Volumetric motion quantification by 3D velocity encoded MRI

Methods 12 volunteers (26±7 years) and 2 patients (46, DCM/29, LBBB) were investigated at a 3T whole body MR scanner (Achieva, Philips) with a 32 channel cardiac coil. A 3D black blood velocity encoded navigated segmented gradient echo sequence (3D-TPM) was applied for whole heart coverage. The acquisition parameters were: FOV=380mm, isotropic resolution of 3x3x3mm, FOV in through-plane direction =63mm in healthy volunteers (this FOV was increased in patients due to their enlarged heart corresponding to the distance between basis and apex), acquisition matrix =128x124, TR/ TE=7.1ms/4.9ms, flip angle =15°, SENSE =4, nominal scan duration =15:30 minutes, 3 k-lines per segment, phase interval =37.3ms and 25 cardiac phases for 60bpm. The acquisition of the whole heart data was split into 3 chunks to ensure sufficient black blood contrast. From the 3D-TPM data, the following parameters were evaluated: longitudinal and radial standard deviation of time to peak systolic and diastolic velocities SD (TTPl,sys), SD(TTPl,dias), SD(TTPr,sys), SD(TTPr,dias)[1], the mean radial, circumferential and longitudinal asynchrony correlation coefficient over all cardiac segments (ACC)[2], the longitudinal and radial velocity range ∆vl = vl,max-vl,min, ∆vr = vr,max-vr,min and the new parameter temporal uniformity of velocity (TUV) in radial, longitudinal and circumferential direction, which was defined analogously to the temporal uniformity of strain defined in [3,4].