Angiographic and Hemodynamic Features in Asymptomatic Hemispheres of Patients With Moyamoya Disease

Abstract

Background and Purpose: There is also a risk of stroke in the asymptomatic hemispheres of moyamoya disease (MMD), but it does not draw enough attention. The study investigated the differences between the three types of asymptomatic hemispheres in MMD and their associations with the two types of symptomatic hemispheres, respectively. Methods: Retrospectively reviewed clinical and imaging characteristics of asymptomatic and symptomatic hemispheres in consecutive cases of single-center MMD patients, with an emphasis on imaging characterization regarding vascular morphology and cerebral perfusion. MMD hemispheres were categorized into 5 types: hemorrhagic hemispheres, ischemic hemispheres, asymptomatic hemispheres in unilateral hemorrhagic MMD, asymptomatic hemispheres in unilateral ischemic MMD, and bilateral asymptomatic hemispheres in MMD. Angiographic feature was assessed by Suzuki’s angiographic stage, while hemodynamic feature was assessed by preinfarction period stage. Results: One hundred ninety-four MMD patients with 388 hemispheres were enrolled. Asymptomatic hemispheres in unilateral hemorrhagic MMD were largely similar to hemorrhagic hemispheres, both had more advanced Suzuki’s angiographic stage and lower degree of hemodynamic failure compared with bilateral asymptomatic hemispheres in MMD and asymptomatic hemispheres in unilateral ischemic MMD. Asymptomatic hemispheres in unilateral ischemic MMD were similar to ischemic hemispheres, both had less advanced Suzuki’s angiographic stage and higher degree of hemodynamic failure compared with bilateral asymptomatic hemispheres in MMD and asymptomatic hemispheres in unilateral hemorrhagic MMD. Bilateral asymptomatic hemispheres in MMD were different from the other hemispheres and had less advanced Suzuki’s angiographic stage and lower degree of hemodynamic failure. ConclusionS: The three types of asymptomatic hemispheres in MMD are defined and have unique angiographic and hemodynamic features. Different combinations of the two features can reflect the tendency of pathological evolution in these different asymptomatic hemispheres.

Thalamic structure and anastomosis in different hemispheres of moyamoya disease

“…Identifying the brain volume, which is an important component of brain structure ( Salinas et al, 2021 ), as well as angiographic features is an essential part of the research on MMD, as it can provide further information about the pathogenesis and neuropathology of the disease ( Kazumata et al, 2019 , 2020 ; Tahedl, 2020 ; Sun et al, 2022 ). However, previous studies have focused primarily on the symptomatic hemisphere.…”

“…According to the clinical presentations and radiological findings, the included MMD patients were divided into ischemic group, hemorrhagic group, and asymptomatic group (without neurological symptoms or only with mild and unspecific symptoms such as headache or dizziness, and with negative findings on MR images). Their hemispheres were classified into five types proposed by Sun et al (2022) : ischemic hemisphere (i-hemisphere), hemorrhagic hemisphere (h-hemisphere), contralateral asymptomatic hemisphere of i-hemisphere (ai-hemisphere), contralateral asymptomatic hemisphere of h-hemisphere (ah-hemisphere), and bilateral asymptomatic hemispheres in asymptomatic group (aa-hemisphere) ( Figure 1 ).…”

“…Cerebral ischemia and intracranial hemorrhage are the two primary phenotypes of MMD. Despite the development of abnormal vessels on both sides of the brain, patients with MMD do not always have bilateral symptoms ( Sun et al, 2022 ). Thus, there is a distinction between the symptomatic and asymptomatic hemispheres.…”

Five-Year Stroke Risk and Its Predictors in Asymptomatic Moyamoya Disease: Asymptomatic Moyamoya Registry (AMORE)

“…They concluded that asymptomatic patients had less advanced Suzuki's angiographic stage and lower degree of hemodynamic failure than the others. 28 However, they did not evaluate the development of periventricular anastomosis such as choroidal anastomosis, which is recognized as very important factors to cause cerebrovascular events in moyamoya disease. [21][22][23] In addition, this study demonstrated that the microbleeds was another predictor for hemorrhagic stroke in asymptomatic moyamoya disease.…”

“…However, as previously reported, cerebral hemodynamics is not always normal even if the disease is superficially silent, and cerebral hemodynamics may be taken into consideration when deciding on a future treatment plan. 11,28 Finally, we did not perform the genetic testing for RNF213 mutations in this study, because in 2012, when this study was started, it was not so common to test for RNF213 mutations in any hospital as it is today. Further studies on the impact of RNF213 mutations on the phenotype and outcome in asymptomatic moyamoya disease should be considered in the future.…”