171009 (H.P)

How to cite this article:
Sharma S, Surya M, Kumar S, Negi A, Agarwal N. Radiological quiz - neuroradiology.Indian J Radiol Imaging 2006;16:971-973

How to cite this URL:
Sharma S, Surya M, Kumar S, Negi A, Agarwal N. Radiological quiz - neuroradiology. Indian J Radiol Imaging [serial online] 2006 [cited 2020 Aug 8 ];16:971-973
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Full Text

A 10 year old male child presented with mild mental retardation, right partial complex seizers involving right upper & lower limbs past 2 months. Motor milestones, sensory milestones, cranial nerves were & head circumference were normal. No evidence of similar complaints in the other siblings. Physical examination was unremarkable. Hematological examinations were normal. CT head [Figure 1] and MRI head were done [Figure 2][Figure 3][Figure 4].

What is your diagnosis?

 Radiological Diagnosis


Plain CT [Figure 1] head shows bilateral symmetrical Perisylvian cortical thickening with abnormal medial extension more so on the left side. There is paucity of white matter adjoining thickened cortex. No evidence of calcification or hydrocephalus seen. MRI T2W axial turbo spin echo [Figure 2] & Coronal turbo spin echo [Figure 3] images done on 1.5 Tesla machine shows, normal bilateral anterior Perisylvian cortex with bilateral symmetrical thickening of posterior Perisylvian cortex measuring 7-8 mm (normal thickness = 3-4 mm) with perirolandic extension, left more than right. Thickened cortex is giving bumpy appearance at surface & the cortical white matter junction. There is paucity of sulci in this region with irregularity of corticomedullary junction. There is paucity of white matter adjacent to it. The signal of the adjacent white matter is normal. On Sagittal T1W spin echo images [Figure 4], there is evidence of bilateral abnormal posterior extension of the sylvian fissure to the parietal convexity with markedly thickened parasylvian gray matter & exposure of insula. The above findings are consistent with bilateral non-lissencephalic cortical dysplasia the subtype "CONGENITAL BILATERAL PERISYLVIAN SYNDROME" (Posterior Perisylvian polymicrogyria).

Malformation of cortical development can be the result of abnormalities of stem cell proliferation and differentiation, neuronal migration, or cortical organization [1],[2]. Abnormalities of cortical organization are a common cause of epilepsy & polymicrogyria is commonest among this abnormality. Polymicrogyria is a malformation of cortical development that is characterized by abnormal arrangement & excessive folding of cerebral cortical cell layer, often with fusion of gyral surfaces. Histologically polymicrogyric cortex is composed of heterogonous collection of neurons & derangement of normal six layered lamination. Because of macroscopic and histological variation found in polymicrogyria, the term "non-lissencephalic cortical dysplasia" may be more appropriate.

Combination of three characteristics is used to identify polymicrogyria: abnormal gyral pattern, increased cortical thickness and irregularity of the cortical-white matter junction. Several syndromes have been described in which patients have rather specific clinical manifestations associated with imaging of bilateral polymicrogyria [3],[4]. These include bilateral Perisylvian microgyria, bilateral parasagittal parieto-occipital polymicrogyria & bilateral fronto-parietal polymicrogyria. Bilateral Perisylvian polymicrogyria is further classified into those in whom nearly the entire Perisylvian cortex is affected termed as holosylvian polymicrogyria & those in whom only the posterior Perisylvian cortex is involved which is termed as posterior Perisylvian polymicrogyria [5]. Corticomedullary junction is also irregular bilaterally.

Congenital bilateral polymicrogyria (CBPS) is a rare neurological disorder which may cause facial diplegia, dysarthria, pseudobulbar palsy, mild to severe mental retardation and epilepsy [4],[5]. Polymicrogyria is better seen with MRI than CT as thickened cortex with poorly defined sulci. In CBPS, the opercula are dysplastic and incomplete & the sylvian fissure is wide and underdeveloped. Sagittal images may show posterior extension of sylvian fissure, exposure of insula, and apperent thickening of the cortex [5], which is also well seen in our case. Like MRI, CT shows bilateral Perisylvian cortical dysplasia, often extending to the perirolandic regions & bodies of the lateral ventricles show inverted appearance, typical of this disorder.

Most patients present with seizures, usually focal motor & developmental delay. Our case presented with focal motor seizure and mild mental retardation and present imaging modalities will easily identify these disorders so awareness about these disorders to all radiologists is necessary.


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