Application Of CTP Combined With Multiphase CTA In Assessment Of Collateral Circulation In Patients With Intracranial Artery Stenosis

Objective: At present,intracranial artery stenosis(ICAS)is the most common cause of cerebral infarction in Asian population.Good collateral circulation can improve prognosis.In recent years,functional imaging combined with structural imaging to evaluate collateral circulation has become a research hotspot.As a noninvasive,rapid and repeatable method,multimodal CT has an important value in the evaluation of patients with ICAS.In this study,we analyzed the risk factors of symptomatic ICAS patients,and analyzed the relationship between collateral circulation and perfusion level through CT perfusion(CTP)imaging combined with multiphase CTA(m CTA),to explore its application value in patients with ICAS.Methods: In this study,120 patients with anterior circulation ICAS were divided into symptomatic group and non-symptomatic group according to whether there are symptoms of responsible vascular ischemia.34 of them completed CTP combined with m CTA.Evaluation of collateral level by using ASPECTS collateral circulation score,and the CBV,CBF,MTT,Tmax were obtained.r CBV,rCBF,r MTT and r Tmax were calculated by "affected side / healthy side".The differences of clinical risk factors,collateral circulation score and perfusion parameters between symptom group and non-symptom group were compared,and the effects of different collateral levels on intracranial perfusion were analyzed.Results:1.Clinical groups: A total of 120 patients with ICAS were enrolled,the average age was(67.55 ± 11.60)years old;66 patients in the symptom group and 54 patients in the non-symptom group;34 patients(18 patients in the symptom group and 16 patients in the non-symptom group)completed CTP combined with m CTA.2.General data: There was no significant difference in gender,age,diabetes,hypertension,malignant tumor,smoking and drinking between the symptom group and the non-symptom group(P > 0.05).3.Laboratory index: The coagulation and biochemical indexes of patients in symptom group and non-symptom group were compared.By multivariate analysis,D-Dimer(OR = 2.533,95% CI 1.063-6.032,P = 0.036)and apo B/AI(OR = 3.129,95% CI 1.250-7.835,P = 0.015)in the symptom group were significantly higher than in the non-symptom group.4.CTP parameters: Symptom group(18 cases): rCBF 0.52(0.48),r CBV 1.10(0.25),r Tmax 2.22(1.25)and r MTT(2.13 ± 0.89).Non-symptom group(16 cases):rCBF 0.76(0.59),r CBV 1.16(0.73),r Tmax 2.18(1.38)and r MTT(1.69 ± 0.66).rCBF in the symptom group was lower than that in the non-symptom group(P = 0.034).5.The level of collateral circulation and its influence on perfusion: the results showed that ASPECTS collateral circulation score in the symptom group was 3(1),lower than that in the non-symptom group 4(1.5),the difference was statistically significant(P=0.018).The perfusion parameters(rCBF,r CBV,r Tmax,r MTT)of the good collateral circulation group(19 cases)and the bad collateral circulation group(15 cases)were compared.rCBF 0.46(0.38),r CBV 1.04(0.18)of the bad collateral circulation group were lower than rCBF 0.79(0.33),r CBV 1.21(0.67)of the good collateral circulation group(P = 0.003,0.025).Conclusions:1.CTP combined with m CTA is helpful to early identify the risk of cerebral infarction recurrence in patients with ICAS and guide the clinical secondary prevention strategy.2.The increase of D-dimer and apo B/AI may be the independent risk factors of patients with symptomatic ICAS.3.The decrease of rCBF indicates the decompensation of intracranial perfusion in patients with ICAS;and the decrease of r CBV and rCBF indicates the poor collateral circulation,indicating the occurrence of acute ischemic events.4.Good collateral circulation can effectively improve intracranial perfusion and reduce the occurrence of acute ischemic events in patients with ICAS.