Free‐breathing inner‐volume black‐blood imaging of the human heart using two‐dimensionally selective local excitation at 3 T

Abstract

Black-blood fast spin-echo imaging is a powerful technique for the evaluation of cardiac anatomy. To avoid fold-over artifacts, using a sufficiently large field of view in phase-encoding direction is mandatory. The related oversampling affects scanning time and respiratory chest motion artifacts are commonly observed. The excitation of a volume that exclusively includes the heart without its surrounding structures may help to improve scan efficiency and minimize motion artifacts. Therefore, and by building on previously reported inner-volume approach, the combination of a black-blood FSE sequence with a two-dimensionally selective radiofrequency pulse is proposed for selective “local excitation” small-FOV imaging of the heart. This local excitation technique has been developed, implemented, and tested in phantoms and in vivo. With this method, small-FOV imaging of a user-specified region in the human thorax is feasible, scanning becomes more time efficient, motion artifacts can be minimized and additional flexibility in the choice of imaging parameters can be exploited.

Combined T2‐preparation and two‐dimensional pencil‐beam inner volume selection

“…It is not, however, the first work to propose using a 2D pulse for cardiovascular imaging. Several previous works have demonstrated the utility of 2D pulses in MRA, such as using them for respiratory navigator gating (7-9), for virtual dye angiography (10), as well as for imaging of the heart (11,12) and coronary vessel wall (13)(14)(15)(16), and for spin labeling (17)(18)(19)(20)(21). Notably, it has been previously demonstrated (12) that unwanted artifacts, such as those originating from respiratory motion, were reduced by using a 2D pulse, which is consistent with our findings.…”

“…Two-dimensional RF pulses have been proposed for a variety of applications, including cardiovascular uses, such as respiratory navigator gating (7)(8)(9), for virtual dye angiography (10), as well as for imaging of the heart (11,12) and coronary vessel wall (13)(14)(15)(16), and for spin labeling (17)(18)(19)(20)(21). They have also been shown to improve image quality by reducing signal from nearby anatomical structures, which may be sources of unwanted artifacts (12).…”

A Cylindrical, Inner Volume Selecting 2D-T2-Prep Improves GRAPPA-Accelerated Image Quality in MRA of the Right Coronary Artery

“…However, we did not study whether using a 2D RF pulse for image excitation would have produced similar results. Though the increase in scan time might currently preclude the clinical utility of 2D excitation in many approaches (e.g steady state free precession), 2D excitation pulses have nonetheless been previously used in spin-echo imaging [ 16 ] to good effect. It would be interesting to see if the results shown here—that the reduction in excited tissue volume particularly benefits parallel imaging—also hold true in the spin-echo case.…”

“…This could possibly be achieved with outer volume suppression [ 5 , 6 , 7 ], or by restricting the excitation volume, such as with two-dimensional spatially selective RF pulses ("2D pulses") [ 8 , 9 , 10 ]. Two dimensional pulses have already been proposed for a variety of applications, including cardiovascular uses like respiratory navigator gating [ 11 , 12 , 13 ], virtual dye angiography [ 14 ], cardiac [ 15 , 16 ] and vessel wall imaging [ 17 , 18 , 19 , 20 , 21 ], and for spin labelling [ 22 , 23 , 24 , 25 , 26 ]. They have also been shown to improve image quality by reducing signal from nearby anatomical structures [ 16 ], which may be sources of unwanted artefacts (e.g.…”

Fast 3D isotropic imaging of the aortic vessel wall by application of 2D spatially selective excitation and a new way of inversion recovery for black blood imaging

“…This can be achieved by limiting the signal generating area, either by orthogonal excitation and refocusing pulses (14) or by 2D spatially selective excitation pulses (2D SSE) (15)(16)(17). The rFOV approach has been used to shorten scan times of DIR TSE and other sequences (18)(19)(20)(21)(22). However, the amount of longitudinal information is still limited because of the slice selective imaging sequences that are being used.…”