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MR phase‐contrast velocity mapping methods for measuring venous blood velocity in the deep veins of the calf
Author(s) -
Pierce Iain T.,
Gatehouse Peter D.,
Xu X. Yun,
Firmin David N.
Publication year - 2011
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22655
Subject(s) - blood flow , biomedical engineering , imaging phantom , nuclear medicine , spiral (railway) , volumetric flow rate , flow velocity , contrast (vision) , materials science , sequence (biology) , flow (mathematics) , medicine , anatomy , mathematics , physics , biology , radiology , geometry , mechanics , mathematical analysis , optics , genetics
Purpose: To evaluate the feasibility of using un‐gated, real‐time MRI for venous blood velocity mapping in the calf, comparing an interleaved spiral k ‐space sequence (ISP) against a standard segmented gradient echo sequence (GRE). Materials and Methods: A flow phantom with a variable flow‐rate was scanned using both GRE and ISP sequences for an in vitro comparison. Seven subjects were scanned prone, performing metronome guided breathing, using the (externally triggered) segmented GRE and real‐time ISP sequences. The segmented GRE acquisition duration was 2.5 mins (22 guided respiratory cycles) and the ISP sequence ran continuously for 35s, 4 full guided respiratory cycles. Mean velocity from each of the deep veins was measured and peak mean velocity, peak flow rate and cumulative volume flow over a respiratory cycle compared between sequences. Results: The two sequences compared well both in vitro and in vivo. The real‐time ISP sequence showed short‐term variations in mean velocity superimposed on the respiratory induced flow, which were averaged out using the segmented GRE sequence. Conclusion: Real‐time ISP provides comparable time‐averaged flow results to the standard sequence with additional information on real‐time flow variations and so could be used for further investigation into venous blood flow in the lower leg. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.