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Fat Separation (fat + separation)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Fast spin-echo triple-echo Dixon: Initial clinical experience with a novel pulse sequence for fat-suppressed T2-weighted abdominal MR imaging

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2009
Russell N. Low MD
Abstract Purpose To evaluate a prototype fast spin echo (FSE) triple-echo-Dixon (fTED) technique for breath-hold, fat-suppressed, T2-weighted abdominal imaging. Materials and Methods Forty patients underwent breath-hold T2-weighted abdominal imaging with fTED and conventional fast recovery (FR) FSE with chemical shift-selective saturation (CHESS). FRFSE and fTED images were compared for overall image quality, homogeneity of fat suppression, image sharpness, anatomic detail, and phase artifact. Depiction of disease was recorded separately for FRFSE and fTED images. Results FTED successfully reconstructed water-only and fat-only images from source images in all 40 cases. Water and fat separation was perfect in 36 (0.90) patients. Homogeneity of fat suppression was superior on the fTED images in 38 (0.95) of 40 cases. FTED images showed better anatomic detail in 27 (0.68), and less susceptibility artifact in 20 (0.50). FRFSE images showed less vascular pulsation artifact in 30 (0.75) cases, and less phase artifact in 21 (0.53) cases. There was no difference in depiction of disease for FRFSE and fTED images. Conclusion FTED is a robust sequence providing breath-hold T2-weighted images with superior fat suppression, excellent image quality, and at least equal depiction of disease compared to conventional breath-hold T2-weighted FRFSE imaging. J. Magn. Reson. Imaging 2009;30:569,577. © 2009 Wiley-Liss, Inc. [source]

Turboprop IDEAL: A motion-resistant fat,water separation technique

MAGNETIC RESONANCE IN MEDICINE, Issue 1 2009
Donglai Huo
Abstract Suppression of the fat signal in MRI is very important for many clinical applications. Multi-point water,fat separation methods, such as IDEAL (Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation), can robustly separate water and fat signal, but inevitably increase scan time, making separated images more easily affected by patient motions. PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) and Turboprop techniques offer an effective approach to correct for motion artifacts. By combining these techniques together, we demonstrate that the new TP-IDEAL method can provide reliable water,fat separation with robust motion correction. The Turboprop sequence was modified to acquire source images, and motion correction algorithms were adjusted to assure the registration between different echo images. Theoretical calculations were performed to predict the optimal shift and spacing of the gradient echoes. Phantom images were acquired, and results were compared with regular FSE-IDEAL. Both T1- and T2-weighted images of the human brain were used to demonstrate the effectiveness of motion correction. TP-IDEAL images were also acquired for pelvis, knee, and foot, showing great potential of this technique for general clinical applications. Magn Reson Med 61:188,195, 2009. © 2008 Wiley-Liss, Inc. [source]

Fast spin-echo triple-echo dixon (fTED) technique for efficient T2 -weighted water and fat imaging,

MAGNETIC RESONANCE IN MEDICINE, Issue 1 2007
Jingfei Ma
Abstract Previously published fast spin-echo (FSE) implementations of a Dixon method for water and fat separation all require multiple scans and thus a relatively long scan time. Further, the minimum echo spacing (esp), a time critical for FSE image quality and scan efficiency, often needs to be increased in order to bring about the required phase shift between the water and fat signals. This work proposes and implements a novel FSE triple-echo Dixon (fTED) technique that can address these limitations. In the new technique, three raw images are acquired in a single FSE scan by replacing each frequency-encoding gradient in a conventional FSE with three consecutive gradients of alternating polarity. The timing of the three gradients is adjusted by selecting an appropriate receiver bandwidth (RBW) so that the water and fat signals for the three corresponding echoes have a relative phase shift of ,180°, 0°, and 180°, respectively. A fully automated postprocessing algorithm is then used to generate separate water-only and fat-only images for each slice. The technique was implemented with and without parallel imaging. We demonstrate that the new fTED technique enables both uniform water/fat separation and fast scanning with uncompromised scan parameters, including applications such as T2 -weighted separate water and fat imaging of the abdomen during breath-holding. Magn Reson Med 58:103,109, 2007. © 2007 Wiley-Liss, Inc. [source]