Rare case of childhood cerebral arterial disease

A 6-year-old female child presented with the complaint of recurrent stroke-like symptoms since her infancy. She had power of 3/5 in bilateral lower limbs 3 years back when she had one of the episodes. It was gradually improving. Her developmental milestones were slower compared to the child of the same age. 6 months back she developed sudden upper limb weakness following loss of consciousness. Now she complains of headaches and is slow to react towards the noxious stimuli. Because of multiplicity of the episodes she was suspected of vasculitis and was sent for cerebral angiographic imaging.

Plain CT head demonstrate no obvious abnormalities. Cerebral CT Angiogram along with head and neck CT Angiography shows moderate to severe stenosis of the right internal carotid artery in the cervical, petrous, laceral and cavernosal segments. The supracliod segment shows near complete occlusion. The terminal branches of the ICA i.e. ACA and MCA are reformed from the normal contralateral side. There are tiny innumerable tortuous cortical and penetrating vessels, which are seen supplying the cerebral cortex and the deep white mater as well as the grey mater nucleus. Bilateral MCA shows loss of smooth luminal contour. On sagittal and coronal MIP images the reformed collaterals due to compensatory mechanisms shows puff of smoke appearance, which are seen arising from the deep arterial territory to the cortical superficial aspect. These vessels are seen fanning out from the centre to the periphery.

MoyaMoya disease is a chronic childhood progressive cerebrovascular disease of unknown origin. If there is know cause i.e. Neurofibromatosis, Down’s syndrome, thyroid disorder and vasoocclusive disease like sickle cell anemia it is termed Moya Moya syndrome. There is predilection for the ICA, which is stenosed causing recurrent stroke-like symptoms. The literal meaning of “Moya Moya” is puff of smoke. The name is suggested due to its characteristic appearance in cerebral angiographic images. The child may present with recurrent stroke-like symptoms, headache, recurrent episodes of seizure, cognitive decline and altered sensorium[1,2,5]. There is bimodal occurrence of the disease i.e. among the 5-6 years and 30-40 years of age. The condition is more prevalent in the Asian population especially in Japan and China with incidence up to 0.35 in 100000 in Japan [2,3,4].

Various imaging modalities can be used for imaging of the disease namely conventional catheter angiography, CT angiography and MR angiography. Conventional catheter angiography is considered the gold standard. However, recently CT and MR angiography are considered the first line of imaging due to less invasive nature and also due to betterment in their spatial resolution and their ability to reformat images in multiple planes as desired. Brain parenchyma changes are also well visualized with the help of cross-sectional imaging, which is a limitation for the conventional angiography. Imaging findings in case of the disease are symmetrical stenosis of the bilateral ICA and their subsequent branches without evidence of atheromatous changes. There may be absent formation of the major cerebral vessels. Brain parenchymal changes may be seen in form of atrophy or infarction depending upon the time frame from presentation.

The hallmark of the disease are formation of mutiple variable-sized tortuous collaterals from the pial circulation or from the penetrating vessels. These small collaterals are the cause for characterstic “puff of smoke” appearance. MR angiography may show serpentine pial vessel which is otherwise known as “Ivy sign”. Angiographic grading of the disease is known as Suzuki grading, which consist of six grades and ranges from narrowing of the carotid fork in the least severe spectrum to the disappearance of the ICA and establishment of the collateral supply from the ECA or vertebral arteries[3,4,5].