Hemodynamic characteristics of vertebrobasilar artery fenestration combined with vertebrobasilar dolichoectasia: a study based on magnetic resonance angiography.

Am J Nucl Med Mol Imaging 2024;14(4):253-260 www.ajnmmi.us /ISSN:2160-8407/ajnmmi0158878 Original Article Hemodynamic characteristics of vertebrobasilar artery fenestration combined with vertebrobasilar dolichoectasia: a study based on magnetic resonance angiography Xiao-Qin Chen1, Jie Jiang2, Jian Xing3, Zhao-Kai Ming4, Min Zhu3, Quan Bao3, Ming-Cheng Hu3 Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China; 2Department of Infectious Diseases, Mudanjiang Forestry Central Hospital, Mudanjiang, Heilongjiang, China; 3Department of Magnetic Resonance Imaging, Hongqi Hospital Affiliated to Mudanjiang Medical University, Mudanjiang, Heilongjiang, China; 4Department of Radiology, The First Hospital of Qiqihar, Qiqihar, Heilongjiang, China 1 Received July 1, 2024; Accepted July 31, 2024; Epub August 25, 2024; Published August 30, 2024 Abstract: Purpose: This study delves into the hemodynamic characteristics of Vertebrobasilar Artery Fenestration (VBAF) combined with Vertebrobasilar Dolichoectasia (VBD) using Magnetic Resonance Angiography (MRA). By summarizing the hemodynamic features and identifying high-risk populations, we aim to provide insights for clinical treatment. Methods: Utilizing MRA images as a foundation, arterial three-dimensional geometric models were constructed. A total of 22 cases were categorized into control, S, L, U, and Spiral groups, and numerical simulation analysis of the vessels was conducted using computational fluid dynamics methods. Results: Hemodynamic parameters of the VBAF combined with the VBD model were obtained, including blood flow velocity, oscillatory shear stress (OSI), wall shear stress (WSS), and aneurysm formation indicator (AFI). The V, OSI, and WSS indices of the L, U, and Spiral groups were significantly higher than those of the control group (P < 0.05). High-speed blood flow, elevated WSS, and increased OSI in these groups were concentrated at the fenestration site, with scattered distribution along the tortuous vertebral artery and basilar artery segments, accompanied by significant differences in the parameters of the bilateral vertebral arteries. Conclusion: This preliminary investigation identifies the L, U, and Spiral groups as high-risk populations. Abnormal hemodynamics may lead to a vicious cycle in vascular wall pathology, increasing the likelihood of adverse events such as cerebral infarction. Clinical attention should focus on individuals within these groups and their corresponding vascular regions. Keywords: Vertebrobasilar artery fenestration, vertebrobasilar dolichoectasia, hemodynamics, turbulence, cerebral infarction Introduction Cerebral artery fenestration is a congenital vascular anomaly resulting from the failed fusion of embryonic blood vessels, characterized by arterial lumen division and reconnection distally to form a single lumen, involving local replication of endothelial cells and media splitting [1, 2]. Cerebral artery fenestration can occur in multiple vessels, with a predilection for the vertebrobasilar arteries [3]. Vertebrobasilar Artery Fenestration (VBAF) typically ranges from 1-5 mm, and due to its small diameter, it may often be an easily overlooked cerebrovascular abnormality in clinical practice. While VBAF is rare, its association with cerebral infarction (CI), aneurysms, arteriovenous malformations, and subarachnoid hemorrhage has been reported [4]. Vertebrobasilar dolichoectasia (VBD) represents an arterial pathology characterized by the vertebral or basilar arteries’ elongation, dilation, or tortuosity. VBD can lead to alterations in intracranial hemodynamics, subsequently resulting in corresponding clinical symptoms closely associated with posterior circulation ischemia and, in severe cases, cerebral infarction. Studies have indicated that hemodynamic alterations caused by morphological changes in the vertebral or basilar arteries are significant contributors to adverse events such as CI [5]. It is currently believed that the formation of VBD may result from the interaction between arterial wall pathology and vascular mechanics, with hemodynamic forces playing a pivotal role [6]. VBD formation factors include arterial wall structure, vascular wall pressure, and wall shear stress [7]. Both VBAF and VBD alter the geometric characteristics of arteries, leading to changes in internal flow dynamics such as the formation of high-viscosity blood and stasis, which affect the biological function of endothelial cells lining the arterial walls and predispose to pathological thrombotic events, culminating in adverse events like CI [8]. Therefore, analyzing relevant hemodynamic parameters of VBAF combined with VBD is imperative. This study conducts a hemodynamic analysis of VBAF combined with VBD based on MRA, extracting hemodynamic parameters of the VBAF combined with the VBD model to understand the hemodynamic changes within abnormal vessels, extract and summarize parameter characteristics, and provide relevant evidence for clinical treatment and early intervention. https://doi.org/10.62347/TLNN8316 Vertebrobasilar artery fenestration and dolichoectasia: hemodynamic insights from MRI Materials and methods Data collection This study selected 22 patients diagnosed with VBAF combined with VBD who underwent MRA scans at the Hongqi Hospital, affiliated with Mudanjiang Medical University, between October 2022 and December 2023. Head MRA was conducted using a Philips Intera 3.0 T superconducting MR scanner with an 8-channel head coil. MRA scan parameters were as follows: TR 32 ms, TE 4 ms, slice thickness 5 mm, slice gap 1 mm, matrix 256×256, FOV 240 mm×240 mm. In previous studies, the vertebral artery (VA) or basilar artery (BA) were often separately analyzed before diagnosing vertebrobasilar dolichoectasia (VBD). There is no consistent imaging standard for defining and classifying VBD, and there has been no proposed comprehensive classification system for VBD (considering VA and BA as a whole) [9]. Building upon prior research, this study categorizes VBD based on overall vascular morphology into four preliminary types (Figure 1): S, L, U, and spiral types. The S-type exhibits doublereversed twists in VA and/or BA, resembling the letter “S”. U-type and L-type predominantly involve BA deviating from the brainstem, with one side of VA crossing to the contralateral side and joining the contralateral VA to form the BA, resembling the letters “U” and “L”. The spiral type involves severe twisting and turning of VA and/or BA, resembling a spiral shape. Inclusion criteria [10]: (1) Diagnosed with VBAF (S, L, U, and Spiral groups) via head MRA; (2) Met one of the following criteria: the length of the basilar artery exceeds 29.5 mm, or the lateral deviation distance exceeds 10 mm from the perpendicular line between the origin and bifurcation of the basilar artery; the intracranial segment of the vertebral artery exceeds 23.5 mm in length, or any deviation distance of t (...truncated)