Characteristics of Moyamoya Syndrome in Sickle-Cell Disease by Magnetic Resonance Angiography: An Adult-Cohort Study

Abstract

Background: Sickle cell disease (SCD) can be complicated by moyamoya syndrome. Brain magnetic resonance angiography (MRA) is a non-invasive method to diagnose this syndrome and, steno-occlusion and moyamoya vessels (MMV) scores have been proposed to evaluate its severity. Previous studies of SCD moyamoya syndrome did not evaluate the severity according to MRA scores. The objective was to assess the characteristics of moyamoya syndrome in an adult cohort of SCD using these MRA scores. Methods: Twenty-five SCD patients with moyamoya syndrome were included using MRA with 3D time of flight technique. We evaluate steno-occlusion score for each hemisphere (range 0-10) from: steno-occlusion severity of internal carotid (ICA) (0-3), anterior cerebral (ACA) (0-3), middle cerebral (MCA) (0-2), and posterior cerebral (PCA) (0-2) arteries. MMV score for each hemisphere (range 0-5) depended from 5 MMV areas: (1) anterior communicating artery (2) basal ganglia (3) ICA/MCA (4) posterior communicating artery/PCA (5) basilar artery. Results: Eight patients (32%) showed unilateral moyamoya syndrome. ICA steno-occlusion was involved in 22 patients (88%), MCA in 23 patients (92%), ACA in 9 patients (36%), and PCA in 3 patients (12%). MMV involved ACoA area in 10 patients (40%), basal ganglia in 13 patients (52%), PCoA/PCA in 10 patients (40%), MCA/ICA in 7 patients (28%), and BA in 1 patient (4%). Steno-occlusion and MMV mean hemisphere scores were 3.4/10 (± 1.42) and 1.6/5 (± 0.71), respectively. Conclusion: Frequent unilateral moyamoya syndrome, uncommon PCA involvement and, moderate steno-occlusion and MMV scores seem to be features of SCD moyamoya syndrome. In future studies, MRA scores could be collected to assess the follow-up in these patients.

Keywords: magnetic resonance angiography; magnetic resonance imaging; moyamoya syndrome; sickle-cell disease; time-of-flight.

Figure 1

Examples of time-of-flight (TOF) evaluations in maximal intensity projection (MIP) of three patients with SCD moyamoya syndrome. (A) Coronal TOF images in a 27-year-old patient showed bilateral ICA steno-occlusions (arrowheads), with MCA discontinuity (^*) and basal ganglia moyamoya vessels (MMV) (arrow). He also had a circle of Willis aneurysm (circle). (B) Axial TOF images demonstrated PCoA/PCA MMV (arrow) due to left PCA occlusion (^*). For the left hemisphere and the right hemisphere, respectively, his MRA steno-occlusion score was 6/10 and 3/10, and MMV score was 3/5 and 2/5. (C) Another 28-year-old patient had unilateral steno-occlusion involving right MCA (arrowhead) which was invisible and he had right basal ganglia and MCA/ICA MMV (arrows). His right steno-occlusion and MMV scores were 3/10 and 2/10, respectively. (D) A 29-year-old patient revealed bilateral ACA stenosis (arrows) without ICA stenosis.