| Objective:To investigate the effect of CT attenuation correction on image quality,diagnostic performance of coronary artery disease and measurement of left ventricular function parameters in SPECT/CT gated myocardial perfusion imaging.Methods:（1）A total of 85 suspected or confirmed CAD patients with complete clinical data and imaging data were collected from July 2018 to December 2020 in Affiliated Hospital of Youjiang Medical University for Nationalities as the research subjects.There were 45males and 40 females,39 patients with normal BMI and 46 patients with high BMI.All patients underwent 99mTc-MIBI SPECT/CT rest GMPI and the ECHO examination should be perfected within one week before and after this examination and the CAG examination was performed in two months before and after.（2）NOAC and CTAC images were reconstructed from GMPI of 85 patients,compare the difference of myocardial radioactivity count in each wall of left ventricle in bullseye image between the two groups,and then stratified comparisons were made by gender and body mass index.（3）Taking CAG results as the"gold standard"for CAD diagnosis,compare the diagnostic efficiency of NOAC and CTAC images for CAD,and then the stratified comparisons were made by gender and body mass index.（4）Using QGS software to process GMPI data,and the left ventricular function parameters of NOAC and CTAC were obtained respectively,including EDV,ESV and LVEF.The left ventricular function parameters measured by NOAC and CTAC were compared.Then the correlation and consistency between GMPI and ECHO in measuring left ventricular function parameters were investigated.Results:（1）In the NOAC image,the myocardial radioactivity counts of the inferior wall and inferoseptal wall in male patients were lower than those in female patients（P<0.05）.The myocardial radioactivity counts of the inferior wall in high BMI patients was lower than that of normal BMI patients（P<0.05）.There was no significant difference in the myocardial radioactivity counts of apex,anterior wall,anteroseptal wall,anterolateral wall and inferolateral wall among patients with different genders and different BMI（P>0.05）.The myocardial radioactivity counts of inferior wall,inferoseptal wall and inferolateral wall in CTAC images were higher than those in NOAC images（P<0.05）.The apex,anterior wall and anterolateral wall myocardial radioactivity counts of CTAC were lower than those of NOAC images（P<0.05）.There was no significant difference in anteroseptal wall myocardial radioactivity count（P>0.05）.The difference of CTAC and NOAC radioactivity counts in inferior wall and inferoseptal wall was greater in males than in females（P<0.05）.The difference of CTAC and NOAC radioactivity counts in inferior wall was greater in high BMI patients than normal BMI patients（P<0.05）.Compared with NOAC images,78.8%CTAC images showed significantly increased radioactivity distribution in inferior wall,with a higher proportion in males than females（P<0.05）,the proportion of patients with high BMI was higher than those with normal BMI（P<0.05）.And 60.0%CTAC images showed significantly increased radioactivity distribution in inferoseptal wall,with a higher proportion in males than females（P<0.05）.（2）In the total sample,the sensitivity,specificity and accuracy of NOAC and CTAC diagnostic CAD were 81.8%vs84.1%,56.1%vs75.6%and69.4%vs80.0%,respectively.Compared with NOAC,the specificity of CTAC was improved（P<0.05）,and the differences in sensitivity and accuracy were not statistically significant（P>0.05）.In males and high BMI patients,CTAC improved the specificity of GMPI for CAD diagnosis（P<0.05）,the sensitivity was slightly reduced and the accuracy was slightly improved,but the difference was not significant（P>0.05）.In females and normal BMI patients,the sensitivity,specificity and accuracy of NOAC and CTAC for CAD diagnosis were not significantly different（P>0.05）.The sensitivity,specificity and accuracy of NOAC+CTAC combined imaging for CAD diagnosis were 90.9%,78.1%and 84.7%,respectively.Compared with NOAC imaging,both specificity and accuracy were significantly improved（P<0.05）,and the sensitivity was also slightly increased,but the difference was not significant（P>0.05）.（3）The EDV,ESV and LVEF measured by CTAC and NOAC were（93.48±20.34）ml and（93.61±20.38）ml,（43.53±15.68）ml and（43.38±16.26）ml,（54.14±9.30）%and（54.54±9.80）%,with no statistically significant difference（all P>0.05）.The EDV,ESV and LVEF measured by ECHO were（88.22±18.44）ml,（35.59±13.58）ml and（60.34±9.65）%,respectively.EDV and ESV measured by ECHO were lower than GMPI（all P<0.05）,and LEVF was higher than GMPI（P<0.05）.The correlation coefficients of EDV,ESV and LVEF measured by GMPI and ECHO were 0.88,0.87and0.78,and with good consistency.Conclusion:（1）CTAC can increase the distribution of myocardial radioactivity in the inferior wall,inferoseptal wall and inferolateral wall,reduced the distribution of radioactivity in the apex,anterior wall and anterolateral wall,no effect on anteroseptal wall.The effects of CTAC on the myocardial radioactivity count of GMPI images were different in patients with different genders and different BMI.（2）CTAC can improve the specificity of SPECT/CT GMPI for CAD diagnosis,not reduce the sensitivity,the gains were greater in males and high BMI patients.Combined with the patient’s clinical data,and comprehensive analysis of NOAC and CTAC images can further improve the diagnostic efficiency of MPI.（3）The left ventricular function parameters measured by SPECT/CT GMPI were not affected by CTAC,the results showed good correlation and consistency with ECHO. |
