Background and purpose Moyamoya disease and syndrome are well known to affect the anterior cerebral circulation by progressive steno-occlusive disease of the supraclinoid internal carotid arteries. Less attention has been paid to changes in posterior arterial circulation hemodynamics in this condition. We sought to better understand the latter using a relatively novel noninvasive imaging technique, quantitative magnetic resonance angiography (qMRA). We assessed the diagnostic utility of qMRA for posterior arterial circulation flows before and after surgical revascularization.
Materials and methods This retrospective review included patients who met the following inclusion criteria: (1) diagnosis of moyamoya disease or syndrome with revascularization surgery at Stanford University between September 2008 and March 2012; (2) preoperative and postoperative qMRA scans on record within a two-year time frame; and (3) high-quality qMRA images without motion artefact. Cerebral blood-vessel flow was quantified after non-contrast magnetic resonance imaging (MRI) through the use of a commercially available software tool, non-invasive optimal vessel analysis (NOVA, VasSol, Chicago, USA).
Results A total of 191 patients underwent 281 surgeries during this period of time. Of these, a cohort of 64 patients (78% female, mean age 38.5 years, 55% unilateral disease) had pre- and post-operative qMRA studies. Preoperative arterial flows in the posterior circulation were markedly elevated compared to normal controls. These flows significantly decreased after revascularization (94% direct STA–MCA bypass) with right PCA flow 145 mL/min pre-surgery vs. 123 mL/min post-surgery (p = 0.005, n = 51) and basilar artery flow 264 mL/min pre-surgery vs. 222 mL/min post-surgery (p < 0.001, n = 58). A notable decrease in flow rates was also appreciated within the left PCA distribution, albeit not to a statistically significant degree (p = 0.121, n = 53). No statistically significant changes were noted in posterior communicating artery flows.
Conclusions Quantitative MRA shows that posterior circulation arterial flows are markedly increased in patients with moyamoya disease. After revascularization, there is an overall decrease in these flows that is significant in the basilar artery and right posterior cerebral artery. Further use of qMRA might be warranted to better understand moyamoya hemodynamics before and after surgery.
Abbreviations MMD = moyamoya disease NOVA = noninvasive optimal vessel analysis; qMRA = quantitative magnetic resonance angiography
Keywords moyamoya disease, quantitative magnetic resonance angiography, cerebral blood flow
Disclosures R. Navarro: None. A. Feroze: None. O. Choudhri: None. R. Lober: None. N. Khan: None. G. Steinberg: None.