Magnetic Resonance Imaging Combined With Venous Ultrasonography of the Legs for Pulmonary Embolism

In case of positive D-dimer testing or in patients with a high probability of PE, MRI and a venous ultrasonography of the legs are done.MRI protocol includes 2 sequences: 1-Unenhanced steady-state-free precession sequences (SSFP) are acquired first without ECG-gating or breath-holding in the axial plane in the multiphase cine mode, with 6 phases per location.The acquisition is repeated to cover 2-3 of the thorax, from the roof of the aorta to the diaphragm. 2- A pulmonary gradient recalled echo (GRE) sequence is performed in the axial plane.The acquisition is triggered to start when contrast enhancement occurred in the right ventricle.Two acquisitions are necessary to cover the anatomy. For each acquisition, 0.15 mL kg-1 body weight of DOTAREM Gadolinium is injected at a rate of 3 mL s-1 followed by an injection of 15 mL of normal saline at 3 mL s-1.Venous ultrasonography of the legs: the examination consists of a real-time B-mode examination of the common femoral and popliteal veins.