Effect of Neck Size on the Inflow Magnitude Evaluated on 4D Flow MRI in Unruptured Internal Carotid Artery Aneurysms

AbstractCarotid endarterectomy (CEA) influences the carotid endoluminal anatomy, which results in hemodynamic changes before and after surgery. We investigated the hemodynamics of severe carotid artery stenosis before and after conventional endarterectomy with/without patch repair. An in vitro experiment utilizing carotid phantoms, which underwent a procedure that emulated CEA with/without the patch repair, was performed with a high-spatiotemporal resolution using 4D flow MRI. We evaluated an abnormal region of carotids, which consists of the normalized time-averaged wall shear stress (NTA|WSS|) and the oscillatory shear index (OSI), to account for continuous high-shear regions (high NTA|WSS| and low OSI) and chaotic low-shear regions, i.e., stenosis-prone regions (low NTA|WSS| and high OSI). The use of normalized hemodynamic parameters (e.g., NTA|WSS|) allowed comparison of diverse cases with different conditions of hemodynamics and vessel geometry. We observed that the stenosis-prone regions of the carotids with patches were noticeably larger than the corresponding regions in no-patch carotids. A large recirculating flow zone found in the stenosis-prone region of the internal carotid artery (ICA) of the postoperative carotids with patches partially blocks the flow path into ICA, and consequently the flow rate was not recovered after surgery unlike an expectation.

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Comparison of Hemodynamic Visualization in Cerebral Arteries: Can Magnetic Resonance Imaging Replace Computational Fluid Dynamics?

Journal of Personalized Medicine ◽

10.3390/jpm11040253 ◽

2021 ◽

Vol 11 (4) ◽

pp. 253

Author(s):

Minh Tri Ngo ◽

Ui Yun Lee ◽

Hojin Ha ◽

Ning Jin ◽

Gyung Ho Chung ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Cerebral Artery ◽

Internal Carotid ◽

Cerebral Arteries ◽

Resonance Imaging ◽

4D Flow Mri ◽

4D Flow ◽

Tof Mra ◽

Flow Mri

A multimodality approach was applied using four-dimensional flow magnetic resonance imaging (4D flow MRI), time-of-flight magnetic resonance angiography (TOF-MRA) signal intensity gradient (SIG), and computational fluid dynamics (CFD) to investigate the 3D blood flow characteristics and wall shear stress (WSS) of the cerebral arteries. TOF-MRA and 4D flow MRI were performed on the major cerebral arteries in 16 healthy volunteers (mean age 34.7 ± 7.6 years). The flow rate measured with 4D flow MRI in the internal carotid artery, middle cerebral artery, and anterior cerebral artery were 3.8, 2.5, and 1.2 mL/s, respectively. The 3D blood flow pattern obtained through CFD and 4D flow MRI on the cerebral arteries showed reasonable consensus. CFD delivered much greater resolution than 4D flow MRI. TOF-MRA SIG and CFD WSS of the major cerebral arteries showed reasonable consensus with the locations where the WSS was relatively high. However, the visualizations were very different between TOF-MRA SIG and CFD WSS at the internal carotid artery bifurcations, the anterior cerebral arteries, and the anterior communicating arteries. 4D flow MRI, TOF-MRA SIG, and CFD are complementary methods that can provide additional insight into the hemodynamics of the human cerebral artery.

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GDC Embolisation of Cavernous Internal Carotid Artery Aneurysms with Parent Artery Preservation

Interventional Neuroradiology ◽

10.1177/159101990000600403 ◽

2000 ◽

Vol 6 (4) ◽

pp. 291-298 ◽

Cited By ~ 2

Author(s):

S.J. Kim ◽

I.S. Choi

Keyword(s):

Carotid Artery ◽

Internal Carotid Artery ◽

Internal Carotid ◽

Mass Effect ◽

Parent Artery ◽

Total Occlusion ◽

Neck Size ◽

Presenting Symptoms ◽

Incomplete Occlusion

We evaluated the clinical and angiographic results of endosaccular treatment with Guglielmi detachable coils (GDCs) in 19 cases of cavernous internal carotid artery (ICA) aneurysms. The size of the aneurysms ranged from 10 to 30 mm (mean 18.4 mm) and neck size ranged from 2 to 15 mm (mean 6.7 mm). Intraluminal thrombosis was found in ten cases. Main presenting symptoms were related to mass effect in 17 cases including cranial nerve palsy, headache and vomiting. On initial GDC embolisation, total occlusion was obtained in two cases, subtotal in eight, and incomplete in nine. In two cases with incomplete occlusion, parent arteries were occluded with balloons or GDCs during or just after the procedure because of underlying diseases. A higher rate of initial occlusion was obtained in smaller and non-thrombosed aneurysms. Symptoms resolved or improved in all cases except one after initial treatment. No complication occurred related to the procedure. Follow-up angiography was obtained in 15 cases among which ten cases (66.7%) showed luminal recanalisation. Symptoms recurred in one case with luminal recanalisation. Incidence of recanalisation was similar in both large and giant aneurysms but higher in the thrombosed than non-thrombosed group. Retreatment was done in five cases with success. In conclusion, although embolisation of cavernous ICA aneurysms with GDCs was safe and effective in relieving symptoms, the incidences of initial incomplete occlusion and follow-up recanalisation were high. Therefore, we think judicious selection of the cases is necessary for endosaccular GDC embolisation in cavernous ICA aneurysms.

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CALCIFICATIONS OF THE INTRACRANIAL CAROTID ARTERY SELDOM CAUSE STENOSIS: A 4D FLOW MRI STUDY

10.26226/morressier.5ab8f560d462b8029238cd93 ◽

2018 ◽

Author(s):

Elias Johansson

Keyword(s):

Carotid Artery ◽

4D Flow Mri ◽

4D Flow ◽

Flow Mri ◽

Mri Study

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Improving Blood Flow Visualization of Recirculation Regions at Carotid Bulb in 4D Flow MRI Using Semi-Automatic Segmentation with ITK-SNAP

Diagnostics ◽

10.3390/diagnostics11101890 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1890

Author(s):

Minh Tri Ngo ◽

Ui Yun Lee ◽

Hojin Ha ◽

Jinmu Jung ◽

Dong Hwan Lee ◽

...

Keyword(s):

Blood Flow ◽

Carotid Artery ◽

Flow Visualization ◽

Automatic Generation ◽

4D Flow Mri ◽

4D Flow ◽

Recirculation Flow ◽

Bilateral Carotid ◽

Flow Mri ◽

Carotid Bulb

Assessment of carotid bulb hemodynamics using four-dimensional (4D) flow magnetic resonance imaging (MRI) requires accurate segmentation of recirculation regions that is frequently hampered by limited resolution. This study aims to improve the accuracy of 4D flow MRI carotid bulb segmentation and subsequent recirculation regions analysis. Time-of-flight (TOF) MRI and 4D flow MRI were performed on bilateral carotid artery bifurcations in seven healthy volunteers. TOF-MRI data was segmented into 3D geometry for computational fluid dynamics (CFD) simulations. ITK-SNAP segmentation software was included in the workflow for the semi-automatic generation of 4D flow MRI angiographic data. This study compared the velocities calculated at the carotid bifurcations and the 3D blood flow visualization at the carotid bulbs obtained by 4D flow MRI and CFD. By applying ITK-SNAP segmentation software, an obvious improvement in the 4D flow MRI visualization of the recirculation regions was observed. The 4D flow MRI images of the recirculation flow characteristics of the carotid artery bulbs coincided with the CFD. A reasonable agreement was found in terms of velocity calculated at the carotid bifurcation between CFD and 4D flow MRI. However, the dispersion of velocity data points relative to the local errors of measurement in 4D flow MRI remains. Our proposed strategy showed the feasibility of improving recirculation regions segmentation and the potential for reliable blood flow visualization in 4D flow MRI. However, quantitative analysis of recirculation regions in 4D flow MRI with ITK-SNAP should be enhanced for use in clinical situations.

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