The Application Of 256-SCT Whole Brain CT Perfusion Imaging In Combination With Neck CT Angiography In The Diagnosis And Curative Effect Evaluation Of Ischemic Cerebrovascular Disease

Objective:To discuss the value of CT perfusion combined with head-neck CT angiography in the diagnosis and curative effect evaluation of Ischemic cerebrovascular disease through regular head scan,whole brain CT perfusion(CTP)imaging in combination with head-neck CT angiography with 256-SCT.To discuss the feasibility of regular head scan,whole brain CT perfusion imaging in combination with neck CT angiography mode to replace regular head scan,whole brain CT perfusion imaging in combination with head-neck CT angiography mode through comparing the quality differences of cranial vascular image between whole brain CTP and conventional head CTA.Material and methods:Conventional head scan,whole brain CT perfusion and head-neck CT angiography were performed on performed on 45 patients diagnosed as Ischemic cerebrovascular disease from April 2014 to February 2015 in our hospital,of which 32 patients underwent the same examinations after treatment.Perfusion scan data was transmitted to Philips IntelliSpace Portal,after image post-processing,whole brain perfusion pseudo color map and parameters were got.The parameters consist of cerebral blood volume(CBV),cerebral blood flow(CBF),mean transit time(MTT),time to peak(TTP)were measured in the perfusion abnormality area and the contralateral mirror area for three times.According to the time density curve,the perfusion scan data of artery peak cycle filled with contrast medium were retrospectively reconstructed with thin layer,using idose5 reconstruction algorithm.Thin layer reconstruction images of CTP and CTA were post-processed with vessels analysis software respectively,the images quality of volume rendering(VR),maximum density projection(MIP)were evaluated.All the data was analyzed with SPSS 17.0 software:lesions showed by regular CT scanning,whole brain CT perfusion scanning and head-neck CTA were recorded respectively.The perfusion parameters were compared between the abnormality area(ROI)and the contralateral mirror area before the treatment and after the treatment respectively.The perfusion parameters of the same abnormality area(ROI)were compared before and after treatment.rCBV,rCBF,rMTT,rTTP were calculated before and after treatment respectively.The quality differences of cranial vascular image between whole brain CTP and conventional head CTA were compared.The numbers of cranial vascular lesions found by CTP and conventional head CTA were recorded respectively.The average radiation dose of regular head scan,whole brain CT perfusion imaging in combination with the head-neck CT angiography mode and regular head scan,whole brain CT perfusion imaging in combination with neck CT angiography mode was calculate with ED(mSv)=DLP(mGy·cm)×k,k=0.0023mSv/(mGy·cm).The perfusion parameters value and effective dose was presented as means ± standard deviation using paired t test,Image quality score was presented as a level data using rank and inspection,the difference has statistically significant with P<0.05.Results:Of 45 patients,ischemic lesions were found in 17 cases with conventional CT scan,abnormal perfusion areas were found in 39 cases with whole brain CTP,different degree of vascular stenosis were found in 38 patient with head-neck CTA,perfusion abnormity was found in 5 cases without obvious head-neck vessel abnormity,lesions with different degree of vascular stenosis were found in 4 cases without perfusion abnormity.The parameters of CBF,MTT,TTP were significantly different between the affected side and the contralateral mirror side(P<0.05)before treatment,CBF in the affected side decreased compared to the contralateral side,MTT,TTP prolonged.CBV has no significant differences(P>0.05),rCBF was 0.54,rMTT 1.62,rTTP 1.13,rCBV 0.99.The parameters of CBF,MTT were significantly different between the afifected side and the contralateral side(P<0.05)after treatment,CBV,TTP has no significant differences(P>0.05),rCBF was 0.90,rMTT 1.04,rTTP 1.01,rCBV 1.07,the difference of CBF,MTT,TTP in the affected side was reduced before and after treatment.The parameters of CBF,MTT,TTP were significantly different before and after treatment in the affected side(P<0.05).CBF increased,MTT and TTP shortened after treatment.The quality of VR image was significantly different between whole brain CTP and conventional head CTA(P<0.05),conventional head CTA was better,MIP image quality has no significant differences(P>0.05).Both CTP and head CTA showed 32 lesions with different degree of vascular stenosis in 25 patients.The average radiation dose of regular head scan,whole brain CT perfusion imaging in combination with the head-neck CT angiography was 6.71±0.14mSv,the average radiation dose of regular head scan,whole brain CT perfusion imaging in combination with neck CT angiography was 5.74±0.15mSv,The difference was statistically significant.Conclusion:The sensitivity of the whole brain CT perfusion imaging washigher than conventional CT scan in the diagnosis of ischemic cerebrovascular disease.By whole brain CT perfusion imaging,the perfusion parameters(CBV,CBF,MTT,TTP)and Perfusion pseudo color map can be got to reflect brain hemodynamic changes of patients with ischemic encephalopathy.CTA can display the scope and degree of vascular lesions.It was important significant to combine the two scan methods in diagnosis and curative effect evaluation.Cranial vascular imaging reconstructed by whole brain CT perfusion can achieve the same diagnostic ability of conventional head CTA and can replace it.So regular head scan,whole brain CT perfusion imaging in combination with the neck CT angiography mode can replace regular head scan,whole brain CT perfusion imaging in combination with head-neck CT angiography mode to reduce radiation dose absorbed by patients and wear of the machine.