Comparison of muscle BOLD responses to arterial occlusion at 3 and 7 Tesla. Issue 3 (17th April 2015)

• Record Type: Journal Article
• Authors: Towse, Theodore F.; Childs, Benjamin T.; Sabin, Shea A.; Bush, Emily C.; Elder, Christopher P.; Damon, Bruce M.
• Is Part Of: Magnetic resonance in medicine. Volume 75:Issue 3(2016:Mar.)
• Page Start: 1333
• Page End: 1340
• Publication Date: 2015-04-17
• Subjects: NIRS -- Doppler ultrasound -- transverse relaxation -- human -- ultra‐high field MRI; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25562
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: The purpose of this study was to determine the feasibility of muscle BOLD (mBOLD) imaging at 7 Tesla (T) by comparing the changes in R 2 * of muscle at 3 and 7T in response to a brief period of tourniquet‐induced ischemia. Methods: Eight subjects (three male), aged 29.5 ± 6.1 years (mean ± standard deviation, SD), 167.0 ± 10.6 cm tall with a body mass of 62.0 ± 18.0 kg, participated in the study. Subjects reported to the lab on four separate occasions including a habituation session, two MRI scans, and in a subset of subjects, a session during which changes in blood flow and blood oxygenation were quantified using Doppler ultrasound (U/S) and near‐infrared spectroscopy (NIRS) respectively. For statistical comparisons between 3 and 7T, R2 * rate constants were calculated as R2 * = 1/ T2 *. Results: The mean preocclusion R2 * value was greater at 7T than at 3T (60.16 ± 2.95 vs. 35.17 ± 0.35 s −1, respectively, P < 0.001). Also, the mean Δ R2 *END and Δ R2 *POST values were greater for 7T than for 3T (−2.36 ± 0.25 vs. −1.24 ± 0.39 s −1, respectively, Table 1). Conclusion: Muscle BOLD contrast at 7T is as much as six‐fold greater than at 3T. In addition to providing greater SNR and CNR, 7T mBOLD studies may offer further advantages in the form of greater sensitivity to pathological changes in the muscle microcirculation. Magn Reson Med 75:1333–1340, 2016. © 2015 Wiley Periodicals, Inc.