Evaluating recanalization of relevant lenticulostriate arteries in acute ischemic stroke using high-resolution MRA at 7T

Abstract

Background Occluded major intracranial arteries can spontaneously recanalize in patients with acute ischemic stroke mainly due to embolic mechanisms. However, it remains unknown whether recanalization can occur in perforating arteries, such as lenticulostriate arteries. Therefore, in the present study, we assessed changes suggesting recanalization of the lenticulostriate arteries in patients with acute ischemic stroke of the lenticulostriate artery territory using high-resolution magnetic resonance angiography (HR-MRA) at 7T. Methods We prospectively examined 39 consecutive patients with acute infarcts confined within the lenticulostriate artery territory. Using a 7T scanner during the acute period and one month thereafter, we evaluated imaging findings indicating the recanalization of the relevant lenticulostriate arteries, following which we examined differences in other imaging findings and clinical characteristics between patients with/without recanalization. Results HR-MRA findings suggestive of recanalization (i.e. patent lenticulostriate arteries within acute infarct lesions with/without hemorrhagic changes) were observed in 8 (25%) of 32 patients who were eligible for analyses. These findings were detected in three and five patients on the baseline and follow-up images, respectively. The lengths of relevant lenticulostriate arteries on the follow-up MRA were significantly larger in patients with recanalization than in those without ( P = 0.01). However, there were no significant differences in the infarct volume or clinical outcomes between the recanalization and non-recanalization groups. Conclusion HR-MRA at 7T revealed that recanalization of the relevant lenticulostriate arteries can occur in patients with acute ischemic stroke confined to the lenticulostriate artery territory.

The Potential Impact of Neuroimaging and Translational Research on the Clinical Management of Lacunar Stroke

“…Perforating arteries in lacunar strokes may be patent in pathology studies [8] and advanced 7T MRI techniques [27]. Increased blood flow on CT perfusion suggests recanalization of an embolic occlusion of a perforating artery [28].…”

“…Neuroimaging of lacunar stroke has the main advantage of shortening the time from symptoms onset to examination, providing imaging with high temporospatial accuracy and offering insights on the mechanisms occurring during infarction and on the course over time in longitudinal studies. However, imaging evidence has to be considered indirect in most cases, especially in SVD studies, as the small branches of perforating vessel are not visible, not even using high-definition MRI (although the main branches may be visualized using high resolution MRI angiography at 7T [27]). Much information provided by imaging studies is difficult to generalize and depends on many factors, including different criteria to define markers in imaging, acquisition protocols, processing software, and interobserver reliability.…”

Preliminary Study on the Application of Ultrahigh Field Magnetic Resonance in Moyamoya Disease

“…In this study, the resolution of TOF-MRA is almost comparable to DSA and the detectability of the arterial structures using 7.0 T TOF could be useful in noninvasive characterization of MMD. The advantages of TOF at 7.0 T include the increased SNR, longer T1 relaxation times augmenting the vessel-tissue contrast, and inherently hyperintense arterial vasculature at higher field strengths [ 19 – 21 ]. Specifically, on the small intracranial vessel of TOF-MRA, 7.0 T was shown to be sensitive to the slow-flowing blood within smaller peripheral vessels when using appropriate acquisition parameters [ 22 ], which makes it a powerful tool to diagnose MMD.…”

Imaging methods for surgical revascularization in patients with moyamoya disease: an updated review

“…Although 1.5-T and 3.0-T MRI are commonly used, ultrahigh field (7.0-T) MRI is a promising neuroimaging technique for the evaluating of MMD especially the risk of hemorrhage. The advantages of TOF at 7.0-T include the increased SNR, longer T1 relaxation times augmenting the vessel-tissue contrast, and inherently hyperintense arterial vasculature at higher field strengths [ 34 , 62 , 63 ]. There was no significant difference between 3.0-T MRI and 7.0-T MRI in depicting the main intracranial arteries, but 7.0-T MRI could excellently delineate the collateral network pathways in MMD and is better correlated with Suzuki’s stage [ 12 ].…”