Follow-up of supraclinoid internal carotid artery aneurysm and occlusion of the right middle cerebral artery with collaterals (moyamoya phenomenon) on outside imaging. Brain MRI:The brain is notable for few T2/T2 FLAIR hyperintense foci in the left frontal white matter that are nonspecific. The were present on the previous examination. There is no mass effect or midline shift. There is no intracranial hemorrhage. There are slightly conspicuous lenticulostriate vessels in the lentiform nuclei, as best seen on SWI, as post-contrast images are not available. There is no abnormal brain diffusion restriction. The dural venous sinuses are patent.There is minimal mucosal thickening in the frontal and anterior ethmoid sinuses without fluid.Cranial MR Angiography:There is fusiform dilatation and tortuosity of the supraclinoid/intradural segment (just distal to the takeoff of the ophthalmic artery) of the right internal carotid artery, with a maximum diameter of 8 mm. The fusiform dilatation extends to more mildly involve the right A1 segment. There is no visualized right M1 segment. There is an apparent small, triangular outpouching arising anteriorly from the most inferior loop of the aneurysmal segment from which a tiny vessel appears to arise. This may represent an enlarged infundibulum. The tortuous fusiform aneurysm results in mild mass effect on the right hippocampus. Attenuation of the flow-related signal in this aneurysmal right ICA/A1 segment may in part relate to tortuosity. An anterior communicating artery is present and flow in the downstream right anterior cerebral artery is preserved.As discussed above, there is no visualization of the right M1 segment. There is severe attenuation of caliber and flow-related signal involving the more downstream right middle cerebral artery and its branches. This minimal, residual flow might be coming from enlarged, tortuous right lenticulostriate and thalamostriate arteries.Compared to the previous examination of 2013, there has not been significant change regarding the diffuse fusiform aneurysm and nonvisualization of the right M1 segment. However, previously there was more flow-related signal in the more downstream right middle cerebral artery and branches. The left internal carotid artery is preserved in caliber and flow-related signal. The left anterior and middle cerebral arteries are preserved as well. The basilar artery is codominantly supplied by the vertebral arteries. There is a large right posterior communicating artery which connects to the dilated right internal carotid artery. The caliber and the flow in the posterior cerebral arteries are preserved and symmetric.
1.Fusiform, aneurysmal dilatation of the intradural segment of the right internal carotid artery with extension into the right A1 segment. This has not changed since the previous examination. Small outpouching from the inferior aspect of the aneurysmal segment is again noted, and may represent an enlarged infundibulum which was less conspicuous on the previous examination although may relate to technique.2.There is nonvisualization of the right M1 segment with severe downstream attenuation of flow-related signal in the right middle cerebral artery and its branches with mildly prominent lenticulostriates. The appearance would be compatible with moyamoya phenomenon. Findings are slightly progressed since the previous examination but there are no signs of ischemia in the right cerebral MCA territory on this resting examination.3.Few small left frontal white matter lesions are nonspecific.I personally reviewed the Images and/or procedure with the Resident/Fellow and agree with this report.