3D MR-ANGIOGRAPHY OF PULMONARY-ARTERIES USING REALTIME NAVIGATOR GATING AND MAGNETIZATION PREPARATION

An EGG-triggered magnetization-prepared segmented 3D fast gradient ech o sequence was developed to perform pulmonary arterial MR angiography, A selective inversion recovery pulse was used in the magnetization pr eparation to suppress venous vasculature, A real-time gating technique based on navigator echoes was implemented to reduce respiration effec ts. Pencil-beam navigator echoes were acquired immediately before and after the readout train and processed in real-time to dynamically meas ure the diaphragm position, which was used to control data acquisition with an accept-or-reject-reacquire logic, In a study of 10 volunteers , a gated 3D acquisition with 28 slices required on average approximat ely 4 min of acquisition time, and six to seven segmental arteries rel ated to the interlobar trunk of the pulmonary artery were depicted. Th e use of SIR pulse reduced venous signal by 99%, The gated acquisition s were superior to the ungated acquisitions (n 10, P < 0.005), The rea l-time navigator gating technique is effective for reduction of respir ation effects and thereby makes high resolution 3D MRA of the pulmonar y arteries feasible.