Role of CT angiography in the detection of mechanical obstructive cause of deep vein thrombosis of lower extremity / 中华放射学杂志

ABSTRACT

Objective To explore the diagnostic value of the CT angiography (CTA) in the detection of mechanical obstructive cause of deep venous thrombosis of lower extremity. Methods Forty-seven cases of CTA and DSA image data of DVT in lower extremity with mechanical obstruction were retrospectively analyzed. The CTA three-dimensional reconstruction images were compared with DSA results, and the position and size of thrombus, collateral circulation of blood vessels, vascular compression area and the corresponding outside vascular lesions were evaluated. The causes of venous occlusion were analyzed. Diagnostic agreement of CTA and DSA was assessed by Kappa statistics. The difference of the accuracy between CTA and DSA in the diagnosis of the left and right iliac femoral vein, inferior vena cava, internal iliac vein thrombosis were analyzed with χ2 test. Results There were 47 patients with lower extremity DVT. Of them, DVT was detected in the left leg in 28 patients, in the right leg in 14 patients and in both lower extremities in 5 patients. Mechanical obstruction caused DVT in all of them. There were 27 patients of iliac vein compression syndrome(IVCS)complicated with lower limb DVT. The left iliac vein was oppressed by the right common iliac artery with compression degree from 55.41%to 100.00%,and mean of(77.1 ± 16.8)%. There was congenital stenosis or occlusion of inferior vena cava in 3 patients. There was Budd-Chiari syndrome in 2 patients. There was pelvic mass pressing the common iliac vein in 4 patients. Enlarged right inguinal lymph nodes oppressed the right femoral vein in 3 patients and enlarged left inguinal lymph nodes oppressed the left femoral vein in 2 patients. Other mechanical obstruction factors caused DVT in 6 patients, including right iliac artery aneurysms,spontaneous hematoma, etc. The agreement of CTA and DSA on the diagnosis of the iliac femoral thrombosis was good (Kappa=0.978), the diagnosis agreement on the inferior vena cava thrombus was good (Kappa = 0.737), while the diagnosis agreement on the internal iliac vein thrombosis was poor (Kappa=0.189). The difference of CTA and DSA in the diagnosis of left and right iliac femoral venous thrombosis was not statistically significant (52,51 case;χ2=0.00, P>0.05), neither was the diagnostic difference of inferior vena cava thrombus (21,17 cases;χ2=1.50, P>1.50). However, the difference of the diagnosis of the iliac vein thrombosis was statistically significant (14,2 cases;χ2=8.33, P<0.05) . Conclusions CTA can clearly show the location and scope of the thrombus. Compared with conventional DSA, CTA shows higher diagnostic coincidence rate, and can accurately determine the mechanical obstruction causes of lower extremity DVT.