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Teng Z, Wang S, Tokgoz A, Taviani V, Bird J, Sadat U, Huang Y, Patterson AJ, Figg N, Graves MJ, Gillard JH. Study on the association of wall shear stress and vessel structural stress with atherosclerosis: An experimental animal study. Atherosclerosis 2021; 320:38-46. [PMID: 33524908 DOI: 10.1016/j.atherosclerosis.2021.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND AIMS Artery is subject to wall shear stress (WSS) and vessel structural stress (VSS) simultaneously. This study is designed to explore the role of VSS in development of atherosclerosis. METHODS Silastic collars were deployed on the carotid to create two constrictions on 13 rabbits for a distinct mechanical environment at the constriction. MRI was performed to visualize arteries' configuration. Animals with high fat (n = 9; Model-group) and normal diet (n = 4; Control-group) were sacrificed after 16 weeks. 3D fluid-structure interaction analysis was performed to quantify WSS and VSS simultaneously. RESULTS Twenty plaques were found in Model-group and 3 in Control-group. In Model-group, 8 plaques located proximally to the first constriction (Region-1, close to the heart) and 7 distally to the second (Region-2, close to the head) and 5 plaques were found on the contralateral side of 3 rabbits. Plaques at Region-1 tended to be bigger than those at Region-2 and the macrophage density at these locations was comparable. Minimum time-averaged WSS (TAWSS) in Region-1 was significantly higher than that in Region-2, and both maximum oscillatory shear index (OSI) and particle relative residence time (RRT) were significantly lower. Peak and mean VSS in Region-1 were significantly higher than those in Region-2. Correlation analyses indicated that low TAWSS, high OSI and RRT were only associated with plaque in Region-2, while lesions in Region-1 were only associated with high VSS. Moreover, only VSS was associated with wall thickness of plaque-free regions in both regions. CONCLUSIONS VSS might contribute to the initialization and development of atherosclerosis solely or in combination with WSS.
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Affiliation(s)
- Zhongzhao Teng
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom; Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
| | - Shuo Wang
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom
| | - Aziz Tokgoz
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Valentina Taviani
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom
| | - Joseph Bird
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom
| | - Umar Sadat
- Cambridge Vascular Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Yuan Huang
- EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging, University of Cambridge, Cambridge, United Kingdom
| | - Andrew J Patterson
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom
| | - Nichola Figg
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom
| | - Martin J Graves
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom
| | - Jonathan H Gillard
- Department of Radiology, University of Cambridge, Cambridge, United Kingdom
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Jabarkheel R, Tong E, Lee EH, Cullen TM, Yousaf U, Loening AM, Taviani V, Iv M, Grant GA, Holdsworth SJ, Vasanawala SS, Yeom KW. Variable Refocusing Flip Angle Single-Shot Imaging for Sedation-Free Fast Brain MRI. AJNR Am J Neuroradiol 2020; 41:1256-1262. [PMID: 32586967 DOI: 10.3174/ajnr.a6616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 04/18/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Conventional single-shot FSE commonly used for fast MRI may be suboptimal for brain evaluation due to poor image contrast, SNR, or image blurring. We investigated the clinical performance of variable refocusing flip angle single-shot FSE, a variation of single-shot FSE with lower radiofrequency energy deposition and potentially faster acquisition time, as an alternative approach to fast brain MR imaging. MATERIALS AND METHODS We retrospectively compared half-Fourier single-shot FSE with half- and full-Fourier variable refocusing flip angle single-shot FSE in 30 children. Three readers reviewed images for motion artifacts, image sharpness at the brain-fluid interface, and image sharpness/tissue contrast at gray-white differentiation on a modified 5-point Likert scale. Two readers also evaluated full-Fourier variable refocusing flip angle single-shot FSE against T2-FSE for brain lesion detectability in 38 children. RESULTS Variable refocusing flip angle single-shot FSE sequences showed more motion artifacts (P < .001). Variable refocusing flip angle single-shot FSE sequences scored higher regarding image sharpness at brain-fluid interfaces (P < .001) and gray-white differentiation (P < .001). Acquisition times for half- and full-Fourier variable refocusing flip angle single-shot FSE were faster than for single-shot FSE (P < .001) with a 53% and 47% reduction, respectively. Intermodality agreement between full-Fourier variable refocusing flip angle single-shot FSE and T2-FSE findings was near-perfect (κ = 0.90, κ = 0.95), with an 8% discordance rate for ground truth lesion detection. CONCLUSIONS Variable refocusing flip angle single-shot FSE achieved 2× faster scan times than single-shot FSE with improved image sharpness at brain-fluid interfaces and gray-white differentiation. Such improvements are likely attributed to a combination of improved contrast, spatial resolution, SNR, and reduced T2-decay associated with blurring. While variable refocusing flip angle single-shot FSE may be a useful alternative to single-shot FSE and, potentially, T2-FSE when faster scan times are desired, motion artifacts were more common in variable refocusing flip angle single-shot FSE, and, thus, they remain an important consideration before clinical implementation.
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Affiliation(s)
- R Jabarkheel
- From the Stanford University School of Medicine (R.J.)
| | - E Tong
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - E H Lee
- Electrical Engineering (E.H.L.)
| | - T M Cullen
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
| | - U Yousaf
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
| | - A M Loening
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - V Taviani
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - M Iv
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - G A Grant
- Neurosurgery (G.A.G.), Stanford University, Stanford, California
| | - S J Holdsworth
- Department of Anatomy and Medical Imaging and Centre for Brain Research (S.J.H.), Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - S S Vasanawala
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
| | - K W Yeom
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
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3
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Chen F, Cheng JY, Taviani V, Sheth VR, Brunsing RL, Pauly JM, Vasanawala SS. Data-driven self-calibration and reconstruction for non-cartesian wave-encoded single-shot fast spin echo using deep learning. J Magn Reson Imaging 2019; 51:841-853. [PMID: 31322799 DOI: 10.1002/jmri.26871] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/03/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Current self-calibration and reconstruction methods for wave-encoded single-shot fast spin echo imaging (SSFSE) requires long computational time, especially when high accuracy is needed. PURPOSE To develop and investigate the clinical feasibility of data-driven self-calibration and reconstruction of wave-encoded SSFSE imaging for computation time reduction and quality improvement. STUDY TYPE Prospective controlled clinical trial. SUBJECTS With Institutional Review Board approval, the proposed method was assessed on 29 consecutive adult patients (18 males, 11 females, range, 24-77 years). FIELD STRENGTH/SEQUENCE A wave-encoded variable-density SSFSE sequence was developed for clinical 3.0T abdominal scans to enable 3.5× acceleration with full-Fourier acquisitions. Data-driven calibration of wave-encoding point-spread function (PSF) was developed using a trained deep neural network. Data-driven reconstruction was developed with another set of neural networks based on the calibrated wave-encoding PSF. Training of the calibration and reconstruction networks was performed on 15,783 2D wave-encoded SSFSE abdominal images. ASSESSMENT Image quality of the proposed data-driven approach was compared independently and blindly with a conventional approach using iterative self-calibration and reconstruction with parallel imaging and compressed sensing by three radiologists on a scale from -2 to 2 for noise, contrast, sharpness, artifacts, and confidence. Computation time of these two approaches was also compared. STATISTICAL TESTS Wilcoxon signed-rank tests were used to compare image quality and two-tailed t-tests were used to compare computation time with P values of under 0.05 considered statistically significant. RESULTS An average 2.1-fold speedup in computation was achieved using the proposed method. The proposed data-driven self-calibration and reconstruction approach significantly reduced the perceived noise level (mean scores 0.82, P < 0.0001). DATA CONCLUSION The proposed data-driven calibration and reconstruction achieved twice faster computation with reduced perceived noise, providing a fast and robust self-calibration and reconstruction for clinical abdominal SSFSE imaging. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:841-853.
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Affiliation(s)
- Feiyu Chen
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | - Joseph Y Cheng
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Valentina Taviani
- Global MR Applications and Workflow, GE Healthcare, Menlo Park, California, USA
| | - Vipul R Sheth
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Ryan L Brunsing
- Department of Radiology, Stanford University, Stanford, California, USA
| | - John M Pauly
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
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Tamir JI, Taviani V, Alley MT, Perkins B, Hart L, Obrien K, Wishah F, Sandberg JK, Anderson MJ, Turek JS, Willke TL, Lustig M, Vasanawala SS. Targeted rapid knee MRI exam using T 2 shuffling. J Magn Reson Imaging 2019; 49:e195-e204. [PMID: 30637847 PMCID: PMC6551292 DOI: 10.1002/jmri.26600] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/18/2018] [Accepted: 11/19/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND MRI is commonly used to evaluate pediatric musculoskeletal pathologies, but same-day/near-term scheduling and short exams remain challenges. PURPOSE To investigate the feasibility of a targeted rapid pediatric knee MRI exam, with the goal of reducing cost and enabling same-day MRI access. STUDY TYPE A cost effectiveness study done prospectively. SUBJECTS Forty-seven pediatric patients. FIELD STRENGTH/SEQUENCE 3T. The 10-minute protocol was based on T2 Shuffling, a four-dimensional acquisition and reconstruction of images with variable T2 contrast, and a T1 2D fast spin-echo (FSE) sequence. A distributed, compressed sensing-based reconstruction was implemented on a four-node high-performance compute cluster and integrated into the clinical workflow. ASSESSMENT In an Institutional Review Board-approved study with informed consent/assent, we implemented a targeted pediatric knee MRI exam for assessing pediatric knee pain. Pediatric patients were subselected for the exam based on insurance plan and clinical indication. Over a 2-year period, 47 subjects were recruited for the study and 49 MRIs were ordered. Date and time information was recorded for MRI referral, registration, and completion. Image quality was assessed from 0 (nondiagnostic) to 5 (outstanding) by two readers, and consensus was subsequently reached. STATISTICAL TESTS A Wilcoxon rank-sum test assessed the null hypothesis that the targeted exam times compared with conventional knee exam times were unchanged. RESULTS Of the 49 cases, 20 were completed on the same day as exam referral. Median time from registration to exam completion was 18.7 minutes. Median reconstruction time for T2 Shuffling was reduced from 18.9 minutes to 95 seconds using the distributed implementation. Technical fees charged for the targeted exam were one-third that of the routine clinical knee exam. No subject had to return for additional imaging. DATA CONCLUSION The targeted knee MRI exam is feasible and reduces the imaging time, cost, and barrier to same-day MRI access for pediatric patients. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2019.
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Affiliation(s)
- Jonathan I. Tamir
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Valentina Taviani
- Global Applied Science Laboratory, GE Healthcare, Menlo Park, California, USA
| | - Marcus T. Alley
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Becki Perkins
- Department of Radiology, Lucile Packard Children’s Hospital, Stanford, California, USA
| | - Lori Hart
- Department of Radiology, Lucile Packard Children’s Hospital, Stanford, California, USA
| | - Kendall Obrien
- Department of Radiology, Lucile Packard Children’s Hospital, Stanford, California, USA
| | - Fidaa Wishah
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Jesse K Sandberg
- Department of Radiology, Stanford University, Stanford, California, USA
| | | | - Javier S. Turek
- Brain-Inspired Computing Lab, Intel Labs, Hillsboro, Oregon, USA
| | | | - Michael Lustig
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
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Winkler SA, Corea J, Lechêne B, O'Brien K, Bonanni JR, Chaudhari A, Alley M, Taviani V, Grafendorfer T, Robb F, Scott G, Pauly J, Lustig M, Arias AC, Vasanawala S. Evaluation of a Flexible 12-Channel Screen-printed Pediatric MRI Coil. Radiology 2019; 291:180-185. [PMID: 30806599 DOI: 10.1148/radiol.2019181883] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Background Screen-printed MRI coil technology may reduce the need for bulky and heavy housing of coil electronics and may provide a better fit to patient anatomy to improve coil performance. Purpose To assess the performance and caregiver and clinician acceptance of a pediatric-sized screen-printed flexible MRI coil array as compared with conventional coil technology. Materials and Methods A pediatric-sized 12-channel coil array was designed by using a screen-printing process. Element coupling and phantom signal-to-noise ratio (SNR) were assessed. Subjects were scanned by using the pediatric printed array between September and November 2017; results were compared with three age- and sex-matched historical control subjects by using a commercial 32-channel cardiac array at 3 T. Caregiver acceptance was assessed by asking nurses, technologists, anesthesiologists, and subjects or parents to rate their coil preference. Diagnostic quality of the images was evaluated by using a Likert scale (5 = high image quality, 1 = nondiagnostic). Image SNR was evaluated and compared. Results Twenty study participants were evaluated with the screen-printed coil (age range, 2 days to 12 years; 11 male and nine female subjects). Loaded pediatric phantom testing yielded similar noise covariance matrices and only slightly degraded SNR for the printed coil as compared with the commercial coil. The caregiver acceptance survey yielded a mean score of 4.1 ± 0.6 (scale: 1, preferred the commercial coil; 5, preferred the printed coil). Diagnostic quality score was 4.5 ± 0.6. Mean image SNR was 54 ± 49 (paraspinal muscle), 78 ± 51 (abdominal wall muscle), and 59 ± 35 (psoas) for the printed coil, as compared with 64 ± 55, 65 ± 48, and 57 ± 43, respectively, for the commercial coil; these SNR differences were not statistically significant (P = .26). Conclusion A flexible screen-printed pediatric MRI receive coil yields adequate signal-to-noise ratio in phantoms and pediatric study participants, with similar image quality but higher preference by subjects and their caregivers when compared with a conventional MRI coil. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Lamb in this issue.
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Affiliation(s)
- Simone Angela Winkler
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Joseph Corea
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Balthazar Lechêne
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Kendall O'Brien
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - John Ross Bonanni
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Akshay Chaudhari
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Marcus Alley
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Valentina Taviani
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Thomas Grafendorfer
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Fraser Robb
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Greig Scott
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - John Pauly
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Michael Lustig
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Ana Claudia Arias
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
| | - Shreyas Vasanawala
- From the Department of Radiology, Stanford University, 300 Pasteur Dr, Stanford, CA 94305 (S.A.W., A.C., M.A., S.V.); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Calif (J.C., B.L., M.L., A.C.A.); Lucile Packard Children's Hospital at Stanford, Stanford, Calif (K.O., J.R.B.); GE Healthcare, Menlo Park, Calif (V.T.); GE Healthcare, Aurora, Ohio (T.G., F.R.); and Department of Electrical Engineering, Stanford University, Stanford, Calif (G.S., J.P.)
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6
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Hu Y, Levine EG, Tian Q, Moran CJ, Wang X, Taviani V, Vasanawala S, McNab JA, Daniel BL, Hargreaves BA. Motion-robust reconstruction of multishot diffusion-weighted images without phase estimation through locally low-rank regularization. Magn Reson Med 2019; 81:1181-1190. [PMID: 30346058 PMCID: PMC6289606 DOI: 10.1002/mrm.27488] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 07/11/2018] [Accepted: 07/18/2018] [Indexed: 11/12/2022]
Abstract
PURPOSE The goal of this work is to propose a motion robust reconstruction method for diffusion-weighted MRI that resolves shot-to-shot phase mismatches without using phase estimation. METHODS Assuming that shot-to-shot phase variations are slowly varying, spatial-shot matrices can be formed using a local group of pixels to form columns, in which each column is from a different shot (excitation). A convex model with a locally low-rank constraint on the spatial-shot matrices is proposed. In vivo brain and breast experiments were performed to evaluate the performance of the proposed method. RESULTS The proposed method shows significant benefits when the motion is severe, such as for breast imaging. Furthermore, the resulting images can be used for reliable phase estimation in the context of phase-estimation-based methods to achieve even higher image quality. CONCLUSION We introduced the shot-locally low-rank method, a reconstruction technique for multishot diffusion-weighted MRI without explicit phase estimation. In addition, its motion robustness can be beneficial to neuroimaging and body imaging.
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Affiliation(s)
- Yuxin Hu
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Evan G. Levine
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Qiyuan Tian
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
- Department of Radiology, Stanford University, Stanford, California, USA
| | | | - Xiaole Wang
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | | | | | - Jennifer A. McNab
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Bruce L. Daniel
- Department of Radiology, Stanford University, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Brian A. Hargreaves
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
- Department of Radiology, Stanford University, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
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7
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Chen F, Taviani V, Malkiel I, Cheng JY, Tamir JI, Shaikh J, Chang ST, Hardy CJ, Pauly JM, Vasanawala SS. Variable-Density Single-Shot Fast Spin-Echo MRI with Deep Learning Reconstruction by Using Variational Networks. Radiology 2018; 289:366-373. [PMID: 30040039 PMCID: PMC6209075 DOI: 10.1148/radiol.2018180445] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/08/2018] [Accepted: 05/15/2018] [Indexed: 02/01/2023]
Abstract
Purpose To develop a deep learning reconstruction approach to improve the reconstruction speed and quality of highly undersampled variable-density single-shot fast spin-echo imaging by using a variational network (VN), and to clinically evaluate the feasibility of this approach. Materials and Methods Imaging was performed with a 3.0-T imager with a coronal variable-density single-shot fast spin-echo sequence at 3.25 times acceleration in 157 patients referred for abdominal imaging (mean age, 11 years; range, 1-34 years; 72 males [mean age, 10 years; range, 1-26 years] and 85 females [mean age, 12 years; range, 1-34 years]) between March 2016 and April 2017. A VN was trained based on the parallel imaging and compressed sensing (PICS) reconstruction of 130 patients. The remaining 27 patients were used for evaluation. Image quality was evaluated in an independent blinded fashion by three radiologists in terms of overall image quality, perceived signal-to-noise ratio, image contrast, sharpness, and residual artifacts with scores ranging from 1 (nondiagnostic) to 5 (excellent). Wilcoxon tests were performed to test the hypothesis that there was no significant difference between VN and PICS. Results VN achieved improved perceived signal-to-noise ratio (P = .01) and improved sharpness (P < .001), with no difference in image contrast (P = .24) and residual artifacts (P = .07). In terms of overall image quality, VN performed better than did PICS (P = .02). Average reconstruction time ± standard deviation was 5.60 seconds ± 1.30 per section for PICS and 0.19 second ± 0.04 per section for VN. Conclusion Compared with the conventional parallel imaging and compressed sensing reconstruction (PICS), the variational network (VN) approach accelerates the reconstruction of variable-density single-shot fast spin-echo sequences and achieves improved overall image quality with higher perceived signal-to-noise ratio and sharpness. © RSNA, 2018 Online supplemental material is available for this article.
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Affiliation(s)
| | | | - Itzik Malkiel
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
| | - Joseph Y. Cheng
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
| | - Jonathan I. Tamir
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
| | - Jamil Shaikh
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
| | - Stephanie T. Chang
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
| | - Christopher J. Hardy
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
| | - John M. Pauly
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
| | - Shreyas S. Vasanawala
- From the Departments of Electrical Engineering (F.C., J.M.P.) and Radiology (J.Y.C., J.S., S.T.C., S.S.V.), Stanford University, Stanford, Calif 94305-9510; Global MR Applications and Workflow, GE Healthcare, Menlo Park, Calif (V.T.); GE Global Research Center, Herzliya, Israel (I.M.); Department of Electrical Engineering and Computer Sciences, University of California–Berkeley, Berkeley, Calif (J.I.T.); Department of Radiology, VA Palo Alto Healthcare System, Palo Alto, Calif (S.T.C.); and GE Global Research Center, Niskayuna, NY (C.J.H.)
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8
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Wang H, Felt SA, Guracar I, Taviani V, Zhou J, Sigrist RMS, Zhang H, Liau J, Vilches-Moure JG, Tian L, Saenz Y, Bettinger T, Hargreaves BA, Lutz AM, Willmann JK. Anatomical Road Mapping Using CT and MR Enterography for Ultrasound Molecular Imaging of Small Bowel Inflammation in Swine. Eur Radiol 2017; 28:2068-2076. [PMID: 29170798 DOI: 10.1007/s00330-017-5148-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/27/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To evaluate the feasibility and time saving of fusing CT and MR enterography with ultrasound for ultrasound molecular imaging (USMI) of inflammation in an acute small bowel inflammation of swine. METHODS Nine swine with ileitis were scanned with either CT (n = 3) or MR (n = 6) enterography. Imaging times to load CT/MR images onto a clinical ultrasound machine, fuse them to ultrasound with an anatomical landmark-based approach, and identify ileitis were compared to the imaging times without anatomical road mapping. Inflammation was then assessed by USMI using dual selectin-targeted (MBSelectin) and control (MBControl) contrast agents in diseased and healthy control bowel segments, followed by ex vivo histology. RESULTS Cross-sectional image fusion with ultrasound was feasible with an alignment error of 13.9 ± 9.7 mm. Anatomical road mapping significantly reduced (P < 0.001) scanning times by 40%. Localising ileitis was achieved within 1.0 min. Subsequently performed USMI demonstrated significantly (P < 0.001) higher imaging signal using MBSelectin compared to MBControl and histology confirmed a significantly higher inflammation score (P = 0.006) and P- and E-selectin expression (P ≤ 0.02) in inflamed vs. healthy bowel. CONCLUSIONS Fusion of CT and MR enterography data sets with ultrasound in real time is feasible and allows rapid anatomical localisation of ileitis for subsequent quantification of inflammation using USMI. KEY POINTS • Real-time fusion of CT/MRI with ultrasound to localise ileitis is feasible. • Anatomical road mapping using CT/MRI significantly decreases the scanning time for USMI. • USMI allows quantification of inflammation in swine, verified with ex vivo histology.
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Affiliation(s)
- Huaijun Wang
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | - Stephen A Felt
- Department of Comparative Medicine, Stanford University, Stanford, CA, USA
| | - Ismayil Guracar
- Siemens Healthcare, Ultrasound Business Unit, Mountain View, CA, USA
| | - Valentina Taviani
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | - Jianhua Zhou
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | - Rosa Maria Silveira Sigrist
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | - Huiping Zhang
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | - Joy Liau
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | | | - Lu Tian
- Department of Health, Research & Policy, Stanford University, Stanford, CA, USA
| | - Yamil Saenz
- Department of Comparative Medicine, Stanford University, Stanford, CA, USA
| | | | - Brian A Hargreaves
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | - Amelie M Lutz
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA
| | - Jürgen K Willmann
- Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Room H1307, Stanford, CA, 94305-5621, USA.
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9
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Obara P, Loening A, Taviani V, Iagaru A, Hargreaves BA, Vasanawala S. Relative value of three whole-body MR approaches for PET-MR, including gadofosveset-enhanced MR, in comparison to PET-CT. Clin Imaging 2017; 48:62-68. [PMID: 29031209 DOI: 10.1016/j.clinimag.2017.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/02/2017] [Accepted: 09/27/2017] [Indexed: 01/16/2023]
Abstract
PURPOSE Evaluate MR protocol for PET-MR including coronal DWI (cDWI), fat-suppressed T2 (T2w), and gadofosveset-enhanced T1 (CE). MATERIALS AND METHODS 18 patients underwent same-day PET-CT and PET-MR. Image quality and performance of each sequence, and combination of all three sequences, was evaluated with respect to PET-CT. RESULTS Lesion conspicuity was best on cDWI, while delineation was best on CE. Considering all three sequences combined, both readers showed good sensitivity and specificity (>80%). Relative sensitivity was highest on CE and lowest on T2w. CONCLUSIONS Whole-body MR performed well in detecting malignant lesions compared to PET-CT. CE showed overall highest performance.
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Affiliation(s)
- Piotr Obara
- Stanford University, 300 Pastuer Drive, Stanford, CA 94305, United States.
| | - Andreas Loening
- Stanford University, 300 Pastuer Drive, Stanford, CA 94305, United States.
| | - Valentina Taviani
- Stanford University, Lucas Center for Imaging, 1201 Welch Rd, Stanford, CA 94305, United States.
| | - Andrei Iagaru
- Stanford University, 300 Pastuer Drive, Stanford, CA 94305, United States.
| | - Brian A Hargreaves
- Stanford University, Lucas Center for Imaging, 1201 Welch Rd, Stanford, CA 94305, United States.
| | - Shreyas Vasanawala
- Stanford University, 300 Pastuer Drive, Stanford, CA 94305, United States.
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10
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Chen F, Taviani V, Tamir JI, Cheng JY, Zhang T, Song Q, Hargreaves BA, Pauly JM, Vasanawala SS. Self-Calibrating Wave-Encoded Variable-Density Single-Shot Fast Spin Echo Imaging. J Magn Reson Imaging 2017; 47:954-966. [PMID: 28906567 DOI: 10.1002/jmri.25853] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/24/2017] [Indexed: 11/10/2022] Open
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.
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Affiliation(s)
- Feiyu Chen
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | - Valentina Taviani
- Global MR Applications and Workflow, GE Healthcare, Menlo Park, California, USA
| | - Jonathan I Tamir
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Joseph Y Cheng
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Tao Zhang
- Global MR Applications and Workflow, GE Healthcare, Houston, Texas, USA
| | - Qiong Song
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Radiology, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang, PRC
| | | | - John M Pauly
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
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11
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Hargreaves BA, Taviani V, Litwiller DV, Yoon D. 2D multi-spectral imaging for fast MRI near metal. Magn Reson Med 2017; 79:968-973. [PMID: 28444805 DOI: 10.1002/mrm.26724] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/07/2017] [Accepted: 03/29/2017] [Indexed: 01/19/2023]
Abstract
PURPOSE To develop a fast 2D method for MRI near metal with reduced B0 in-plane and through-slice artifacts. METHODS Multi-spectral imaging (MSI) approaches reduce artifacts in MR images near metal, but require 3D imaging of multiple excited volumes regardless of imaging geometry or artifact severity. The proposed 2D MSI method rapidly excites a limited slice and spectral region using gradient reversal between excitation and refocusing pulses, then uses standard 2D imaging, with the process repeating to cover multiple spectral offsets that are combined as in other MSI techniques. 2D MSI was implemented in a spin-echo-train sequence and validated in phantoms and in vivo by comparing it with standard spin-echo imaging and existing MSI techniques. RESULTS 2D MSI images for each spatial-spectral region follow isocontours of the dipole-like B0 field variation, and thus frequency variation, near metal devices. Artifact correction in phantoms and human subjects with metal is comparable to 3D MSI methods, and superior to standard spin-echo techniques. Scan times are reduced compared with 3D MSI methods in cases where a limited number of slices are needed, though signal-to-noise ratio is also reduced as expected. CONCLUSION 2D MSI offers a fast and flexible alternative to 3D MSI for artifact reduction near metal. Magn Reson Med 79:968-973, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Brian A Hargreaves
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | | | | | - Daehyun Yoon
- Department of Radiology, Stanford University, Stanford, California, USA
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Fowlkes B, Ghanouni P, Sanghvi N, Coussios C, Lyon PC, Gray M, Mannaris C, Victor MDS, Stride E, Cleveland R, Carlisle R, Wu F, Middleton M, Gleeson F, Aubry JF, Pauly KB, Moonen C, Vortman J, Ghanouni P, Sharabi S, Daniels D, Last D, Guez D, Levy Y, Volovick A, Grinfeld J, Rachmilevich I, Amar T, Zibly Z, Mardor Y, Harnof S, Plaksin M, Weissler Y, Shoham S, Kimmel E, Naor O, Farah N, Shoham S, Paeng DG, Xu Z, Snell J, Quigg AH, Eames M, Jin C, Everstine AC, Sheehan JP, Lopes BS, Kassell N, Looi T, Khokhlova V, Mougenot C, Hynynen K, Drake J, Slayton M, Amodei RC, Compton K, McNelly A, Latt D, Slayton M, Amodei RC, Compton K, Kearney J, Melodelima D, Dupre A, Chen Y, Perol D, Vincenot J, Chapelon JY, Rivoire M, Guo W, Ren G, Shen G, Neidrauer M, Zubkov L, Weingarten MS, Margolis DJ, Lewin PA, McDannold N, Sutton J, Vykhodtseva N, Livingstone M, Kobus T, Zhang YZ, Vykhodtseva N, McDannold N, Schwartz M, Huang Y, Lipsman N, Jain J, Chapman M, Sankar T, Lozano A, Hynynen K, Schwartz M, Yeung R, Huang Y, Lipsman N, Jain J, Chapman M, Lozano A, Hynynen K, Damianou C, Papadopoulos N, Volovick A, Grinfeld J, Levy Y, Brokman O, Zadicario E, Brenner O, Castel D, Wu SY, Grondin J, Zheng W, Heidmann M, Karakatsani ME, Sánchez CJS, Ferrera V, Konofagou EE, Damianou C, Yiannakou M, Cho H, Lee H, Han M, Choi JR, Lee T, Ahn S, Chang Y, Park J, Ellens N, Partanen A, Farahani K, Airan R, Carpentier A, Canney M, Vignot A, Lafon C, Chapelon JY, Delattre JY, Idbaih A, Odéen H, Bolster B, Jeong EK, Parker DL, Gaur P, Feng X, Fielden S, Meyer C, Werner B, Grissom W, Marx M, Ghanouni P, Pauly KB, Weber H, Taviani V, Pauly KB, Ghanouni P, Hargreaves B, Tanaka J, Kikuchi K, Ishijima A, Azuma T, Minamihata K, Yamaguchi S, Nagamune T, Sakuma I, Takagi S, Santin MD, Marsac L, Maimbourg G, Monfort M, Larrat B, François C, Lehéricy S, Tanter M, Aubry JF, Karakatsani ME, Samiotaki G, Wang S, Acosta C, Feinberg ER, Konofagou EE, Kovacs ZI, Tu TW, Papadakis GZ, Reid WC, Hammoud DA, Frank JA, Kovacs ZI, Kim S, Jikaria N, Bresler M, Qureshi F, Frank JA, Xia J, Tsui PS, Liu HL, Plata JC, Fielden S, Sveinsson B, Hargreaves B, Meyer C, Pauly KB, Plata JC, Salgaonkar VA, Adams M, Diederich C, Ozhinsky E, Bucknor MD, Rieke V, Partanen A, Mikhail A, Severance L, Negussie AH, Wood B, de Greef M, Schubert G, Moonen C, Ries M, Poorman ME, Dockery M, Chaplin V, Dudzinski SO, Spears R, Caskey C, Giorgio T, Grissom W, Costa MM, Papaevangelou E, Shah A, Rivens I, Box C, Bamber J, ter Haar G, Burks SR, Nagle M, Nguyen B, Bresler M, Frank JA, Burks SR, Nagle M, Nguyen B, Bresler M, Kim S, Milo B, Frank JA, Le NM, Song S, Zhou K, Nabi G, Huang Z, Ben-Ezra S, Rosen S, Mihcin S, Strehlow J, Karakitsios I, Le N, Schwenke M, Demedts D, Prentice P, Haase S, Preusser T, Melzer A, Mestas JL, Chettab K, Gomez GS, Dumontet C, Werle B, Lafon C, Marquet F, Bour P, Vaillant F, Amraoui S, Dubois R, Ritter P, Haïssaguerre M, Hocini M, Bernus O, Quesson B, Livneh A, Kimmel E, Adam D, Robin J, Arnal B, Fink M, Tanter M, Pernot M, Khokhlova TD, Schade GR, Wang YN, Kreider W, Simon J, Starr F, Karzova M, Maxwell A, Bailey MR, Khokhlova V, Lundt JE, Allen SP, Sukovich JR, Hall T, Xu Z, Schade GR, Wang YN, Khokhlova TD, May P, Lin DW, Bailey MR, Khokhlova V, Constans C, Deffieux T, Tanter M, Aubry JF, Park EJ, Ahn YD, Kang SY, Park DH, Lee JY, Vidal-Jove J, Perich E, Ruiz A, Jaen A, Eres N, del Castillo MA, Myers R, Kwan J, Coviello C, Rowe C, Crake C, Finn S, Jackson E, Carlisle R, Coussios C, Pouliopoulos A, Li C, Tinguely M, Tang MX, Garbin V, Choi JJ, Lyon PC, Mannaris C, Gray M, Folkes L, Stratford M, Carlisle R, Wu F, Middleton M, Gleeson F, Coussios C, Nwokeoha S, Carlisle R, Cleveland R, Wang YN, Khokhlova TD, Li T, Farr N, D’Andrea S, Starr F, Gravelle K, Chen H, Partanen A, Lee D, Hwang JH, Tardoski S, Ngo J, Gineyts E, Roux JP, Clézardin P, Melodelima D, Conti A, Magnin R, Gerstenmayer M, Lux F, Tillement O, Mériaux S, Penna SD, Romani GL, Dumont E, Larrat B, Sun T, Power C, Zhang YZ, Sutton J, Miller E, McDannold N, Sapozhnikov O, Tsysar S, Yuldashev PV, Khokhlova V, Svet V, Kreider W, Li D, Pellegrino A, Petrinic N, Siviour C, Jerusalem A, Cleveland R, Yuldashev PV, Karzova M, Cunitz BW, Dunmire B, Kreider W, Sapozhnikov O, Bailey MR, Khokhlova V, Inserra C, Guedra M, Mauger C, Gilles B, Solovchuk M, Sheu TWH, Thiriet M, Zhou Y, Neufeld E, Baumgartner C, Payne D, Kyriakou A, Kuster N, Xiao X, McLeod H, Melzer A, Dillon C, Rieke V, Ghanouni P, Parker DL, Payne A, Khokhova VA, Yuldashev PV, Sinilshchikov I, Andriyakhina Y, Khokhlova TD, Kreider W, Maxwell A, Sapozhnikov O, Partanen A, Rybyanets A, Shvetsova N, Berkovich A, Shvetsov I, Sapozhnikov O, Khokhlova V, Shaw CJ, Rivens I, Civale J, Giussani D, ter Haar G, Lees C, Bour P, Marquet F, Ozenne V, Toupin S, Quesson B, Dumont E, Ozhinsky E, Salgaonkar V, Diederich C, Rieke V, Kaye E, Monette S, Maybody M, Srimathveeravalli G, Solomon S, Gulati A, Preusser T, Haase S, Bezzi M, Jenne JW, Lango T, Levy Y, Müller M, Sat G, Tanner C, Zangos S, Günther M, Melzer A, Lafon C, Dinh AH, Niaf E, Bratan F, Guillen N, Souchon R, Lartizien C, Crouzet S, Rouviere O, Chapelon JY, Han Y, Wang S, Konofagou EE, Payen T, Palermo C, Sastra S, Chen H, Han Y, Olive K, Konofagou EE, van Breugel JM, de Greef M, Mougenot C, van den Bosch MA, Moonen C, Ries M, Gerstenmayer M, Magnin R, Fellah B, Le Bihan D, Larrat B, Gerstenmayer M, Magnin R, Mériaux S, Le Bihan D, Larrat B, Allen SP, Hernandez-Garcia L, Cain CA, Hall T, Lyka E, Elbes D, Coviello C, Cleveland R, Coussios C, Zhou K, Le NM, Li C, Huang Z, Tamano S, Jimbo H, Azuma T, Yoshizawa S, Fujiwara K, Itani K, Umemura SI, Damianou C, Yiannakou M, Ellens N, Partanen A, Stoianovici D, Farahani K, Zaini Z, Takagi R, Yoshizawa S, Umemura SI, Zong S, Shen G, Watkins R, Pascal-Tenorio A, Adams M, Plata JC, Salgaonkar V, Jones P, Butts-Pauly K, Diederich C, Bouley D, Rybyanets A, Ren G, Guo W, Shen G, Chen Y, Lin CY, Hsieh HY, Wei KC, Liu HL, Garnier C, Renault G, Farr N, Partanen A, Negussie AH, Mikhail A, Seifabadi R, Wilson E, Eranki A, Kim P, Wood B, Lübke D, Jenne JW, Huber P, Günther M, Lübke D, Georgii J, Schwenke M, Dresky CV, Haller J, Günther M, Preusser T, Jenne JW, Eranki A, Farr N, Partanen A, Yarmolenko P, Negussie AH, Sharma K, Celik H, Wood B, Kim P, Li G, Qiu W, Zheng H, Tsai MY, Chu PC, Liu HL, Webb T, Vyas U, Pauly KB, Walker M, Zhong J, Looi T, Waspe AC, Drake J, Hodaie M, Yang FY, Huang SL, Zur Y, Volovick A, Assif B, Aurup C, Kamimura H, Wang S, Chen H, Acosta C, Carneiro AA, Konofagou EE, Volovick A, Grinfeld J, Castel D, Rothlübbers S, Schwaab J, Tanner C, Mihcin S, Houston G, Günther M, Jenne JW, Ozhinsky E, Bucknor MD, Rieke V, Azhari H, Weiss N, Sosna J, Goldberg SN, Barrere V, Melodelima D, Jang KW, Burks SR, Kovacs ZI, Tu TW, Lewis B, Kim S, Nagle M, Jikaria N, Frank JA, Zhou Y, Wang X, Ahn YD, Park EJ, Park DH, Kang SY, Lee JY, Suomi V, Konofagou EE, Edwards D, Cleveland R, Larrabee Z, Eames M, Hananel A, Aubry JF, Rafaely B, Volovick A, Grinfeld J, Kimmel E, Debbiny RE, Dekel CZ, Assa M, Kimmel E, Menikou G, Damianou C, Mouratidis P, Rivens I, ter Haar G, Pineda-Pardo JA, de Pedro MDÁ, Martinez R, Hernandez F, Casas S, Oliver C, Pastor P, Vela L, Obeso J, Greillier P, Zorgani A, Souchon R, Melodelima D, Catheline S, Lafon C, Solovov V, Vozdvizhenskiy MO, Orlov AE, Wu CH, Sun MK, Shih TT, Chen WS, Prieur F, Pillon A, Mestas JL, Cartron V, Cebe P, Chansard N, Lafond M, Lafon C, Inserra C, Seya PM, Chen WS, Bera JC, Boissenot T, Larrat B, Fattal E, Bordat A, Chacun H, Guetin C, Tsapis N, Maruyama K, Unga J, Suzuki R, Fant C, Lafond M, Rogez B, Ngo J, Lafon C, Mestas JL, Afadzi M, Myhre OF, Vea S, Bjørkøy A, Yemane PT, van Wamel A, Berg S, Hansen R, Angelsen B, Davies C. International Society for Therapeutic Ultrasound Conference 2016. J Ther Ultrasound 2017. [PMCID: PMC5374646 DOI: 10.1186/s40349-016-0079-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Weber H, Taviani V, Yoon D, Ghanouni P, Pauly KB, Hargreaves BA. MR thermometry near metallic devices using multispectral imaging. Magn Reson Med 2016; 77:1162-1169. [PMID: 26991803 DOI: 10.1002/mrm.26203] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/27/2016] [Accepted: 02/16/2016] [Indexed: 11/07/2022]
Abstract
PURPOSE The lack of a technique for MR thermometry near metal excludes a growing patient population from promising treatments such as MR-guided focused ultrasound therapy. Here we explore the feasibility of multispectral imaging (MSI) for noninvasive temperature measurement in the presence of strong field inhomogeneities by exploiting the temperature dependency of the T1 relaxation time. METHODS A two-dimensional inversion-recovery-prepared MSI pulse sequence (2DMSI) was implemented for artifact-reduced T1 mapping near metal. A series of T1 maps was acquired in a metallic implant phantom while increasing the phantom temperature. The measured change in T1 was analyzed with respect to the phantom temperature. For comparison, proton resonance frequency shift (PRFS) thermometry was performed. RESULTS 2DMSI achieved artifact-reduced, single-slice T1 mapping in the presence of strong off-resonance with a spatial resolution of 1.9 mm in-plane and a temporal resolution of 5 min. The maps enabled temperature measurements over a range of 30°C with an uncertainty below 1.4°C. The quality of the resulting temperature maps was independent of the distance from the metal, whereas the PRFS-based temperature measurements were increasingly impaired with increasing off-resonance. CONCLUSION We demonstrated the ability to noninvasively measure temperature near metal using MSI and the T1 temperature sensitivity. Magn Reson Med 77:1162-1169, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hans Weber
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Valentina Taviani
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Daehyun Yoon
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Pejman Ghanouni
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Kim Butts Pauly
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Brian A Hargreaves
- Department of Radiology, Stanford University, Palo Alto, California, USA
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Taviani V, Alley MT, Banerjee S, Nishimura DG, Daniel BL, Vasanawala SS, Hargreaves BA. High-resolution diffusion-weighted imaging of the breast with multiband 2D radiofrequency pulses and a generalized parallel imaging reconstruction. Magn Reson Med 2016; 77:209-220. [PMID: 26778549 DOI: 10.1002/mrm.26110] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 11/20/2015] [Accepted: 12/07/2015] [Indexed: 12/25/2022]
Abstract
PURPOSE To develop a technique for high-resolution diffusion-weighted imaging (DWI) and to compare it with standard DWI methods. METHODS Multiple in-plane bands of magnetization were simultaneously excited by identically phase modulating each subpulse of a two-dimensional (2D) RF pulse. Several excitations with the same multiband pattern progressively shifted in the phase-encode direction were used to cover the prescribed field of view (FOV). The phase-encoded FOV was limited to the width of a single band to reduce off-resonance-induced distortion and blurring. Parallel imaging (PI) techniques were used to resolve aliasing from the other bands and to combine the different excitations. Following validation in phantoms and healthy volunteers, a preliminary study in breast cancer patients (N=14) was performed to compare the proposed method to conventional DWI with PI and to reduced-FOV DWI. RESULTS The proposed method gave high-resolution diffusion-weighted images with minimal artifacts at the band intersections. Compared to PI alone, higher phase-encoded FOV-reduction factors and reduced noise amplification were obtained, which translated to higher resolution images than conventional (non-multiband) DWI. The same resolution and image quality achievable over targeted regions using existing reduced-FOV methods was obtained, but the proposed method also enables complete bilateral coverage. CONCLUSION We developed an in-plane multiband technique for high-resolution DWI and compared its performance with other standard DWI methods. Magn Reson Med 77:209-220, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Valentina Taviani
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Marcus T Alley
- Department of Radiology, Stanford University, Stanford, California, USA
| | | | - Dwight G Nishimura
- Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA
| | - Bruce L Daniel
- Department of Radiology, Stanford University, Stanford, California, USA
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Artz NS, Hernando D, Taviani V, Samsonov A, Brittain JH, Reeder SB. Spectrally resolved fully phase-encoded three-dimensional fast spin-echo imaging. Magn Reson Med 2015; 71:681-90. [PMID: 23483631 DOI: 10.1002/mrm.24704] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE To develop and test the feasibility of a spectrally resolved fully phase-encoded (SR-FPE) three-dimensional fast spin-echo technique and to demonstrate its application for distortion-free imaging near metal and chemical species separation. METHODS In separate scans at 1.5 T, a hip prosthesis phantom and a sphere filled with gadolinium solution were imaged with SR-FPE and compared to conventional three-dimensional-fast spin-echo. Spectral modeling was performed on the SR-FPE data to generate the following parametric maps: species-specific signal (ρspecies), B0 field inhomogeneity, and R*2. The prosthesis phantom was also scanned using a 16-channel coil at 1.5 T. The fully sampled k-space data were retrospectively undersampled to demonstrate the feasibility of parallel imaging acceleration in all three phase-encoding directions, in combination with corner-cutting and half-Fourier sampling. Finally, SR-FPE was performed with an acetone/water/oil phantom to test chemical species separation. RESULTS High quality distortion-free images and parametric maps were generated from SR-FPE. A 4 h SR-FPE scan was retrospectively accelerated to 12 min while preserving spectral information and 7.5 min without preserving spectral data. Chemical species separation was demonstrated in the acetone/water/oil phantom. CONCLUSION This work demonstrates the feasibility of SR-FPE to perform chemical species separation and spectrally resolved imaging near metal without distortion, in scan times appropriate for the clinical setting.
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Affiliation(s)
- Nathan S Artz
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
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Minamimoto R, Loening A, Jamali M, Barkhodari A, Mosci C, Jackson T, Obara P, Taviani V, Gambhir SS, Vasanawala S, Iagaru A. Prospective Comparison of 99mTc-MDP Scintigraphy, Combined 18F-NaF and 18F-FDG PET/CT, and Whole-Body MRI in Patients with Breast and Prostate Cancer. J Nucl Med 2015; 56:1862-8. [DOI: 10.2967/jnumed.115.162610] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/10/2015] [Indexed: 12/27/2022] Open
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Barentsz MW, Taviani V, Chang JM, Ikeda DM, Miyake KK, Banerjee S, van den Bosch MAAJ, Hargreaves BA, Daniel BL. Assessment of tumor morphology on diffusion-weighted (DWI) breast MRI: Diagnostic value of reduced field of view DWI. J Magn Reson Imaging 2015; 42:1656-65. [PMID: 25914178 DOI: 10.1002/jmri.24929] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 04/06/2015] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To compare the diagnostic value of conventional, bilateral diffusion-weighted imaging (DWI) and high-resolution targeted DWI of known breast lesions. MATERIALS AND METHODS Twenty-one consecutive patients with known breast cancer or suspicious breast lesions were scanned with the conventional bilateral DWI technique, a high-resolution, reduced field of view (rFOV) DWI technique, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) (3.0 T). We compared bilateral DWI and rFOV DWI quantitatively by measuring the lesions' apparent diffusion coefficient (ADC) values. For qualitative comparison, three dedicated breast radiologists scored image quality and performed lesion interpretation. RESULTS In a phantom, ADC values were in good agreement with the reference values. Twenty-one patients (30 lesions: 14 invasive carcinomas, 10 benign lesions [of which 5 cysts], 3 high-risk, and 3 in situ carcinomas) were included. Cysts and high-risk lesions were excluded from the quantitative analysis. Quantitatively, both bilateral and rFOV DWI measured lower ADC values in invasive tumors than other lesions. In vivo, rFOV DWI gave lower ADC values than bilateral DWI (1.11 × 10(-3) mm(2) /s vs. 1.24 × 10(-3) mm(2) /s, P = 0.002). Regions of interest (ROIs) were comparable in size between the two techniques (2.90 vs. 2.13 cm(2) , P = 0.721). Qualitatively, all three radiologists scored sharpness of rFOV DWI images as significantly higher than bilateral DWI (P ≤ 0.002). Receiver operating characteristic (ROC) curve analysis showed a higher area under the curve (AUC) in BI-RADS classification for rFOV DWI compared to bilateral DWI (0.71 to 0.93 vs. 0.61 to 0.76, respectively). CONCLUSION Tumor morphology can be assessed in more detail with high-resolution DWI (rFOV) than with standard bilateral DWI by providing significantly sharper images.
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Affiliation(s)
- Maarten W Barentsz
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Valentina Taviani
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Jung M Chang
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Debra M Ikeda
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Kanae K Miyake
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan
| | | | | | | | - Bruce L Daniel
- Department of Radiology, Stanford University, Stanford, California, USA
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Motosugi U, Hernando D, Bannas P, Holmes JH, Wang K, Shimakawa A, Iwadate Y, Taviani V, Rehm JL, Reeder SB. Quantification of liver fat with respiratory-gated quantitative chemical shift encoded MRI. J Magn Reson Imaging 2015; 42:1241-8. [PMID: 25828696 DOI: 10.1002/jmri.24896] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 03/11/2015] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To evaluate free-breathing chemical shift-encoded (CSE) magnetic resonance imaging (MRI) for quantification of hepatic proton density fat-fraction (PDFF). A secondary purpose was to evaluate hepatic R2* values measured using free-breathing quantitative CSE-MRI. MATERIALS AND METHODS Fifty patients (mean age, 56 years) were prospectively recruited and underwent the following four acquisitions to measure PDFF and R2*; 1) conventional breath-hold CSE-MRI (BH-CSE); 2) respiratory-gated CSE-MRI using respiratory bellows (BL-CSE); 3) respiratory-gated CSE-MRI using navigator echoes (NV-CSE); and 4) single voxel MR spectroscopy (MRS) as the reference standard for PDFF. Image quality was evaluated by two radiologists. MRI-PDFF measured from the three CSE-MRI methods were compared with MRS-PDFF using linear regression. The PDFF and R2* values were compared using two one-sided t-test to evaluate statistical equivalence. RESULTS There was no significant difference in the image quality scores among the three CSE-MRI methods for either PDFF (P = 1.000) or R2* maps (P = 0.359-1.000). Correlation coefficients (95% confidence interval [CI]) for the PDFF comparisons were 0.98 (0.96-0.99) for BH-, 0.99 (0.97-0.99) for BL-, and 0.99 (0.98-0.99) for NV-CSE. The statistical equivalence test revealed that the mean difference in PDFF and R2* between any two of the three CSE-MRI methods was less than ±1 percentage point (pp) and ±5 s(-1) , respectively (P < 0.046). CONCLUSION Respiratory-gated CSE-MRI with respiratory bellows or navigator echo are feasible methods to quantify liver PDFF and R2* and are as valid as the standard breath-hold technique.
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Affiliation(s)
- Utaroh Motosugi
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.,Department of Radiology, University of Yamanashi, Yamanashi, Japan
| | - Diego Hernando
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
| | - Peter Bannas
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.,Department of Radiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - James H Holmes
- Global MR Applications and Workflow, GE Healthcare, Madison, Wisconsin, USA
| | - Kang Wang
- Global MR Applications and Workflow, GE Healthcare, Madison, Wisconsin, USA
| | - Ann Shimakawa
- Global MR Applications and Workflow, GE Healthcare, Menlo Park, California, USA
| | - Yuji Iwadate
- Global MR Applications and Workflow, GE Healthcare, Hino, Japan
| | - Valentina Taviani
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Jennifer L Rehm
- Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, USA
| | - Scott B Reeder
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.,Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.,Department of Biomedical Engineering and Medicine, University of Wisconsin, Madison, Wisconsin, USA.,Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA.,Department of Emergency Medicine, University of Wisconsin, Madison, Wisconsin, USA
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Taviani V, Hickson SS, Hardy CJ, Patterson AJ, Young VE, McEniery CM, Wilkinson IB, Gillard JH, Graves MJ. Estimation of aortic pulse pressure using fourier velocity encoded M-mode MR. J Magn Reson Imaging 2013; 39:85-93. [DOI: 10.1002/jmri.24109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 02/11/2013] [Indexed: 01/21/2023] Open
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Taviani V, Hernando D, Francois CJ, Shimakawa A, Vigen KK, Nagle SK, Schiebler ML, Grist TM, Reeder SB. Whole-heart chemical shift encoded water-fat MRI. Magn Reson Med 2013; 72:718-25. [PMID: 24186810 DOI: 10.1002/mrm.24982] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 09/12/2013] [Accepted: 09/12/2013] [Indexed: 12/21/2022]
Abstract
PURPOSE To develop and evaluate a free-breathing chemical-shift-encoded (CSE) spoiled gradient-recalled echo (SPGR) technique for whole-heart water-fat imaging at 3 Tesla (T). METHODS We developed a three-dimensional (3D) multi-echo SPGR pulse sequence with electrocardiographic gating and navigator echoes and evaluated its performance at 3T in healthy volunteers (N = 6) and patients (N = 20). CSE-SPGR, 3D SPGR, and 3D balanced-SSFP with chemical fat saturation were compared in six healthy subjects with images evaluated for overall image quality, level of residual artifacts, and quality of fat suppression. A similar scoring system was used for the patient datasets. RESULTS Images of diagnostic quality were acquired in all but one subject. CSE-SPGR performed similarly to SPGR with fat saturation, although it provided a more uniform fat suppression over the whole field of view. Balanced-SSFP performed worse than SPGR-based methods. In patients, CSE-SPGR produced excellent fat suppression near metal. Overall image quality was either good (7/20) or excellent (12/20) in all but one patient. There were significant artifacts in 5/20 clinical cases. CONCLUSION CSE-SPGR is a promising technique for whole-heart water-fat imaging during free-breathing. The robust fat suppression in the water-only image could improve assessment of complex morphology at 3T and in the presence of off-resonance, with additional information contained in the fat-only image.
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Affiliation(s)
- Valentina Taviani
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
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Priest AN, Taviani V, Graves MJ, Lomas DJ. Improved artery-vein separation with acceleration-dependent preparation for non-contrast-enhanced magnetic resonance angiography. Magn Reson Med 2013; 72:699-706. [PMID: 24136812 DOI: 10.1002/mrm.24981] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/09/2013] [Accepted: 09/12/2013] [Indexed: 11/11/2022]
Abstract
PURPOSE To compare the use of acceleration-dependent and velocity-dependent flow-preparation for non-contrast-enhanced magnetic resonance angiography (NCE-MRA), investigating both image quality and the ability to discriminate between arteries and veins. We develop an acceleration-dependent NCE-MRA method known as acceleration dependent vascular anatomy for non-contrast-enhanced MRA (ADVANCE-MRA). METHODS Acceleration-dependent and velocity-dependent images were acquired using a constant and pulsatile flow-phantom and from the lower legs of six healthy volunteers and one patient with peripheral vascular disease. The volunteer images were assessed both by quantitative signal measurements and qualitative scoring by a radiologist. RESULTS In the phantom, acceleration-dependent preparation depicted pulsatile but not constant flow, while velocity-dependent preparation depicted both. In the volunteers and the patient, the velocity-dependent preparation was unable to separate the arterial and venous signals completely, with some overlap of arterial and venous signals for all acquired flow sensitizations whereas the acceleration-dependent preparation gave complete artery-vein separation over a wide range of flow sensitizations. Acceleration-dependent preparation received the best overall qualitative scores for arterial image quality and venous contamination. CONCLUSION Acceleration-dependent NCE-MRA improves arterial image quality and reduces venous contamination, compared with velocity-dependent NCE-MRA, and warrants further investigation in patients.
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Taviani V, Nagala S, Priest AN, McLean MA, Jani P, Graves MJ. 3T diffusion-weighted MRI of the thyroid gland with reduced distortion: preliminary results. Br J Radiol 2013; 86:20130022. [PMID: 23770539 PMCID: PMC3745056 DOI: 10.1259/bjr.20130022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/23/2013] [Accepted: 06/07/2013] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging the thyroid, is characterised by severe blurring and distortion. The objectives of this work were: 1, to show that a reduced-field of view (r-FOV) DW EPI technique can improve image quality; and 2, to investigate the effect of different reconstruction strategies on the resulting apparent diffusion coefficients (ADCs). METHODS We implemented a single-shot, r-FOV DW EPI technique with a two-dimensional radiofrequency excitation pulse for DW imaging of the thyroid at 3T. Images were reconstructed using root sum of squares (SOS) and an optimal-B1 reconstruction (OBR). Phantom and in vivo experiments were performed to compare r-FOV and conventional full-FOV DW EPI with root SOS and OBR. RESULTS r-FOV with OBR substantially improved image quality at 3T. In phantoms, r-FOV gave more accurate ADCs than full-FOV. In vivo r-FOV always gave lower ADC values with respect to the full-FOV technique irrespective of the reconstruction used and whether only two or multiple b-values were used to compute the ADCs. CONCLUSION r-FOV DW EPI can reduce image blurring and distortion at the expense of a low signal-to-noise ratio. OBR is a promising reconstruction technique for accurate ADC measurements in lower signal-to-noise ratio regimes, although further studies are needed to characterise its performance. ADVANCES IN KNOWLEDGE DW imaging of the thyroid at 3T could potentially benefit from r-FOV acquisition strategies, such as the r-FOV DW EPI technique proposed in this paper.
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Affiliation(s)
- V Taviani
- Department of Radiology, University of Cambridge, Cambridge, UK.
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Sadat U, Howarth SPS, Usman A, Taviani V, Tang TY, Graves MJ, Gillard JH. Effect of Low-and High-Dose Atorvastatin on Carotid Artery Distensibility Using Carotid Magnetic Resonance Imaging ^|^mdash;A Post-Hoc Sub Group Analysis of ATHEROMA (Atorvastatin Therapy: Effects on Reduction of Macrophage Activity) Study. J Atheroscler Thromb 2013; 20:46-56. [DOI: 10.5551/jat.12633] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Taviani V, Hickson SS, Hardy CJ, McEniery CM, Patterson AJ, Gillard JH, Wilkinson IB, Graves MJ. Age-related changes of regional pulse wave velocity in the descending aorta using Fourier velocity encoded M-mode. Magn Reson Med 2011; 65:261-8. [PMID: 20878761 DOI: 10.1002/mrm.22590] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Aortic pulse wave velocity (PWV) is an independent determinant of cardiovascular risk. Although aortic stiffening with age is well documented, the interaction between aging and regional aortic PWV is still a debated question. We measured global and regional PWV in the descending aorta of 56 healthy subjects aged 25-76 years using a one-dimensional, interleaved, Fourier velocity encoded pulse sequence with cylindrical excitation. Repeatability across two magnetic resonance examinations (n = 19) and accuracy against intravascular pressure measurements (n = 4) were assessed. The global PWV was found to increase nonlinearly with age. The thoracic aorta was found to stiffen the most with age (PWV [thoracic, 20-40 years] = 4.7 ± 1.1 m/s; PWV [thoracic, 60-80 years] = 7.9 ± 1.5 m/s), followed by the mid- (PWV [mid-abdominal, 20-40 years] = 4.9 ± 1.3 m/s; PWV [mid-abdominal, 60-80 years] = 7.4 ± 1.9 m/s) and distal abdominal aorta (PWV [distal abdominal, 20-40 years] = 4.8 ± 1.4 m/s; PWV [distal abdominal, 60-80 years] = 5.7 ± 1.4 m/s). Good agreement was found between repeated magnetic resonance measurements and between magnetic resonance PWVs and the gold-standard. Fourier velocity encoded M-mode allowed to measure global and regional PWV in the descending aorta. There was a preferential stiffening of the thoracic aorta with age, which may be due to progressive fragmentation of elastin fibers in this region.
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Affiliation(s)
- Valentina Taviani
- Department of Radiology, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
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Hickson SS, Butlin M, Graves M, Taviani V, Avolio AP, McEniery CM, Wilkinson IB. The relationship of age with regional aortic stiffness and diameter. JACC Cardiovasc Imaging 2011; 3:1247-55. [PMID: 21163453 DOI: 10.1016/j.jcmg.2010.09.016] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 09/16/2010] [Accepted: 09/17/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The purpose of this study was to determine the impact of age on regional aortic pulse wave velocity (aPWV). BACKGROUND aPWV is an independent predictor of cardiovascular risk and increases exponentially with age. However, it is unclear whether such changes occur uniformly along the length of the aorta or vary by region. METHODS A total of 162 subjects, aged 18 to 77 years and free of cardiovascular disease and medication, were recruited from the Anglo-Cardiff Collaborative Trial. Cine phase contrast magnetic resonance imaging was performed at 5 aortic levels. Systolic diameter and average blood flow were measured at each level and regional aPWV (regional aPWV measured by cine phase contrast magnetic resonance imaging) determined in 4 aortic segments: the arch (R1), the thoracic-descending aorta (R2), mid-descending aorta (R3), and the abdominal aorta (R4) and across the entire aorta. RESULTS Regional PWV measured by cine phase contrast magnetic resonance imaging values increased from the valve to the bifurcation in the 4 segments (PWV-R1- PWV-R4: 4.6 ± 1.5 m/s, 5.5 ± 2.0 m/s, 5.7 ± 2.3 m/s, 6.1 ± 2.9 m/s, respectively) and did not differ between genders. The greatest age-related difference in stiffness occurred in the abdominal aorta (+0.9 m/s per decade, p < 0.001) followed by the thoracic-descending region (+0.7 m/s, p < 0.001), the mid-descending region (+0.6 m/s, p < 0.001) and aortic arch (+0.4 m/s, p < 0.001). The average systolic diameters decreased moving distally (L1-5: 3.1 ± 0.4 cm, 2.3 ± 0.3 cm, 2.1 ± 0.3 cm, 1.9 ± 0.2 cm, and 1.7 ± 0.2 cm, respectively). The greatest variation in systolic diameter as a function of age occurred in the ascending region (+0.96 mm/decade, p < 0.001). Values of aPWV measured across the entire aorta were strongly correlated with PWV-tonometry (R = 0.71, p < 0.001), although they were significantly lower (mean difference 1.7 ± 1.6 m/s, p < 0.001). CONCLUSIONS The greatest difference in aortic stiffness occurs in the abdominal region, whereas the greatest difference in diameter occurs in the ascending aorta, which may help offset an increase in wall stiffness.
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Affiliation(s)
- Stacey S Hickson
- Clinical Pharmacology Unit, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
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Herment A, Lefort M, Kachenoura N, De Cesare A, Taviani V, Graves MJ, Pellot-Barakat C, Frouin F, Mousseaux E. Automated estimation of aortic strain from steady-state free-precession and phase contrast MR images. Magn Reson Med 2010; 65:986-93. [DOI: 10.1002/mrm.22678] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 09/09/2010] [Accepted: 09/19/2010] [Indexed: 01/23/2023]
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Taviani V, Patterson AJ, Graves MJ, Hardy CJ, Worters P, Sutcliffe MP, Gillard JH. Accuracy and repeatability of fourier velocity encoded M-mode and two-dimensional cine phase contrast for pulse wave velocity measurement in the descending aorta. J Magn Reson Imaging 2010; 31:1185-94. [DOI: 10.1002/jmri.22143] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Li ZY, Taviani V, Tang T, Sutcliffe MPF, Gillard JH. The hemodynamic effects of in-tandem carotid artery stenosis: implications for carotid endarterectomy. J Stroke Cerebrovasc Dis 2010; 19:138-45. [PMID: 20189090 DOI: 10.1016/j.jstrokecerebrovasdis.2009.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 03/04/2009] [Accepted: 03/09/2009] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVES It remains controversial whether patients with severe disease of the internal carotid artery and a coexisting stenotic lesion downstream would benefit from a carotid endarterectomy (CEA) of the proximal lesion. The aim of this study was to simulate the hemodynamic and wall shear effects of in-tandem internal carotid artery stenosis using a computational fluid dynamic (CFD) idealized model to give insight into the possible consequences of CEA on these lesions. METHODS A CFD model of steady viscous flow in a rigid tube with two asymmetric stenoses was introduced to simulate blood flow in arteries with multiple constrictions. The effect of varying the distance between the two stenoses, and the severity of the upstream stenosis on the pressure and wall shear stress (WSS) distributions on the second plaque, was investigated. The influence of the relative positions of the two stenoses was also assessed. RESULTS The distance between the plaques was found to have minimal influence on the overall hemodynamic effect except for the presence of a zone of low WSS (range -20 to 30 dyne/cm2) adjacent to both lesions when the two stenoses were sufficiently close (<4 times the arterial diameter). The upstream stenosis was protective if it was larger than the downstream stenosis. The relative positions of the stenoses were found to influence the WSS but not the pressure distribution. CONCLUSIONS The geometry and positions of the lesions need to be considered when considering the hemodynamic effects of an in-tandem stenosis. Low WSS is thought to cause endothelial dysfunction and initiate atheroma formation. The fact that there was a flow recirculation zone with low WSS in between the two stenoses may demonstrate how two closely positioned plaques may merge into one larger lesion. Decision making for CEA may need to take into account the hemodynamic situation when an in-tandem stenosis is found. CFD may aid in the risk stratification of patients with this problem.
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Affiliation(s)
- Zhi-Yong Li
- University Department of Radiology, Cambridge University Hospitals National Health Service Foundation Trust, United Kingdom.
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Taviani V, Patterson AJ, Worters P, Sutcliffe MP, Graves MJ, Gillard JH. Accuracy of phase contrast, black-blood, and bright-blood pulse sequences for measuring compliance and distensibility coefficients in a human-tissue mimicking phantom. J Magn Reson Imaging 2009; 31:160-7. [DOI: 10.1002/jmri.22005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Taviani V, Sutcliffe MPF, Wong P, Li ZY, Young V, Graves MJ, Gillard JH. In vivo non-invasive high resolution MR-based method for the determination of the elastic modulus of arterial vessels. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2008:5569-72. [PMID: 19163979 DOI: 10.1109/iembs.2008.4650476] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The mechanical properties of arterial walls have long been recognized to play an essential role in the development and progression of cardiovascular disease (CVD). Early detection of variations in the elastic modulus of arteries would help in monitoring patients at high cardiovascular risk stratifying them according to risk. An in vivo, non-invasive, high resolution MR-phase-contrast based method for the estimation of the time-dependent elastic modulus of healthy arteries was developed, validated in vitro by means of a thin walled silicon rubber tube integrated into an existing MR-compatible flow simulator and used on healthy volunteers. A comparison of the elastic modulus of the silicon tube measured from the MRI-based technique with direct measurements confirmed the method's capability. The repeatability of the method was assessed. Viscoelastic and inertial effects characterizing the dynamic response of arteries in vivo emerged from the comparison of the pressure waveform and the area variation curve over a period. For all the volunteers who took part in the study the elastic modulus was found to be in the range 50-250 kPa, to increase during the rising part of the cycle, and to decrease with decreasing pressure during the downstroke of systole and subsequent diastole.
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Affiliation(s)
- Valentina Taviani
- Department of Engineering, University of Cambridge, CB21PZ UK. vt232@ cam.ac.uk
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Li ZY, Taviani V, Gillard JH. The impact of wall shear stress and pressure drop on the stability of the atherosclerotic plaque. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2008:1373-6. [PMID: 19162923 DOI: 10.1109/iembs.2008.4649420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rupture of vulnerable atheromatous plaque in the carotid and coronary arteries often leads to stroke and heart attack respectively. The mechanism of blood flow and plaque rupture in stenotic arteries is still not fully understood. A three dimensional rigid wall model was solved under steady state conditions and unsteady conditions by assuming a time-varying inlet velocity profile to investigate the relative importance of axial forces and pressure drops in arteries with asymmetric stenosis. Flow-structure interactions were investigated for the same geometry and the results were compared with those retrieved with the corresponding 2D cross-section structural models. The Navier-Stokes equations were used as the governing equations for the fluid. The tube wall was assumed hyperelastic, homogeneous, isotropic and incompressible. The analysis showed that the three dimensional behavior of velocity, pressure and wall shear stress is in general very different from that predicted by cross-section models. Pressure drop across the stenosis was found to be much higher than shear stress. Therefore, pressure may be the more important mechanical trigger for plaque rupture other than shear stress, although shear stress is closely related to plaque formation and progression.
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Affiliation(s)
- Zhi-Yong Li
- Departments of Radiology and Engineering, University of Cambridge and Addenbrooke¿s Hospital, CB2 0QQ, UK
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Li ZY, Taviani V, Tang T, Sadat U, Young V, Patterson A, Graves M, Gillard JH. The mechanical triggers of plaque rupture: shear stressvspressure gradient. Br J Radiol 2009; 82 Spec No 1:S39-45. [DOI: 10.1259/bjr/15036781] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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