title: Accelerating cine phase-contrast flow measurements using k-t BLAST and k-t SENSE.
abstract: Conventional phase-contrast velocity mapping in the ascending aorta was combined with k-t BLAST and k-t SENSE. Up to 5.3-fold net acceleration was achieved, enabling single breath-hold acquisitions. A standard phase-contrast (PC) sequence with interleaved acquisition of the velocity-encoded segments was modified to collect data in 2 stages, a high-resolution under sampled and a low-resolution fully sampled training stage. In addition, a modification of the k-t reconstruction strategy was tested. This strategy, denoted as "plug-in," incorporates data acquired in the training stage into the final reconstruction for improved data consistency, similar to conventional keyhole. "k-t SENSE plug-in" was found to provide best image quality and most accurate flow quantification. For this strategy, at least 10 training profiles are required to yield accurate stroke volumes (relative deviation <5%) and good image quality. In vivo 2D cine velocity mapping was performed in 6 healthy volunteers with 30-32 cardiac phases (spatial resolution 1.3 x 1.3 x 8-10 mm(3), temporal resolution of 18-38 ms), yielding relative stroke volumes of 106 +/- 18% (mean +/- 2*SD) and 112 +/- 15% for 3.8 x and 5.3 x net accelerations, respectively. In summary, k-t BLAST and k-t SENSE are promising approaches that permit significant scan-time reduction in PC velocity mapping, thus making high-resolution breath-held flow quantification possible.
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
authors.forename: Christof
authors.initials: C
authors.lastname: Baltes
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kozerke
authors.forename: Michael S
authors.initials: MS
authors.lastname: Hansen
authors.forename: Klaas P
authors.initials: KP
authors.lastname: Pruessmann
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Tsao
authors.forename: Peter
authors.initials: P
authors.lastname: Boesiger
mesh_terms: D000465:Algorithms; D001011:Aorta / Q000033:anatomy & histology* / Q000502:physiology*; D016477:Artifacts; D001185:Artificial Intelligence; D001783:Blood Flow Velocity / Q000502:physiology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity