Objective:To investigate the clinical application value of whole brain computed tomography perfusion(CTP)imaging combined with computed tomography angiography(CTA)on head and neck in treating chronic ischemic cerebrovascular disease(ICVD)by superficial temporal artery-middle cerebral artery(STA-MCA)bypass.Methods:Fifty patients with suspected chronic ICVD who admitted to Chengdu Second People's Hospital and Deyang People's Hospital(29 cases from Chengdu Second People's Hospital and 21 cases from Deyang People's Hospital)from May 2020 to October 2024 were selected.All patients underwent whole-brain CTP examination and CTA examination on head and neck before the surgery,and then,the preoperative assessment efficacy of the combination of the two examination for patients with STA-MCA surgical indication was analyzed.The changes of the CTP parameters[cerebral blood volume(CBV),cerebral blood flow(CBF),mean transit time(MTT),time to drain(TTD),and time to maximum(Tmax)]between the affected side and the healthy side before surgery,and between them after surgery,and these parameter of affected side between before and after surgery were compared respectively.The course and the anastomosis conditions of the bypass vessels were analyzed through CTA images.The CTP parameters of patients with postoperative cerebral hyperperfusion syndrome(CHS)were statistically analyzed.Then,the relationship between the changes of cerebral perfusion values on the affected side after surgery and CHS,as well as the follow-up situation,were analyzed.Results:In 50 patients with suspected chronic ICVD,34 patients with surgical indication of STA-MCA bypass were screened out by CTA combined with CTP,who existed severely narrowed or occluded blood vessels accompanied by reduced CTP,and other 16 cases who did not meet surgical indication of STA-MCA bypass were excluded.In 34 patients with chronic ICVD,the preoperative CBF value of affected side was lower than that of healthy side,and the preoperative MTT,TTD and Tmax values of affected side were all higher than those of the healthy side,and the differences were statistically significant(t=6.648,6.030,10.638,14.063,P<0.05),while there was not significant difference in CBV value between two sides(P>0.05).In the affected side,the postoperative CBF value was higher than preoperative CBF value,and the postoperative MTT,TTD and Tmax values were lower than preoperative these indicators,and the differences were statistically significant(t=8.578,7.166,11.321,11.912,P<0.05).There was no significant difference in the CBV value between before and after surgery(P>0.05).In 34 patients with chronic ICVD,there was not significant difference in CTP parameters between the affected side and the healthy side in 28 patients with chronic ICVD after 6 patients with CHS were excluded(P>0.05).The results of CTA showed that the diameter size and course of superficial temporal artery of all patients were clearly displayed,and the bypass vessels of them were unblocked,and the anastomoses of them were well developed.All 34 patients with chronic ICVD successfully completed unilateral STA-MCA bypass surgery.After the surgery,based on the clinical symptoms and the CTP reexamination results of the patients,it was determined that 6 patients(17.7%)were CHS,whose appearances were the CBF value of affected side was(60.81±5.79)ml/100(g·min),which was significantly higher than that[(53.30±5.21)ml/100(g·min)]of the healthy side.The MTT value of affected side was(2.9±0.82)s,which was significantly lower than that of the healthy side(4.2±1.1)s,and the differences were statistically significant(t=2.358,2.341,P<0.05).In the postoperative follow-up of 2 to 17 months for patients,there was not dead case,and the clinical symptoms of the most of patients were improved significantly,and there was no serious adverse events.Conclusion:Whole-brain CTP combined with CTA examination on head and neck is conducive to accurately determine the degree of vascular stenosis and cerebral perfusion before surgery,and screen patients with chronic ICVD who occurred indications of STA-MCA surgery,and can also assess the patency of bypass vessels,the recovery degree of cerebral perfusion,and the possibility of occurring CHS after surgery,which has important clinical guiding value.

Objective:To investigate the clinical application value of whole brain computed tomography perfusion(CTP)imaging combined with computed tomography angiography(CTA)on head and neck in treating chronic ischemic cerebrovascular disease(ICVD)by superficial temporal artery-middle cerebral artery(STA-MCA)bypass.Methods:Fifty patients with suspected chronic ICVD who admitted to Chengdu Second People's Hospital and Deyang People's Hospital(29 cases from Chengdu Second People's Hospital and 21 cases from Deyang People's Hospital)from May 2020 to October 2024 were selected.All patients underwent whole-brain CTP examination and CTA examination on head and neck before the surgery,and then,the preoperative assessment efficacy of the combination of the two examination for patients with STA-MCA surgical indication was analyzed.The changes of the CTP parameters[cerebral blood volume(CBV),cerebral blood flow(CBF),mean transit time(MTT),time to drain(TTD),and time to maximum(Tmax)]between the affected side and the healthy side before surgery,and between them after surgery,and these parameter of affected side between before and after surgery were compared respectively.The course and the anastomosis conditions of the bypass vessels were analyzed through CTA images.The CTP parameters of patients with postoperative cerebral hyperperfusion syndrome(CHS)were statistically analyzed.Then,the relationship between the changes of cerebral perfusion values on the affected side after surgery and CHS,as well as the follow-up situation,were analyzed.Results:In 50 patients with suspected chronic ICVD,34 patients with surgical indication of STA-MCA bypass were screened out by CTA combined with CTP,who existed severely narrowed or occluded blood vessels accompanied by reduced CTP,and other 16 cases who did not meet surgical indication of STA-MCA bypass were excluded.In 34 patients with chronic ICVD,the preoperative CBF value of affected side was lower than that of healthy side,and the preoperative MTT,TTD and Tmax values of affected side were all higher than those of the healthy side,and the differences were statistically significant(t=6.648,6.030,10.638,14.063,P<0.05),while there was not significant difference in CBV value between two sides(P>0.05).In the affected side,the postoperative CBF value was higher than preoperative CBF value,and the postoperative MTT,TTD and Tmax values were lower than preoperative these indicators,and the differences were statistically significant(t=8.578,7.166,11.321,11.912,P<0.05).There was no significant difference in the CBV value between before and after surgery(P>0.05).In 34 patients with chronic ICVD,there was not significant difference in CTP parameters between the affected side and the healthy side in 28 patients with chronic ICVD after 6 patients with CHS were excluded(P>0.05).The results of CTA showed that the diameter size and course of superficial temporal artery of all patients were clearly displayed,and the bypass vessels of them were unblocked,and the anastomoses of them were well developed.All 34 patients with chronic ICVD successfully completed unilateral STA-MCA bypass surgery.After the surgery,based on the clinical symptoms and the CTP reexamination results of the patients,it was determined that 6 patients(17.7%)were CHS,whose appearances were the CBF value of affected side was(60.81±5.79)ml/100(g·min),which was significantly higher than that[(53.30±5.21)ml/100(g·min)]of the healthy side.The MTT value of affected side was(2.9±0.82)s,which was significantly lower than that of the healthy side(4.2±1.1)s,and the differences were statistically significant(t=2.358,2.341,P<0.05).In the postoperative follow-up of 2 to 17 months for patients,there was not dead case,and the clinical symptoms of the most of patients were improved significantly,and there was no serious adverse events.Conclusion:Whole-brain CTP combined with CTA examination on head and neck is conducive to accurately determine the degree of vascular stenosis and cerebral perfusion before surgery,and screen patients with chronic ICVD who occurred indications of STA-MCA surgery,and can also assess the patency of bypass vessels,the recovery degree of cerebral perfusion,and the possibility of occurring CHS after surgery,which has important clinical guiding value.