Objective and importance: Moyamoya disease is a progressive arteriopathy of the intracerebral vessels resulting in stroke, intracerebral hemorrhage, and alteration of cerebral perfusion. Perfusion-weighted magnetic resonance imaging (PWI) tracks the passage of a bolus of gadolinium contrast material through brain tissue and is reflective of cerebral blood flow. We describe the characteristics of PWI in patients with moyamoya syndrome and present in detail the PWI findings of a patient studied before and after surgical intervention.
Clinical presentation: A 24-year-old woman presented with recurrent ischemic strokes during a period of 1 year. Angiography disclosed findings consistent with bilateral moyamoya disease. PWI showed a striking contrast in perfusion between the anterior and posterior circulations, with relative hyperperfusion in the posterior fossa and marked hypoperfusion in the hemispheric deep white matter. Similar findings are reported in five other patients with moyamoya disease. Differences in time-to-peak measurements between the pons and the cerebral hemispheres ranged between 2 and 10 seconds, with the greatest difference seen in the two patients with recurrent stroke.
Intervention: The patient underwent a left encephalomyosynangiosis. One year later, she showed significant improvement in neurological function, and a repeat PWI study showed marked improvement in perfusion of the left hemisphere. Magnetic resonance imaging confirmed the growth of small vessels into the brain from the surgical site.
Conclusion: PWI demonstrates characteristic patterns of cerebral perfusion in patients with moyamoya disease and documents improved perfusion after successful surgical intervention. Quantitative analysis of the difference of time-to-peak measurements between the anterior and posterior circulation may be a marker of the severity of the disease.