Quantitative assessment of myocardial motion from velocity encoded MRI

Methods 11 Volunteers (30±8 years) and 3 patients (41±11 years) were investigated at a 3T whole body MR scanner (Achieva, Philips) with a 32 channel cardiac coil. The patients suffered from DCM, asynchrony and/or LBBB. A velocity encoded (TPM) navigated segmented gradient echo sequence was applied in the apical, equatorial and basal slice. The acquisition parameters were: FOV=340mm, in-plane resolution =2.5mm, slice thickness=8mm, acquisition matrix MxP=172x168, TR/ TE=6.3ms/4.6ms, a=15°, 3 k-lines per segment, VENC=30cm/s, nominal scan duration =5:51 minutes, black blood imaging with alternating presaturation pulses [1] and a SENSE acceleration factor of 2. For 60 bpm 32 cardiac phases were measured with a phase interval of 29.1ms. From the TPM data, the 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)over 6 segments [2], the radial, circumferential and longitudinal asynchrony correlation coefficient (ACC)[3], the longitudinal and radial velocity range Δvl = vl,max-vl,min, Δvr = vr,max-vr,min and the temporal uniformity of velocity (TUV) in radial, longitudinal and circumferential direction were derived. The latter one was defined in analogy to the temporal uniformity of strain [4,5].