Therapeutic Evaluation Of Intravascular Stenting In Intracranial Atherosclerotic Stenosis By SPECT Brain Perfusion Imaging

Intracranial atherosclerotic stenosis (IAS) is a ischemic cerebrovasculardisease with high-risk and high incidence, and it is one of the important reasons inthe occurrence and recurrence of ischemic stroke (IS). In European and Americancountries, IAS accounts for about8%to10%of Ischemic stroke. The rate ofincidence in Asians is much higher, about22%to26%. The risk of the recurrenceof ischemic stroke in the patients with symptomatic intracranial atheroscleroticstenosis is about10%to50%. Even with optimal medical therapy, the rate ofrecurrence is still up to10%to24%.Endovascular treatment technology has developed from the initial simpleballoon expansion into the current intracranial stent-assisted angioplasty. From themechanism of ischemic stroke, intracranial stent-assisted angioplasty can onlyimprove cerebral blood flow perfusion in the treatment of decompensatedischemia, and it is of little significance for ischemic stroke caused by othermechanisms. so it has the greatest clinical values for the therapeutic implications to the most narrow-related intracranial artery atherosclerotic stenosis patients withbrain hypoperfusion. Currently, the indications for intracranial stent-assistedangioplasty, only considering from symptom-related vascular stenosis rate, are stillnot complete, and the examination of cerebral hemodynamics should become animportant part of preoperative evaluation. Intracranial stent-assisted angioplastyremains controversial with intensive medical treatment in the prevention ofrecurrent stroke of the patients with intracranial artery atherosclerotic stenosis.Long-term Therapeutic Effects and preoperative evaluation will be the focus andemphasis of the study.Objective: By use of SPECT brain perfusion imaging, the therapeutic effectsof symptomatic intracranial atherosclerotic stenosis (the patients were divided intolow and normal perfusion groups) would be assessed before and after intracranialstent-assisted angioplasty, and long-term efficacy evaluation would be made afterfollow-up to analyze the significance of the preoperative SPECT brain perfusionimaging grouping to preoperative assessment.Methods:42cases of symptomatic intracranial atherosclerotic stenosisconfirmed by DSA (the degree of stenosis>50%) patients were divided intohypoperfusion perfusion group and normal perfusion group through preoperativeSPECT brain perfusion imaging before intracranial stent-assisted angioplasty.3months after operation, the patients were examined with SPECT brain perfusionimaging again. By comparison before and after surgery, two groups both made theevaluation of the cerebral hemodynamic changes. After1year follow-up, wecompared low perfusion group with normal perfusion group in long-term efficacy,and analyzed the guiding significance of the preoperative SPECT brain perfusionimaging grouping for preoperative evaluation.Results: The incidence of symptoms was statistically related to perfusion: low perfusion commonly caused ischemic stroke and ischemic events with normalperfusion were generally TIA （P＜0.01）. The perfusion was improvedsignificantly (P <0.01) in low perfusion group compared with preoperative, and noobvious improvement in the normal perfusion group was observed compared withpreoperative (P=0.059). The postoperative follow-up indicated that the incidenceof recurrent TIA in normal perfusion group is significantly higher than lowperfusion group (P <0.05). There is a significant difference between preoperativeModified Rankin Scales and postoperative for the low perfusion group（P <0.05）,suggesting that stent-assisted angioplasty can improve neurological function of thegroup.Conclusion: For the patients of symptomatic intracranial atheroscleroticstenosis with stenotic-related cerebral hypoperfusion, they usually present withischemic stroke, while patients with normal perfusion usually show TIA. Inhemodynamics, intracranial stent assisted angioplasty could clearly improve theperfusion of the intracranial regions with hypoperfusion, but no obviousimprovement was observed in the normal perfusion group. Postoperativefollow-up also indicated that intracranial stent-assisted angioplasty in theprevention of ischemic events in symptomatic intracranial atherosclerotic stenosishad a better effect in stenotic-related patients with low perfusion regions. There isa significant difference between preoperative Modified Rankin Scales andpostoperative for the low perfusion group, suggesting that stent-assistedangioplasty can improve neurological function of the group. Therefore,stenotic-related patients with low perfusion regions are at higher risk in stroke, andthey have more operative indications for intracranial stent-assisted angioplasty.And the preoperative assessment to symptomatic intracranial atheroscleroticstenosis by SPECT is quite important.