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Kolokythas O, Yaman Akcicek E, Akcicek H, Briller N, Rajamohan N, Yokoo T, Peeters HM, Revels JW, Moura Cunha G, Sahani DV, Mileto A. T1-weighted Motion Mitigation in Abdominal MRI: Technical Principles, Clinical Applications, Current Limitations, and Future Prospects. Radiographics 2024; 44:e230173. [PMID: 38990776 DOI: 10.1148/rg.230173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
T1-weighted (T1W) pulse sequences are an indispensable component of clinical protocols in abdominal MRI but usually require multiple breath holds (BHs) during the examination, which not all patients can sustain. Patient motion can affect the quality of T1W imaging so that key diagnostic information, such as intrinsic signal intensity and contrast enhancement image patterns, cannot be determined. Patient motion also has a negative impact on examination efficiency, as multiple acquisition attempts prolong the duration of the examination and often remain noncontributory. Techniques for mitigation of motion-related artifacts at T1W imaging include multiple arterial acquisitions within one BH; free breathing with respiratory gating or respiratory triggering; and radial imaging acquisition techniques, such as golden-angle radial k-space acquisition (stack-of-stars). While each of these techniques has inherent strengths and limitations, the selection of a specific motion-mitigation technique is based on several factors, including the clinical task under investigation, downstream technical ramifications, patient condition, and user preference. The authors review the technical principles of free-breathing motion mitigation techniques in abdominal MRI with T1W sequences, offer an overview of the established clinical applications, and outline the existing limitations of these techniques. In addition, practical guidance for abdominal MRI protocol strategies commonly encountered in clinical scenarios involving patients with limited BH abilities is rendered. Future prospects of free-breathing T1W imaging in abdominal MRI are also discussed. ©RSNA, 2024 See the invited commentary by Fraum and An in this issue.
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Affiliation(s)
- Orpheus Kolokythas
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Ebru Yaman Akcicek
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Halit Akcicek
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Noah Briller
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Naveen Rajamohan
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Takeshi Yokoo
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Hans M Peeters
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Jonathan W Revels
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Guilherme Moura Cunha
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Dushyant V Sahani
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
| | - Achille Mileto
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195 (O.K., N.B., G.M.C., D.V.S., A.M.); Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah (E.Y.A., H.A.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (N.R., T.Y.); Department of MRI Development, Philips Healthcare, Best, the Netherlands (H.M.P.); Department of Radiology, New York University Langone Health-Long Island Division, New York, NY (J.W.R.)
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Mio M, Tabata N, Toyofuku T, Nakamura H. [Reduction of Motion Artifacts in Liver MRI Using Deep Learning with High-pass Filtering]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2024; 80:510-518. [PMID: 38462509 DOI: 10.6009/jjrt.2024-1408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
PURPOSE To investigate whether deep learning with high-pass filtering can be used to effectively reduce motion artifacts in magnetic resonance (MR) images of the liver. METHODS The subjects were 69 patients who underwent liver MR examination at our hospital. Simulated motion artifact images (SMAIs) were created from non-artifact images (NAIs) and used for deep learning. Structural similarity index measure (SSIM) and contrast ratio (CR) were used to verify the effect of reducing motion artifacts in motion artifact reduction image (MARI) output from the obtained deep learning model. In the visual assessment, reduction of motion artifacts and image sharpness were evaluated between motion artifact images (MAIs) and MARIs. RESULTS The SSIM values were 0.882 on the MARIs and 0.869 on the SMAIs. There was no statistically significant difference in CR between NAIs and MARIs. The visual assessment showed that MARIs had reduced motion artifacts and improved sharpness compared to MAIs. CONCLUSION The learning model in this study is indicated to be reduced motion artifacts without decreasing the sharpness of liver MR images.
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Affiliation(s)
- Motohira Mio
- Department of Radiology, Fukuoka University Chikushi Hospital
| | - Nariaki Tabata
- Department of Radiology, Fukuoka University Chikushi Hospital
| | - Tatsuo Toyofuku
- Department of Radiology, Fukuoka University Chikushi Hospital
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Abrishami Kashani M, Campbell-Washburn AE, Murphy MC, Catalano OA, McDermott S, Fintelmann FJ. Magnetic Resonance Imaging for Guidance and Follow-up of Thoracic Needle Biopsies and Thermal Ablations. J Thorac Imaging 2022; 37:201-216. [PMID: 35426857 PMCID: PMC10441002 DOI: 10.1097/rti.0000000000000651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Magnetic resonance imaging (MRI) is used for the guidance and follow-up of percutaneous minimally invasive interventions in many body parts. In the thorax, computed tomography (CT) is currently the most used imaging modality for the guidance and follow-up of needle biopsies and thermal ablations. Compared with CT, MRI provides excellent soft tissue contrast, lacks ionizing radiation, and allows functional imaging. The role of MRI is limited in the thorax due to the low hydrogen proton density and many air-tissue interfaces of the lung, as well as respiratory and cardiac motion. Here, we review the current experience of MR-guided thoracic needle biopsies and of MR-guided thermal ablations targeting lesions in the lung, mediastinum, and the chest wall. We provide an overview of MR-compatible biopsy needles and ablation devices. We detail relevant MRI sequences and their relative advantages and disadvantages for procedural guidance, assessment of complications, and long-term follow-up. We compare the advantages and disadvantages of CT and MR for thoracic interventions and identify areas in need of improvement and additional research.
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Affiliation(s)
| | - Adrienne E Campbell-Washburn
- Division of Intramural Research, Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Mark C Murphy
- Division of Thoracic Imaging and Intervention, Department of Radiology
| | - Onofrio A Catalano
- Division of Abdominal Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA
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Oh G, Lee JE, Ye JC. Unpaired MR Motion Artifact Deep Learning Using Outlier-Rejecting Bootstrap Aggregation. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:3125-3139. [PMID: 34133276 DOI: 10.1109/tmi.2021.3089708] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Recently, deep learning approaches for MR motion artifact correction have been extensively studied. Although these approaches have shown high performance and lower computational complexity compared to classical methods, most of them require supervised training using paired artifact-free and artifact-corrupted images, which may prohibit its use in many important clinical applications. For example, transient severe motion (TSM) due to acute transient dyspnea in Gd-EOB-DTPA-enhanced MR is difficult to control and model for paired data generation. To address this issue, here we propose a novel unpaired deep learning scheme that does not require matched motion-free and motion artifact images. Specifically, the first step of our method is k -space random subsampling along the phase encoding direction that can remove some outliers probabilistically. In the second step, the neural network reconstructs fully sampled resolution image from a downsampled k -space data, and motion artifacts can be reduced in this step. Last, the aggregation step through averaging can further improve the results from the reconstruction network. We verify that our method can be applied for artifact correction from simulated motion as well as real motion from TSM successfully from both single and multi-coil data with and without k -space raw data, outperforming existing state-of-the-art deep learning methods.
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Duffy PB, Stemmer A, Callahan MJ, Cravero JP, Johnston PR, Warfield SK, Bixby SD. Free-breathing radial stack-of-stars three-dimensional Dixon gradient echo sequence in abdominal magnetic resonance imaging in sedated pediatric patients. Pediatr Radiol 2021; 51:1645-1653. [PMID: 33830291 DOI: 10.1007/s00247-021-05054-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/30/2021] [Accepted: 03/16/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND There is a strong need for improvements in motion robust T1-weighted abdominal imaging sequences in children to enable high-quality, free-breathing imaging. OBJECTIVE To compare imaging time and quality of a radial stack-of-stars, free-breathing T1-weighted gradient echo acquisition (volumetric interpolated breath-hold examination [VIBE]) three-dimensional (3-D) Dixon sequence in sedated pediatric patients undergoing abdominal magnetic resonance imaging (MRI) against conventional Cartesian T1-weighed sequences. MATERIALS AND METHODS This study was approved by the institutional review board with informed consent obtained from all subjects. Study subjects included 31 pediatric patients (19 male, 12 female; median age: 5 years; interquartile range: 5 years) undergoing abdominal MRI at 3 tesla with a free-breathing T1-weighted radial stack-of-stars 3-D VIBE Dixon prototype sequence, StarVIBE Dixon (radial technique), between October 2018 and June 2019 with previous abdominal MR imaging using conventional Cartesian T1-weighed imaging (traditional technique). MRI component times were recorded as well as the total number of non-contrast T1-weighted sequences. Two radiologists independently rated images for quality using a scale from 1 to 5 according to the following metrics: overall image quality, hepatic edge sharpness, hepatic vessel clarity and respiratory motion robustness. Scores were compared between the groups. RESULTS Mean T1-weighted imaging times for all subjects were 3.63 min for radial exams and 8.01 min for traditional exams (P<0.001), and total non-contrast imaging time was 32.7 min vs. 43.9 min (P=0.002). Adjusted mean total MRI time for all subjects was 60.2 min for radial exams and 65.7 min for traditional exams (P=0.387). The mean number of non-contrast T1-weighted sequences performed in radial MRI exams was 1.0 compared to 1.9 (range: 0-6) in traditional exams (P<0.001). StarVIBE Dixon outperformed Cartesian methods in all quality metrics. The mean overall image quality (scale 1-5) was 3.95 for radial exams and 3.31 for traditional exams (P<0.001). CONCLUSION Radial stack-of-stars 3-D VIBE Dixon during free-breathing abdominal MRI in pediatric patients offers improved image quality compared to Cartesian T1-weighted imaging techniques with decreased T1-weighted and total non-contrast imaging time. This has important implications for children undergoing sedation for imaging.
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Affiliation(s)
- Patrick B Duffy
- Department of Radiology, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA
| | | | - Michael J Callahan
- Department of Radiology, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA
| | - Joseph P Cravero
- Department of Anesthesiology, Boston Children's Hospital, Boston, MA, USA
| | - Patrick R Johnston
- Department of Radiology, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA
| | - Simon K Warfield
- Department of Radiology, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA
| | - Sarah D Bixby
- Department of Radiology, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA.
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Li H, Meng X, Guan X, Zhou N, Liu H, Zhang Y, Yu B, Zhu H, Li N, Yang Z. Clinical Evaluation of MR-Gated Respiratory Motion Correction in Simultaneous PET/MRI. Clin Nucl Med 2021; 46:297-302. [PMID: 33512946 DOI: 10.1097/rlu.0000000000003510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE The recently available gated T1-weighted imaging with the Dixon technique enables the synchronized gating signal for both MR acquisition and PET reconstruction. Herein, we evaluated the clinical value of this MR-gated PET reconstruction in the thoracic-abdominal PET/MRI compared with non-MR-gated method. METHODS Twenty patients (28 hypermetabolic target lesions) underwent PET/MRI. Four types of PET images were reconstructed: non-MR-gating + gated attenuation correction (AC) (group A), MR-gating + gated AC (group B), non-MR-gating + breath-hold (BH) AC (group C), and MR-gating + BH AC (group D). A 4-point objective scale (from well match to obvious mismatch was scored from 3 to 0) was proposed to evaluate the mismatch. The detection rate and quantitative metrics were also evaluated. RESULTS In the patient-based analysis, for groups A through D, the detection rates were 90%, 100%, 85%, and 90% as well as 95%, 100%, 85%, and 85%, assessed by readers 1 and 2, respectively, and significant difference of mismatch score was observed with the highest proportion of 3 points in group B (85%, 90%, 35%, and 40%, and 80%, 90%, 35%, and 20%, assessed by readers 1 and 2, respectively). The lesion-based analysis demonstrated significant differences in quantitative metrics for groups A through D (all P's < 0.05), with the highest quantitative metrics in group B (SUVmax: 7.49 ± 3.37, 8.45 ± 3.82, 6.90 ± 3.24, and 7.69 ± 3.50; SUVmean: 3.90 ± 1.60, 4.34 ± 1.84, 3.67 ± 1.61, and 4.03 ± 1.81; SUVpeak: 5.60 ± 2.50, 6.10 ± 2.80, 5.22 ± 2.40, and 5.65 ± 2.68; signal-to-noise ratio: 136.06 ± 90.58, 136.24 ± 81.63, 99.52 ± 53.16, and 107.57 ± 69.05). CONCLUSIONS The MR-gated reconstruction using gated AC reduced the mismatch between MR and PET images and improved the thoracic-abdominal PET image quality in simultaneous PET/MRI systems.
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Affiliation(s)
- Hui Li
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Xiangxi Meng
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Xiangping Guan
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Nina Zhou
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Hui Liu
- United Imaging Healthcare, Shanghai, China
| | - Yan Zhang
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Boqi Yu
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Hua Zhu
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Nan Li
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
| | - Zhi Yang
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing
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Liang X, Su P, Patil SG, Elsaid NMH, Roys S, Stone M, Gullapalli RP, Prince JL, Zhuo J. Prospective motion detection and re-acquisition in diffusion MRI using a phase image-based method-Application to brain and tongue imaging. Magn Reson Med 2021; 86:725-737. [PMID: 33665929 DOI: 10.1002/mrm.28729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 11/08/2022]
Abstract
PURPOSE To develop an image-based motion-robust diffusion MRI (dMRI) acquisition framework that is able to minimize motion artifacts caused by rigid and nonrigid motion, applicable to both brain and tongue dMRI. METHODS We developed a novel prospective motion-correction technique in dMRI using a phase image-based real-time motion-detection method (PITA-MDD) with re-acquisition of motion-corrupted images. The prospective PITA-MDD acquisition technique was tested in the brains and tongues of volunteers. The subjects were instructed to move their heads or swallow, to induce motion. Motion-detection efficacy was validated against visual inspection as the gold standard. The effect of the PITA-MDD technique on diffusion-parameter estimates was evaluated by comparing reconstructed fiber tracts using tractography with and without re-acquisition. RESULTS The prospective PITA-MDD technique was able to effectively and accurately detect motion-corrupted data as compared with visual inspection. Tractography results demonstrated that PITA-MDD motion detection followed by re-acquisition helps in recovering lost and misshaped fiber tracts in the brain and tongue that would otherwise be corrupted by motion and yield erroneous estimates of the diffusion tensor. CONCLUSION A prospective PITA-MDD technique was developed for dMRI acquisition, providing improved dMRI image quality and motion-robust diffusion estimation of the brain and tongue.
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Affiliation(s)
- Xiao Liang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Pan Su
- Siemens Medical Solutions USA Inc, Malvern, Pennsylvania, USA
| | - Sunil G Patil
- Siemens Medical Solutions USA Inc, Malvern, Pennsylvania, USA
| | - Nahla M H Elsaid
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA
| | - Steven Roys
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Maureen Stone
- Department of Neural and Pain Sciences and Department of Orthodontics, University of Maryland School of Dentistry, Baltimore, Maryland, USA
| | - Rao P Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jerry L Prince
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jiachen Zhuo
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Huber S, Balcacer De la Cruz P, Mahan M, Spektor M, Lo R, Block KT, Israel G. Comparison of image quality of subtracted and nonsubtracted breath hold VIBE and free breathing GRASP in the evaluation of renal masses. Clin Imaging 2021; 74:15-18. [PMID: 33421698 DOI: 10.1016/j.clinimag.2020.12.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To compare the image quality of subtracted and nonsubtracted images obtained using volumetric interpolated breath-hold exam (VIBE) and free breathing T1 weighted Golden-angle Radial Sparse Parallel (GRASP). METHODS We retrospectively evaluated 27 consecutive patients who underwent MRI for the evaluation of renal masses. Contrast enhanced VIBE and free breathing GRASP imaging were performed, and subtraction images generated. Two radiologists performed quantitative and qualitative evaluations of image quality of nonsubtracted and subtracted data sets. Statistical analysis was performed using the Wilcoxon signed-rank test, paired t-test and kappa statistics. RESULTS VIBE images scored statistically higher for the following parameters in the coronal and axial plane: sharpness, streak artifact, image noise, and overall image quality for standard and subtracted images (all P values P < 0.001). GRASP images had significantly less subtraction artifact in the coronal (P = 0.042) plane with a similar trend in the axial plane (P = 0.079). Interreader Kappa values for qualitative images scores were fair to good (0.23-0.71). Quantitative subtracted GRASP images had significant less subtraction artifact compared to VIBE in the anterior-posterior (3.9 mm SD 2.6 mm versus 5.8 mm SD 3.6 mm, P = 0.010), and craniocaudal direction (4.4 mm SD 2.9 mm versus 7.0 mm SD 5.3 mm, P = 0.010); a trend was seen in the left-right direction (2.6 mm SD 1.4 mm versus 4.0 mm SD 3.9 mm, P = 0.084). CONCLUSION VIBE images have significantly better image quality than free breathing GRASP images, however free breathing GRASP images have significantly less subtraction artifact.
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Affiliation(s)
- Steffen Huber
- Yale University School of Medicine, Department of Radiology and Biomedical Imaging, 333 Cedar St., PO Box 208042, New Haven, CT 06520, United States of America
| | - Patricia Balcacer De la Cruz
- Yale University School of Medicine, Department of Radiology and Biomedical Imaging, 333 Cedar St., PO Box 208042, New Haven, CT 06520, United States of America
| | - Mathur Mahan
- Yale University School of Medicine, Department of Radiology and Biomedical Imaging, 333 Cedar St., PO Box 208042, New Haven, CT 06520, United States of America
| | - Michael Spektor
- Yale University School of Medicine, Department of Radiology and Biomedical Imaging, 333 Cedar St., PO Box 208042, New Haven, CT 06520, United States of America
| | - Ryan Lo
- Yale University School of Medicine, Department of Radiology and Biomedical Imaging, 333 Cedar St., PO Box 208042, New Haven, CT 06520, United States of America
| | - Kai Tobias Block
- Siemens Healthcare GmbH, Diagnostic Imaging, Magnetic Resonance, SHS DI MR DL EPX, Allee am Roethelheimpark 2, 91052 Erlangen, Germany
| | - Gary Israel
- Yale University School of Medicine, Department of Radiology and Biomedical Imaging, 333 Cedar St., PO Box 208042, New Haven, CT 06520, United States of America.
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9
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Kromrey ML, Tamada D, Johno H, Funayama S, Nagata N, Ichikawa S, Kühn JP, Onishi H, Motosugi U. Reduction of respiratory motion artifacts in gadoxetate-enhanced MR with a deep learning-based filter using convolutional neural network. Eur Radiol 2020; 30:5923-5932. [PMID: 32556463 PMCID: PMC7651696 DOI: 10.1007/s00330-020-07006-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/17/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022]
Abstract
Objectives To reveal the utility of motion artifact reduction with convolutional neural network (MARC) in gadoxetate disodium–enhanced multi-arterial phase MRI of the liver. Methods This retrospective study included 192 patients (131 men, 68.7 ± 10.3 years) receiving gadoxetate disodium–enhanced liver MRI in 2017. Datasets were submitted to a newly developed filter (MARC), consisting of 7 convolutional layers, and trained on 14,190 cropped images generated from abdominal MR images. Motion artifact for training was simulated by adding periodic k-space domain noise to the images. Original and filtered images of pre-contrast and 6 arterial phases (7 image sets per patient resulting in 1344 sets in total) were evaluated regarding motion artifacts on a 4-point scale. Lesion conspicuity in original and filtered images was ranked by side-by-side comparison. Results Of the 1344 original image sets, motion artifact score was 2 in 597, 3 in 165, and 4 in 54 sets. MARC significantly improved image quality over all phases showing an average motion artifact score of 1.97 ± 0.72 compared to 2.53 ± 0.71 in original MR images (p < 0.001). MARC improved motion scores from 2 to 1 in 177/596 (29.65%), from 3 to 2 in 119/165 (72.12%), and from 4 to 3 in 34/54 sets (62.96%). Lesion conspicuity was significantly improved (p < 0.001) without removing anatomical details. Conclusions Motion artifacts and lesion conspicuity of gadoxetate disodium–enhanced arterial phase liver MRI were significantly improved by the MARC filter, especially in cases with substantial artifacts. This method can be of high clinical value in subjects with failing breath-hold in the scan. Key Points • This study presents a newly developed deep learning–based filter for artifact reduction using convolutional neural network (motion artifact reduction with convolutional neural network, MARC). • MARC significantly improved MR image quality after gadoxetate disodium administration by reducing motion artifacts, especially in cases with severely degraded images. • Postprocessing with MARC led to better lesion conspicuity without removing anatomical details.
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Affiliation(s)
- M-L Kromrey
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
- Department of Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Greifswald, Germany.
| | - D Tamada
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - H Johno
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - S Funayama
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - N Nagata
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - S Ichikawa
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - J-P Kühn
- Institute of Diagnostic and Interventional Radiology, University Medicine, Carl-Gustav Carus University, Dresden, Germany
| | - H Onishi
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - U Motosugi
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
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Ma JJ, Nakarmi U, Kin CYS, Sandino CM, Cheng JY, Syed AB, Wei P, Pauly JM, Vasanawala SS. DIAGNOSTIC IMAGE QUALITY ASSESSMENT AND CLASSIFICATION IN MEDICAL IMAGING: OPPORTUNITIES AND CHALLENGES. PROCEEDINGS. IEEE INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING 2020; 2020:337-340. [PMID: 33274013 PMCID: PMC7710391 DOI: 10.1109/isbi45749.2020.9098735] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magnetic Resonance Imaging (MRI) suffers from several artifacts, the most common of which are motion artifacts. These artifacts often yield images that are of non-diagnostic quality. To detect such artifacts, images are prospectively evaluated by experts for their diagnostic quality, which necessitates patient-revisits and rescans whenever non-diagnostic quality scans are encountered. This motivates the need to develop an automated framework capable of accessing medical image quality and detecting diagnostic and non-diagnostic images. In this paper, we explore several convolutional neural network-based frameworks for medical image quality assessment and investigate several challenges therein.
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Affiliation(s)
- Jeffrey J Ma
- Department of Computing and Mathematical Sciences, California Institute of Technology
- Department of Radiology, Stanford University
| | | | | | | | | | - Ali B Syed
- Department of Radiology, Stanford University
| | - Peter Wei
- Department of Radiology, Stanford University
| | - John M Pauly
- Department of Electrical Engineering, Stanford University
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Zhu C, Cao L, Wen Z, Ahn S, Raithel E, Forman C, Hope M, Saloner D. Surveillance of abdominal aortic aneurysm using accelerated 3D non-contrast black-blood cardiovascular magnetic resonance with compressed sensing (CS-DANTE-SPACE). J Cardiovasc Magn Reson 2019; 21:66. [PMID: 31660983 PMCID: PMC6816154 DOI: 10.1186/s12968-019-0571-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/27/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND 3D non-contrast high-resolution black-blood cardiovascular magnetic resonance (CMR) (DANTE-SPACE) has been used for surveillance of abdominal aortic aneurysm (AAA) and validated against computed tomography (CT) angiography. However, it requires a long scan time of more than 7 min. We sought to develop an accelerated sequence applying compressed sensing (CS-DANTE-SPACE) and validate it in AAA patients undergoing surveillance. METHODS Thirty-eight AAA patients (all males, 73 ± 6 years) under clinical surveillance were recruited for this study. All patients were scanned with DANTE-SPACE (scan time 7:10 min) and CS-DANTE-SPACE (scan time 4:12 min, a reduction of 41.4%). Nine 9 patients were scanned more than 2 times. In total, 50 pairs of images were available for comparison. Two radiologists independently evaluated the image quality on a 1-4 scale, and measured the maximal diameter of AAA, the intra-luminal thrombus (ILT) and lumen area, ILT-to-muscle signal intensity ratio, and the ILT-to-lumen contrast ratio. The sharpness of the aneurysm inner/outer boundaries was quantified. RESULTS CS-DANTE-SPACE achieved comparable image quality compared with DANTE-SPACE (3.15 ± 0.67 vs. 3.03 ± 0.64, p = 0.06). There was excellent agreement between results from the two sequences for diameter/area and ILT ratio measurements (ICCs> 0.85), and for quantifying growth rate (3.3 ± 3.1 vs. 3.3 ± 3.4 mm/year, ICC = 0.95.) CS-DANTE-SPACE showed a higher ILT-to-lumen contrast ratio (p = 0.01) and higher sharpness than DANTE-SPACE (p = 0.002). Both sequences had excellent inter-reader reproducibility for quantitative measurements (ICC > 0.88). CONCLUSION CS-DANTE-SPACE can reduce scan time while maintaining image quality for AAA imaging. It is a promising tool for the surveillance of patients with AAA disease in the clinical setting.
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Affiliation(s)
- Chengcheng Zhu
- Department of Radiology and Biomedical Imaging, UCSF, 4150 Clement Street, San Francisco, CA 94121 USA
| | - Lizhen Cao
- Department of Radiology and Biomedical Imaging, UCSF, 4150 Clement Street, San Francisco, CA 94121 USA
- Department of Radiology, Xuanwu Hospital, Beijing, China
| | - Zhaoying Wen
- Department of Radiology and Biomedical Imaging, UCSF, 4150 Clement Street, San Francisco, CA 94121 USA
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing, 100029 China
| | | | | | | | - Michael Hope
- Department of Radiology and Biomedical Imaging, UCSF, 4150 Clement Street, San Francisco, CA 94121 USA
| | - David Saloner
- Department of Radiology and Biomedical Imaging, UCSF, 4150 Clement Street, San Francisco, CA 94121 USA
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Tamada D, Kromrey ML, Ichikawa S, Onishi H, Motosugi U. Motion Artifact Reduction Using a Convolutional Neural Network for Dynamic Contrast Enhanced MR Imaging of the Liver. Magn Reson Med Sci 2019; 19:64-76. [PMID: 31061259 PMCID: PMC7067907 DOI: 10.2463/mrms.mp.2018-0156] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose: To improve the quality of images obtained via dynamic contrast enhanced MRI (DCE-MRI), which contain motion artifacts and blurring using a deep learning approach. Materials and Methods: A multi-channel convolutional neural network-based method is proposed for reducing the motion artifacts and blurring caused by respiratory motion in images obtained via DCE-MRI of the liver. The training datasets for the neural network included images with and without respiration-induced motion artifacts or blurring, and the distortions were generated by simulating the phase error in k-space. Patient studies were conducted using a multi-phase T1-weighted spoiled gradient echo sequence for the liver, which contained breath-hold failures occurring during data acquisition. The trained network was applied to the acquired images to analyze the filtering performance, and the intensities and contrast ratios before and after denoising were compared via Bland–Altman plots. Results: The proposed network was found to be significantly reducing the magnitude of the artifacts and blurring induced by respiratory motion, and the contrast ratios of the images after processing via the network were consistent with those of the unprocessed images. Conclusion: A deep learning-based method for removing motion artifacts in images obtained via DCE-MRI of the liver was demonstrated and validated.
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Affiliation(s)
- Daiki Tamada
- Department of Radiology, University of Yamanashi
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Corrias G, Raeside MC, Agostini A, Huicochea-Castellanos S, Aramburu-Nunez D, Paudyal R, Shukla-Dave A, Smelianskaia O, Capanu M, Zheng J, Fung M, Kelsen DP, Mangino DA, Robson ME, Goldfrank DJ, Carter J, Allen PJ, Conti B, Monti S, Do RKG, Mannelli L. Pilot study of rapid MR pancreas screening for patients with BRCA mutation. Eur Radiol 2019; 29:3976-3985. [PMID: 30689033 DOI: 10.1007/s00330-018-5975-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/16/2018] [Accepted: 12/14/2018] [Indexed: 01/03/2023]
Abstract
PURPOSE To develop and optimize a rapid magnetic resonance imaging (MRI) screening protocol for pancreatic cancer to be performed in conjunction with breast MRI screening in breast cancer susceptibility gene (BRCA)-positive individuals. METHODS An IRB-approved prospective study was conducted. The rapid screening pancreatic MR protocol was designed to be less than 10 min to be performed after a standard breast MRI protocol. Protocol consisted of coronal NT T2 SSFSE, axial NT T2 SSFSE and axial NT rFOV FOCUS DWI, and axial T1. Images were acquired with the patient in the same prone position of breast MRI using the built-in body coil. Image quality was qualitatively assessed by two radiologists with 12 and 13 years of MRI experience, respectively. The imaging protocol was modified until an endpoint of five consecutive patients with high-quality diagnostic images were achieved. Signal-to-noise ratio and contrast-to-noise ratio were assessed. RESULTS The rapid pancreas MR protocol was successfully completed in all patients. Diagnostic image quality was achieved for all patients. Excellent image quality was achieved for low b values; however, image quality at higher b values was more variable. In one patient, a pancreatic neuroendocrine tumor was found and the patient was treated surgically. In four patients, small pancreatic cystic lesions were detected. In one subject, a hepatic mass was identified and confirmed as adenoma by liver MRI. CONCLUSION Rapid MR protocol for pancreatic cancer screening is feasible and has the potential to play a role in screening BRCA patients undergoing breast MRI. KEY POINT • Develop and optimize a rapid magnetic resonance imaging (MRI) screening protocol for pancreatic cancer to be performed in conjunction with breast MRI screening in BRCA mutation positive individuals.
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Affiliation(s)
- Giuseppe Corrias
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
- Department of Radiology, University of Cagliari, Cagliari, Italy
| | - Mitchell C Raeside
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Andrea Agostini
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
- Department of Radiology, Università Politecnica delle Marche, Ancona, Italy
| | | | - David Aramburu-Nunez
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ramesh Paudyal
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Amita Shukla-Dave
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Olga Smelianskaia
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Marinela Capanu
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Junting Zheng
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Maggie Fung
- GE Healthcare, Global MR Applications and Workflow, New York, NY, USA
| | - David P Kelsen
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Debra A Mangino
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Mark E Robson
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Deborah J Goldfrank
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jean Carter
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Peter J Allen
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Bettina Conti
- Policlinico Umberto I, Department of Radiology, Sapienza University of Rome, Rome, Italy
| | | | - Richard K G Do
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Lorenzo Mannelli
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
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DIfferential Subsampling With Cartesian Ordering With Respiratory Triggering Versus Conventional Liver Acquisition With Volume Acquisition. J Comput Assist Tomogr 2019; 43:623-627. [DOI: 10.1097/rct.0000000000000888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Evaluation of a free-breathing respiratory-triggered (Navigator) 3-D T1-weighted (T1W) gradient recalled echo sequence (LAVA) for detection of enhancement in cystic and solid renal masses. Eur Radiol 2018; 29:2507-2517. [PMID: 30506224 DOI: 10.1007/s00330-018-5839-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/15/2018] [Accepted: 10/17/2018] [Indexed: 01/14/2023]
Abstract
OBJECTIVES To evaluate free-breathing Navigator-triggered 3-D T1-weighted MRI (NAV-LAVA) compared to breath-hold (BH)-LAVA among cystic and solid renal masses. MATERIALS AND METHODS With an IRB waiver, 44 patients with 105 renal masses (71 non-enhancing cysts and 14 cystic and 20 solid renal masses) underwent MRI between 2016 and 2017 where BH-LAVA and NAV-LAVA were performed. Subtraction images were generated for BH-LAVA and NAV-LAVA using pre- and 3-min post-gadolinium-enhanced images and were evaluated by two blinded radiologists for overall image quality, image sharpness, motion artifact, and quality of subtraction (using 5-point Likert scales) and presence/absence of enhancement. Percentage signal intensity change (Δ%SI) = ([SI.post-gadolinium-SI.pre-gadolinium]/SI.pre-gadolinium)*100, was measured on BH-LAVA and NAV-LAVA. Likert scores were compared using Wilcoxon's sign-rank test and accuracy for detection of enhancement compared using receiver operator characteristic (ROC) analysis. RESULTS Overall image quality (p = 0.002-0.141), image sharpness (p = 0.002-0.031), and motion artifact were better (p = 0.002) comparing BH-LAVA to NAV-LAVA for both radiologists; however, quality of image subtraction did not differ between groups (p = 0.09-0.14). Sensitivity/specificity/area under ROC curve for enhancement in cystic and solid renal masses using subtraction and %SIΔ were (1) BH-LAVA: 64.7%/98.6%/0.82 (radiologist 1), 61.8%/95.8%/0.79 (radiologist 2), and 70.6%/81.7%/0.76 (%SIΔ) versus 2) NAV-LAVA: 58.8%/95.8%/0.79 (radiologist 1, p = 0.16), 58.8%/88.7%/0.73 (radiologist 2, p = 0.37), and 73.5%/76.1%/0.75 (%SIΔ, p = 0.74). CONCLUSIONS NAV-LAVA showed similar quality of subtraction and ability to detect enhancement compared to BH-LAVA in renal masses albeit with lower image quality, image sharpness, and increased motion artifact. NAV-LAVA may be considered in renal MRI for patients where BH is suboptimal. KEY POINTS • Free-breathing Navigator (NAV) 3-D subtraction MRI is comparable to breath-hold (BH) images. • Accuracy for subjective and quantitative diagnosis of enhancement in renal masses on NAV 3-D T1W is comparable to BH MRI. • NAV 3-D T1W renal MRI is useful in patients who may not be able to adequately BH.
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Chu ML, Chang HC, Chung HW, Bashir MR, Cai J, Zhang L, Sun D, Chen NK. Free-breathing abdominal MRI improved by repeated k-t-subsampling and artifact-minimization (ReKAM). Med Phys 2017; 45:178-190. [PMID: 29148576 DOI: 10.1002/mp.12674] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 11/08/2022] Open
Abstract
PURPOSE We report an approach, termed Repeated k-t-subsampling and artifact-minimization (ReKAM), for removing motion artifacts in free-breathing abdominal MRI. The method is particularly valuable for challenging patients who may not hold their breath for a long time or have irregular respiratory rate. METHODS The ReKAM framework comprises one acquisition module and two reconstruction modules. A fast MRI sequence is used to repeatedly acquire multiple sets of k-t space data. Motion artifacts are then minimized by two reconstruction modules: (a) a bootstrapping module in k-t-space is used to identify a low-artifact image; (b) a constrained reconstruction module that integrates projection onto convex set (POCS) and multiplexed sensitivity encoding (MUSE), termed POCSMUSE, is applied to further remove residual artifact. The ReKAM framework is compatible with different pulse sequences, and generally applicable to irregular data sampling patterns in k-space. Free-breathing fast spin-echo MRI data, acquired from healthy volunteers and patients, were used to evaluate the developed ReKAM method. RESULTS Experimental results show that the ReKAM technique can produce high-quality free-breathing images with the artifact levels comparable to that of breath-holding MRI. CONCLUSION The ReKAM framework improves the quality of free-breathing abdominal MRI data, and is compatible with various MRI pulse sequences.
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Affiliation(s)
- Mei-Lan Chu
- Department of Biomedical Engineering, University of Arizona, 1127 E. James E. Rogers Way, P.O. Box 210020, Tucson, AZ, 85721-0020, USA
| | - Hing-Chiu Chang
- Department of Diagnostic Radiology, The University of Hong Kong, Room 406, Block K, Queen Mary Hospital, Pok Fu Lam Road, Hong Kong, China
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, Taiwan, 106
| | - Mustafa R Bashir
- Department of Radiology, Duke University Medical Center, 2301 Erwin Road, Durham, NC, 27710, USA.,Center for Advanced Magnetic Resonance Development, Duke University Medical Center, 2301 Erwin Road, Durham, NC, 27710, USA
| | - Jing Cai
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Room Y934, 9/F, Lee Shau Kee Building, Hung Hom, Kowloon, Hong Kong, China.,Department of Radiation Oncology, Duke University Medical Center, 2301 Erwin Road, Durham, NC, 27710, USA
| | - Lei Zhang
- Medical Physics Graduate Program, Duke University, 2424 Erwin Road, Hock Plaza, Suite 101, Durham, NC, 27705, USA
| | - Duohua Sun
- Department of Biomedical Engineering, University of Arizona, 1127 E. James E. Rogers Way, P.O. Box 210020, Tucson, AZ, 85721-0020, USA
| | - Nan-Kuei Chen
- Department of Biomedical Engineering, University of Arizona, 1127 E. James E. Rogers Way, P.O. Box 210020, Tucson, AZ, 85721-0020, USA.,Department of Radiology, Duke University Medical Center, 2301 Erwin Road, Durham, NC, 27710, USA.,Medical Physics Graduate Program, Duke University, 2424 Erwin Road, Hock Plaza, Suite 101, Durham, NC, 27705, USA.,Brain Imaging and Analysis Center, Duke University Medical Center, 40 Duke Medicine Circle, Room 414, Durham, NC, 27710, USA
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Iwadate Y, Nozaki A, Nunokawa Y, Okuda S, Jinzaki M, Kabasawa H. Silent navigator-triggered silent MRI of the abdomen. Magn Reson Med 2017; 79:2170-2175. [PMID: 28782173 DOI: 10.1002/mrm.26869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 07/15/2017] [Accepted: 07/19/2017] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop and demonstrate the feasibility of a silent respiratory navigator technique for prospective triggering, which was incorporated into a three-dimensional radial zero-echo-time sequence for respiratory navigated silent abdominal imaging. METHODS A nonselective hard excitation radiofrequency pulse was used for the navigator sequence with a derated readout gradient, to avoid generation of high levels of acoustic noise. The acquired navigator signals were processed in real time and used for prospective triggering of the zero-echo-time sequence. Ten healthy volunteers were scanned using the proposed and conventional techniques at 1.5 T. An acoustic noise measurement with A-weighted continuous equivalent sound pressure level was also performed. RESULTS The sound pressure-level values of the background noise, zero-echo-time imaging, conventional, and silent navigators were 68.3, 68.4, 102.5, and 69.4 dBA, respectively. Excellent correlation with correlation coefficients greater than 0.9 was observed between the bellows signals and displacement values calculated from the navigators. Sharpness of the portal vein of both conventional and silent navigator-triggered images was significantly higher than those of nontriggered images. CONCLUSIONS The silent navigator-triggered zero-echo-time technique is feasible and might improve image quality and workflow of abdominal MRI of patients who are prone to acoustic noise. Magn Reson Med 79:2170-2175, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Yuji Iwadate
- Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan
| | - Atsushi Nozaki
- Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan
| | | | - Shigeo Okuda
- Department of Radiology, Keio University School of Medicine, Tokyo, Japan
| | - Masahiro Jinzaki
- Department of Radiology, Keio University School of Medicine, Tokyo, Japan
| | - Hiroyuki Kabasawa
- Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan
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Janssen NN, ter Beek LC, Loo CE, Winter-Warnars G, Lange CA, van Loveren M, Alderliesten T, Sonke JJ, Nijkamp J. Supine Breast MRI Using Respiratory Triggering. Acad Radiol 2017; 24:818-825. [PMID: 28256441 DOI: 10.1016/j.acra.2017.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/06/2017] [Accepted: 01/07/2017] [Indexed: 10/20/2022]
Abstract
RATIONALE AND OBJECTIVES This study aims to evaluate if navigator-echo respiratory-triggered magnetic resonance acquisition can acquire supine high-quality breast magnetic resonance imaging (MRI). MATERIALS AND METHODS Supine respiratory-triggered magnetic resonance imaging (Trig-MRI) was compared to supine non-Trig-MRI to evaluate breathing-induced motion artifacts (group 1), and to conventional prone non-Trig-MRI (group 2, 16-channel breast coil), all at 3T. A 32-channel thorax coil was placed on top of a cover to prevent breast deformation. Ten volunteers were scanned in each group, including one patient. The acquisition time was recorded. Image quality was compared by visual examination and by calculation of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image sharpness (IS). RESULTS Scan time increased from 56.5 seconds (non-Trig-MRI) to an average of 306 seconds with supine Trig-MRI (range: 120-540 seconds). In group 1, the median values (interquartile range) of SNR, CNR, and IS improved from 11.5 (6.0), 7.3 (3.1), and 0.23 (0.2) cm on supine non-Trig-MRI to 38.1 (29.1), 32.8 (29.7), and 0.12 (0) cm (all P < 0.01) on supine Trig-MRI. All qualitative image parameters in group 1 improved on supine Trig-MRI (all P < 0.01). In group 2, SNR and CNR improved from 14.7 (6.8) and 12.6 (5.6) on prone non-Trig-MRI to 36.2 (12.2) and 32.7 (12.1) (both P < 0.01) on supine Trig-MRI. IS was similar: 0.10 (0) cm vs 0.11 (0) cm (P = 0.88). CONCLUSIONS Acquisition of high-quality supine breast MRI is possible when respiratory triggering is applied, in a similar setup as during subsequent treatment. Image quality improved when compared to supine non-triggered breast MRI and prone breast MRI, but at the cost of increased acquisition time.
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Advanced imaging techniques in pediatric body MRI. Pediatr Radiol 2017; 47:522-533. [PMID: 28409251 DOI: 10.1007/s00247-017-3778-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/19/2016] [Accepted: 01/03/2017] [Indexed: 12/13/2022]
Abstract
While there are many challenges specific to pediatric abdomino-pelvic MRI, many recent advances are addressing these challenges. It is therefore essential for radiologists to be familiar with the latest advances in MR imaging. Laudable efforts have also recently been implemented in many centers to improve the overall experience of pediatric patients, including the use of dedicated radiology child life specialists, MRI video goggles, and improved MR suite environments. These efforts have allowed a larger number of children to be scanned while awake, with fewer studies being done under sedation or anesthesia; this has resulted in additional challenges from patient motion and difficulties with breath-holding and tolerating longer scan times. In this review, we highlight common challenges faced in imaging the pediatric abdomen and pelvis and discuss the application of the newest techniques to address these challenges. Additionally, we highlight the newest advances in quantified imaging techniques, specifically in MR liver iron quantification. The techniques described in this review are all commercially available and can be readily implemented.
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Loeffler RB, McCarville MB, Wagstaff AW, Smeltzer MP, Krafft AJ, Song R, Hankins JS, Hillenbrand CM. Can multi-slice or navigator-gated R2* MRI replace single-slice breath-hold acquisition for hepatic iron quantification? Pediatr Radiol 2017; 47:46-54. [PMID: 27752732 PMCID: PMC5203961 DOI: 10.1007/s00247-016-3700-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 07/21/2016] [Accepted: 08/26/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND Liver R2* values calculated from multi-gradient echo (mGRE) magnetic resonance images (MRI) are strongly correlated with hepatic iron concentration (HIC) as shown in several independently derived biopsy calibration studies. These calibrations were established for axial single-slice breath-hold imaging at the location of the portal vein. Scanning in multi-slice mode makes the exam more efficient, since whole-liver coverage can be achieved with two breath-holds and the optimal slice can be selected afterward. Navigator echoes remove the need for breath-holds and allow use in sedated patients. OBJECTIVE To evaluate if the existing biopsy calibrations can be applied to multi-slice and navigator-controlled mGRE imaging in children with hepatic iron overload, by testing if there is a bias-free correlation between single-slice R2* and multi-slice or multi-slice navigator controlled R2*. MATERIALS AND METHODS This study included MRI data from 71 patients with transfusional iron overload, who received an MRI exam to estimate HIC using gradient echo sequences. Patient scans contained 2 or 3 of the following imaging methods used for analysis: single-slice images (n = 71), multi-slice images (n = 69) and navigator-controlled images (n = 17). Small and large blood corrected region of interests were selected on axial images of the liver to obtain R2* values for all data sets. Bland-Altman and linear regression analysis were used to compare R2* values from single-slice images to those of multi-slice images and navigator-controlled images. RESULTS Bland-Altman analysis showed that all imaging method comparisons were strongly associated with each other and had high correlation coefficients (0.98 ≤ r ≤ 1.00) with P-values ≤0.0001. Linear regression yielded slopes that were close to 1. CONCLUSION We found that navigator-gated or breath-held multi-slice R2* MRI for HIC determination measures R2* values comparable to the biopsy-validated single-slice, single breath-hold scan. We conclude that these three R2* methods can be interchangeably used in existing R2*-HIC calibrations.
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Affiliation(s)
- Ralf B Loeffler
- Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA
| | - M Beth McCarville
- Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA
| | - Anne W Wagstaff
- Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA
- Rhodes College, Memphis, TN, USA
- University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Matthew P Smeltzer
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN, USA
- Division of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, University of Memphis, Memphis, TN, USA
| | - Axel J Krafft
- Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA
- Department of Radiology, University Hospital Center Freiburg, Freiburg, Germany
| | - Ruitian Song
- Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA
| | - Jane S Hankins
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Claudia M Hillenbrand
- Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA.
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Ogasawara G, Inoue Y, Matsunaga K, Fujii K, Hata H, Miyatake H, Iwadate Y. Evaluation of a respiratory navigator-gating technique in Gd-EOB-DTPA-enhanced magnetic resonance imaging for the assessment of liver tumors. Eur J Radiol 2016; 85:1232-7. [DOI: 10.1016/j.ejrad.2016.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/21/2016] [Accepted: 04/10/2016] [Indexed: 12/22/2022]
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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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Jaimes C, Gee MS. Strategies to minimize sedation in pediatric body magnetic resonance imaging. Pediatr Radiol 2016; 46:916-27. [PMID: 27229508 DOI: 10.1007/s00247-016-3613-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 01/11/2016] [Accepted: 02/05/2016] [Indexed: 12/13/2022]
Abstract
The high soft-tissue contrast of MRI and the absence of ionizing radiation make it a valuable tool for assessment of body pathology in children. Infants and young children are often unable to cooperate with awake MRI so sedation or general anesthesia might be required. However, given recent data on the costs and potential risks of anesthesia in young children, there is a need to try to decrease or avoid sedation in this population when possible. Child life specialists in radiology frequently use behavioral techniques and audiovisual support devices, and they practice with children and families using mock scanners to improve child compliance with MRI. Optimization of the MR scanner environment is also important to create a child-friendly space. If the child can remain inside the MRI scanner, a variety of emerging techniques can reduce the effect of involuntary motion. Using sequences with short acquisition times such as single-shot fast spin echo and volumetric gradient echo can decrease artifacts and improve image quality. Breath-holding, respiratory triggering and signal averaging all reduce respiratory motion. Emerging techniques such as radial and multislice k-space acquisition, navigator motion correction, as well as parallel imaging and compressed sensing reconstruction methods can further accelerate acquisition and decrease motion. Collaboration among radiologists, anesthesiologists, technologists, child life specialists and families is crucial for successful performance of MRI in young children.
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Affiliation(s)
- Camilo Jaimes
- Division of Pediatric Imaging, Department of Radiology, Massachusetts General Hospital, 55 Fruit St., Ellison 237, Boston, MA, 02114, USA.,Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Michael S Gee
- Division of Pediatric Imaging, Department of Radiology, Massachusetts General Hospital, 55 Fruit St., Ellison 237, Boston, MA, 02114, USA. .,Department of Radiology, Harvard Medical School, Boston, MA, USA.
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25
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Higano NS, Hahn AD, Tkach JA, Cao X, Walkup LL, Thomen RP, Merhar SL, Kingma PS, Fain SB, Woods JC. Retrospective respiratory self-gating and removal of bulk motion in pulmonary UTE MRI of neonates and adults. Magn Reson Med 2016; 77:1284-1295. [PMID: 26972576 DOI: 10.1002/mrm.26212] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/09/2016] [Accepted: 02/20/2016] [Indexed: 12/30/2022]
Abstract
PURPOSE To implement pulmonary three-dimensional (3D) radial ultrashort echo-time (UTE) MRI in non-sedated, free-breathing neonates and adults with retrospective motion tracking of respiratory and intermittent bulk motion, to obtain diagnostic-quality, respiratory-gated images. METHODS Pulmonary 3D radial UTE MRI was performed at 1.5 tesla (T) during free breathing in neonates and adult volunteers for validation. Motion-tracking waveforms were obtained from the time course of each free induction decay's initial point (i.e., k-space center), allowing for respiratory-gated image reconstructions that excluded data acquired during bulk motion. Tidal volumes were calculated from end-expiration and end-inspiration images. Respiratory rates were calculated from the Fourier transform of the motion-tracking waveform during quiet breathing, with comparison to physiologic prediction in neonates and validation with spirometry in adults. RESULTS High-quality respiratory-gated anatomic images were obtained at inspiration and expiration, with less respiratory blurring at the expense of signal-to-noise for narrower gating windows. Inspiration-expiration volume differences agreed with physiologic predictions (neonates; Bland-Altman bias = 6.2 mL) and spirometric values (adults; bias = 0.11 L). MRI-measured respiratory rates compared well with the observed rates (biases = -0.5 and 0.2 breaths/min for neonates and adults, respectively). CONCLUSIONS Three-dimensional radial pulmonary UTE MRI allows for retrospective respiratory self-gating and removal of intermittent bulk motion in free-breathing, non-sedated neonates and adults. Magn Reson Med 77:1284-1295, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Nara S Higano
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Andrew D Hahn
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jean A Tkach
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Xuefeng Cao
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Laura L Walkup
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Robert P Thomen
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Stephanie L Merhar
- Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Paul S Kingma
- Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Sean B Fain
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason C Woods
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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Motion detection improvement of a pencil-beam navigator echo using a gradient reversal technique. Magn Reson Imaging 2015; 33:1168-1172. [DOI: 10.1016/j.mri.2015.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/25/2015] [Accepted: 06/21/2015] [Indexed: 11/22/2022]
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Navigated three-dimensional T1-weighted gradient-echo sequence for gadoxetic acid liver magnetic resonance imaging in patients with limited breath-holding capacity. ACTA ACUST UNITED AC 2015; 40:278-88. [PMID: 25112454 DOI: 10.1007/s00261-014-0214-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE To determine whether a navigator-gated three-dimensional T1-weighted gradient-echo sequence (T1W-GRE, navigated LAVA) can improve diagnostic performance for the detection of focal liver lesions (FLLs) compared to standard breath-hold (BH) T1W-GRE breath-hold LAVA (BH-LAVA) during the hepatobiliary phase (HBP) of gadoxetic acid liver magnetic resonance imaging (MRI) in patients with limited breath-holding capacity. MATERIALS AND METHODS This retrospective study was approved by our institutional review board and the requirement for informed consent was waived. We included 372 patients who underwent liver MRI including both navigated LAVA and BH-LAVA sequences. Overall image quality of the two HBP image sets was compared. In patients with limited breath-holding capacity, diagnostic performances in detecting FLLs on the two HBP images were compared using jackknife-alternative free-response receiver-operating characteristic (JAFROC) analysis by two reviewers. RESULTS There were 13 cases (13/372; 3.5%) of image acquisition failure using the navigated LAVA sequence due to severe irregular breathing, and 50 of 359 patients had limited breath-holding capacity. In these patients, overall image quality of navigated LAVA (2.78 ± 0.95) was significantly better than that of BH-LAVA (2.42 ± 0.81, P < 0.005), and both readers showed significantly higher JAFROC figure-of-merit values with navigated LAVA compared to BH-LAVA (0.94 and 0.86 in reviewer 1, respectively; 0.89 and 0.83 in reviewer 2, respectively, P < 0.005). Overall image quality of navigated LAVA was also better than that of BH-LAVA in patients with sufficient breath-holding capacity (n = 309, 3.96 ± 0.88, 3.81 ± 0.66, respectively, P < 0.001). CONCLUSION The navigated LAVA sequence could provide better image quality and diagnostic performance in detecting FLLs than BH-LAVA in patients with limited breath-holding capacity during HBP of gadoxetic acid MRI.
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Herédia V, Dale B, Op de Campos R, Ramalho M, Burke L, Sams C, de Toni M, Semelka R. Comparación de una secuencia en 3D con eco de gradiente potenciada en T1 con 3 factores de reducción de imagen en paralelo diferentes, en apnea y respiración libre, utilizando una bobina de 32 canales a 1,5T. Estudio preliminar. RADIOLOGIA 2014; 56:533-40. [DOI: 10.1016/j.rx.2012.06.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 04/11/2012] [Accepted: 06/20/2012] [Indexed: 10/27/2022]
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29
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Herédia V, Dale B, Op de Campos R, Ramalho M, Burke L, Sams C, de Toni M, Semelka R. A comparison of a T1 weighted 3D gradient-echo sequence with three different parallel imaging reduction factors, breath hold and free breathing, using a 32 channel coil at 1.5T. A preliminary study. RADIOLOGIA 2014. [DOI: 10.1016/j.rxeng.2012.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Inoue Y, Hata H, Nakajima A, Iwadate Y, Ogasawara G, Matsunaga K. Optimal techniques for magnetic resonance imaging of the liver using a respiratory navigator-gated three-dimensional spoiled gradient-recalled echo sequence. Magn Reson Imaging 2014; 32:975-80. [DOI: 10.1016/j.mri.2014.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 02/19/2014] [Accepted: 05/26/2014] [Indexed: 12/22/2022]
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Post-contrast T1-weighted sequences in pediatric abdominal imaging: comparative analysis of three different sequences and imaging approach. Pediatr Radiol 2014; 44:1258-65. [PMID: 24723237 DOI: 10.1007/s00247-014-2969-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/07/2014] [Accepted: 03/10/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Post-contrast T1-weighted imaging is an essential component of a comprehensive pediatric abdominopelvic MR examination. However, consistent good image quality is challenging, as respiratory motion in sedated children can substantially degrade the image quality. OBJECTIVE To compare the image quality of three different post-contrast T1-weighted imaging techniques-standard three-dimensional gradient-echo (3-D-GRE), magnetization-prepared gradient-recall echo (MP-GRE) and 3-D-GRE with radial data sampling (radial 3-D-GRE)-acquired in pediatric patients younger than 5 years of age. MATERIALS AND METHODS Sixty consecutive exams performed in 51 patients (23 females, 28 males; mean age 2.5 ± 1.4 years) constituted the final study population. Thirty-nine scans were performed at 3 T and 21 scans were performed at 1.5 T. Two different reviewers independently and blindly qualitatively evaluated all sequences to determine image quality and extent of artifacts. RESULTS MP-GRE and radial 3-D-GRE sequences had the least respiratory motion (P < 0.0001). Standard 3-D-GRE sequences displayed the lowest average score ratings in hepatic and pancreatic edge definition, hepatic vessel clarity and overall image quality. Radial 3-D-GRE sequences showed the highest scores ratings in overall image quality. CONCLUSIONS Our preliminary results support the preference of fat-suppressed radial 3-D-GRE as the best post-contrast T1-weighted imaging approach for patients under the age of 5 years, when dynamic imaging is not essential.
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Bultman EM, Brodsky EK, Horng DK, Irarrazaval P, Schelman WR, Block WF, Reeder SB. Quantitative hepatic perfusion modeling using DCE-MRI with sequential breathholds. J Magn Reson Imaging 2014; 39:853-65. [PMID: 24395144 PMCID: PMC3962525 DOI: 10.1002/jmri.24238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 05/01/2013] [Indexed: 12/23/2022] Open
Abstract
PURPOSE To develop and demonstrate the feasibility of a new formulation for quantitative perfusion modeling in the liver using interrupted DCE-MRI data acquired during multiple sequential breathholds. MATERIALS AND METHODS A new mathematical formulation to estimate quantitative perfusion parameters using interrupted data was developed. Using this method, we investigated whether a second degree-of-freedom in the tissue residue function (TRF) improves quality-of-fit criteria when applied to a dual-input single-compartment perfusion model. We subsequently estimated hepatic perfusion parameters using DCE-MRI data from 12 healthy volunteers and 9 cirrhotic patients with a history of hepatocellular carcinoma (HCC); and examined the utility of these estimates in differentiating between healthy liver, cirrhotic liver, and HCC. RESULTS Quality-of-fit criteria in all groups were improved using a Weibull TRF (2 degrees-of-freedom) versus an exponential TRF (1 degree-of-freedom), indicating nearer concordance of source DCE-MRI data with the Weibull model. Using the Weibull TRF, arterial fraction was greater in cirrhotic versus normal liver (39 ± 23% versus 15 ± 14%, P = 0.07). Mean transit time (20.6 ± 4.1 s versus 9.8 ± 3.5 s, P = 0.01) and arterial fraction (39 ± 23% versus 73 ± 14%, P = 0.04) were both significantly different between cirrhotic liver and HCC, while differences in total perfusion approached significance. CONCLUSION This work demonstrates the feasibility of estimating hepatic perfusion parameters using interrupted data acquired during sequential breathholds.
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Affiliation(s)
- Eric M. Bultman
- Dept. of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
| | - Ethan K. Brodsky
- Dept. of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Debra K. Horng
- Dept. of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Pablo Irarrazaval
- Dept. of Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | | | - Walter F. Block
- Dept. of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Dept. of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Scott B. Reeder
- Dept. of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Dept. of Medical Physics, University of Wisconsin, Madison, WI, USA
- Dept. of Medicine, University of Wisconsin, Madison, WI, USA
- Dept. of Radiology, University of Wisconsin, Madison, WI, USA
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Secuencia de disparo único eco de gradiente en fase y fase opuesta con preparación de la magnetización: descripción y optimización de la técnica con equipo de 1,5 T. RADIOLOGIA 2014; 56:136-47. [DOI: 10.1016/j.rx.2012.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 01/26/2012] [Accepted: 02/17/2012] [Indexed: 01/17/2023]
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34
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In-phase and out-of-phase single-shot magnetization-prepared gradient recalled echo: Description and optimization of technique at 1.5T. RADIOLOGIA 2014. [DOI: 10.1016/j.rxeng.2014.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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35
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Kühn JP, Holmes JH, Brau AC, Iwadate Y, Hernando D, Reeder SB. Navigator flip angle optimization for free-breathing T1-weighted hepatobiliary phase imaging with gadoxetic acid. J Magn Reson Imaging 2013; 40:1129-36. [DOI: 10.1002/jmri.24480] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/17/2013] [Indexed: 02/02/2023] Open
Affiliation(s)
- Jens-P. Kühn
- Department of Radiology and Neuroradiology; Ernst Moritz Arndt University Greifswald; Greifswald Germany
- Department of Radiology; University of Wisconsin; Madison Wisconsin USA
| | - James H. Holmes
- Global Applied Science Laboratory GE Healthcare; Madison Wisconsin USA
| | - Anja C.S. Brau
- MR Applications and Workflow GE Healthcare; Munich Germany
| | - Yuji Iwadate
- Global Applied Science Laboratory GE Healthcare; Hino Japan
| | - Diego Hernando
- Department of Radiology and Neuroradiology; Ernst Moritz Arndt University Greifswald; Greifswald Germany
- Department of Radiology; University of Wisconsin; Madison Wisconsin USA
| | - Scott B. Reeder
- Global Applied Science Laboratory GE Healthcare; Hino Japan
- Department of Medical Physics, Biomedical Engineering and Medicine; University of Wisconsin; Madison Wisconsin USA
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Chandarana H, Block KT, Winfeld MJ, Lala SV, Mazori D, Giuffrida E, Babb JS, Milla SS. Free-breathing contrast-enhanced T1-weighted gradient-echo imaging with radial k-space sampling for paediatric abdominopelvic MRI. Eur Radiol 2013; 24:320-6. [PMID: 24220754 DOI: 10.1007/s00330-013-3026-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/13/2013] [Accepted: 09/06/2013] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To compare the image quality of contrast-enhanced abdominopelvic 3D fat-suppressed T1-weighted gradient-echo imaging with radial and conventional Cartesian k-space acquisition schemes in paediatric patients. METHODS Seventy-three consecutive paediatric patients were imaged at 1.5 T with sequential contrast-enhanced T1-weighted Cartesian (VIBE) and radial gradient echo (GRE) acquisition schemes with matching parameters when possible. Cartesian VIBE was acquired as a breath-hold or as free breathing in patients who could not suspend respiration, followed by free-breathing radial GRE in all patients. Two paediatric radiologists blinded to the acquisition schemes evaluated multiple parameters of image quality on a five-point scale, with higher score indicating a more optimal examination. Lesion presence or absence, conspicuity and edge sharpness were also evaluated. Mixed-model analysis of variance was performed to compare radial GRE and Cartesian VIBE. RESULTS Radial GRE had significantly (all P < 0.001) higher scores for overall image quality, hepatic edge sharpness, hepatic vessel clarity and respiratory motion robustness than Cartesian VIBE. More lesions were detected on radial GRE by both readers than on Cartesian VIBE, with significantly higher scores for lesion conspicuity and edge sharpness (all P < 0.001). CONCLUSION Radial GRE has better image quality and lesion conspicuity than conventional Cartesian VIBE in paediatric patients undergoing contrast-enhanced abdominopelvic MRI. KEY POINTS • Numerous techniques are required to provide optimal MR images in paediatric patients. • Radial free-breathing contrast-enhanced acquisition demonstrated excellent image quality. • Image quality and lesion conspicuity were better with radial than Cartesian acquisition. • More lesions were detected on contrast-enhanced radial than on Cartesian acquisition. • Radial GRE can be used for performing abdominopelvic MRI in paediatric patients.
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Affiliation(s)
- Hersh Chandarana
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY, 10016, USA,
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Iwadate Y, Brau ACS, Vasanawala SS, Kabasawa H. Enhancement of respiratory navigator-gated three-dimensional spoiled gradient-recalled echo sequence with variable flip angle scheme. Magn Reson Med 2013; 72:172-7. [DOI: 10.1002/mrm.24902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/13/2013] [Accepted: 07/02/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Yuji Iwadate
- Global Applied Science Laboratory, GE Healthcare; Hino Tokyo Japan
| | - Anja C. S. Brau
- Global Applied Science Laboratory, GE Healthcare; Menlo Park California USA
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Gdaniec N, Eggers H, Börnert P, Doneva M, Mertins A. Robust abdominal imaging with incomplete breath-holds. Magn Reson Med 2013; 71:1733-42. [DOI: 10.1002/mrm.24829] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/08/2013] [Accepted: 05/08/2013] [Indexed: 01/19/2023]
Affiliation(s)
- Nadine Gdaniec
- Institute for Signal Processing; University of Lübeck; Lübeck Germany
| | | | - Peter Börnert
- Philips Research Europe; Hamburg Germany
- Department of Radiology; Leiden University Medical Center; Leiden The Netherlands
| | | | - Alfred Mertins
- Institute for Signal Processing; University of Lübeck; Lübeck Germany
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Bamrungchart S, Tantaway EM, Midia EC, Hernandes MA, Srirattanapong S, Dale BM, Semelka RC. Free breathing three-dimensional gradient echo-sequence with radial data sampling (radial 3D-GRE) examination of the pancreas: Comparison with standard 3D-GRE volumetric interpolated breathhold examination (VIBE). J Magn Reson Imaging 2013; 38:1572-7. [PMID: 23417838 DOI: 10.1002/jmri.24064] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 01/10/2013] [Indexed: 02/06/2023] Open
Abstract
PURPOSE To evaluate the diagnostic performance of free breathing three-dimensional gradient echo-sequence with radial data sampling (radial 3D-GRE) in MR imaging of the normal and diseased pancreas, using standard 3D-GRE for comparison in cooperative patients, and to perform a preliminary assessment in noncooperative patients. MATERIALS AND METHODS One hundred and eight consecutive patients underwent 1.5 Tesla MR imaging of the abdomen that included pre- and postcontrast free breathing radial 3D-GRE. The sequences were evaluated by two radiologists retrospectively, independently, and blindly. The results were compared using Wilcoxon-Mann-Whitney test. Kappa statistics were used to measure the extent of agreement between the reviewers. RESULTS The average scores indicated that the overall images quality of radial 3D-GRE was lower than 3D-GRE-VIBE in both pre- and postcontrast study (P = 0.0172 and 0.0001), however it achieved a rating that approximated good. In all patients, radial 3D-GRE had a mild extent of streak artifact, pulsation, susceptibility, and respiratory artifact. Radial 3D-GRE approximated good results for pancreatic edge sharpness and pancreatic ductal clarity, and did not differ significantly between cooperative and noncooperative patients. Respiratory artifact was worse in cooperative than in noncooperative patients (P = 0.02). Demonstration of pancreatic disease was slightly inferior with radial 3D-VIBE, but quality approximated good. CONCLUSION Free breathing radial 3D-GRE may be applicable for pancreatic MR imaging in patients who are unable to suspend respiration.
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Affiliation(s)
- Saraporn Bamrungchart
- Department of Radiology, University of North Carolina at Chapel Hill, North Carolina, USA; Department of Radiology, Lerdsin hospital, Bangkok, Thailand
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Tran PVP, Jhaveri KS. Comparison of high spatial resolution respiratory triggered inversion recovery-prepared spoiled gradient echo sequence with standard breathhold T1 sequence MRI of the liver using gadoxetic acid. J Magn Reson Imaging 2013; 37:700-6. [PMID: 23335396 DOI: 10.1002/jmri.23864] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Accepted: 09/06/2012] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To assess if a high resolution respiratory triggered inversion recovery prepared GRE sequence (RT) improved image quality and detection of lesions compared with breathhold GRE T1 weighted MR sequence (BH) in the hepatobiliary uptake phase of MR of the liver using gadoxetic acid (Gd-EOB-DTPA). MATERIALS AND METHODS Thirty-eight consecutive patients from July 2009 to September 2010 who had undergone Gd-EOB-DTPA enhanced liver exams were retrospectively identified. Qualitative assessment performed on reference lesions and background liver by two independent readers. Quantitative assessment performed by one reader. RESULTS Liver parenchyma signal-to-noise ratio for BH was 90.3 ± 23.9 (mean ± SD) and RT, 106.1 ± 40.4 (P = 0.119). For BH, 320 lesions were detected compared with 257 for RT. Lesion to liver contrast was significantly better on RT sequences (0.26 ± 0.24; mean ± SD) compared with BH sequence (0.21 ± 0.20; P = 0.044). Fifty-seven reference lesions assessed. Both reviewers rated BH better for lesion margin and hepatic vessel sharpness. BH was rated with less artifact (P < 0.05). Lesion to liver contrast on BH was significantly better for one reviewer. CONCLUSION BH sequence had better overall image quality than RT in several quantitative and qualitative factors including number of lesions detected and level of artifact.
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Affiliation(s)
- Phillip V P Tran
- Department of Medical Imaging, University of Toronto, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada
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Free-breathing radial 3D fat-suppressed T1-weighted gradient echo sequence: a viable alternative for contrast-enhanced liver imaging in patients unable to suspend respiration. Invest Radiol 2012; 46:648-53. [PMID: 21577119 DOI: 10.1097/rli.0b013e31821eea45] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE : To compare free-breathing radially sampled 3D fat suppressed T1-weighted gradient-echo acquisitions (radial volumetric interpolated breath-hold examination [VIBE]) with breath-hold (BH) and free-breathing conventional (rectilinearly sampled k-space) VIBE acquisitions for postcontrast imaging of the liver. MATERIALS AND METHODS : Eighteen consecutive patients referred for clinically indicated liver magnetic resonance imaging were imaged at 3 T. Three minutes after a single dose of gadolinium contrast injection, free-breathing radial VIBE, BH VIBE, and free-breathing VIBE with 4 averages were acquired in random order with matching sequence parameters. Radial VIBE was acquired with the "stack-of-stars" scheme, which uses conventional sampling in the slice direction and radial sampling in-plane.All image data sets were evaluated independently by 3 radiologists blinded to patient and sequence information. Each reader scored the following parameters: overall image quality, respiratory motion artifact, pulsation artifact, liver edge sharpness, and hepatic vessel clarity using a 5-point scale, with the highest score indicating the most optimum examination. Mixed model analysis of variance was used to compare sequences in terms of each measure of image quality. RESULTS : When scores were averaged over readers, there was no statistically significant difference between radial VIBE and BH VIBE regarding overall image quality (P = 0.1015), respiratory motion artifact (P = 1.0), and liver edge sharpness (P = 0.2955). Radial VIBE demonstrated significantly lower pulsation artifact (P < 0.0001), but had lower hepatic vessel clarity (P = 0.0176), when compared with BH VIBE. Radial VIBE had significantly higher image quality scores for all parameters when compared with free-breathing VIBE (P < 0.0001). Acquisition time for BH VIBE was 14 seconds and that of free-breathing radial VIBE and conventional VIBE with multiple averages was 56 seconds each. CONCLUSION : Radial VIBE can be performed during free breathing for contrast-enhanced imaging of the liver with comparable image quality to BH VIBE. However, further work is necessary to shorten the acquisition time to perform dynamic imaging.
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Free-breathing 3D T1-weighted gradient-echo sequence with radial data sampling in abdominal MRI: preliminary observations. AJR Am J Roentgenol 2011; 197:650-7. [PMID: 21862807 DOI: 10.2214/ajr.10.5881] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The purposes of this study were to evaluate the feasibility of a free-breathing 3D gradient-recalled echo sequence with radial data sampling (radial 3D GRE) in abdominal MRI compared with a standard 3D GRE volumetric interpolated breath-hold examination (VIBE) sequence for imaging of cooperative patients and to perform a preliminary assessment in imaging of noncooperative patients. MATERIALS AND METHODS Fifty-five consecutively registered patients who underwent unenhanced and contrast-enhanced abdominal MRI with the free-breathing radial 3D GRE technique constituted the study population. Two readers independently and blindly evaluated the images. RESULTS Overall image quality with the contrast-enhanced radial 3D GRE sequence was lower than but rated at least nearly as good as that with the 3D GRE VIBE sequence (p < 0.0001). Higher scores were recorded for 3D GRE VIBE images with respect to pixel graininess, streaking artifact, and sharpness (p = 0.0009 to p < 0.0001). Except for sharpness of vessels on unenhanced images, results for the radial 3D GRE sequence did not differ significantly in the comparison of cooperative and noncooperative patients (p = 0.004). For imaging of noncooperative patients, radial 3D GRE images of children had higher ratings for shading (unenhanced, p = 0.0004; contrast-enhanced, p < 0.0001) and streaking artifacts on contrast-enhanced images (p = 0.0017) than did those of adults. Overall image quality was higher for pediatric patients. In lesion analysis, use of the 3D GRE VIBE sequence was associated with significantly greater detectability, confidence, and conspicuity than was use of the radial 3D GRE sequence (p = 0.00026-0.011). CONCLUSION A free-breathing radial 3D GRE sequence is feasible for abdominal MRI and may find application in imaging of patients who are unable to suspend respiration, especially children.
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Herédia V, Ramalho M, de Campos ROP, Lee CH, Dale B, Vaidean GD, Semelka RC. Comparison of a single shot T1-weighted in- and out-of-phase magnetization prepared gradient recalled echo with a standard two-dimensional gradient recalled echo: preliminary findings. J Magn Reson Imaging 2011; 33:1482-90. [PMID: 21591019 DOI: 10.1002/jmri.22572] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To compare in-phase (IP)/out-of-phase (OP) single shot magnetization-prepared gradient-recalled-echo (MP-GRE) with a standard two-dimensional gradient-recalled-echo (2D-GRE), and to compare image quality of MP-GRE in cooperative and noncooperative subjects. MATERIALS AND METHODS Ninety-six consecutive subjects (52 males, 44 females; mean age, 53.2 ± 16.7 years), both cooperative (n = 73) and noncooperative (n = 23) subjects who had MRI examinations including precontrast T1-weighted IP/OP MP-GRE with or without IP/OP 2D-GRE were included in the study. The sequences were independently qualitatively evaluated by two radiologists. Quantitative analysis of liver fat index, signal-to-noise ratio (SNR) and liver-lesion contrast-to-noise ratio (CNR) was also performed. Data were subjected to statistical analysis. RESULTS The visual detection of the presence or absence of liver steatosis showed no differences between 2D-GRE and MP-GRE imaging (k = 1). Minor differences were observed on image quality between MP-GRE and 2D-GRE in cooperative subjects, and between MP-GRE sequences performed in cooperative and noncooperative subjects. Liver fat index results were strongly positively correlated (r = .98; 95% confidence interval [CI] 0.97 to 0.98; P < .0001). Intercept (.14; 95% CI .13 to .15; P < .0001) and slope (.83; 95% CI .79 to .86; P < .0001) were statistically significant. CONCLUSION IP/OP MP-GRE and 2D-GRE comparably demonstrate the presence or absence of hepatic steatosis. Image quality of MP-GRE was also comparable to 2D-GRE, and was not substantially adversely affected if subjects were unable to cooperate with breathholding instructions.
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Affiliation(s)
- Vasco Herédia
- Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7510, USA
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Advances in pediatric body MRI. Pediatr Radiol 2011; 41 Suppl 2:549-54. [PMID: 21847737 PMCID: PMC3505997 DOI: 10.1007/s00247-011-2103-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 02/14/2011] [Accepted: 03/15/2011] [Indexed: 10/17/2022]
Abstract
MRI offers an alternative to CT, and thus is central to an ALARA strategy. However, long exam times, limited magnet availability, and motion artifacts are barriers to expanded use of MRI. This article reviews developments in pediatric body MRI that might reduce these barriers: high field systems, acceleration, navigation and newer contrast agents.
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Goo HW. Regional and whole-body imaging in pediatric oncology. Pediatr Radiol 2011; 41 Suppl 1:S186-94. [PMID: 21523595 DOI: 10.1007/s00247-011-2050-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 01/01/2011] [Indexed: 11/29/2022]
Abstract
The goals of tumor imaging include tumor detection, tumor characterization and differential diagnosis, imaging-guided biopsy, evaluation of tumor extent and staging, assessment of treatment responses, and surveillance for residual tumor or tumor recurrence. In clinical practice, various combinations of imaging modalities are used to achieve these goals. Recently introduced tumor imaging methods, such as diffusion MRI, perfusion MRI, whole-body MRI, and positron emission tomography (PET-CT), have shown promising results. Depending on tumor type and management plan, imaging protocols for children should be individually optimized to achieve the shortest examination time, the highest image quality, the lowest risk, and maximum clinical benefits. In this article, the roles of regional and whole-body tumor imaging will be reviewed, and several important issues related to recent technical developments will be discussed.
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Affiliation(s)
- Hyun Woo Goo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 86 Asanbyeongwon-gil, Songpa-gu, Seoul 138-736, South Korea.
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