Feiyu Chen1, Valentina Taviani2, Jonathan I Tamir3, Joseph Y Cheng4, Tao Zhang5, Qiong Song4,6, Brian A Hargreaves4, John M Pauly1, Shreyas S Vasanawala4. 1. Department of Electrical Engineering, Stanford University, Stanford, California, USA. 2. Global MR Applications and Workflow, GE Healthcare, Menlo Park, California, USA. 3. Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA. 4. Department of Radiology, Stanford University, Stanford, California, USA. 5. Global MR Applications and Workflow, GE Healthcare, Houston, Texas, USA. 6. Department of Radiology, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang, PRC.
Abstract
BACKGROUND: It is highly desirable in clinical abdominal MR scans to accelerate single-shot fast spin echo (SSFSE) imaging and reduce blurring due to T2 decay and partial-Fourier acquisition. PURPOSE: To develop and investigate the clinical feasibility of wave-encoded variable-density SSFSE imaging for improved image quality and scan time reduction. STUDY TYPE: Prospective controlled clinical trial. SUBJECTS: With Institutional Review Board approval and informed consent, the proposed method was assessed on 20 consecutive adult patients (10 male, 10 female, range, 24-84 years). FIELD STRENGTH/SEQUENCE: A wave-encoded variable-density SSFSE sequence was developed for clinical 3.0T abdominal scans to enable high acceleration (3.5×) with full-Fourier acquisitions by: 1) introducing wave encoding with self-refocusing gradient waveforms to improve acquisition efficiency; 2) developing self-calibrated estimation of wave-encoding point-spread function and coil sensitivity to improve motion robustness; and 3) incorporating a parallel imaging and compressed sensing reconstruction to reconstruct highly accelerated datasets. ASSESSMENT: Image quality was compared pairwise with standard Cartesian acquisition independently and blindly by two radiologists on a scale from -2 to 2 for noise, contrast, confidence, sharpness, and artifacts. The average ratio of scan time between these two approaches was also compared. STATISTICAL TESTS: A Wilcoxon signed-rank tests with a P value under 0.05 considered statistically significant. RESULTS: Wave-encoded variable-density SSFSE significantly reduced the perceived noise level and improved the sharpness of the abdominal wall and the kidneys compared with standard acquisition (mean scores 0.8, 1.2, and 0.8, respectively, P < 0.003). No significant difference was observed in relation to other features (P = 0.11). An average of 21% decrease in scan time was achieved using the proposed method. DATA CONCLUSION: Wave-encoded variable-density sampling SSFSE achieves improved image quality with clinically relevant echo time and reduced scan time, thus providing a fast and robust approach for clinical SSFSE imaging. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2018;47:954-966.
BACKGROUND: It is highly desirable in clinical abdominal MR scans to accelerate single-shot fast spin echo (SSFSE) imaging and reduce blurring due to T2 decay and partial-Fourier acquisition. PURPOSE: To develop and investigate the clinical feasibility of wave-encoded variable-density SSFSE imaging for improved image quality and scan time reduction. STUDY TYPE: Prospective controlled clinical trial. SUBJECTS: With Institutional Review Board approval and informed consent, the proposed method was assessed on 20 consecutive adult patients (10 male, 10 female, range, 24-84 years). FIELD STRENGTH/SEQUENCE: A wave-encoded variable-density SSFSE sequence was developed for clinical 3.0T abdominal scans to enable high acceleration (3.5×) with full-Fourier acquisitions by: 1) introducing wave encoding with self-refocusing gradient waveforms to improve acquisition efficiency; 2) developing self-calibrated estimation of wave-encoding point-spread function and coil sensitivity to improve motion robustness; and 3) incorporating a parallel imaging and compressed sensing reconstruction to reconstruct highly accelerated datasets. ASSESSMENT: Image quality was compared pairwise with standard Cartesian acquisition independently and blindly by two radiologists on a scale from -2 to 2 for noise, contrast, confidence, sharpness, and artifacts. The average ratio of scan time between these two approaches was also compared. STATISTICAL TESTS: A Wilcoxon signed-rank tests with a P value under 0.05 considered statistically significant. RESULTS: Wave-encoded variable-density SSFSE significantly reduced the perceived noise level and improved the sharpness of the abdominal wall and the kidneys compared with standard acquisition (mean scores 0.8, 1.2, and 0.8, respectively, P < 0.003). No significant difference was observed in relation to other features (P = 0.11). An average of 21% decrease in scan time was achieved using the proposed method. DATA CONCLUSION: Wave-encoded variable-density sampling SSFSE achieves improved image quality with clinically relevant echo time and reduced scan time, thus providing a fast and robust approach for clinical SSFSE imaging. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2018;47:954-966.
Authors: Feiyu Chen; Valentina Taviani; Itzik Malkiel; Joseph Y Cheng; Jonathan I Tamir; Jamil Shaikh; Stephanie T Chang; Christopher J Hardy; John M Pauly; Shreyas S Vasanawala Journal: Radiology Date: 2018-07-24 Impact factor: 11.105
Authors: Feiyu Chen; Joseph Y Cheng; Valentina Taviani; Vipul R Sheth; Ryan L Brunsing; John M Pauly; Shreyas S Vasanawala Journal: J Magn Reson Imaging Date: 2019-07-19 Impact factor: 4.813
Authors: Yuxin Hu; Xiaole Wang; Qiyuan Tian; Grant Yang; Bruce Daniel; Jennifer McNab; Brian Hargreaves Journal: Magn Reson Med Date: 2019-10-08 Impact factor: 4.668