Comparison of blood velocity between Transcranial Doppler and numerical method in the patient-specific Circle of Willis with aneurysm

2019 ◽  
Vol 30 (4) ◽  
pp. 427-438
Author(s):  
Mahsa Jahed ◽  
Farzan Ghalichi ◽  
Mehdi Farhoudi
Keyword(s):  
Numerical Method ◽  
Transcranial Doppler ◽  
Blood Velocity ◽  
Circle Of Willis ◽  
Patient Specific

Three-dimensional hemodynamics analysis of the circle of Willis in the patient-specific nonintegral arterial structures

2016 ◽  
Vol 15 (6) ◽  
pp. 1439-1456 ◽  
Author(s):  
Xin Liu ◽  
Zhifan Gao ◽  
Huahua Xiong ◽  
Dhanjoo Ghista ◽  
Lijie Ren ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Circle Of Willis ◽  
Patient Specific

scholarly journals Analyzing Circle of Willis blood flow in ischemic stroke patients through 3D Stroke Arterial Flow Estimation

2017 ◽  
Vol 23 (4) ◽  
pp. 427-432 ◽  
Author(s):  
Aichi Chien ◽  
Fernando Viñuela
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Flow Patterns ◽  
Circle Of Willis ◽  
Arterial Flow ◽  
Patient Specific ◽  
Collateral Flow ◽  
Flow Data ◽  
Time Resolved ◽  
Flow Estimation

Background The objective of ischemic stroke (IS) treatment is to achieve revascularization in cerebral arteries to restore blood flow. However, there is no available method to extract arterial flow data from clinical CTA images. We developed 3D Stroke Arterial Flow Estimation (SAFE), which provides blood flow data throughout the Circle of Willis based on 3D CTA and allows comparison of arterial flow distribution in the brain. Methods We implemented a newly developed 3D vascular reconstruction algorithm for clinical stroke CTA images. Based on the patient-specific vascular structure, SAFE calculates time-resolved blood flow information for the entire Circle of Willis and allows quantitative flow study of IS cases. Clinical IS cases are presented to demonstrate the feasibility. Four patients with CTA images and CT perfusion data were studied. To validate the SAFE analysis, correlation analysis comparing blood flow at the MCA, ICA, and BA was performed. Results Different blood flow patterns were found in individual IS patients. Altered flow patterns and high collateral flow rates were found near occlusions in all cases. Quantitative comparison of blood flow data showed that SAFE obtained flow data and CTP were significantly correlated and provide complementary information about cerebral blood flow for individual patients. Conclusions We present SAFE analysis for collecting detailed time-resolved cerebral arterial flow data in the entire Circle of Willis for IS. Further study with more cases may be important to test the clinical utilization of SAFE and helpful to the study of the underlying hemodynamics of stroke.

Development of a Numerical Method for Patient-Specific Cerebral Circulation Using 1D–0D Simulation of the Entire Cardiovascular System with SPECT Data

2015 ◽  
Vol 44 (8) ◽  
pp. 2351-2363 ◽  
Author(s):  
Hao Zhang ◽  
Naoya Fujiwara ◽  
Masaharu Kobayashi ◽  
Shigeki Yamada ◽  
Fuyou Liang ◽  
...  
Keyword(s):  
Cardiovascular System ◽  
Numerical Method ◽  
Cerebral Circulation ◽  
Patient Specific

scholarly journals A novel method for improving the accuracy of MR-derived patient-specific vascular models using X-ray angiography

2021 ◽  
Author(s):  
John D. Horn ◽  
Zbigniew A Starosolski ◽  
Michael J. Johnson ◽  
Avner Meoded ◽  
Shaolie S. Hossain
Keyword(s):  
Mr Imaging ◽  
Cerebral Artery ◽  
Stroke Risk ◽  
Anterior Cerebral Artery ◽  
Imaging Modality ◽  
Circle Of Willis ◽  
Patient Specific ◽  
X Ray ◽  
Novel Method ◽  
Adjusted Model

MR imaging is a noninvasive imaging modality that is commonly used during clinical follow up and has been widely utilized to reconstruct realistic 3D vascular models for patient-specific analysis. In a recent work, we utilized patient-specific hemodynamic analysis of the circle of Willis to noninvasively assess stroke risk in pediatric Moyamoya disease (MMD)—a progressive steno-occlusive cerebrovascular disease that leads to recurrent stroke. The objective was to identify vascular regions with critically high wall shear rate (WSR), signifying elevated stroke risk. However, sources of error including insufficient resolution of MR images can negatively impact vascular model accuracy, especially in areas of severe pathological narrowing, and thus diminish clinical relevance of simulation results, as local hemodynamics are sensitive to vessel geometry. We have developed a novel method to improve the accuracy of MR-derived 3D vascular models utilizing 2D X-ray angiography (XA), which is considered the gold standard for clinically assessing vessel caliber. In this workflow, ″virtual angiographies″ (VA) of 3D MR-derived vascular models are conducted, producing 2D projections that are compared to corresponding XA images guiding the local adjustment of modeled vessels. This VA-comparison-adjustment loop is iterated until the two agree, as confirmed by an expert neuroradiologist. Using this method, we generated models of the circle of Willis of two patients with a history of unilateral stroke. Blood flow simulations were performed using a Navier-Stokes solver within an isogeoemtric analysis framework and WSR distributions were quantified. Results for one patient show as much as 45% underestimation of local WSR in the stenotic left anterior cerebral artery (LACA) and up to a 60% underestimation in the right anterior cerebral artery when using the initial MR-derived model compared to the XA-adjusted model, emphasizing the need for verifying improved accuracy of the adjusted model. To that end, vessel cross-sectional areas of the pre- and post-adjustment models were compared to those seen in 3D CTA images of the same patient. CTA has superior resolution and signal to noise ratio compared to MR imaging but is not commonly used in clinic due to radiation exposure concerns, especially in pediatric patients. While the vessels in the initial model had normalized root mean squared deviations (NRMSDs) ranging from 26% to 182% and 31% to 69% in two patients with respect to CTA, the adjusted vessel NRMSDs were comparatively smaller (32% to 53% and 11% to 42%). In the mildly stenotic LACA of patient 1, the NRMSDs for the pre- and post-adjusted models were 49% and 32%, respectively. These findings suggest that our XA-based adjustment method can considerably improve the accuracy of vascular models, and thus, stroke-risk prediction. An accurate individualized assessment of stroke risk would be of substantial clinical benefit because it would help guide the timing of preventative surgical interventions in pediatric MMD patients.

Abstract TMP103: New Blood Velocity Indices Can Improve the Accuracy of Transcranial Doppler to Detect Vasospasm After Subarachnoid Hemorrhage

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Jaiyoung Ryu ◽  
Xiao Hu ◽  
Shawn C Shadden
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Transcranial Doppler ◽  
Cerebral Autoregulation ◽  
Blood Velocity ◽  
Arterial Blood Flow ◽  
Flow Rates ◽  
Arterial Blood ◽  
Basilar Arteries

Background and Objectives: Early diagnosis of vasospasm after subarachnoid hemorrhage (SAH) can prompt aggressive treatment and improve neurological outcomes. Transcranial Doppler (TCD) is the only diagnosis modality that is noninvasive and available bedside. The purpose of this study was to numerically evaluate the relevance of various blood velocity indices in detection of unbalanced cerebral blood flow due to vasospasm, and to improve the accuracy of diagnosis using TCD. Methods: We employed a well-validated numerical model of arterial blood flow coupled with a sophisticated intracranial model to generate a cerebral blood flow database. Anterior (MCA and/or ACA) and posterior (PCA and/or basilar arteries) vasospasms were considered under normal and impaired cerebral autoregulation conditions. For each case, mean blood velocities and their ratios between ipsilateral and contralateral, downstream and upstream, and anterior and posterior arteries were monitored during the progress of vasospasm. Results: Blood velocities at vasospastic arterial segments demonstrated non-monotonic behavior, i.e. the velocities increased initially with mild and moderate vasospasm, however further vasospasm leads to decreasing values. This may lead to false-negative decisions clinically. Blood flow rates, however, decreased monotonically at the affected arteries. Blood velocities upstream of the vasospastic artery decreased in proportion to the blood flow rates (e.g. for MCA vasospasm, 30% and 20% reduction at ICA and CCA). For all vasospasm locations considered, normalization of velocities by upstream and contralateral velocities provided more robust detection. Moreover, the improvements were most compelling in cases with impaired cerebral autoregulation. Conclusions: The velocity indices and diagnosis strategy proposed in this study can improve the accuracy of TCD diagnosis for cerebral vasospasm. These indices are particularly effective in cases of severe vasospasm where traditional indices (e.g. absolute velocities, Lindegaard index) become problematic.

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