Diagnostic Ability Of Combined Multiple Modalities By Dual-Source CTA For Chronic Total Occlusion Of Lower Extremity Arteries:A Comparative Study With DSA

Objective To investigate the effectiveness of dual-source CTA routine scan combined with delayed scan and the reverse attenuation gradient sign of CT value in the diagnosis of chronic total occlusion of lower extremity arteries with DSA as the gold standard.Methods A total of 120 patients who underwent dual-source CTA examination of lower extremity arteries in our hospital from January 2019 to March 2022 and underwent DSA examination within one week later were included in the study.CTA routine scan showed that the lumen of local artery was completely unseen in all 120 patients or showed complete occlusion,Delayed scan of lower extremity arteries was performed on the above-mentioned patients,and CT values were measured to determine whether there were signs of reverse attenuation gradient.Taking DSA as the gold standard,CTA routine scan,CTA routine scan combined with delayed scan,CTA routine scan combined with the reverse attenuation gradient sign of CT value,CTA routine scan combined with delayed scan and the reverse attenuation gradient sign of CT value were used for diagnosis.Mc Nemar test was used to compare the detection rate,and Kappa test was used for consistency.The specificity and diagnostic coincidence rate of different CTA methods in the diagnosis of total arterial occlusion of lower extremity were calculated.Results Among the 120 patients,there were 236 locations of blood vessels diagnosed as complete occlusion by dual-source CTA routine scan,202 locations of blood vessels were diagnosed as total occlusion by DSA,and 34 locations of blood vessels were diagnosed as severe stenosis;CTA routine scan combined with delayed scan,CTA routine scan combined with the reverse attenuation gradient sign of CT value,CTA routine combined with delayed scan and the reverse attenuation gradient sign of CT value in the diagnosis identified 223,218 and 207 of the 236 locations of blood vessels as completely occluded blood vessels,respectively.Mc Nemar test results showed that the detection rate of DSA for complete arterial occlusion was different from the detection rate of CTA routine scan combined with delayed scan and CTA routine scan combined with the reverse attenuation gradient sign of CT value(p < 0.001);Kappa were 0.514 and 0.658,indicating the two diagnostic results were moderate agreement.The detection rate of DSA for arterial occlusion was not different from the detection rate of CTA routine combined with delayed scan and the reverse attenuation gradient sign of CT value(p = 0.063),so there was no difference in the results of the two methods.Kappa=0.908,indicating almost perfect agreement.The specificity of CTA routine scan,CTA routine scan combined with delayed scan,CTA routine scan combined with the reverse attenuation gradient sign of CT value,CTA routine combined with delayed scan and the reverse attenuation gradient sign of CT value in the diagnosis of complete occlusion of lower extremity arteries were 0%(Only segments diagnosed as completely occluded by CTA routine scan were included in this study),38.2%,52.9%,and 85.3%.The diagnostic coincidence rates of the four methods were 85.6%,91.1%,93.2% and 97.9%,respectively.The specificity and diagnostic coincidence rate were the highest with CTA routine combined with delayed scan and the reverse attenuation gradient sign of CT value followed by CTA routine scan combined with the reverse attenuation gradient sign of CT value,followed by CTA routine scan combined with delayed scan;CTA routine scan was the lowest.Conclusion Dual-source CTA routine scan combined with delayed scan and the reverse attenuation gradient sign of CT value can significantly improve the diagnostic ability of CTA for chronic total occlusion of lower extremity arteries.