PURPOSE: To determine the feasibility of performing MRI of the wrist at 7 Tesla (T) with parallel imaging and to evaluate how acceleration factors (AF) affect signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image quality. MATERIALS AND METHODS: This study had institutional review board approval. A four-transmit eight-receive channel array coil was constructed in-house. Nine healthy subjects were scanned on a 7T whole-body MR scanner. Coronal and axial images of cartilage and trabecular bone micro-architecture (3D-Fast Low Angle Shot (FLASH) with and without fat suppression, repetition time/echo time = 20 ms/4.5 ms, flip angle = 10 degrees , 0.169-0.195 x 0.169-0.195 mm, 0.5-1 mm slice thickness) were obtained with AF 1, 2, 3, 4. T1-weighted fast spin-echo (FSE), proton density-weighted FSE, and multiple-echo data image combination (MEDIC) sequences were also performed. SNR and CNR were measured. Three musculoskeletal radiologists rated image quality. Linear correlation analysis and paired t-tests were performed. RESULTS: At higher AF, SNR and CNR decreased linearly for cartilage, muscle, and trabecular bone (r < -0.98). At AF 4, reductions in SNR/CNR were:52%/60% (cartilage), 72%/63% (muscle), 45%/50% (trabecular bone). Radiologists scored images with AF 1 and 2 as near-excellent, AF 3 as good-to-excellent (P = 0.075), and AF 4 as average-to-good (P = 0.11). CONCLUSION: It is feasible to perform high resolution 7T MRI of the wrist with parallel imaging. SNR and CNR decrease with higher AF, but image quality remains above-average.
PURPOSE: To determine the feasibility of performing MRI of the wrist at 7 Tesla (T) with parallel imaging and to evaluate how acceleration factors (AF) affect signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image quality. MATERIALS AND METHODS: This study had institutional review board approval. A four-transmit eight-receive channel array coil was constructed in-house. Nine healthy subjects were scanned on a 7T whole-body MR scanner. Coronal and axial images of cartilage and trabecular bone micro-architecture (3D-Fast Low Angle Shot (FLASH) with and without fat suppression, repetition time/echo time = 20 ms/4.5 ms, flip angle = 10 degrees , 0.169-0.195 x 0.169-0.195 mm, 0.5-1 mm slice thickness) were obtained with AF 1, 2, 3, 4. T1-weighted fast spin-echo (FSE), proton density-weighted FSE, and multiple-echo data image combination (MEDIC) sequences were also performed. SNR and CNR were measured. Three musculoskeletal radiologists rated image quality. Linear correlation analysis and paired t-tests were performed. RESULTS: At higher AF, SNR and CNR decreased linearly for cartilage, muscle, and trabecular bone (r < -0.98). At AF 4, reductions in SNR/CNR were:52%/60% (cartilage), 72%/63% (muscle), 45%/50% (trabecular bone). Radiologists scored images with AF 1 and 2 as near-excellent, AF 3 as good-to-excellent (P = 0.075), and AF 4 as average-to-good (P = 0.11). CONCLUSION: It is feasible to perform high resolution 7T MRI of the wrist with parallel imaging. SNR and CNR decrease with higher AF, but image quality remains above-average.
Authors: M E Schweitzer; S K Brahme; J Hodler; G J Hanker; T P Lynch; B D Flannigan; C A Godzik; D Resnick Journal: Radiology Date: 1992-01 Impact factor: 11.105
Authors: Andrew H Haims; Andrew E Moore; Mark E Schweitzer; William B Morrison; Diane Deely; Randall W Culp; Howard P Forman Journal: AJR Am J Roentgenol Date: 2004-05 Impact factor: 3.959
Authors: Gregory Chang; Chamith S Rajapakse; James S Babb; Stephen P Honig; Michael P Recht; Ravinder R Regatte Journal: J Bone Miner Metab Date: 2011-11-30 Impact factor: 2.626
Authors: J Ellermann; U Goerke; P Morgan; K Ugurbil; J Tian; S Schmitter; T Vaughan; P-F Van De Moortele Journal: NMR Biomed Date: 2012-02-07 Impact factor: 4.044
Authors: Gregory Chang; Ding Xia; Orrin Sherman; Eric Strauss; Laith Jazrawi; Michael P Recht; Ravinder R Regatte Journal: MAGMA Date: 2013-05-09 Impact factor: 2.310
Authors: Gregory Chang; Ligong Wang; Guoyuan Liang; James S Babb; Punam K Saha; Ravinder R Regatte Journal: MAGMA Date: 2011-01-09 Impact factor: 2.310
Authors: Ryan Brown; Cem Murat Deniz; Bei Zhang; Gregory Chang; Daniel K Sodickson; Graham C Wiggins Journal: Invest Radiol Date: 2014-01 Impact factor: 6.016