Our purpose was to evaluate prospectively the frequency of post surgical venous thromboembolism after hip joint replacement. We compared indirect MDCT venography with Doppler sonography in detecting deep venous thrombosis (DVT) in the lower extremities.
METHOD AND MATERIALS
In thirty consecutive patients treated with total hip replacement surgery, CT pulmonary angiogrphy (CT PAG) and MDCT venography from the pelvis to the calves were done on the seventh postoperative day, just before they left bed. 16-slice MDCT scanners were used with a bolus contrast injection (300mgI/ml, 100ml) at a rate of 3 ml/sec through the antecubital vein. The scan delays for CT PAG and CT venography were 20 sec and 3 minutes after injection, respectively. All patients underwent Doppler sonography from the pelvis to the calves on the next day. Two radiologists analyzed MDCT venography with consensus reading.
Compared with Doppler sonography as a gold standard, MDCT venography has a sensitivity of 100%, specificity of 86%, a positive and negative predictive value of 73% and 100%, respectively. MDCT venography correctly diagnosed DVT without PE in eight patients (26.7%: superficial femoral v.; 1, popliteal v.; 1, calf v.; 6). MDCT venography resulted in false positive in three patients due to insufficient contrast opacification or flow artifact. Pulmonary embolism (PE) was found on CT PAG in one symptomatic patient (3.3%) and one asymptomatic patient (3.3%). In total, DVT/PE occurred in 10 patients (33.3%) without any patient having both of them.
After hip joint replacement, the incidence of venous throboembolism was high (33.3%). MDCT venography showed quite comparative results to Doppler sonography in detecting deep venous thrombosis of the thighs and calves.