A Vessel Wall MRI Investigation in Patients With Moyamoya or Quasi-Moyamoya Disease: Diagnosis, Features, and Outcomes

Background and Purpose: None of the previous studies have investigated the pathologic authenticity of affected arteries in moyamoya disease (MMD) and Quasi-MMD diagnosed by angiography. This study aimed to confirm the angiographic diagnosis of moyamoya as well as investigate the pathologic mechanisms in angiographically proven MMD and Quasi-MMD using high-resolution magnetic resonance imaging (MRI) in a large sample. Methods: We prospectively studied 116 patients who had angiographically proven MMD and Quasi-MMD. Each affected internal carotid artery, and middle cerebral artery was independently evaluated. In addition, clinical features and postoperative outcomes were compared between hemispheres with MMD and moyamoya syndrome (MMS). Results: Among 116 patients analyzed, 88 and 22 patients had angiographically proven MMD and Quasi-MMD, respectively. high-resolution magnetic resonance imaging confirmed bilateral MMD in 73 (83.0%) patients, 1 hemisphere with MMD and the other with intracranial atherosclerotic disease (ICAD) in 10 (11.4%) patients, and bilateral hemispheres with different vasculopathies in 5 (5.7%) patients. Detailed analysis of 204 affected hemispheres showed that several combinations of different vasculopathies were observed in the internal carotid artery and middle cerebral artery of the same hemisphere, such as ICAD-ICAD, ICAD-MMD, dissection-ICAD, and dissection-MMD. Hemispheres were assigned to MMD and MMS groups according to their vasculopathies. Transient ischemic attack occurred more frequently in hemispheres with MMD (48.1% versus 21.1%, P=0.024), whereas symptomatic ischemia was more common in hemispheres with MMS (57.9% versus 24.9%, P=0.002). However, postoperative cerebral infarction, symptom improvement and neo-formative collaterals showed no significant difference between hemispheres with MMD and MMS (P>0.05). Conclusions: Patients with angiographically proven MMD or Quasi-MMD needed more accurate evaluation combined with high-resolution magnetic resonance imaging. Highly selected patients with MMS might also obtain benefits from surgical revascularization.