Moyamoya Disease in Brain Radiology
Moyamoya Disease in Brain Radiology Moyamoya disease is a rare, progressive cerebrovascular disorder characterized by the narrowing or occlusion of the internal carotid arteries and their main branches at the base of the brain. This narrowing leads to the formation of a network of tiny collateral vessels, which appear as a “puff of smoke” on imaging studies—a feature that gives the disease its name, derived from the Japanese term “moyamoya.” Understanding the radiological aspects of moyamoya disease is crucial for accurate diagnosis, assessment of disease progression, and planning appropriate treatment strategies.
Moyamoya Disease in Brain Radiology In brain radiology, digital subtraction angiography (DSA) remains the gold standard for diagnosing moyamoya disease. It vividly reveals the stenosis or occlusion of the terminal portions of the internal carotid arteries and the proximal segments of the anterior and middle cerebral arteries. The hallmark feature on DSA is the presence of a dense collateral network, often described as a “puff of smoke,” which results from numerous small, fragile vessels attempting to bypass the occlusion. These collateral vessels are typically dilated, tortuous, and can be seen radiating from the circle of Willis and other basal arteries.
Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) are non-invasive alternatives increasingly used to evaluate moyamoya disease. MRI can demonstrate areas of chronic ischemia or infarction, especially in the deep white matter and basal ganglia, which often correspond to the patient’s neurological deficits. In addition, MR perfusion imaging provides insights into cerebral blood flow and the extent of hemodynamic compromise. MRA can visualize the characteristic vessel narrowing, although it may lack the spatial resolution of DSA. Moyamoya Disease in Brain Radiology
Moyamoya Disease in Brain Radiology Computed tomography angiography (CTA) also plays a valuable role in the assessment of moyamoya disease. CTA can depict the abnormal collateral networks and vessel stenosis with high spatial resolution, facilitating rapid diagnosis, especially i
n emergency settings. Moreover, it can assist in surgical planning by providing detailed visualization of the vascular anatomy.
A key radiological feature in moyamoya disease is the presence of “ivy sign” on FLAIR MRI sequences, which reflects slow flow or leptomeningeal collaterals filling the cortical sulci. Additionally, the basal collaterals and enlarged lenticulostriate arteries are often prominent on imaging, indicating compensatory vascular changes. These findings are crucial for distinguishing moyamoya disease from other causes of vascular stenosis, such as atherosclerosis or arteriopathies. Moyamoya Disease in Brain Radiology
The radiological evaluation of moyamoya disease not only aids in diagnosis but also monitors disease progression and guides therapeutic decisions. Surgical revascularization procedures, such as bypass surgeries, aim to restore adequate cerebral blood flow. Postoperative imaging assesses the success of revascularization, with DSA and MRI being instrumental in postoperative follow-up to ensure patency of grafts and the development of new collateral vessels.
Moyamoya Disease in Brain Radiology In summary, brain radiology plays a pivotal role in diagnosing and managing moyamoya disease. Recognizing its characteristic imaging features ensures early detection and intervention, which are vital for preventing strokes and improving neurological outcomes in affected patients.
