NEURORADIOLOGY


Case 46 :

8 years male child presented with mental retardation and seizure disorder since childhood with neavus  on face on left side .

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Diagnosis

Sturge- Weber Syndrome

CT Findings

CT Scan plain and contrast examination demonstrates the cortical atrophy in left posterior parietal and occipital lobe with gyral calcifications. A dilated transmedullary vessel is seen crossing from left cerebral cortex upto periventricular region and the left choroids plexus show  angiomatous enlargement .

Discussion:

Sturge- Weber syndrome (SWS) is also known as encephalotrigeminal angiomatosis. It consists of  vascular malformation that affects the CNS (brain and eye) and the soft tissues of  face and  head in the territory innervated by trigeminal (V th )  cranial nerve.

Classical clinical diagnosis is based on observing seizures / mental retardation in association with a port- wine stain of the face; pathologically port- wine stain consists of small thin walled vessels within the skin.

Ocular findings consists of  bupthalmos, choroidalangiomas and episcleral telanajectasis are common in patients with SWS. Bupthalmos occur in upto 15 % of patients due to congenital glaucoma.

Brain is affected in 100%  cases. This  is the defining feature of SWS. Occipital lobe is affected preferentially, followed by temporal and parietal lobe, frontal lobe involvement is uncommon. Infratentorial fossa not affected. There is abnormal persistence of  the primitive / primordial vascular plexus. The cerebral capillary  outflow is thus impaired and the cortical capillary   drains into plexus of small vessels in the subarachnoid space, instead of directly into the dural sinuses. In addition , there may be prominent transmedullary vein that drain the cortex in a centripetal fashion, to the perventricular vein.  After birth chronically impaired circulation produces cerebral ischemia that in turn leads to failure of the blood brain barrier   in the affected posterior region. Imbalance between metabolic needs and  blood supply causes cellular death and subsequent deposition of dystrophic calcification into atrophic cortex producing tram-track’ or rail road appearance on plain films .   

DR . AMOL BITEY , DNB DMRD CONSULTANT RADIOLOGIST NAGPUR