title: In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla.
abstract: Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1(-)) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI.
authors: School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia. Electronic address: mingyan@itee.uq.edu.au.
authors: Mingyan
authors: M
authors: Li
authors: School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Jin
authors: J
authors: Jin
authors: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Centre for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. Electronic address: ztzuo@bcslab.ibp.ac.cn.
authors: Zhentao
authors: Z
authors: Zuo
authors: School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Feng
authors: F
authors: Liu
authors: School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Adnan
authors: A
authors: Trakic
authors: School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Ewald
authors: E
authors: Weber
authors: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Centre for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors: Yan
authors: Y
authors: Zhuo
authors: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Centre for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors: Rong
authors: R
authors: Xue
authors: School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Stuart
authors: S
authors: Crozier
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008280:Magnetics / Q000295:instrumentation; D056888:Patient Positioning / Q000379:methods*; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D013382:Subtraction Technique / Q000295:instrumentation*; D014159:Transducers
keywords: 7 Tesla; Human brain imaging; In vivo sensitivity estimation; Parallel imaging; Phased array coils; Rotating RF coil array (RRFCA); Rotating SENSitivity Encoding (rotating-SENSE); Signal-to-noise ratio (SNR)