The Diagnostic Value Of Low Dose Of Dual-source CT Venography For Deep Venous Thrombosis

Objective To investigate the diagnostic value of low dose of dual-source indirect CT venography examination for DVT(Deep Venous Thrombosis)of lower extremities.Methods A total of 100 patients suspected DVT of the lower extremities ranged from 2 days to 2 months,including 37 males and 43 females,aged 26-84 years,with an average age of 48.23±5.31 years.Among them,A group,40 patients in group A were examine with low dose scanning,80 KV tube voltage,2.0 pitch,automatic tube current,and iterative reconstruction(IR).40 patients in group B were examined by coventional scanning,including 100 KV tube voltage,1.0 pitch,180 m As tube current,and filter back projection(FBP).The average radiation dose and image quality were compared between the two groups.The measurement data were compared by T test.Mann-Whitney U test was used to compare image quality grading data.All patients were examined by DSA within 3 day before and after CTV examination.The sensitivity and specificity of both CTV methods were calculated based on the gold standard of DSA.The sensitivity and specificity of both CTV methods were compared by Fisher’s Exact Probability Method.Kappa Consistency test was used to confirm the DVT results according to the examination of CTV and DSA.Mc Nemar test was used to check if there were any significant differences between two examinations.Results The mean radiation dose of patients in group A was 248.55±45.47 m Gy cm and that of group B was 672.93±170.16 m Gy cm,There was staistical difference between the two groups.The image quality of group Bore was higher than that of group A.There was no staistical difference between the two groups.Based on DSA,the sensitivity and specificity of DVT detection by lose dose CTV were 94.59% and 100%.Kappa=0.762,P=0.00<0.05,and the result of Mc Nemar test is P=0.25>0.05.The sensitivity and specificity of DVT detection by routine CTV were 97.37% and 100%.Kappa=0.844,P=0.00<0.05,and the result of Mc Nemar test is P=1.00>0.05.Conclusions Low dose of dual-source indirect CTV examination for DVT of lower extremity is feasible,which can significantly reduce radiation dose on the premise of guaranteeing image quality.This method can be used to observe and evaluate the property,size and extent of thrombus,and to diagnose whether the surrounding tissues of vascular is merged with other diseases.Low dose of dual-source indirect CTV examination has a high clinical value in the diagnosis of DVT of lower extremity.