Quantitative Evaluation Of Postoperative Perfusion Recovery In Patients With Severe Chronic Internal Carotid Artery Stenosis By Multimodal MRI

Objective:Using multimodal magnetic resonance technology,including time of flight magnetic resonance angiography?TOF-MRA?,3D arterial spin labeling?3D-ASL?,and territory arterial spin labeling?T-ASL?et al,to quantitatively evaluate the status of blood perfusion recovery before and after recanalization in patients with chronic severe internal carotid artery stenosis,and to explore the relationship between collateral circulation based on magnetic resonance imaging and postoperative perfusion recovery after recanalization.Methods:A total of 20 patients with severe chronic internal carotid artery stenosis or occlusion?stenosis degree?70%?confirmed by high resolution magnetic resonance imaging?HR-MRI?,computed tomography angiography?CTA?,and transcranial doppler?TCD?,in the First Hospital of Jilin University from January 2018 to January2020 were recruited,and vascular recanalization was performed in our hospital.Postoperative revascularization was successfully achieved.All patients received time of flight magnetic resonance angiography?TOF-MRA?,3D arterial spin labeling?3D-ASL?,territory arterial spin labeling?T-ASL?and other examinations within 5 days before and within 7 days after recanalization.We evaluated the preoperative collateral circulation and its correlation with the postoperative perfusion recovery of the patients by using the perfusion volume?PV?based on the preoperative T-ASL image,the ATA score and rCBF value based on the preoperative 3D-ASL image,the ACA-PCOA score based on the preoperative MRA image,the diameter and variation of the blood vessels in the circle of Willis,etc.The general clinical data and risk factors of cerebrovascular diseases of the patients were analyzed,and the image data of the patients were processed in the following ways:?1?Using the software Matlab?The MathWorks,Inc.?to semi-automatic delineation and segmentation of the preoperative and postoperative T-ASL perfusion areas of ICA on the affected side,ICA on the benign side and VBA respectively.The perfusion volume ratios of ICA on the benign side,ICA on the affected side and VBA before and after recanalization were calculated.?2?In GE AW workstation 4.5,use Functool tools for preoperative and postoperative 3D-ASL image on PLD=2.5s ACA/MCA/PCA of regional cerebral blood flow?CBF?,and calculate the rCBF and?rCBF,images according to the ASPECT level.?3?Two radiologists are requested to conduct double-blind ATA scores on the same patient's 3D-ASL PLD=1.5s and PLD=2.5s images respectively.If the scores are inconsistent,the results can be obtained through negotiation.?4?Transfer the patient's image to GE AW 4.5 workstation,use the SUB tool to obtain the perfusion image silhouette of 3D-ASL PLD=2.5s and PLD=1.5s.Matlab software?The MathWorks,Inc.?is used for semi-automatic delineation and segmentation,and calculate the PV_sub ratio.?5?The integrity and degree of variation of the patient's circle of Willis were evaluated by the TOF-MRA sequence.The software Sante DICOM Viewer was used to measure the diameter of bilateral anterior cerebral artery A₁ segment?ACA A₁?,anterior communicating artery?ACoA?,bilateral posterior cerebral artery P₁ segment?PCA P₁?and posterior communicating artery?PCoA??unit:mm?.The mean value of the same segment of vessel was calculated twice,and ACA-PCoA score was obtained at the same time.Results:1.It is feasible to detect postoperative perfusion recovery in patients with severe chronic internal carotid artery stenosis with T-ASL,and there is a significant difference in preoperative and postoperative perfusion volume ratio?P<0.05?.In terms of rCBF value,there were 3 delineated regions?ACA/MCA?with significant differences in the postoperative value of CBF?P<0.05?.2.Occlusion side and healthy side perfusion volume ratio values(?PV_ip ratio and?PV_coo ratio)were positively correlated with ATA score,significant correlation?P<0.05?.3.The value of preoperative PV_sub with?PV_ip thewire were positively correlated,significant correlation?P<0.01?.4.ACA-PCoA grouping is no correlation with?PV,and the regions of ACA/MCA?rCBF are correlated with ACA-PCoA group?P<0.05?.5.ACoA?PV,bilateral PCoA?PV,?rCBF,between open and closed group no significant difference?P>0.05?.6.There was a certain correlation between the vessel diameter of circle of Willis and collateral circulation compensation:the vessel diameter of benign side ACA A₁ was correlated with PV_co ratio before and after surgery?P<0.05?.ACoA diameter was significantly correlated with preoperative PV_co ratio and?PV_co ratio?P<0.05?.PCA P₁ diameter in the occlusion side was significantly correlated with preoperative PV_vbaba ratio?P<0.05?.Conclusions:Multimodal magnetic resonance technique has good clinical value in evaluating the vascular and intracranial perfusion of patients with severe chronic internal carotid artery stenosis.The formation of good collateral circulation in patients with severe chronic internal carotid artery stenosis is correlated with the recovery of the perfusion area of the affected side and the recovery of CBF value in the corresponding perfusion area after vascular recanalization.To a certain extent,the recovery of postoperative blood perfusion can be estimated based on the results of the examination of patients with multi-mode magnetic resonance technique before surgery.