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MRI of the wrist at 7 tesla using an eight‐channel array coil combined with parallel imaging: Preliminary results
Author(s) -
Chang Gregory,
Friedrich Klaus M.,
Wang Ligong,
Vieira Renata L.R.,
Schweitzer Mark E.,
Recht Michael P.,
Wiggins Graham C.,
Regatte Ravinder R.
Publication year - 2010
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22072
Subject(s) - flip angle , image quality , nuclear medicine , wrist , scanner , contrast to noise ratio , medicine , coronal plane , signal to noise ratio (imaging) , magnetic resonance imaging , biomedical engineering , physics , radiology , computer science , image (mathematics) , optics , artificial intelligence
Abstract 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°, 0.169–0.195 × 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. J. Magn. Reson. Imaging 2010;31:740–746. © 2010 Wiley‐Liss, Inc.