[Combined diagnostic approach to venous thromboembolism with multidetector computed tomography]

Abstract

Background: Multidetector computed tomography (CT) improves scan length and spatial resolution. The availability of a single test that allows a comprehensive evaluation of the chest and pulmonary arteries, of the deep venous system of the abdomen and legs and the hemodynamic impact of pulmonary emboli on the right heart could be a new and effective strategy for patients with venous thromboembolic disease. We assess a combined study protocol on venous thromboembolic disease by multidetector CT.

Methods: Twenty-four patients with confirmed acute pulmonary embolism, in stable clinical conditions, underwent multidetector CT. After antecubital intravenous infusion of 120 ml of contrast medium at a rate of 4 ml/s followed by 30 ml of saline solution a CT of the chest was performed using 4 x 1 mm collimation, pitch 1.5 and 500 ms rotation time of the X-ray tube; the start delay was checked for each single patient. Indirect CT venography study was acquired 150s after starting the infusion using a 5 mm section width from the diaphragm to the popliteal zone. We evaluated: 1) the presence of intraluminal filling defects in the pulmonary arteries and in the deep venous system from the inferior vena cava to the popliteal veins, and 2) the presence of right ventricular dilation with a right ventricle/left ventricle (RV/LV) ratio > 1. The patients with CT diagnosis of deep vein thrombosis (DVT) and and RV/LV ratio > 1 underwent venous compressive ultrasound and/or echocardiography.

Results: Pulmonary embolism was detected in 12% in the main arteries and in 66, 87 and 20% in the lobar, segmental and subsegmental arteries respectively. DVT was found in 14/24 (58%) patients with pulmonary embolism involving the ileo-femoral district in 14% of the whole group. Thirteen patients (54%) showed a volumetric prevalence of the right ventricle on the left ventricle. CT data in the presence of DVT and an RV/LV ratio > 1 was confirmed at ultrasonography.

Conclusions: Multidetector CT allows to obtain rapidly and in one examination useful information about the source and pulmonary involvement of venous thromboembolic disease and about the hemodynamic impact on the right heart.