Autocalibrated cardiac tissue phase mapping with multiband imaging and k‐t acceleration

Abstract

Purpose To develop an autocalibrated multiband (MB) CAIPIRINHA acquisition scheme with in‐plane k‐t acceleration enabling multislice three‐directional tissue phase mapping in one breath‐hold. Methods A k‐t undersampling scheme was integrated into a time‐resolved electrocardiographic‐triggered autocalibrated MB gradient‐echo sequence. The sequence was used to acquire data on 4 healthy volunteers with MB factors of two (MB2) and three (MB3), which were reconstructed using a joint reconstruction algorithm that tackles both k‐t and MB acceleration. Forward simulations of the imaging process were used to tune the reconstruction model hyperparameters. Direct comparisons between MB and single‐band tissue phase‐mapping measurements were performed. Results Simulations showed that the velocities could be accurately reproduced with MB2 k‐t (average ± twice the SD of the RMS error of 0.08 ± 0.22 cm/s and velocity peak reduction of 1.03% ± 6.47% compared with fully sampled velocities), whereas acceptable results were obtained with MB3 k‐t (RMS error of 0.13 ± 0.58 cm/s and peak reduction of 2.21% ± 13.45%). When applied to tissue phase‐mapping data, the proposed technique allowed three‐directional velocity encoding to be simultaneously acquired at two/three slices in a single breath‐hold of 18 heartbeats. No statistically significant differences were detected between MB2/MB3 k‐t and single‐band k‐t motion traces averaged over the myocardium. Regional differences were found, however, when using the American Heart Association model for segmentation. Conclusion An autocalibrated MB k‐t acquisition/reconstruction framework is presented that allows three‐directional velocity encoding of the myocardial velocities at multiple slices in one breath‐hold.

All‐systolic first‐pass myocardial rest perfusion at a long saturation time using simultaneous multi‐slice imaging and compressed sensing acceleration

“…As in Refs. 24 and 25 , these calibration data were averaged in time to reduce respiratory artefacts.…”

Myocardial First‐Pass Perfusion With Increased Anatomic Coverage at 3 T Using Autocalibrated Multiband Imaging

“…Each of the datasets was subsequently averaged line-by-line. After that, the slice unaliased reference data were calculated by applying Hadamard decoding 18,20 (i.e. Slice 1 = Dodd + Deven and Slice 2 = Dodd À Deven) because the phase offsets are predefined in image space based on the temporal modulation of the MB pulses.…”

“…Thus, the purpose of this study was to investigate the potential clinical value of autocalibrated MB + CS-FPP at 3.0 T without the need for additional reference data from additional scans. Specifically, the aim was to improve the myocardial coverage without increasing scan time by integrating an autocalibrated MB technique [18][19][20] into a spoiled GRE readout based FPP sequence with k-t acceleration and CS reconstruction [21][22][23] and to compare the results with conventional FPP. The combination of the autocalibrated MB with slice-GRAPPA reconstruction was also evaluated.…”

Improved simultaneous multislice cardiac MRI using readout concatenated k‐space SPIRiT (ROCK‐SPIRiT)

“…8 Multiple studies have explored the use of SMS imaging in CMR for faster coverage. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] In particular, SMS acceleration has been used for myocardial T 1 mapping, 13,18 for cine imaging, 16,21 and for perfusion imaging 11,14,15,17,22 using both Cartesian and non-Cartesian acquisitions at different acceleration rates. However, due to coil geometry limitations, SMS acceleration remains limited for CMR, especially in conjunction with in-plane parallel imaging, in which leakage artifacts and noise amplification are observed at high acceleration rates, 23 necessitating improvements in reconstruction.…”

“…Simultaneous multislice imaging is typically coupled with controlled aliasing, to further increase dissimilarities among the coil profiles across the slices and to reduce g‐factor noise amplification 8 . Multiple studies have explored the use of SMS imaging in CMR for faster coverage 9‐22 . In particular, SMS acceleration has been used for myocardial T 1 mapping, 13,18 for cine imaging, 16,21 and for perfusion imaging 11,14,15,17,22 using both Cartesian and non‐Cartesian acquisitions at different acceleration rates.…”