Hemimegalencephaly: A rare cause of hemihypoperfusion on 99m technetium-ethyl cysteinate dimer brain perfusion single-photon emission computed tomography
An 11-year-old male child was referred to a tertiary care hospital with history of gradually increasing seizures frequency since infancy. The child had delayed milestones and right hemiparesis. Seizures were mainly right sided, complex partial in nature and refractory to medical treatment over the past decade. The child was born out of non-consanguineous marriage, at term with a normal vaginal delivery. There was no family history of neurologic diseases. Non-contrast computed tomography (CT) of head showed diffuse enlargement of left cerebral hemisphere with midline shift towards right while the right cerebral hemisphere was normal []. T2W magnetic resonance imaging (MRI) images showed diffuse gyral thickening involving the left cerebral cortex causing midline shift and scalloping of inner table of left calvarium []. White matter in both cerebral hemispheres show normal myelination. Linear hyperintensities involving the subcortical U fibers of left fronto-parietal region were seen on the fluid attenuation inversion recovery image [].\nPost-gadolinium T1W image in axial plane showed no abnormal enhancement []. Tc-99m ECD brain perfusion SPECT revealed diffusely decreased tracer uptake in the left cerebral hemisphere, with normal uptake in the right hemisphere suggestive of left cerebral hemihypoperfusion [-].