| Objective : To assess the clinical value of dual-phase multi-slice CT angiography(MSCTA) in diagnosing deep venous thrombosis(DVT) of lower extremity and to compare the value of MSCTA with digital subtraction angiography (DSA) and color doppler ultrasound (CDU).Methods: 57 patients suspected with deep venous thrombosis of lower extremity underwent dual-phase enhanced 16-slice helical CT. The MSCTA effects were evaluated. The CT value and standard deviation were measured in normal femoral vein in dual-phase scanning. The difference of dual-phase MSCTA were evaluated. In the first phase MPR, CPR, VR and MIP of 3D reconstruction were done, in the second phase only MPR and CPR were done. The CT angiography technique were analyzed. 47 of them underwent DSA simultaneously. Compared with DSA, the value of MSCTA in the diagnosis of DVT of lower extremity was assessed. 12 of them underwent CDU at the same time. The advantages and disadvantages of MSCTA and CDU in the diagnosis of DVT of lower extremity were compared. Results: The excellent and good rate was 88.7% in the first phase, and 86.8% in the second phase. There was no statistical difference between dual-phase(x2=0.727,P>0.05). In the first phase CT value was 102.76±13.71Hu, and standard deviation was 13.85±2.30Hu; In the second phase CT value was 92.00±9.24Hu, and standard deviation was 9.27±2.01Hu. There were statistical difference between dual-phase CT value and standard deviation (CT value t=2.369,P<0.05;standard deviation t=4.476,P<0.05). 10 of 57 cases did not undergo DSA, 6 of them examined by MSCTA were normal, 3 of them were varicose veins of lower extremity, 1 of them was a tumor in the pelvis compressing inferior vena cava. There were 47 DVT patients, 31(66.0%) in left lower extremity, 12(25.5%) in right lower extremity, and 4(8.5%) in both lower extremities. 7 patients of DVT of lower extremity companied with pulmonary embolism. 21 patients of DVT of lower extremity companied with iliac vein compression syndrome. The other 5 patients of deep vein occlusive included 1 case of the deformity of inferior vena cava, 1 case of cyst in the left poples, 1 cases of the tumor in the pelvis compressing the right iliac vein, 1 case of a cyst in left inguinal region compressing the left external iliac vein, and 1 case of recurrence of the ureter tumor invading right iliac vein. When the results of DSA were regarded as golden standard, the accuracy of MSCTA was 100%. But 3 internal iliac vein thrombosis and 3 deep femoral vein thrombosis were examined by MSCTA, not by DSA. And MSCTA was superior to DSA in showing thrombosis of the proximal end, but not superior to DSA in showing collateral circulation. 12 of DVT patients underwent CDU at the same time, and 1 internal iliac vein thrombosis was examined by MSCTA, not by CDU.Conclusion: Dual-phase MSCTA has appilication value in the diagnosis of DVT of lower extremity. MSCTA has better observation of the relationship between artery and venous in the first phase, and has more uniform density of contrast agent in the second phase, so MSCTA has fewer false-positive in diagnosing DVT and has a high accuracy with DSA. MSCTA is superior to CDU in showing the location and extent of thrombosis, and MSCTA can show pelvic vein thrombosis not showed by CDU clearly. The clinical value of dual-phase MSCTA in diagnosing DVT of lower extremity is very high. |
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