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CArtesian sampling with Variable density and Adjustable temporal resolution (CAVA)
Author(s) -
Rich Adam,
Gregg Michael,
Jin Ning,
Liu Yingmin,
Potter Lee,
Simonetti Orlando,
Ahmad Rizwan
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28059
Subject(s) - imaging phantom , sampling (signal processing) , pulsatile flow , temporal resolution , computer science , cartesian coordinate system , image resolution , inferior vena cava , radiology , nuclear medicine , artificial intelligence , mathematics , computer vision , medicine , physics , optics , geometry , filter (signal processing)
Purpose To develop a variable density Cartesian sampling method that allows retrospective adjustment of temporal resolution for dynamic MRI applications and to validate it in real‐time phase contrast MRI (PC‐MRI). Theory and Methods The proposed method, called CArtesian sampling with Variable density and Adjustable temporal resolution (CAVA), begins by producing a sequence of phase encoding indices based on the golden ratio increment. Then, variable density is introduced by nonlinear stretching of the indices. Finally, the elements of the resulting sequence are rounded up to the nearest integer. The performance of CAVA is evaluated using PC‐MRI data from a pulsatile flow phantom and real‐time, free‐breathing data from ten healthy volunteers. Results CAVA enabled image recovery at various temporal resolutions that were selected retrospectively. For the pulsatile flow phantom, image quality and flow quantification accuracy from CAVA were comparable to that from another pseudo‐random sampling pattern with fixed temporal resolution. In addition, flow quantification results based on CAVA were in good agreement with a breath‐held segmented acquisition. Conclusions By allowing retrospective binning of the MRI data, CAVA provides an avenue to retrospectively adjust the temporal resolution of PC‐MRI.