SSFP fMRI at 3 tesla: Efficiency of polar acquisition-reconstruction technique

Malekian, Vahid; Rastegar, Fatemeh; Shafieizargar, Banafshe; Nasiraei-Moghaddam, Abbas

doi:10.1016/j.mri.2020.09.005

Cited by 1 publication

(3 citation statements)

References 37 publications

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“…(The diameter of FOV is prescribed by number of spokes in the radial acquisition as described in the Supporting Information for more explanation.) The PFT is a novel linear reconstruction technique that, in contrast to re‐gridding, 36 preserves this unique advantage of radial acquisition due to the “central focusing behavior.” 28,29 The offline PFT reconstruction was therefore used in this study separately on each coil channel and images were then combined through the conventional root sum of squares.…”

Section: Methodsmentioning

confidence: 99%

“…A highly undersampled fast radial acquisition is adopted for this study to take advantage of the “reduced FOV” (rFOV) concept, which is: “under the assumption that dynamic changes are restricted to a local circular field of view, angular undersampled dynamic imaging allows the recording of rapid changes at high temporal and spatial resolution” 27 . The efficiency of the method is further underlined based on the “coherency” of radial tagging and radial acquisition, followed by Polar Fourier Transform (PFT) reconstruction 28,29 …”

Section: Introductionmentioning

confidence: 99%

“…27 The efficiency of the method is further underlined based on the "coherency" of radial tagging and radial acquisition, followed by Polar Fourier Transform (PFT) reconstruction. 28,29 We also aim to capture the torsional motion from simultaneous acquisition of at least two slices within a single cardiac cycle, to avoid errors caused by slice dependent delays and beat-to-beat variations of cardiac loading conditions. The performance of the proposed approach is demonstrated in both simulation and human studies.…”

Section: Introductionmentioning

confidence: 99%

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Real‐time radial tagging for quantification of left ventricular torsion

Mohammadi

Nasiraei-Moghaddam

Uecker

2022

Magnetic Resonance in Med

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To develop a real-time radial tagging MRI for accurate measurement of rotational motion and twist of the left ventricle (LV).Methods: A FLASH-based radial tagging sequence with an undersampled radial reading scheme was developed for both single and double-slice imaging in real-time. The Polar Fourier Transform was used for reconstruction to push the undersampling artifacts out of a reduced FOV. The developed technique was used to image five normal subjects during rest, plus one during both exercise and rest conditions. LV rotational motions were estimated for five consecutive cardiac cycles in all cases. The process was validated using a numerical phantom.The real-time measurement of global rotational motion was compared with those measured from a non-real-time exam using linear regression analysis and the Bland-Altman plot. Results:The real-time acquisition was performed successfully with a temporal resolution of 46.2 ms. Image quality was sufficient for the reproducible calculation of rotation at rest and exercise. The feasibility of double-slice acquisition on human was further studied and a real-time twist of the left ventricle was demonstrated. The difference between LV global rotations from real-time and nonreal-time approaches was 0.27 degrees. A significant reverse recoiling, induced by exercise, was reproducibly measured by the technique. Conclusion: A real-time radial tagging MRI technique was developed based on the undersampled radial acquisition and Polar Fourier Transform reconstruction, for accurate measuring of the heart rotational motion and twist. The technique was able to extract a meaningful change of diastolic recoiling under stress test conditions during physical activities (cycling).

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%