Background: Hemorrhage is a major category of the clinical symptoms of moyamoya disease (MMD). Intracerebral and intraventricular hemorrhages are the most common hemorrhages in MMD, and subarachnoid hemorrhages (SAHs) are notably rare. There have only been a few previous case reports of this imaging manifestation. In the present study, we investigated the clinical and neuroimaging features of MMD patients who presented with SAH and sought to identify the possible causes of hemorrhage.
Methods: The right and left cerebral hemispheres of each patient were identified as hemorrhagic or non-hemorrhagic. Each hemisphere was assessed for Suzuki stage, and dilatation and branch extension of the anterior choroidal artery (AChA) and posterior communicating artery (P-CoM) and for the degree of transdural anastomosis and posterior circulation compensation. Next, these data were statistically analyzed for correlations with the SAH events.
Results: In 34 of 349 hemorrhagic MMD patients, the first episode of hemorrhage was a SAH, among which, 26 (76.5%) patients were women and there was only one pediatric patient. The Suzuki stage was not statistically correlated with the SAH events. There were also no correlations between SAH and dilatation or abnormal branching of the AChA and P-CoM. In contrast, SAH and transdural anastomosis were correlated. 25 of the 34 hemorrhagic hemispheres (73.5%) were positive for transdural anastomosis, and this number was 15 (44.1%) in the non-hemorrhagic hemispheres; this difference was statistically significant (P<0.05).
Conclusions: SAH is an important type of hemorrhage in MMD patients and ranks as the fourth most common type after intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), and ICH + IVH. It mainly occurs in adult women, and the rupture of the transdural anastomosis might be the main cause of this condition.
Keywords: clinical features; moyamoya disease; neuroimaging; subarachnoid hemorrhage.