Comparison of conventional fast spin echo, single‐shot two‐dimensional and three‐dimensional half‐fourier RARE for T2‐weighted female pelvic imaging

Abstract

Purpose:To evaluate the usefulness of the three-dimensional half-Fourier RARE sequence in comparison with single-shot two-dimensional half-Fourier RARE and conventional fast spin echo (FSE) for female pelvic imaging. Materials and Methods:Imaging with all sequences was performed in 146 patients with 166 focal lesions on a 1.5-T system. The images were compared on the basis of quality, lesion conspicuity, and lesion to the uterus contrast-tonoise ratio (CNR). Results:The sharpness of intrapelvic organs on the threedimensional half-Fourier RARE sequence was better than that on two-dimensional half-Fourier RARE and worse than that on FSE. Motion-related artifacts for three-dimensional half-Fourier RARE were more frequent than those for twodimensional half-Fourier RARE. There was no statistical difference between the three-dimensional half-Fourier RARE sequence and FSE in regard to lesion conspicuity and overall image quality. The CNR of leiomyoma to myometrium and cervical cancer to cervical stroma was the highest with threedimensional half-Fourier RARE (P Ͻ 0.05). Conclusion:The three-dimensional half-Fourier RARE sequence generates images with higher contrast and better image resolution than two-dimensional-RARE. The threedimensional data set provided images that can be observed in any orientation without acquiring an additional scan by using the multiplanar reconstruction (MPR) method. T2-WEIGHTED MAGNETIC RESONANCE imaging (MRI) is essential for the detection and characterization of diseases of the pelvis (1,2). The recent refinement of MRI sequences and hardware has allowed ultrafast imaging to be made available by using single-shot sequences such as echo planar imaging (EPI) and singleshot half-Fourier RARE. The theoretical advantages of ultrafast sequences include elimination of motion artifacts and increased time effectiveness. Its severe susceptibility artifacts and image distortion due to magnetic heterogeneity caused by intestinal gas limit the clinical use of single-shot EPI in the pelvic region (3). The application of the half-Fourier RARE sequence may be an effective approach for imaging the female pelvis. However, the two-dimensional RARE sequence has several limitations, such as severe blurring artifacts, poor spatial resolution in a slice-selective direction, and low lesion contrast (4). The three-dimensional volume acquisition technique allows for the generation of multiplanar thin slices without interslice gaps. The threedimensional technique may have potential advantages relating to the signal-to-noise ratio (SNR) and to visualizing fine anatomic structures over the two-dimensional method. In this study, we evaluated the usefulness of the three-dimensional half-Fourier RARE sequence in comparison with single-shot two-dimensional half-Fourier RARE and conventional fast spin echo (FSE) for female pelvic imaging. MATERIALS AND METHODS Patient PopulationThis study was carried out in 146 consecutive female patients (mean age ϭ 46.2, range ϭ 19 -83) referred for MRI because of suspected abnormalities ...

Uterine anatomy and function on cine magnetic resonance imaging

“…Instead, SSFSE sequences may be used to obtain relatively motion-free breath-hold sequences with tissue contrast similar to that obtained when using more conventional fast spin-echo T2-weighted images [23]. The drawback of this sequence is the inherently low signal-tonoise ratio (SNR) and contrast-to-noise ratio (CNR) in the uterus [23,24]. Therefore, Nakai et al examined the optimal scan interval for the evaluation of uterine peristalsis and the best performance was obtained with a 4-s scan interval, which yielded a superior CNR and peristaltic detection compared with the 2-or 3-s scan intervals [25].…”

Optimizing cine MRI for uterine peristalsis: A comparison of three different single shot fast spin echo techniques

“…There are two potentially opposing factors that need to be considered when selecting an appropriate interscan delay for cine MRI. The 2D SSFSE sequence has an inherently low signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) in the uterus . Cine MR images acquired with a short scan interval result in progressive tissue saturation from incomplete signal recovery and reduce SNR and CNR .…”

MRI of the Pelvis in Women: 3D Versus 2D T2-Weighted Technique

“…Studies have been conducted to compare 2D and 3D half-Fourier TSE sequences with standard 2D T2-weighted TSE sequences in MRI of the female pelvis. These studies [7][8][9] showed good image quality and improved time efficiency with the 2D half-Fourier TSE sequence and higher contrast, improved time efficiency, and superior through-plane resolution (2-3 mm) with the 3D half-Fourier TSE sequence. However, no attempt was made in those studies to generate multiplanar reconstructions of the 3D source data sets because the slice thickness of 2-3 mm seemed insufficient for acquisition of reformations of high quality.…”