Sliding‐slab three‐dimensional TSE imaging with a spiral‐In/Out readout

Abstract

3D sliding-slab TSE with a spiral-in/out readout provides good-quality T2 -weighted images, and, therefore, may become a promising alternative to Cartesian TSE.

Single‐shot spiral imaging at 7 T

“…As illustrated in the second part of this study, extended spiral readouts can also be used to acquire two images after a single excitation in what may be called a half‐shot strategy. This approach was pioneered in fMRI, particularly for physiological noise correction and multi‐echo combination, and has also been used for joint water‐fat estimation . Two successive spiral readouts may also be of different length and k‐space range.…”

“…In particular, a leading or trailing low‐resolution spiral could serve for supporting purposes such as navigation or and coil sensitivity mapping. Finally, good quality of depiction with single‐shot 2D spirals suggests that other long and non‐Cartesian readouts, particularly 3D and multiband spirals, may hold promise for similar levels of robustness.…”

Correction of B0 eddy current effects in spiral MRI

“…Spiral MRI promises many benefits including high acquisition and SNR efficiency, short minimum echo‐times, robustness to motion and flow, and higher geometric fidelity (compared to EPI). In the past few years, spiral has been shown to provide unique capabilities or substantial advantages over conventional imaging in post‐Gad T 1 weighted imaging, 3D TSE imaging, cardiac flow imaging, diffusion weighted imaging, real‐time imaging, perfusion imaging, functional MRI, MR fingerprinting, and many other applications. Despite its potential and long history, spiral MRI has struggled to find widespread clinical adoption, in large part due to artifacts from susceptibility‐induced field inhomogeneity and eddy current‐induced gradient errors.…”

A 2D spiral turbo‐spin‐echo technique

“…With the approval of the institutional review board, volunteer data were acquired with standard Cartesian TSE and the proposed spiral TSE to evaluate the overall image quality. Relevant spiral imaging parameters include FOV = 230 × 230 mm 2 , resolution = 0.65 × 0.65 mm 2 , 20 slices with 4 mm thickness and 2 mm gap, refocusing RF flip angle = 180 °, ETL = 5, TE shift = 0 and 1.15 ms, 45 spiral interleaves with ADC = 17.57 ms, effective TE ∼81 ms, TR ∼3100 ms (1 package, or pass/concatenation), and scan time = 1 min 53 s. The data were acquired with 2 TE shifts to provide water–fat separation (single‐TE data with fat suppression can be comparably deblurred) . In vivo data were also acquired with a variant of spiral TSE, which skips the first echo to improve the contrast, with slight penalty in scan time (2 min 20 s).…”

“…Compared to Cartesian imaging, spiral acquisitions have advantages such as high acquisition efficiency and insensitivity to motion artifacts . Spiral trajectories have been incorporated into 2D SE, 2D TSE, and 3D TSE . With spiral acquisition, long readouts can be achieved, which reduces the number of RF pulses in 2D TSE.…”