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Fast, free-breathing and motion-minimized techniques for pediatric body magnetic resonance imaging. Pediatr Radiol 2018; 48:1197-1208. [PMID: 30078042 DOI: 10.1007/s00247-018-4116-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/26/2018] [Accepted: 03/11/2018] [Indexed: 12/26/2022]
Abstract
Magnetic resonance imaging (MRI) is the preferred imaging modality in children with complex medical issues. Patient motion and respiration remain major challenges in pediatric abdominal MRI. Young children ages 3 months to 6 years are unable to cooperate or perform breath-holding and frequently require deep sedation or general anesthesia to undergo MRI. Given the growing concerns associated with the use of sedation and anesthesia as well as the adverse impact on workflow, developing and implementing fast and motion-resistant MRI sequences are of great interest. Fast sequences such as single-shot fast spin echo and balanced steady-state free precession are useful as quick anatomical surveys on routine abdominal MRI. The widespread utilization of parallel imaging and sequences with radial k-space sampling has contributed to decreasing scan time and improving image quality, respectively. Newer strategies including compressed sensing, simultaneous multi-slice acquisition, and hybrid approaches hold the prospect of faster image acquisition that could significantly reduce the need for sedation in this vulnerable population and decrease the time of anesthesia in cases where it is indicated.
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Crombé A, Le Loarer F, Cornelis F, Stoeckle E, Buy X, Cousin S, Italiano A, Kind M. High-grade soft-tissue sarcoma: optimizing injection improves MRI evaluation of tumor response. Eur Radiol 2018; 29:545-555. [DOI: 10.1007/s00330-018-5635-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/31/2018] [Accepted: 06/27/2018] [Indexed: 12/21/2022]
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Abstract
Clinical magnetic resonance imaging (MRI) offers a multitude of different techniques with which anatomical, functional and metabolic information can be gained. The technical basis of an MRI method is the so-called pulse sequence, which determines the manner in which data is acquired. Pulse sequences are differentiated between gradient and spin echo sequences. The aim of this article is to present the principal physical properties of both techniques. From these properties, specific applications arise that are routinely used in clinical practice.
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Kobayashi Y, Terada Y. Diffusion-weighting Caused by Spoiler Gradients in the Fast Imaging with Steady-state Precession Sequence May Lead to Inaccurate T 2 Measurements in MR Fingerprinting. Magn Reson Med Sci 2018; 18:96-104. [PMID: 29794408 PMCID: PMC6326765 DOI: 10.2463/mrms.tn.2018-0027] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Magnetic resonance fingerprinting (MRF) is a promising framework that allows the quantification of multiple magnetic resonance parameters with a single scan. MRF using fast imaging with steady-state precession (MRF-FISP) has robustness to off-resonance artifacts and has many applications in inhomogeneous fields. However, the spoiler gradient used in MRF-FISP is sensitive to diffusion motion, and may lead to quantification errors when the spoiler moment increases. In this study, we examined the effect of the diffusion weighting in MRF-FISP caused by spoiler gradients. The T2 relaxation times were greatly underestimated when large spoiler moments were used. The T2 underestimation was prominent for tissues with large values of T2 and diffusion coefficients. The T2 bias was almost independent of the apparent diffusion coefficient (ADC) and T2 values when the ADC map was measured and incorporated into the matching process. These results reveal that the T2 underestimation resulted from the diffusion weighting caused by the spoiler gradients.
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Pulickal GG, Navaratnam AV, Nguyen T, Dragan AD, Dziedzic M, Lingam RK. Imaging Sinonasal disease with MRI: Providing insight over and above CT. Eur J Radiol 2018; 102:157-168. [PMID: 29685531 DOI: 10.1016/j.ejrad.2018.02.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/22/2018] [Accepted: 02/26/2018] [Indexed: 02/06/2023]
Abstract
This article illustrates and discusses the applications and value of magnetic resonance imaging (MRI) in the evaluation of sinonasal disease. There are several clinical scenarios where MRI can add value over conventional computed tomography (CT) evaluation of the sinonasal spaces. Specifically, MRI can provide insight through better depiction of the anatomy of certain sinonasal sub-sites including the olfactory structures. It can aid in evaluating anosmia, sinusitis (fungal sinusitis and complications), benign and malignant lesions, CSF leaks and pathology extending into sinonasal spaces.
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Affiliation(s)
- Geoiphy George Pulickal
- Department of Diagnostic Radiology at Khoo Teck Puat Hospital, 90 Yishun Central, 768828, Singapore.
| | - Annakan V Navaratnam
- Department of ENT Surgery, London North West University Healthcare NHS Trust, Watford Road, Harrow, HA1 3UJ, United Kingdom.
| | - Thi Nguyen
- Benson Radiology, Greenhill Road, Unley, Australia.
| | - Alina Denisa Dragan
- Department of Radiology, Northwick Park & Central Middlesex Hospitals, London North West University Healthcare NHS Trust, Watford Road, Harrow, HA1 3UJ, United Kingdom.
| | - Magdalena Dziedzic
- Department of Radiology, Maria Sklodowska - Curie Cancer Center, Institute of Oncology, Warsaw, Poland.
| | - Ravi K Lingam
- Department of Radiology, Northwick Park & Central Middlesex Hospitals, London North West University Healthcare NHS Trust, Watford Road, Harrow, HA1 3UJ, United Kingdom.
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Feng X, Blemker SS, Inouye J, Pelland CM, Zhao L, Meyer CH. Assessment of velopharyngeal function with dual-planar high-resolution real-time spiral dynamic MRI. Magn Reson Med 2018; 80:1467-1474. [PMID: 29508458 DOI: 10.1002/mrm.27139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 01/25/2018] [Accepted: 01/25/2018] [Indexed: 02/05/2023]
Abstract
PURPOSE To develop a real-time dynamic MRI method for comprehensive evaluation of velum movement during speech. METHODS Dynamic MRI has been used to study velopharyngeal insufficiency (VPI) by imaging the movement of the velum during speech, because it can provide good anatomic details with no exposed radiation. To be able to comprehensively evaluate dynamic velum movement, a real-time spiral non-balanced SSFP sequence was developed with simultaneous dual-planar coverage and improved spatial and temporal resolution using a combination of parallel imaging and spatial and temporal compressed sensing to achieve 6 × acceleration. New off-resonance correction and post-processing methods were also developed to reduce blurring and slice crosstalk. RESULTS The method demonstrated good image quality for visualizing dynamic velum movement with reduced blurring and improved image homogeneity. Spatial resolution of 1.2*1.2 mm2 with 150 mm FOV and temporal resolution of 20 frames-per-second with simultaneous dual-planar coverage was achieved. CONCLUSIONS This work describes a new technique for studying speech disorders using dual-planar accelerated spiral dynamic MRI.
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Affiliation(s)
- Xue Feng
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Silvia S Blemker
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.,Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Josh Inouye
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Catherine M Pelland
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Li Zhao
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Craig H Meyer
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.,Department of Radiology, University of Virginia, Charlottesville, Virginia, USA
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Williams SN, Nielsen JF, Fessler JA, Noll DC. Design of spectral-spatial phase prewinding pulses and their use in small-tip fast recovery steady-state imaging. Magn Reson Med 2018; 79:1377-1386. [PMID: 28671320 PMCID: PMC5752636 DOI: 10.1002/mrm.26794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 11/10/2022]
Abstract
PURPOSE Spectrally selective "prewinding" radiofrequency pulses can counteract B0 inhomogeneity in steady-state sequences, but can only prephase a limited range of off-resonance. We propose spectral-spatial small-tip angle prewinding pulses that increase the off-resonance bandwidth that can be successfully prephased by incorporating spatially tailored excitation patterns. THEORY AND METHODS We present a feasibility study to compare spectral and spectral-spatial prewinding pulses. These pulses add a prephasing term to the target magnetization pattern that aims to recover an assigned off-resonance bandwidth at the echo time. For spectral-spatial pulses, the design bandwidth is centered at the off-resonance frequency for each spatial location in a field map. We use these pulses in the small-tip fast recovery steady-state sequence, which is similar to balanced steady-state free precession. We investigate improvement of spectral-spatial pulses over spectral pulses using simulations and small-tip fast recovery scans of a gel phantom and human brain. RESULTS In simulation, spectral-spatial pulses yielded lower normalized root mean squared excitation error than spectral pulses. For both experiments, the spectral-spatial pulse images are also qualitatively better (more uniform, less signal loss) than the spectral pulse images. CONCLUSION Spectral-spatial prewinding pulses can prephase over a larger range of off-resonance than their purely spectral counterparts. Magn Reson Med 79:1377-1386, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sydney N Williams
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Jon-Fredrik Nielsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Jeffrey A Fessler
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Douglas C Noll
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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Martin T, Wang Y, Rashid S, Shao X, Moeller S, Hu P, Sung K, Wang DJJ. Highly Accelerated SSFP Imaging with Controlled Aliasing in Parallel Imaging and integrated-SSFP (CAIPI-iSSFP). INVESTIGATIVE MAGNETIC RESONANCE IMAGING 2017; 21:210-222. [PMID: 29520372 PMCID: PMC5839645 DOI: 10.13104/imri.2017.21.4.210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/26/2017] [Accepted: 09/09/2017] [Indexed: 11/15/2022]
Abstract
PURPOSE To develop a novel combination of controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) with integrated SSFP (CAIPI-iSSFP) for accelerated SSFP imaging without banding artifacts at 3T. MATERIALS AND METHODS CAIPI-iSSFP was developed by adding a dephasing gradient to the balanced SSFP (bSSFP) pulse sequence with a gradient area that results in 2π dephasing across a single pixel. Extended phase graph (EPG) simulations were performed to show the signal behaviors of iSSFP, bSSFP, and RF-spoiled gradient echo (SPGR) sequences. In vivo experiments were performed for brain and abdominal imaging at 3T with simultaneous multi-slice (SMS) acceleration factors of 2, 3 and 4 with CAIPI-iSSFP and CAIPI-bSSFP. The image quality was evaluated by measuring the relative contrast-to-noise ratio (CNR) and by qualitatively assessing banding artifact removal in the brain. RESULTS Banding artifacts were removed using CAIPI-iSSFP compared to CAIPI-bSSFP up to an SMS factor of 4 and 3 on brain and liver imaging, respectively. The relative CNRs between gray and white matter were on average 18% lower in CAIPI-iSSFP compared to that of CAIPI-bSSFP. CONCLUSION This study demonstrated that CAIPI-iSSFP provides up to a factor of four acceleration, while minimizing the banding artifacts with up to a 20% decrease in the relative CNR.
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Affiliation(s)
- Thomas Martin
- Department of Radiological Sciences, University of California Los Angeles, California, USA
| | - Yi Wang
- Philips, MR Clinical Science NA, Florida, USA
| | - Shams Rashid
- Department of Radiological Sciences, University of California Los Angeles, California, USA
| | - Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), Stevens Neuroimaging and Informatics Institute, University of Southern California, California, USA
| | - Steen Moeller
- Center of Magnetic Resonance Research, University of Minnesota, Minnesota, USA
| | - Peng Hu
- Department of Radiological Sciences, University of California Los Angeles, California, USA
| | - Kyunghyun Sung
- Department of Radiological Sciences, University of California Los Angeles, California, USA
| | - Danny JJ Wang
- Laboratory of FMRI Technology (LOFT), Stevens Neuroimaging and Informatics Institute, University of Southern California, California, USA
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Chaudhari AS, Black MS, Eijgenraam S, Wirth W, Maschek S, Sveinsson B, Eckstein F, Oei EHG, Gold GE, Hargreaves BA. Five-minute knee MRI for simultaneous morphometry and T 2 relaxometry of cartilage and meniscus and for semiquantitative radiological assessment using double-echo in steady-state at 3T. J Magn Reson Imaging 2017; 47:1328-1341. [PMID: 29090500 DOI: 10.1002/jmri.25883] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 10/14/2017] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Biomarkers for assessing osteoarthritis activity necessitate multiple MRI sequences with long acquisition times. PURPOSE To perform 5-minute simultaneous morphometry (thickness/volume measurements) and T2 relaxometry of both cartilage and meniscus, and semiquantitative MRI Osteoarthritis Knee Scoring (MOAKS). STUDY TYPE Prospective. SUBJECTS Fifteen healthy volunteers for morphometry and T2 measurements, and 15 patients (five each Kellgren-Lawrence grades 0/2/3) for MOAKS assessment. FIELD STRENGTH/SEQUENCE A 5-minute double-echo steady-state (DESS) sequence was evaluated for generating quantitative and semiquantitative osteoarthritis biomarkers at 3T. ASSESSMENT Flip angle simulations evaluated tissue signals and sensitivity of T2 measurements. Morphometry and T2 reproducibility was compared against morphometry-optimized and relaxometry-optimized sequences. Repeatability was assessed by scanning five volunteers twice. MOAKS reproducibility was compared to MOAKS derived from a clinical knee MRI protocol by two readers. STATISTICAL TESTS Coefficients of variation (CVs), concordance confidence intervals (CCI), and Wilcoxon signed-rank tests compared morphometry and relaxometry measurements with their reference standards. DESS MOAKS positive percent agreement (PPA), negative percentage agreement (NPA), and interreader agreement was calculated using the clinical protocol as a reference. Biomarker variations between Kellgren-Lawrence groups were evaluated using Wilcoxon rank-sum tests. RESULTS Cartilage thickness (P = 0.65), cartilage T2 (P = 0.69), and meniscus T2 (P = 0.06) did not significantly differ from their reference standard (with a 20° DESS flip angle). DESS slightly overestimated meniscus volume (P < 0.001). Accuracy and repeatability CVs were <3.3%, except the meniscus T2 accuracy (7.6%). DESS MOAKS had substantial interreader agreement and high PPA/NPA values of 87%/90%. Bone marrow lesions and menisci had slightly lower PPAs. Cartilage and meniscus T2 , and MOAKS (cartilage surface area, osteophytes, cysts, and total score) was higher in Kellgren-Lawrence groups 2 and 3 than group 0 (P < 0.05). DATA CONCLUSION The 5-minute DESS sequence permits MOAKS assessment for a majority of tissues, along with repeatable and reproducible simultaneous cartilage and meniscus T2 relaxometry and morphometry measurements. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1328-1341.
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Affiliation(s)
- Akshay S Chaudhari
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Marianne S Black
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Susanne Eijgenraam
- Department of Radiology & Nuclear Medicine, Erasmus MC, University Medical Center, Rotterdam, Netherlands
| | - Wolfgang Wirth
- Institute of Anatomy, Paracelsus Medical University Salzburg and Nuremberg, Salzburg, Austria.,Chondrometrics GmbH, Ainring, Germany
| | - Susanne Maschek
- Institute of Anatomy, Paracelsus Medical University Salzburg and Nuremberg, Salzburg, Austria.,Chondrometrics GmbH, Ainring, Germany
| | - Bragi Sveinsson
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Felix Eckstein
- Institute of Anatomy, Paracelsus Medical University Salzburg and Nuremberg, Salzburg, Austria.,Chondrometrics GmbH, Ainring, Germany
| | - Edwin H G Oei
- Department of Radiology & Nuclear Medicine, Erasmus MC, University Medical Center, Rotterdam, Netherlands
| | - Garry E Gold
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford, California, USA
| | - 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
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60
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Khajehim M, Nasiraei Moghaddam A. Investigating the spatial specificity of S2-SSFP fMRI: A Monte Carlo simulation approach. Magn Reson Imaging 2017; 37:282-289. [DOI: 10.1016/j.mri.2016.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 11/21/2016] [Accepted: 11/21/2016] [Indexed: 11/29/2022]
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Sun K, Xue R, Zhang P, Zuo Z, Chen Z, Wang B, Martin T, Wang Y, Chen L, He S, Wang DJJ. Integrated SSFP for functional brain mapping at 7T with reduced susceptibility artifact. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 276:22-30. [PMID: 28092785 PMCID: PMC5336405 DOI: 10.1016/j.jmr.2016.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 06/06/2023]
Abstract
Balanced steady-state free precession (bSSFP) offers an alternative and potentially important tool to the standard gradient-echo echo-planar imaging (GE-EPI) for functional MRI (fMRI). Both passband and transition band based bSSFP have been proposed for fMRI. The applications of these methods, however, are limited by banding artifacts due to the sensitivity of bSSFP signal to off-resonance effects. In this article, a unique case of the SSFP-FID sequence, termed integrated-SSFP or iSSFP, was proposed to overcome the obstacle by compressing the SSFP profile into the width of a single voxel. The magnitude of the iSSFP signal was kept constant irrespective of frequency shift. Visual stimulation studies were performed to demonstrate the feasibility of fMRI using iSSFP at 7T with flip angles of 4° and 25°, compared to standard bSSFP and gradient echo (GRE) imaging. The signal changes for the complex iSSFP signal in activated voxels were 2.48±0.53 (%) and 2.96±0.87 (%) for flip angles (FA) of 4° and 25° respectively at the TR of 9.88ms. Simultaneous multi-slice acquisition (SMS) with the CAIPIRIHNA technique was carried out with iSSFP scanning to detect the anterior temporal lobe activation using a semantic processing task fMRI, compared with standard 2D GE-EPI. This study demonstrates the feasibility of iSSFP for fMRI with reduced susceptibility artifacts, while maintaining robust functional contrast at 7T.
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Affiliation(s)
- Kaibao Sun
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rong Xue
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Institute for Brain Disorders, Beijing 100053, China.
| | - Peng Zhang
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhentao Zuo
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhongwei Chen
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bo Wang
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Thomas Martin
- Department of Neurology, University of California Los Angeles, Los Angeles 90095, United States
| | - Yi Wang
- Department of Neurology, University of California Los Angeles, Los Angeles 90095, United States
| | - Lin Chen
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, China.
| | - Sheng He
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Psychology, University of Minnesota, Minneapolis, MN 55455, United States
| | - Danny J J Wang
- Department of Neurology, University of California Los Angeles, Los Angeles 90095, United States; Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States
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Zhang S, Liu Z, Grant A, Keupp J, Lenkinski RE, Vinogradov E. Balanced Steady-State Free Precession (bSSFP) from an effective field perspective: Application to the detection of chemical exchange (bSSFPX). JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 275:55-67. [PMID: 28012297 PMCID: PMC5810596 DOI: 10.1016/j.jmr.2016.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/02/2016] [Accepted: 12/03/2016] [Indexed: 05/08/2023]
Abstract
Chemical exchange saturation transfer (CEST) is a novel contrast mechanism and it is gaining increasing popularity as many promising applications have been proposed and investigated. Fast and quantitative CEST imaging techniques are further needed in order to increase the applicability of CEST for clinical use as well as to derive quantitative physiological and biological information. Steady-state methods for fast CEST imaging have been reported recently. Here, we observe that an extreme case of these methods is a balanced steady-state free precession (bSSFP) sequence. The bSSFP in itself is sensitive to the exchange processes; hence, no additional saturation or preparation is needed for CEST-like data acquisition. The bSSFP experiment can be regarded as observation during saturation, without separate saturation and acquisition modules as used in standard CEST and similar experiments. One of the differences from standard CEST methods is that the bSSFP spectrum is an XY-spectrum not a Z-spectrum. As the first proof-of-principle step, we have implemented the steady-state bSSFP sequence for chemical exchange detection (bSSFPX) and verified its feasibility in phantom studies. These studies have shown that bSSFPX can achieve exchange-mediated contrast comparable to the standard CEST experiment. Therefore, the bSSFPX method has a potential for fast and quantitative CEST data acquisition.
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Affiliation(s)
- Shu Zhang
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Zheng Liu
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Aaron Grant
- Division of MR Research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Robert E Lenkinski
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Elena Vinogradov
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Hesse L, Masselter T, Leupold J, Spengler N, Speck T, Korvink JG. Magnetic resonance imaging reveals functional anatomy and biomechanics of a living dragon tree. Sci Rep 2016; 6:32685. [PMID: 27604526 PMCID: PMC5015020 DOI: 10.1038/srep32685] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
Magnetic resonance imaging (MRI) was used to gain in vivo insight into load-induced displacements of inner plant tissues making a non-invasive and non-destructive stress and strain analysis possible. The central aim of this study was the identification of a possible load-adapted orientation of the vascular bundles and their fibre caps as the mechanically relevant tissue in branch-stem-attachments of Dracaena marginata. The complex three-dimensional deformations that occur during mechanical loading can be analysed on the basis of quasi-three-dimensional data representations of the outer surface, the inner tissue arrangement (meristem and vascular system), and the course of single vascular bundles within the branch-stem-attachment region. In addition, deformations of vascular bundles could be quantified manually and by using digital image correlation software. This combination of qualitative and quantitative stress and strain analysis leads to an improved understanding of the functional morphology and biomechanics of D. marginata, a plant that is used as a model organism for optimizing branched technical fibre-reinforced lightweight trusses in order to increase their load bearing capacity.
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Affiliation(s)
- Linnea Hesse
- Plant Biomechanics Group and Botanic Garden, University of Freiburg, Germany.,Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT), Germany
| | - Tom Masselter
- Plant Biomechanics Group and Botanic Garden, University of Freiburg, Germany.,Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT), Germany.,Competence Network Biomimetics, Germany
| | - Jochen Leupold
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Germany
| | - Nils Spengler
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Germany
| | - Thomas Speck
- Plant Biomechanics Group and Botanic Garden, University of Freiburg, Germany.,Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT), Germany.,Competence Network Biomimetics, Germany
| | - Jan Gerrit Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Germany
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Agostini A, Kircher MF, Do R, Borgheresi A, Monti S, Giovagnoni A, Mannelli L. Magnetic Resonance Imaging of the Liver (Including Biliary Contrast Agents) Part 1: Technical Considerations and Contrast Materials. Semin Roentgenol 2016; 51:308-316. [PMID: 27743567 DOI: 10.1053/j.ro.2016.05.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- A Agostini
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY; Department of Radiology, School of Radiology, Universita' Politecnica delle Marche Ancona, Italy
| | - M F Kircher
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - R Do
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - A Borgheresi
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY; Department of Radiology, School of Radiology, Universita' degli Studi di Firenze Firenze, Italy
| | | | - A Giovagnoni
- Department of Radiology, School of Radiology, Universita' Politecnica delle Marche Ancona, Italy
| | - L Mannelli
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY.
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Drăgan OC, Fărcăşanu AŞ, Câmpian RS, Turcu RVF. Human tooth and root canal morphology reconstruction using magnetic resonance imaging. ACTA ACUST UNITED AC 2016; 89:137-42. [PMID: 27004037 PMCID: PMC4777457 DOI: 10.15386/cjmed-555] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 09/25/2015] [Indexed: 01/09/2023]
Abstract
Background and aims Visualization of the internal and external root canal morphology is very important for a successful endodontic treatment; however, it seems to be difficult considering the small size of the tooth and the complexity of the root canal system. Film-based or digital conventional radiographic techniques as well as cone beam computed tomography provide limited information on the dental pulp anatomy or have harmful effects. A new non-invasive diagnosis tool is magnetic resonance imaging, due to its ability of imaging both hard and soft tissues. The aim of this study was to demonstrate magnetic resonance imaging to be a useful tool for imaging the anatomic conditions of the external and internal root canal morphology for endodontic purposes. Methods The endodontic system of one freshly extracted wisdom tooth, chosen for its well-known anatomical variations, was mechanically shaped using a hybrid technique. After its preparation, the tooth was immersed into a recipient with saline solution and magnetic resonance imaged immediately. A Bruker Biospec magnetic resonance imaging scanner operated at 7.04 Tesla and based on Avance III radio frequency technology was used. InVesalius software was employed for the 3D reconstruction of the tooth scanned volume. Results The current ex-vivo experiment shows the accurate 3D volume rendered reconstruction of the internal and external morphology of a human extracted and endodontically treated tooth using a dataset of images acquired by magnetic resonance imaging. The external lingual and vestibular views of the tooth as well as the occlusal view of the pulp chamber, the access cavity, the distal canal opening on the pulp chamber floor, the coronal third of the root canals, the degree of root separation and the apical fusion of the two mesial roots, details of the apical region, root canal curvatures, furcal region and interradicular root grooves could be clearly bordered. Conclusions Magnetic resonance imaging offers 3D image datasets with more information than the conventional radiographic techniques. Due to its ability of imaging both hard and soft dental tissues, magnetic resonance imaging can be successfully used as a 3D diagnostic imaging technique in dentistry. When choosing the imaging method, dental clinicians should weight the benefit-risk ratio, taking into account the costs associated to magnetic resonance imaging and the harmful effects of ionizing radiations when cone beam computed tomography or conventional x-ray are used.
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Affiliation(s)
- Oana Carmen Drăgan
- Faculty of Dental Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | | | - Radu Septimiu Câmpian
- Faculty of Dental Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
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Lingala SG, Sutton BP, Miquel ME, Nayak KS. Recommendations for real-time speech MRI. J Magn Reson Imaging 2016; 43:28-44. [PMID: 26174802 PMCID: PMC5079859 DOI: 10.1002/jmri.24997] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/23/2015] [Indexed: 11/11/2022] Open
Abstract
Real-time magnetic resonance imaging (RT-MRI) is being increasingly used for speech and vocal production research studies. Several imaging protocols have emerged based on advances in RT-MRI acquisition, reconstruction, and audio-processing methods. This review summarizes the state-of-the-art, discusses technical considerations, and provides specific guidance for new groups entering this field. We provide recommendations for performing RT-MRI of the upper airway. This is a consensus statement stemming from the ISMRM-endorsed Speech MRI summit held in Los Angeles, February 2014. A major unmet need identified at the summit was the need for consensus on protocols that can be easily adapted by researchers equipped with conventional MRI systems. To this end, we provide a discussion of tradeoffs in RT-MRI in terms of acquisition requirements, a priori assumptions, artifacts, computational load, and performance for different speech tasks. We provide four recommended protocols and identify appropriate acquisition and reconstruction tools. We list pointers to open-source software that facilitate implementation. We conclude by discussing current open challenges in the methodological aspects of RT-MRI of speech.
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Affiliation(s)
| | - Brad P. Sutton
- University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois, USA
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Morphological MR imaging of the articular cartilage of the knee at 3 T-comparison of standard and novel 3D sequences. Insights Imaging 2015; 6:285-93. [PMID: 25855564 PMCID: PMC4444789 DOI: 10.1007/s13244-015-0405-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/05/2015] [Accepted: 03/08/2015] [Indexed: 12/22/2022] Open
Abstract
Objectives This study sought to compare various 3D cartilage sequences and to evaluate the usefulness of ultrashort TE (UTE) imaging, a new technique to isolate signal from the osteochondral junction. Methods Twenty knees were examined at 3 T with 3D spoiled GRE (FLASH), double-echo steady-state (DESS), balanced SSFP, 3D turbo spin-echo (TSE), and a prototype UTE sequence. Two radiologists independently evaluated all images. Consensus readings of all sequences were the reference standard. Statistical analysis included Friedman and pairwise Wilcoxon tests. Retrospective analysis of UTE morphology of osteochondral tissue in normal and abnormal cartilage seen at conventional MR was also performed. Results Three-dimensional TSE was superior to other sequences for detecting cartilage lesions. FLASH and DESS performed best in the subjective quality analysis. On UTE images, normal cartilage exhibited a high-intensity linear signal near the osteochondral junction. Retrospective analysis revealed abnormal UTE morphology of the osteochondral junction in 50 % of cartilage lesions diagnosed at conventional MR. Conclusions Cartilage imaging of the knee at 3 T can be reliably performed using 3D TSE, showing high accuracy when compared to standard sequences. Although UTE depicts signal from the deep cartilage layer, further studies are needed to establish its role for assessment of cartilage. Main Messages • MRI is the best available imaging method for assessment of knee cartilage. • Cartilage imaging can be reliably performed using 3D TSE. • UTE cannot be used as a single sequence to assess cartilage.
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Lagendijk JJW, Raaymakers BW, Van den Berg CAT, Moerland MA, Philippens ME, van Vulpen M. MR guidance in radiotherapy. Phys Med Biol 2014; 59:R349-69. [PMID: 25322150 DOI: 10.1088/0031-9155/59/21/r349] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jan J W Lagendijk
- Department of Radiotherapy, University Medical Centre Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
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Extended phase graphs: Dephasing, RF pulses, and echoes - pure and simple. J Magn Reson Imaging 2014; 41:266-95. [DOI: 10.1002/jmri.24619] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 02/10/2014] [Accepted: 02/19/2014] [Indexed: 11/07/2022] Open
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Graves MJ, Mitchell DG. Body MRI artifacts in clinical practice: A physicist's and radiologist's perspective. J Magn Reson Imaging 2013; 38:269-87. [DOI: 10.1002/jmri.24288] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 05/24/2013] [Indexed: 11/07/2022] Open
Affiliation(s)
- Martin J. Graves
- Department of Radiology; Cambridge University Hospitals; Cambridge; United Kingdom
| | - Donald G. Mitchell
- Department of Radiology; Thomas Jefferson University; Philadelphia; Pennsylvania; USA
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