Diagnostive Value Of 64-slice Spiral CT Combined Venography And Pulmonary Angiography In Pulmonary Embolism And Deep Venous Thrombosis

Objective:To evaluate the combined 64-slice spiral CT venography and pulmonary angiography(CTVPA) in the diagnosis of pulmonary embolism(PE) and deep venous thrombosis(DVT)Materials and methods:Form Aug 2006 to Mar 2009,106 patients with clinically suspected pulmonary embolism underwent CTVPA.Findings for PE and DVT were categorized as positive,negative and indeterminate.The distribution of PE and DVT were recorded.The CT density measurements were obtained in the thrombus of PE and DVT.The pulmonary bed were divided into six arterial zones:fisrt zone: pumlonary trunk;second zone:right and left pulmonary arteries;third zone:lober, interlober,anterio-medial and posterio- lateral trunk of the lower lobe of pulmonary arteries;fourth zone:segmental arteries:fifth zone:subsegmental;sixth zone:fifth,sixth-order pulmonary arteries.The interobserver agreement were assessed on a patient diagnostic basis and on a per artery basis respectively in the diagnosis of PE.It was also assessed on a patient diagnostic basis in the diagnosis of DVT.Findings other than PE and DVT were recorded.13 patients among the underwent follow-up evaluation with CT pulmonary angiography(CTPA)or combined with CT venography (CTV) at 3 day to 6 months after treatment.Among the 106 initial examinations, results of 73 results of CTV were compared with the lower extremities deep venous ultrasonic results.The acquired risk factors in 50 VTE patients.Results:(1) PE were diagnosed in 45(42.45%) patients.DVT were diagnosed in 24 patients,among which 19 patients had combined PE and 5 patients without PE.So CTVPA increased the diagnostic rate of VTE of 10%compared with CTPA alone.(2) 729 PEs were detected in 62 patients.The mean number of emboli detected was 16.2 per patient.6 patients had PE in isolated subsegmental or fifth-order pulmonary arteries.578 emboli were located in subsegmental or fifth,sixht-order pulmonary arteries.The CT value(56±21HU) of acute pulmonary emboli was equal to that (50±13HU) of chronic pulmonary emboli.(3) The interobserver agreement and Kappa value on a patient basis were 98.6%and 0.96 respectively those on a per artery basis for all arteries were 98.8%and 0.94,while those for 1st to 5th artery zones were 98.6%-100%and 0.92～1.0 respectively.(4) Additional diagnostic information was porvided by CTPA in 30 non-PE patients(49.41%).(5) CTPA showed a complete resolution of acute PE in 6 patients after treatment,no changes in one chronic PE,and a complete resoulsion in one chronic patients after thromboendarterectomy.(6) 113 thrombi were detected in 24 patients,among which 35 DVTs(31%) were located in abdominal and pelvic venis,42 DVTs(37%) were located in femoropopli- teal veins and the other 36 DVTs(32%) were located in the calf veins.The CT value of DVT was 42±14Hu,which was remarkably lower than the CT value of PE(p＜0.05).(7) Agreement was achieved in 90%patients.The interobserver agreement was very good (Kappa=0.86).(8) The CTV has a sensitivity of 92.3%,a specificity of 100%,a positive predictive value of 100%and a negative predictive value of 97.2%in the diagnosis of femoropopliteal venous thrombosis.Among the 50 VTE patients,20 (39.7%) patients had 1 risk factors,16(32.4%) patients had 2 risk factors and 13 (25%) patients had 3 more risk factors.1 patients were with no obvious risk factors.Conclusion:(1) 64-slice spiral CT improved the detection of subsegmental PE with very good interobserver agreement.(2) CTVPA had lower proportion of indeterminate diagnosis and could provide additional information that was related to clinical symptoms in non-PE patinets.(3) CTPA followed by CTV,CTVPA increased the diagnostic rate of VTE compared with CTPA alone.(4) CTV was an accurate method in the diagnosis of femoropopliteal venous thrombosis.The interobserver agreement was very good.(5) CTVPA could also reveal the thrombosis in the inferior vena cava and iliac veins superior than sonography.(6) CTVPA cuold be a good choice in VTE follow-up after treatment.(7) patient suffered from VTE commonly had one or more risk factors.It is quite helpful for early diagnosis of VTE to acknowledge those risk factors.