1
|
Sacher SE, Koff MF, Tan ET, Burge A, Potter HG. The role of advanced metal artifact reduction MRI in the diagnosis of periprosthetic joint infection. Skeletal Radiol 2024; 53:1969-1978. [PMID: 37875571 PMCID: PMC11039568 DOI: 10.1007/s00256-023-04483-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/09/2023] [Accepted: 10/10/2023] [Indexed: 10/26/2023]
Abstract
Identification and diagnosis of periprosthetic joint infection (PJI) are challenging, requiring a multi-disciplinary approach involving clinical evaluation, laboratory tests, and imaging studies. MRI is advantageous to alternative imaging techniques due to superior soft tissue contrast and absence of ionizing radiation. However, the presence of metallic implants can cause signal loss and artifacts. Metal artifact suppression (MARS) MRI techniques have been developed that mitigate metal artifacts and improve periprosthetic soft tissue visualization. This paper provides a review of the various MARS MRI techniques, their clinical applicability and accuracy in PJI diagnosis and evaluation, and current challenges and future perspectives.
Collapse
Affiliation(s)
- Sara E Sacher
- Department of Radiology and Imaging, Hospital for Special Surgery, 535 East 70th St, New York, NY, 10021, USA.
| | - Matthew F Koff
- Department of Radiology and Imaging, Hospital for Special Surgery, 535 East 70th St, New York, NY, 10021, USA
| | - Ek T Tan
- Department of Radiology and Imaging, Hospital for Special Surgery, 535 East 70th St, New York, NY, 10021, USA
| | - Alissa Burge
- Department of Radiology and Imaging, Hospital for Special Surgery, 535 East 70th St, New York, NY, 10021, USA
| | - Hollis G Potter
- Department of Radiology and Imaging, Hospital for Special Surgery, 535 East 70th St, New York, NY, 10021, USA.
| |
Collapse
|
2
|
Yoon D, Doyle Z, Lee P, Hargreaves B, Stevens K. Clinical evaluation of isotropic MAVRIC-SL for symptomatic hip arthroplasties at 3 T MRI. Magn Reson Imaging 2024; 111:256-264. [PMID: 38621551 PMCID: PMC11186338 DOI: 10.1016/j.mri.2024.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/07/2024] [Accepted: 04/12/2024] [Indexed: 04/17/2024]
Abstract
BACKGROUND 3D multi-spectral imaging (MSI) of metal implants necessitates relatively long scan times. OBJECTIVE We implemented a fast isotropic 3D MSI technique at 3 T and compared its image quality and clinical utility to non-isotropic MSI in the evaluation of hip implants. METHODS Two musculoskeletal radiologists scored images from coronal proton density-weighted conventional MAVRIC-SL and an isotropic MAVRIC-SL sequence accelerated with robust-component-analysis on a 3-point scale (3: diagnostic, 2: moderately diagnostic, 1: non-diagnostic) for overall image quality, metal artifact, and visualization around femoral and acetabular components. Grades were compared using a signed Wilcoxon test. Images were evaluated for effusion, synovitis, osteolysis, loosening, pseudotumor, fracture, and gluteal tendon abnormalities. Reformatted axial and sagittal images for both sequences were subsequently generated and compared for image quality with the Wilcoxon test. Whether these reformats increased diagnostic confidence or revealed additional pathology, including findings unrelated to arthroplasty that may contribute to hip pain, was also compared using the McNemar test. Inter-rater agreement was measured by Cohen's kappa. RESULTS 39 symptomatic patients with a total of 59 hip prostheses were imaged (mean age, 70 years ±9, 14 males, 25 females). Comparison scores between coronal images showed no significant difference in image quality, metal artifact, or visualization of the femur and acetabulum. Except for loosening, reviewers identified more positive cases of pathology on the original coronally-acquired isotropic sequence. In comparison of reformatted axial and sagittal images, the isotropic sequence scored significantly (p < 0.01) higher for overall image quality (3.0 vs 2.0) and produced significantly (p < 0.01) more cases of increased diagnostic confidence (42.4% vs 7.6%) or additional diagnoses (50.8% vs 22.9%). Inter-rater agreement was substantial (k = 0.798) for image quality. Mean scan times were 4.2 mins (isotropic) and 7.1 mins (non-isotropic). CONCLUSION Compared to the non-isotropic sequence, isotropic 3D MSI was acquired in less time while maintaining diagnostically acceptable image quality. It identified more pathology, including postoperative complications and potential pain-generating pathology unrelated to arthroplasty. This fast isotropic 3D MSI sequence demonstrates promise for improving diagnostic evaluation of symptomatic hip prostheses at 3 T while simultaneously reducing scan time.
Collapse
Affiliation(s)
- Daehyun Yoon
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Welch Road, Stanford, CA 94305, USA.
| | - Zoe Doyle
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Welch Road, Stanford, CA 94305, USA; Department of Radiology, VA Palo Alto Health Care System, 3801 Miranda Ave, Palo Alto, CA 94304, USA.
| | - Philip Lee
- Department of Electrical Engineering, Stanford University, 350 Jane Stanford Way, Stanford, CA 94305, USA.
| | - Brian Hargreaves
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Welch Road, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, 350 Jane Stanford Way, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, 443 Via Ortega, Rm 119, Stanford, CA 94305, USA.
| | - Kathryn Stevens
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Welch Road, Stanford, CA 94305, USA; Department of Orthopaedic Surgery, Stanford University, 430 Broadway Street, MC: 6342, Pavilion C, 4th Floor, Redwood City, CA 94063, USA.
| |
Collapse
|
3
|
Berangi M, Kuehne A, Waiczies H, Niendorf T. MRI of Implantation Sites Using Parallel Transmission of an Optimized Radiofrequency Excitation Vector. Tomography 2023; 9:603-620. [PMID: 36961008 PMCID: PMC10037644 DOI: 10.3390/tomography9020049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/03/2023] [Accepted: 03/05/2023] [Indexed: 03/25/2023] Open
Abstract
Postoperative care of orthopedic implants is aided by imaging to assess the healing process and the implant status. MRI of implantation sites might be compromised by radiofrequency (RF) heating and RF transmission field (B1+) inhomogeneities induced by electrically conducting implants. This study examines the applicability of safe and B1+-distortion-free MRI of implantation sites using optimized parallel RF field transmission (pTx) based on a multi-objective genetic algorithm (GA). Electromagnetic field simulations were performed for eight eight-channel RF array configurations (f = 297.2 MHz), and the most efficient array was manufactured for phantom experiments at 7.0 T. Circular polarization (CP) and orthogonal projection (OP) algorithms were applied for benchmarking the GA-based shimming. B1+ mapping and MR thermometry and imaging were performed using phantoms mimicking muscle containing conductive implants. The local SAR10g of the entire phantom in GA was 12% and 43.8% less than the CP and OP, respectively. Experimental temperature mapping using the CP yielded ΔT = 2.5-3.0 K, whereas the GA induced no extra heating. GA-based shimming eliminated B1+ artefacts at implantation sites and enabled uniform gradient-echo MRI. To conclude, parallel RF transmission with GA-based excitation vectors provides a technical foundation en route to safe and B1+-distortion-free MRI of implantation sites.
Collapse
Affiliation(s)
- Mostafa Berangi
- Berlin Ultrahigh Field Facility, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
- Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
- MRI.TOOLS GmbH, 13125 Berlin, Germany
| | | | | | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
- Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
- MRI.TOOLS GmbH, 13125 Berlin, Germany
| |
Collapse
|
4
|
Burke CJ, Khodarahmi I, Fritz J. Postoperative MR Imaging of Joints. Magn Reson Imaging Clin N Am 2022; 30:583-600. [DOI: 10.1016/j.mric.2022.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
5
|
Kuah T, Vellayappan BA, Makmur A, Nair S, Song J, Tan JH, Kumar N, Quek ST, Hallinan JTPD. State-of-the-Art Imaging Techniques in Metastatic Spinal Cord Compression. Cancers (Basel) 2022; 14:3289. [PMID: 35805059 PMCID: PMC9265325 DOI: 10.3390/cancers14133289] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 12/23/2022] Open
Abstract
Metastatic Spinal Cord Compression (MSCC) is a debilitating complication in oncology patients. This narrative review discusses the strengths and limitations of various imaging modalities in diagnosing MSCC, the role of imaging in stereotactic body radiotherapy (SBRT) for MSCC treatment, and recent advances in deep learning (DL) tools for MSCC diagnosis. PubMed and Google Scholar databases were searched using targeted keywords. Studies were reviewed in consensus among the co-authors for their suitability before inclusion. MRI is the gold standard of imaging to diagnose MSCC with reported sensitivity and specificity of 93% and 97% respectively. CT Myelogram appears to have comparable sensitivity and specificity to contrast-enhanced MRI. Conventional CT has a lower diagnostic accuracy than MRI in MSCC diagnosis, but is helpful in emergent situations with limited access to MRI. Metal artifact reduction techniques for MRI and CT are continually being researched for patients with spinal implants. Imaging is crucial for SBRT treatment planning and three-dimensional positional verification of the treatment isocentre prior to SBRT delivery. Structural and functional MRI may be helpful in post-treatment surveillance. DL tools may improve detection of vertebral metastasis and reduce time to MSCC diagnosis. This enables earlier institution of definitive therapy for better outcomes.
Collapse
Affiliation(s)
- Tricia Kuah
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
| | - Balamurugan A. Vellayappan
- Department of Radiation Oncology, National University Cancer Institute Singapore, National University Hospital, Singapore 119074, Singapore;
| | - Andrew Makmur
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
| | - Shalini Nair
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
| | - Junda Song
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
| | - Jiong Hao Tan
- University Spine Centre, Department of Orthopaedic Surgery, National University Health System, 1E Lower Kent Ridge Road, Singapore 119228, Singapore; (J.H.T.); (N.K.)
| | - Naresh Kumar
- University Spine Centre, Department of Orthopaedic Surgery, National University Health System, 1E Lower Kent Ridge Road, Singapore 119228, Singapore; (J.H.T.); (N.K.)
| | - Swee Tian Quek
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
| | - James Thomas Patrick Decourcy Hallinan
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
| |
Collapse
|
6
|
Doyle Z, Yoon D, Lee PK, Rosenberg J, Hargreaves BA, Beaulieu CF, Stevens KJ. Clinical utility of accelerated MAVRIC-SL with robust-PCA compared to conventional MAVRIC-SL in evaluation of total hip arthroplasties. Skeletal Radiol 2022; 51:549-556. [PMID: 34223946 PMCID: PMC8727641 DOI: 10.1007/s00256-021-03848-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/15/2021] [Accepted: 06/20/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare the diagnostic performance of a conventional metal artifact suppression sequence MAVRIC-SL (multi-acquisition variable-resonance image combination selective) and a novel 2.6-fold faster sequence employing robust principal component analysis (RPCA), in the MR evaluation of hip implants at 3 T. MATERIALS AND METHODS Thirty-six total hip implants in 25 patients were scanned at 3 T using a conventional MAVRIC-SL proton density-weighted sequence and an RPCA MAVRIC-SL proton density-weighted sequence. Comparison was made of image quality, geometric distortion, visualization around acetabular and femoral components, and conspicuity of abnormal imaging findings using the Wilcoxon signed-rank test and a non-inferiority test. Abnormal findings were correlated with subsequent clinical management and intraoperative findings if the patient underwent subsequent surgery. RESULTS Mean scores for conventional MAVRIC-SL were better than RPCA MAVRIC-SL for all qualitative parameters (p < 0.05), although the probability of RPCA MAVRIC-SL being clinically useful was non-inferior to conventional MAVRIC-SL (within our accepted 10% difference, p < 0.05), except for visualization around the acetabular component. Abnormal imaging findings were seen in 25 hips, and either equally visible or visible but less conspicuous on RPCA MAVRIC-SL in 21 out of 25 cases. In 4 cases, a small joint effusion was queried on MAVRIC-SL but not RPCA MAVRIC-SL, but the presence or absence of a small effusion did not affect subsequent clinical management and patient outcome. CONCLUSION While the overall image quality is reduced, RPCA MAVRIC-SL allows for significantly reduced scan time and maintains almost equal diagnostic performance.
Collapse
Affiliation(s)
- Zoe Doyle
- Department of Radiology, Stanford University, Stanford, CA 94305
| | - Daehyun Yoon
- Department of Radiology, Stanford University, Stanford, CA 94305
| | - Philip K. Lee
- Department of Radiology, Stanford University, Stanford, CA 94305.,Department of Electrical Engineering, Stanford University, Stanford, CA 94305
| | | | - Brian A. Hargreaves
- Department of Radiology, Stanford University, Stanford, CA 94305.,Department of Electrical Engineering, Stanford University, Stanford, CA 94305,Department of Bioengineering, Stanford University, Stanford, CA 94305
| | - Christopher F. Beaulieu
- Department of Radiology, Stanford University, Stanford, CA 94305.,Department of Orthopaedic Surgery, Stanford University, Redwood City, CA 94063
| | - Kathryn J. Stevens
- Department of Radiology, Stanford University, Stanford, CA 94305.,Department of Orthopaedic Surgery, Stanford University, Redwood City, CA 94063
| |
Collapse
|
7
|
Germann C, Nanz D, Sutter R. Magnetic Resonance Imaging Around Metal at 1.5 Tesla: Techniques From Basic to Advanced and Clinical Impact. Invest Radiol 2021; 56:734-748. [PMID: 34074944 DOI: 10.1097/rli.0000000000000798] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABSTRACT During the last decade, metal artifact reduction in magnetic resonance imaging (MRI) has been an area of intensive research and substantial improvement. The demand for an excellent diagnostic MRI scan quality of tissues around metal implants is closely linked to the steadily increasing number of joint arthroplasty (especially knee and hip arthroplasties) and spinal stabilization procedures. Its unmatched soft tissue contrast and cross-sectional nature make MRI a valuable tool in early detection of frequently encountered postoperative complications, such as periprosthetic infection, material wear-induced synovitis, osteolysis, or damage of the soft tissues. However, metal-induced artifacts remain a constant challenge. Successful artifact reduction plays an important role in the diagnostic workup of patients with painful/dysfunctional arthroplasties and helps to improve patient outcome. The artifact severity depends both on the implant and the acquisition technique. The implant's material, in particular its magnetic susceptibility and electrical conductivity, its size, geometry, and orientation in the MRI magnet are critical. On the acquisition side, the magnetic field strength, the employed imaging pulse sequence, and several acquisition parameters can be optimized. As a rule of thumb, the choice of a 1.5-T over a 3.0-T magnet, a fast spin-echo sequence over a spin-echo or gradient-echo sequence, a high receive bandwidth, a small voxel size, and short tau inversion recovery-based fat suppression can mitigate the impact of metal artifacts on diagnostic image quality. However, successful imaging of large orthopedic implants (eg, arthroplasties) often requires further optimized artifact reduction methods, such as slice encoding for metal artifact correction or multiacquisition variable-resonance image combination. With these tools, MRI at 1.5 T is now widely considered the modality of choice for the clinical evaluation of patients with metal implants.
Collapse
|
8
|
Mullen M, Garwood M. Dual polarity encoded MRI using high bandwidth radiofrequency pulses for robust imaging with large field inhomogeneity. Magn Reson Med 2021; 86:1271-1283. [PMID: 33780035 DOI: 10.1002/mrm.28771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 02/02/2021] [Accepted: 02/22/2021] [Indexed: 11/09/2022]
Abstract
PURPOSE The ability to use dual polarity encoded MRI with the missing pulse steady-state free precession (MP-SSFP) sequence is demonstrated to perform robust MRI with low radiofrequency (RF) amplitude, where the field is distorted by embedding metallic screws in an agar phantom. Image-based estimation of the 3D ΔB0 map and image distortion correction is shown to require ~1 minute to perform. THEORY AND METHODS Dual polarity encoded MP-SSFP was implemented at 1.5T and used to image agar phantoms with one stainless steel and one titanium screw embedded inside. A multispectral fast spin-echo acquisition was performed for comparison. Self-consistent ΔB0 estimation is performed iteratively using a 3D B-spline basis, which is compared to the ΔB0 estimate generated by the multispectral sequence. RESULTS Dual polarity encoded MP-SSFP yields image quality similar to the multispectral sequence used with substantially less imaging time, provided the MP-SSFP experimental parameters are chosen well. The multispectral sequence appears to visualize modestly closer in proximity to the metallic screws used, despite the spectral bins covering the same bandwidth as the pulses used in MP-SSFP. However, MP-SSFP avoids ripple artifacts characteristic of the multispectral sequence. The ΔB0 estimate generated by MP-SSFP is qualitatively similar to that generated by the multispectral sequence but larger in magnitude. CONCLUSION Despite longer processing time compared to multispectral imaging, MP-SSFP yields similar image quality with significantly lower acquisition times in the absence of parallel imaging. The work herein demonstrates the ability to perform 3D ΔB0 estimation and image correction within a reasonable amount of time, ~1 minute.
Collapse
Affiliation(s)
- Michael Mullen
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael Garwood
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| |
Collapse
|
9
|
Accelerated metallic artifact reduction imaging using spectral bin modulation of multiacquisition variable-resonance image combination selective imaging. Magn Reson Imaging 2020; 72:19-24. [PMID: 32574683 DOI: 10.1016/j.mri.2020.06.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 05/11/2020] [Accepted: 06/13/2020] [Indexed: 11/21/2022]
Abstract
OBJECTIVES To assess the clinical utility of a prototype sequence for metal artifact reduction, the multiacquisition variable-resonance image combination selective (MAVRIC-SL) at 3 T. This sequence allows a surgical prosthesis-dependent reduction in the number of spectral bins. We compared the prototype MAVRIC SL to the conventional two-dimensional fast spin-echo (FSE) sequences and MAVRIC SL images acquired with all spectral bins to those acquired with the optimized number of spectral bins. METHODS MAVRIC SL images were acquired in 25 image sets from August 2017 to April 2018. For each subject, the optimized number of spectral bins was determined using a short spectral calibration scan. The image sets obtained with magnetic resonance imaging that were used for the analysis consisted of MAVRIC-SL proton density (PD)-weighted or short inversion time inversion recovery (STIR) images acquired with all 24 spectral bins, the corresponding images with the optimized number of spectral bins, and the conventional two-dimensional FSE or STIR PD-weighted images. A musculoskeletal radiologist reviewed and scored the images using a five-point scale for artifact reduction around the prosthesis and visualization of the prosthesis and peri-prosthetic tissues. Quantitative evaluation of the peri-prosthetic tissues was also performed. The Wilcoxon rank-sum test was used to test for significance. RESULTS The MAVRIC SL images enabled a significantly improved reduction in metallic artifacts compared to the conventional two-dimensional FSE sequences. The optimized number of spectral bins ranged from 6 to 20, depending on the prosthesis susceptibility difference, size, and orientation to the B0 field. The scan times significantly decreased with a reduced number of spectral bins (354.0 ± 139.1 versus 283.0 ± 89.6 s; 20% reduced scan time; p < .05). Compared to the MAVRIC SL images acquired with all 24 bins, the artifact reduction and visualization of the prosthesis and peri-prosthetic tissues on the MAVRIC SL images acquired with calibrated bins were not significantly different. CONCLUSIONS Compared to the MAVRIC SL images acquired with all 24 spectral bins, those acquired with an optimized number of spectral bins can reduce metallic artifacts with no significant image quality degradation while providing reduced scan time.
Collapse
|
10
|
Choo HJ, Lee SJ, Lee YH. [Metallic Artifacts on MR Imaging and Methods for Their Reduction]. TAEHAN YONGSANG UIHAKHOE CHI 2020; 81:41-57. [PMID: 36238112 PMCID: PMC9432103 DOI: 10.3348/jksr.2020.81.1.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/06/2019] [Accepted: 12/17/2019] [Indexed: 06/16/2023]
Abstract
Metallic artifacts on MR imaging are typically induced by differences in magnetic susceptibility between the metallic implant and surrounding tissue. Conventional techniques for metal artifact reduction require MR machines with low field strength, shift in the frequency-encoding and phase-encoding directions according to the axis of metallic implant, increased receiver bandwidth and matrix, decreased slice thickness, and utilization of the short tau inversion recovery or Dixon method for fat-suppression. Slice-encoding for metal artifact correction and multi-acquisition variable-resonance image combination can dramatically reduce the number of metallic artifacts. However, these sequences have a considerably long acquisition time. Furthermore, the recently developed acceleration techniques including compressed sensing can solve this problem.
Collapse
|
11
|
Seo S, Do W, Luu HM, Kim KH, Choi SH, Park S. Artificial neural network for Slice Encoding for Metal Artifact Correction (SEMAC) MRI. Magn Reson Med 2019; 84:263-276. [DOI: 10.1002/mrm.28126] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 11/21/2019] [Accepted: 11/21/2019] [Indexed: 01/09/2023]
Affiliation(s)
- Sunghun Seo
- Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology Daejeon Korea
| | - Won‐Joon Do
- Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology Daejeon Korea
| | - Huan Minh Luu
- Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology Daejeon Korea
| | - Ki Hwan Kim
- Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology Daejeon Korea
| | - Seung Hong Choi
- Department of Radiology Seoul National University College of Medicine Seoul Korea
| | - Sung‐Hong Park
- Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology Daejeon Korea
| |
Collapse
|
12
|
Schramm G, Ladefoged CN. Metal artifact correction strategies in MRI-based attenuation correction in PET/MRI. BJR Open 2019; 1:20190033. [PMID: 33178954 PMCID: PMC7592486 DOI: 10.1259/bjro.20190033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/27/2019] [Accepted: 10/20/2019] [Indexed: 12/31/2022] Open
Abstract
In hybrid positron emission tomography (PET) and MRI systems, attenuation correction for PET image reconstruction is commonly based on processing of dedicated MR images. The image quality of the latter is strongly affected by metallic objects inside the body, such as e.g. dental implants, endoprostheses, or surgical clips which all lead to substantial artifacts that propagate into MRI-based attenuation images. In this work, we review publications about metal artifact correction strategies in MRI-based attenuation correction in PET/MRI. Moreover, we also give an overview about publications investigating the impact of MRI-based attenuation correction metal artifacts on the reconstructed PET image quality and quantification.
Collapse
Affiliation(s)
- Georg Schramm
- Department of Imaging and Pathology, Division of Nuclear Medicine, KU/UZ Leuven, Leuven, Belgium
| | - Claes Nøhr Ladefoged
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
13
|
Eskreis-Winkler S, Simon K, Reichman M, Spincemaille P, Nguyen T, Kee Y, Cho J, Christos PJ, Drotman M, Prince MR, Morris EA, Wang Y. Dipole modeling of multispectral signal for detecting metallic biopsy markers during MRI-guided breast biopsy: a pilot study. Magn Reson Med 2019; 83:1380-1389. [PMID: 31631408 DOI: 10.1002/mrm.28017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 09/05/2019] [Accepted: 09/05/2019] [Indexed: 12/15/2022]
Abstract
PURPOSE During MRI-guided breast biopsy, a metallic biopsy marker is deployed at the biopsy site to guide future interventions. Conventional MRI during biopsy cannot distinguish such markers from biopsy site air, and a post-biopsy mammogram is therefore performed to localize marker placement. The purpose of this pilot study is to develop dipole modeling of multispectral signal (DIMMS) as an MRI alternative to eliminate the cost, inefficiency, inconvenience, and ionizing radiation of a mammogram for biopsy marker localization. METHODS DIMMS detects and localizes the biopsy marker by fitting the measured multispectral imaging (MSI) signal to the MRI signal model and marker properties. MSI was performed on phantoms containing titanium biopsy markers and air to illustrate the clinical challenge that DIMMS addresses and on 20 patients undergoing MRI-guided breast biopsy to assess DIMMS feasibility for marker detection. DIMMS was compared to conventional MSI field map thresholding, using the post-procedure mammogram as the reference standard. RESULTS Biopsy markers were detected and localized in 20 of 20 cases using MSI with automated DIMMS post-processing (using a threshold of 0.7) and in 18 of 20 cases using MSI field mapping (using a threshold of 0.65 kHz). CONCLUSION MSI with DIMMS post-processing is a feasible technique for biopsy marker detection and localization during MRI-guided breast biopsy. With a 2-min MSI scan, DIMMS is a promising MRI alternative to the standard-of-care post-biopsy mammogram.
Collapse
Affiliation(s)
- Sarah Eskreis-Winkler
- Department of Radiology, Weill Cornell Medicine, New York, New York.,Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Katherine Simon
- Department of Radiology, Weill Cornell Medicine, New York, New York
| | - Melissa Reichman
- Department of Radiology, Weill Cornell Medicine, New York, New York
| | | | - Thanh Nguyen
- Department of Radiology, Weill Cornell Medicine, New York, New York
| | - Youngwook Kee
- Department of Radiology, Weill Cornell Medicine, New York, New York
| | - Junghun Cho
- Department of Radiology, Weill Cornell Medicine, New York, New York
| | - Paul J Christos
- Division of Biostatistics and Epidemiology, Department of Healthcare Policy & Research, Weill Cornell Medicine, New York, New York
| | - Michele Drotman
- Department of Radiology, Weill Cornell Medicine, New York, New York
| | - Martin R Prince
- Department of Radiology, Weill Cornell Medicine, New York, New York
| | - Elizabeth A Morris
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Yi Wang
- Department of Radiology, Weill Cornell Medicine, New York, New York
| |
Collapse
|
14
|
Tran LTX, Sakamoto J, Kuribayashi A, Watanabe H, Tomisato H, Kurabayashi T. Quantitative evaluation of artefact reduction from metallic dental materials in short tau inversion recovery imaging: efficacy of syngo WARP at 3.0 tesla. Dentomaxillofac Radiol 2019; 48:20190036. [PMID: 31188678 PMCID: PMC6775784 DOI: 10.1259/dmfr.20190036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 06/05/2019] [Accepted: 06/07/2019] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To evaluate the effects of syngo WARP on reducing metal artefacts from dental materials. METHODS Short tau inversion recovery (STIR) with syngo WARP [a dedicated metal artefact reduction sequence in combination with view-angle-tilting (VAT)] was performed using phantoms of three dental alloys: cobalt-chromium (Co-Cr), nickel-chromium (Ni-Cr), and titanium (Ti). Artefact volumes and reduction ratios of black, white and overall artefacts in the standard STIR and syngo WARP images with several different parameter settings were quantified according to standards of the American Society for Testing and Materials F2119-07. In all sequences, the artefact volumes and reduction ratios were compared. The modulation transfer function (MTF) and contrast-to-noise ratio (CNR) were also measured for evaluation of image quality. RESULTS In standard STIR, the overall artefact volume of Co-Cr was markedly larger than those of Ni-Cr and Ti. All types of artefacts tended to be reduced with increasing receiver bandwidth (rBW) and VAT. The effect of artefact reduction tended to be more obvious in the axial plane than in the sagittal plane. Compared with standard STIR, syngo WARP with a matrix of 384 × 384, receiver bandwidth of 620 Hz/pixel, and VAT of 100 % in the axial plane obtained reduction effects of 30 % (white artefacts), 45 % (black artefacts), and 38 % (overall artefacts) although MTF and CNR decreased by 30 and 22 % compared with those of standard STIR, respectively. CONCLUSIONS syngo WARP for STIR can effectively reduce metal artefacts from dental materials.
Collapse
Affiliation(s)
- Lan Thi Xuan Tran
- Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University (TMDU)
| | - Junichiro Sakamoto
- Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University (TMDU)
| | - Ami Kuribayashi
- Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University (TMDU)
| | - Hiroshi Watanabe
- Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University (TMDU)
| | - Hiroshi Tomisato
- Oral and Maxillofacial Radiology Clinic, Dental Hospital, Tokyo Medical and Dental University (TMDU)
| | - Tohru Kurabayashi
- Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University (TMDU)
| |
Collapse
|
15
|
Wimmer W, Hakim A, Kiefer C, Pastore-Wapp M, Anschuetz L, Caversaccio M, Wagner F. MRI Metal Artifact Reduction Sequence for Auditory Implants: First Results with a Transcutaneous Bone Conduction Implant. Audiol Neurootol 2019; 24:56-64. [DOI: 10.1159/000500513] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 04/22/2019] [Indexed: 11/19/2022] Open
Abstract
Objective: Magnetic resonance imaging (MRI) is often limited in patients with auditory implants because of the presence of metallic components and magnets. The aim of this study was to evaluate the clinical usefulness of a customized MRI sequence for metal artifact suppression for patients with implants in the temporal bone region, specifically patients with a transcutaneous bone conduction implant. Methods: Two whole head specimens were unilaterally implanted with a transcutaneous bone conduction implant. MRI examinations with and without a primarily self-build sequence (SEMAC-VAT WARP) for metal artifact suppression were performed. The diagnostic usefulness of the acquired MRI scans was rated independently by two neuroradiologists. The sequence was also used to acquire postimplantation follow-up MRI in a patient with a transcutaneous bone conduction implant. Results: The customized SEMAC-VAT WARP sequence significantly improved the diagnostic usefulness of the postimplantation MRIs. The image acquisition time was 12 min and 20 s for the T1-weighted and 12 min and 12 s for the T2-weighted MRI. There was good agreement between the two blinded raters (Cohen’s κ = 0.61, p < 0.001). Conclusion: The sequence for metal artifact reduction optimized in Bern enables MRI at 1.5 T in patients with active transcutaneous bone conduction implants without sacrificing diagnostic imaging quality. Particularly on the implanted side, imaging of intracranial and supra- and infratentorial brain pathologies is clinically more valuable than standard diagnostic MRI without any artifact reduction sequences.
Collapse
|
16
|
Spirig JM, Sutter R, Götschi T, Farshad-Amacker NA, Farshad M. Value of standard radiographs, computed tomography, and magnetic resonance imaging of the lumbar spine in detection of intraoperatively confirmed pedicle screw loosening-a prospective clinical trial. Spine J 2019; 19:461-468. [PMID: 29959101 DOI: 10.1016/j.spinee.2018.06.345] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND CONTEXT Pedicle screw loosening is common after spinal fusion and can be associated with pseudoarthrosis and pain. With suspicion of screw loosening on standard radiographs, CT is currently considered the advanced imaging modality of choice. MRI with new metal artifact reduction techniques holds potential to be sensitive in detection of screw loosening. The sensitivity and specificity of either of the imaging modalities are yet clear. PURPOSE To evaluate the sensitivity and specificity of three different image modalities (standard radiographs, CT, and MRI) for detection of pedicle screw loosening. STUDY DESIGN/SETTING Cross-sectional diagnostic study. PATIENT SAMPLE Forty-one patients (159 pedicle screws) undergoing revision surgeries after lumbar spinal fusion between August 2014 and April 2017 with preoperative radiographs, CT, and MRI with spinal metal artifact reduction (STIR WARP and TSE high bandwidth sequences). OUTCOME MEASURES Sensitivity and specificity in detection of screw loosening for each imaging modality. METHODS Screw torque force was measured intraoperatively and compared with preoperative screw loosening signs such as peri-screw edema in MRI and peri-screw osteolysis in CT and radiographs. A torque force of less than 60 Ncm was used to define a screw as loosened. RESULTS Sensitivity and specificity in detection of screw loosening was 43.9% and 92.1% for MRI, 64.8% and 96.7% for CT, and 54.2% and 83.5% for standard radiographs, respectively. CONCLUSIONS Despite improvement of MRI with metal artifact reduction MRI technique, CT remains the modality of choice. Even so, CT fails to detect all loosened pedicle screws.
Collapse
Affiliation(s)
- José Miguel Spirig
- Spine Division, University Hospital Balgrist, University of Zürich, Switzerland.
| | - Reto Sutter
- Department of Radiology, University Hospital Balgrist, University of Zürich, Switzerland
| | | | | | - Mazda Farshad
- Spine Division, University Hospital Balgrist, University of Zürich, Switzerland
| |
Collapse
|
17
|
Improved Visualization of Juxtaprosthetic Tissue Using Metal Artifact Reduction Magnetic Resonance Imaging. Invest Radiol 2019; 54:23-31. [DOI: 10.1097/rli.0000000000000504] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
18
|
Shi X, Levine E, Weber H, Hargreaves BA. Accelerated imaging of metallic implants using model-based nonlinear reconstruction. Magn Reson Med 2018; 81:2247-2263. [PMID: 30515853 DOI: 10.1002/mrm.27536] [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: 03/21/2018] [Revised: 08/23/2018] [Accepted: 08/24/2018] [Indexed: 12/26/2022]
Abstract
PURPOSE To accelerate imaging near metallic implants with multi-spectral imaging (MSI) techniques by exploiting a signal model in the spectral dimension. METHODS MSI techniques resolve metal-induced field perturbations by acquiring separate 3D spatial encodings at multiple excitation frequencies, which are referred to as spectral bins. The proposed model-based reconstruction exploits the correlation between spectral bins in image reconstruction by enforcing a signal model to describe the signal profile across bins. This work evaluates the accuracy of the MSI signal model in simulations and in vivo experiments. The proposed model-based reconstruction was evaluated in 6 subjects at an overall undersampling factor of 17.4 and compared with model-free parallel imaging and compressed sensing (PI & CS). The quality of reconstructed images was evaluated using normalized RMS error (nRMSE) and structural similarity index (SSIM) comparisons, with paired Wilcoxon tests in 6 subjects used to determine whether there was a significant difference in the metrics. RESULTS Both simulations and in vivo experiments show that the proposed signal model can represent the MSI signal profiles in the spectral dimension compactly and accurately. In the in vivo experiments, the model-based reconstruction significantly improved image quality over model-free PI & CS, with P < 0.05 for both nRMSE and SSIM at 17.4× acceleration. CONCLUSION This work presents the feasibility of using a model-based reconstruction to accelerate MSI techniques for faster MR imaging near metal.
Collapse
Affiliation(s)
- Xinwei Shi
- Department of Radiology, Stanford University, Stanford, California.,Department of Electrical Engineering, Stanford University, Stanford, California
| | - Evan Levine
- Department of Radiology, Stanford University, Stanford, California.,Department of Electrical Engineering, Stanford University, Stanford, California
| | - Hans Weber
- Department of Radiology, Stanford University, Stanford, California
| | - Brian A Hargreaves
- Department of Radiology, Stanford University, Stanford, California.,Department of Electrical Engineering, Stanford University, Stanford, California.,Department of Bioengineering, Stanford University, Stanford, California
| |
Collapse
|
19
|
Rendenbach C, Schoellchen M, Bueschel J, Gauer T, Sedlacik J, Kutzner D, Vallittu PK, Heiland M, Smeets R, Fiehler J, Siemonsen S. Evaluation and reduction of magnetic resonance imaging artefacts induced by distinct plates for osseous fixation: an in vitro study @ 3 T. Dentomaxillofac Radiol 2018; 47:20170361. [PMID: 29718688 DOI: 10.1259/dmfr.20170361] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVES: To analyze MRI artefacts induced at 3 T by bioresorbable, titanium (TI) and glass fibre reinforced composite (GFRC) plates for osseous reconstruction. METHODS: Fixation plates including bioresorbable polymers (Inion CPS, Inion Oy, Tampere, Finland; Rapidsorb, DePuy Synthes, Umkirch, Germany; Resorb X, Gebrueder KLS Martin GmbH, Tuttlingen, Germany), GFRC (Skulle Implants Oy, Turku, Finland) and TI plates of varying thickness and design (DePuy Synthes, Umkirch, Germany) were embedded in agarose gel and a 3 T MRI was performed using a standard protocol for head and neck imaging including T1W and T2W sequences. Additionally, different artefact reduction techniques (slice encoding for metal artefact reduction & ultrashort echo time) were used and their impact on the extent of artefacts evaluated for each material. RESULTS: All TI plates induced significantly more artefacts than resorbable plates in T1W and T2W sequences. GFRCs induced the least artefacts in both sequences. The total extent of artefacts increased with plate thickness and height. Plate thickness had no influence on the percentage of overestimation in all three dimensions. TI-induced artefacts were significantly reduced by both artefact reduction techniques. CONCLUSIONS: Polylactide, GFRC and magnesium plates produce less susceptibility artefacts in MRI compared to TI, while the dimensions of TI plates directly influence artefact extension. Slice encoding for metal artefact reduction and ultrashort echo time significantly reduce metal artefacts at the expense of scan time or image resolution.
Collapse
Affiliation(s)
- Carsten Rendenbach
- 1 Department of Oral and Maxillofacial Surgery, Charité - Universitaetsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health , Berlin , Germany.,2 Berlin Institute of Health (BIH) , Berlin , Germany
| | - Max Schoellchen
- 3 Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Julie Bueschel
- 3 Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Tobias Gauer
- 4 Department of Radiotherapy and Radiation Oncology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Jan Sedlacik
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Daniel Kutzner
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Pekka K Vallittu
- 6 Department of Biomaterials Science, Institute of Dentistry, University of Turku, and City of Turku, Welfare Division , Turku , Finland
| | - Max Heiland
- 1 Department of Oral and Maxillofacial Surgery, Charité - Universitaetsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health , Berlin , Germany
| | - Ralf Smeets
- 3 Department of Oral and Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Jens Fiehler
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Susanne Siemonsen
- 5 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| |
Collapse
|
20
|
Levine E, Stevens K, Beaulieu C, Hargreaves B. Accelerated three-dimensional multispectral MRI with robust principal component analysis for separation of on- and off-resonance signals. Magn Reson Med 2018; 79:1495-1505. [PMID: 28686800 PMCID: PMC5756705 DOI: 10.1002/mrm.26819] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 05/19/2017] [Accepted: 06/12/2017] [Indexed: 01/24/2023]
Abstract
PURPOSE To enable highly accelerated distortion-free MRI near metal by separating on- and off-resonance to exploit the redundancy of slice-phase encoding for the dominant on-resonance component. METHODS Multispectral MRI techniques resolve off-resonance distortions by a combination of limited excitation bins and additional encoding. Inspired by robust principal component analysis, a novel compact representation of multispectral images as a sum of rank-one and sparse matrices corresponding to on- and off-resonance respectively is described. This representation is used in a calibration-free and model-free reconstruction for data with an undersampling pattern that varies between bins. Retrospective undersampling was used to compare the proposed reconstruction and bin-by-bin compressed sensing. Hip images were acquired in eight patients with standard and prospectively undersampled three-dimensional multispectral imaging, and image quality was evaluated by two radiologists on a 5-point scale. RESULTS Experiments with retrospective undersampling showed that the enhanced sparsity afforded by the separation greatly reduces reconstruction errors and artifacts. Images from prospectively undersampled multispectral imaging offered 2.6-3.4-fold (18-24-fold overall) acceleration compared to standard multispectral imaging with parallel imaging and partial-Fourier acceleration with equivalence in all qualitative assessments within a tolerance of one point (P < 0.004). CONCLUSION Three-dimensional multispectral imaging can be highly accelerated by varying undersampling between bins and separating on- and off-resonance. Magn Reson Med 79:1495-1505, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Evan Levine
- Department of Electrical Engineering and Radiology, Stanford University, Stanford, California, USA
| | - Kathryn Stevens
- Department of Electrical Engineering and Radiology, Stanford University, Stanford, California, USA
| | - Christopher Beaulieu
- Department of Electrical Engineering and Radiology, Stanford University, Stanford, California, USA
| | - Brian Hargreaves
- Department of Electrical Engineering and Radiology, Stanford University, Stanford, California, USA
| |
Collapse
|
21
|
Wanner L, Ludwig U, Hövener JB, Nelson K, Flügge T. Magnetic resonance imaging-a diagnostic tool for postoperative evaluation of dental implants: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol 2018; 125:e103-e107. [PMID: 29501353 DOI: 10.1016/j.oooo.2018.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 01/03/2018] [Accepted: 01/08/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Compared with cone beam computed tomography (CBCT), magnetic resonance imaging (MRI) might be superior for the diagnosis of nerve lesions associated with implant placement. STUDY DESIGN A patient presented with unilateral pain associated with dysesthesia in the region of the right lower lip and chin after implant placement. Conventional orthopantomography could not identify an association between the position of the inferior alveolar nerve and the implant. For 3-dimensional display of the implant in relation to the surrounding anatomy, CBCT was compared with MRI. RESULTS MRI enabled the precise depiction of the implant position and its spatial relation to the inferior alveolar nerve, whereas the nerve position and its exact course within the mandible could not be directly displayed in CBCT. CONCLUSION MRI may be a valuable, radiation-free diagnostic tool for the visualization of intraoral hard and soft tissues, offering an objective assessment of nerve injuries by a direct visualization of the inferior alveolar neurovascular bundle.
Collapse
Affiliation(s)
- Laura Wanner
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Ute Ludwig
- Department of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Jan-Bernd Hövener
- Department of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Katja Nelson
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tabea Flügge
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| |
Collapse
|
22
|
de Cesar Netto C, Fonseca LF, Fritz B, Stern SE, Raithel E, Nittka M, Schon LC, Fritz J. Metal artifact reduction MRI of total ankle arthroplasty implants. Eur Radiol 2017; 28:2216-2227. [DOI: 10.1007/s00330-017-5153-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 09/26/2017] [Accepted: 10/23/2017] [Indexed: 10/18/2022]
|
23
|
A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties. Acta Biomater 2017; 62:340-351. [PMID: 28842333 DOI: 10.1016/j.actbio.2017.08.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/12/2017] [Accepted: 08/12/2017] [Indexed: 11/21/2022]
Abstract
Different materials have been used for vital dental pulp treatment. Preferably a pulp capping agent should show appropriate biological performance, excellent handling properties, and a good imaging contrast. These features can be delivered into a single material through the combination of therapeutic and diagnostic agents (i.e. theranostic). Calcium phosphate based composites (CPCs) are potentially ideal candidate for pulp treatment, although poor imaging contrast and poor dentino-inductive properties are limiting their clinical use. In this study, a theranostic dental pulp capping agent was developed. First, imaging properties of the CPC were improved by using a core-shell structured dual contrast agent (csDCA) consisting of superparamagnetic iron oxide (SPIO) and colloidal gold, as MRI and CT contrast agent respectively. Second, biological properties were implemented by using a dentinogenic factor (i.e. bone morphogenetic protein 2, BMP-2). The obtained CPC/csDCA/BMP-2 composite was tested in vivo, as direct pulp capping agent, in a male Habsi goat incisor model. Our outcomes showed no relevant alteration of the handling and mechanical properties (e.g. setting time, injectability, and compressive strength) by the incorporation of csDCA particles. In vivo results proved MRI contrast enhancement up to 7weeks. Incisors treated with BMP-2 showed improved tertiary dentin deposition as well as faster cement degradation as measured by µCT assessment. In conclusion, the presented theranostic agent matches the imaging and regenerative requirements for pulp capping applications. STATEMENT OF SIGNIFICANCE In this study, we combined diagnostic and therapeutic agents in order to developed a theranostic pulp capping agent with enhanced MRI and CT contrast and improved dentin regeneration ability. In our study we cover all the steps from material preparation, mechanical and in vitro characterization, to in vivo study in a goat dental model. To the best of our knowledge, this is the first time that a theranostic pulp capping material have been developed and tested in an in vivo animal model. Our promising results in term of imaging contrast enhancement and of induction of new dentin formation, open a new scenario in the development of innovative dental materials.
Collapse
|
24
|
Sonnow L, Gilson WD, Raithel E, Nittka M, Wacker F, Fritz J. Instrument visualization using conventional and compressed sensing SEMAC for interventional MRI at 3T. J Magn Reson Imaging 2017; 47:1306-1315. [DOI: 10.1002/jmri.25858] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/05/2017] [Indexed: 12/13/2022] Open
Affiliation(s)
- Lena Sonnow
- Russell H. Morgan Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine; Baltimore Maryland USA
- Department of Diagnostic and Interventional Radiology; Hannover Medical School; Hannover Germany
- Research Campus STIMULATE; Magdeburg Germany
| | | | | | | | - Frank Wacker
- Department of Diagnostic and Interventional Radiology; Hannover Medical School; Hannover Germany
- Research Campus STIMULATE; Magdeburg Germany
| | - Jan Fritz
- Russell H. Morgan Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine; Baltimore Maryland USA
| |
Collapse
|
25
|
Abstract
MR imaging has an important role in the evaluation of the postoperative foot and ankle. In this article, a variety of operative techniques and postoperative findings in the foot and ankle are described, including tendon and ligament reconstruction, as well as the treatment of tarsal coalition and Morton neuroma. The role of MR imaging in the assessment of complications of foot and ankle surgery is also detailed.
Collapse
Affiliation(s)
- Samuel D Madoff
- Department of Radiology, New England Baptist Hospital, Tufts University School of Medicine, 125 Parker Hill Avenue, Boston, MA 02120, USA.
| | - Jeffrey Kaye
- Department of Radiology, New England Baptist Hospital, Tufts University School of Medicine, 125 Parker Hill Avenue, Boston, MA 02120, USA
| | - Joel S Newman
- Department of Radiology, New England Baptist Hospital, Tufts University School of Medicine, 125 Parker Hill Avenue, Boston, MA 02120, USA
| |
Collapse
|
26
|
Hargreaves BA, Taviani V, Litwiller DV, Yoon D. 2D multi-spectral imaging for fast MRI near metal. Magn Reson Med 2017; 79:968-973. [PMID: 28444805 DOI: 10.1002/mrm.26724] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/07/2017] [Accepted: 03/29/2017] [Indexed: 01/19/2023]
Abstract
PURPOSE To develop a fast 2D method for MRI near metal with reduced B0 in-plane and through-slice artifacts. METHODS Multi-spectral imaging (MSI) approaches reduce artifacts in MR images near metal, but require 3D imaging of multiple excited volumes regardless of imaging geometry or artifact severity. The proposed 2D MSI method rapidly excites a limited slice and spectral region using gradient reversal between excitation and refocusing pulses, then uses standard 2D imaging, with the process repeating to cover multiple spectral offsets that are combined as in other MSI techniques. 2D MSI was implemented in a spin-echo-train sequence and validated in phantoms and in vivo by comparing it with standard spin-echo imaging and existing MSI techniques. RESULTS 2D MSI images for each spatial-spectral region follow isocontours of the dipole-like B0 field variation, and thus frequency variation, near metal devices. Artifact correction in phantoms and human subjects with metal is comparable to 3D MSI methods, and superior to standard spin-echo techniques. Scan times are reduced compared with 3D MSI methods in cases where a limited number of slices are needed, though signal-to-noise ratio is also reduced as expected. CONCLUSION 2D MSI offers a fast and flexible alternative to 3D MSI for artifact reduction near metal. Magn Reson Med 79:968-973, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Brian A Hargreaves
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | | | | | - Daehyun Yoon
- Department of Radiology, Stanford University, Stanford, California, USA
| |
Collapse
|
27
|
Probst M, Richter V, Weitz J, Kirschke JS, Ganter C, Troeltzsch M, Nittka M, Cornelius CP, Zimmer C, Probst FA. Magnetic resonance imaging of the inferior alveolar nerve with special regard to metal artifact reduction. J Craniomaxillofac Surg 2017; 45:558-569. [DOI: 10.1016/j.jcms.2017.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 12/08/2016] [Accepted: 01/09/2017] [Indexed: 11/30/2022] Open
|
28
|
Jones BG, Fosgate GT, Green EM, Habing AM, Hettlich BF. Magnetic resonance imaging susceptibility artifacts in the cervical vertebrae and spinal cord related to monocortical screw-polymethylmethacrylate implants in canine cadavers. Am J Vet Res 2017; 78:458-464. [PMID: 28346006 DOI: 10.2460/ajvr.78.4.458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To characterize and compare MRI susceptibility artifacts related to titanium and stainless steel monocortical screws in the cervical vertebrae and spinal cord of canine cadavers. SAMPLE 12 canine cadavers. PROCEDURES Cervical vertebrae (C4 and C5) were surgically stabilized with titanium or stainless steel monocortical screws and polymethylmethacrylate. Routine T1-weighted, T2-weighted, and short tau inversion recovery sequences were performed at 3.0 T. Magnetic susceptibility artifacts in 20 regions of interest (ROIs) across 4 contiguous vertebrae (C3 through C6) were scored by use of an established scoring system. RESULTS Artifact scores for stainless steel screws were significantly greater than scores for titanium screws at 18 of 20 ROIs. Artifact scores for titanium screws were significantly higher for spinal cord ROIs within the implanted vertebrae. Artifact scores for stainless steel screws at C3 were significantly less than at the other 3 cervical vertebrae. CONCLUSIONS AND CLINICAL RELEVANCE Evaluation of routine MRI sequences obtained at 3.0 T revealed that susceptibility artifacts related to titanium monocortical screws were considered mild and should not hinder the overall clinical assessment of the cervical vertebrae and spinal cord. However, mild focal artifacts may obscure small portions of the spinal cord or intervertebral discs immediately adjacent to titanium screws. Severe artifacts related to stainless steel screws were more likely to result in routine MRI sequences being nondiagnostic; however, artifacts may be mitigated by implant positioning.
Collapse
|
29
|
Jungmann PM, Agten CA, Pfirrmann CW, Sutter R. Advances in MRI around metal. J Magn Reson Imaging 2017; 46:972-991. [PMID: 28342291 DOI: 10.1002/jmri.25708] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 03/03/2017] [Indexed: 01/02/2023] Open
Abstract
The prevalence of orthopedic metal implants is continuously rising in the aging society. Particularly the number of joint replacements is increasing. Although satisfying long-term results are encountered, patients may suffer from complaints or complications during follow-up, and often undergo magnetic resonance imaging (MRI). Yet metal implants cause severe artifacts on MRI, resulting in signal-loss, signal-pileup, geometric distortion, and failure of fat suppression. In order to allow for adequate treatment decisions, metal artifact reduction sequences (MARS) are essential for proper radiological evaluation of postoperative findings in these patients. During recent years, developments of musculoskeletal imaging have addressed this particular technical challenge of postoperative MRI around metal. Besides implant material composition, configuration and location, selection of appropriate MRI hardware, sequences, and parameters influence artifact genesis and reduction. Application of dedicated metal artifact reduction techniques including high bandwidth optimization, view angle tilting (VAT), and the multispectral imaging techniques multiacquisition variable-resonance image combination (MAVRIC) and slice-encoding for metal artifact correction (SEMAC) may significantly reduce metal-induced artifacts, although at the expense of signal-to-noise ratio and/or acquisition time. Adding advanced image acquisition techniques such as parallel imaging, partial Fourier transformation, and advanced reconstruction techniques such as compressed sensing further improves MARS imaging in a clinically feasible scan time. This review focuses on current clinically applicable MARS techniques. Understanding of the main principles and techniques including their limitations allows a considerate application of these techniques in clinical practice. Essential orthopedic metal implants and postoperative MR findings around metal are presented and highlighted with clinical examples. LEVEL OF EVIDENCE 4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:972-991.
Collapse
Affiliation(s)
- Pia M Jungmann
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland.,Department of Radiology, Technical University of Munich, Munich, Germany
| | - Christoph A Agten
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Christian W Pfirrmann
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Department of Radiology, Technical University of Munich, Munich, Germany
| | - Reto Sutter
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland.,Department of Radiology, Technical University of Munich, Munich, Germany
| |
Collapse
|
30
|
Zhou DB, Wang SG, Wang SP, Ai HJ, Xu J. MRI compatibility of several early transition metal based alloys and its influencing factors. J Biomed Mater Res B Appl Biomater 2017; 106:377-385. [PMID: 28160410 DOI: 10.1002/jbm.b.33832] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 07/15/2016] [Accepted: 10/02/2016] [Indexed: 11/06/2022]
Abstract
Magnetic resonance imaging (MRI) compatibility of three early transition metal (ETM) based alloys was assessed in vitro with agarose gel as a phantom, including Zr-20Nb, near-equiatomic (TiZrNbTa)90 Mo10 and Nb-60Ta-2Zr, together with pure tantalum and L605 Co-Cr alloy for comparison. The artifact extent in the MR image was quantitatively characterized according to the maximum area of 2D images and the total volume in reconstructed 3D images with a series of slices under acquisition by fast spin echo (FSE) sequence and gradient echo (GRE) sequence. It was indicated that the artifacts extent of L605 Co-Cr alloy with a higher magnetic susceptibility (χv ) was approximately 3-fold greater than that of the ETM-based alloys with χv in the range of 160-250 ppm. In the ETM group, the MRI compatibility of the materials can be ranked in a sequence of Zr-20Nb, pure tantalum, (TiZrNbTa)90 Mo10 and Nb-60Ta-2Zr. In addition, using a rabbit cadaver with the implanted tube specimens as a model for ex vivo assessment, it was confirmed that the artifact severity of Nb-60Ta-2Zr alloy is significantly reduced in comparison with the L605 alloy. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 377-385, 2018.
Collapse
Affiliation(s)
- Da-Bo Zhou
- School of Stomatology, China Medical University, Shenyang, 110002, China
| | - Shao-Gang Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Shao-Ping Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Hong-Jun Ai
- School of Stomatology, China Medical University, Shenyang, 110002, China
| | - Jian Xu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| |
Collapse
|
31
|
Abstract
Expanding implantable cardioverter-defibrillator (ICD) indications and significant morbidity and mortality reduction benefits have resulted in a large number of routine ICD implants with appropriate ICD shocks for ventricular arrhythmias. The side-effects and lack of long-term efficacy of antiarrhythmics have made ventricular tachycardia (VT) ablation an increasingly attractive treatment option. Although cardiac magnetic resonance imaging (CMR) is considered the gold standard technique for imaging of myocardial fibrosis to diagnose and guide VT ablation targets in patients with cardiac arrhythmia, safety concerns and significant artifacts from the devices significantly limit the application of CMR. We discuss how to decrease artifact from cardiac devices and the role of a modified inversion pulse late gadolinium enhancement (LGE) CMR sequence as a useful tool in this setting, and we review techniques, safety protocols and limitations from the perspective of our institution’s experience.
Collapse
|
32
|
Advanced metal artifact reduction MRI of metal-on-metal hip resurfacing arthroplasty implants: compressed sensing acceleration enables the time-neutral use of SEMAC. Skeletal Radiol 2016; 45:1345-56. [PMID: 27497594 DOI: 10.1007/s00256-016-2437-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 07/10/2016] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Compressed sensing (CS) acceleration has been theorized for slice encoding for metal artifact correction (SEMAC), but has not been shown to be feasible. Therefore, we tested the hypothesis that CS-SEMAC is feasible for MRI of metal-on-metal hip resurfacing implants. MATERIALS AND METHODS Following prospective institutional review board approval, 22 subjects with metal-on-metal hip resurfacing implants underwent 1.5 T MRI. We compared CS-SEMAC prototype, high-bandwidth TSE, and SEMAC sequences with acquisition times of 4-5, 4-5 and 10-12 min, respectively. Outcome measures included bone-implant interfaces, image quality, periprosthetic structures, artifact size, and signal- and contrast-to-noise ratios (SNR and CNR). Using Friedman, repeated measures analysis of variances, and Cohen's weighted kappa tests, Bonferroni-corrected p-values of 0.005 and less were considered statistically significant. RESULTS There was no statistical difference of outcomes measures of SEMAC and CS-SEMAC images. Visibility of implant-bone interfaces and pseudocapsule as well as fat suppression and metal reduction were "adequate" to "good" on CS-SEMAC and "non-diagnostic" to "adequate" on high-BW TSE (p < 0.001, respectively). SEMAC and CS-SEMAC showed mild blur and ripple artifacts. The metal artifact size was 63 % larger for high-BW TSE as compared to SEMAC and CS-SEMAC (p < 0.0001, respectively). CNRs were sufficiently high and statistically similar, with the exception of CNR of fluid and muscle and CNR of fluid and tendon, which were higher on intermediate-weighted high-BW TSE (p < 0.005, respectively). CONCLUSION Compressed sensing acceleration enables the time-neutral use of SEMAC for MRI of metal-on-metal hip resurfacing implants when compared to high-BW TSE and image quality similar to conventional SEMAC.
Collapse
|
33
|
Compressed Sensing SEMAC: 8-fold Accelerated High Resolution Metal Artifact Reduction MRI of Cobalt-Chromium Knee Arthroplasty Implants. Invest Radiol 2016; 51:666-76. [DOI: 10.1097/rli.0000000000000317] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
34
|
Otazo R, Nittka M, Bruno M, Raithel E, Geppert C, Gyftopoulos S, Recht M, Rybak L. Sparse-SEMAC: rapid and improved SEMAC metal implant imaging using SPARSE-SENSE acceleration. Magn Reson Med 2016; 78:79-87. [PMID: 27454003 DOI: 10.1002/mrm.26342] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 05/27/2016] [Accepted: 06/21/2016] [Indexed: 02/03/2023]
Abstract
PURPOSE To develop an accelerated SEMAC metal implant MRI technique (Sparse-SEMAC) with reduced scan time and improved metal distortion correction. METHODS Sparse-SEMAC jointly exploits the inherent sparsity along the additional phase-encoding dimension and multicoil encoding capabilities to significantly accelerate data acquisition. A prototype pulse sequence with pseudorandom ky -kz undersampling and an inline image reconstruction was developed for integration in clinical studies. Three patients with hip implants were imaged using the proposed Sparse-SEMAC with eight-fold acceleration and compared with the standard-SEMAC technique used in clinical studies (three-fold GRAPPA acceleration). Measurements were performed with SEMAC-encoding steps (SES) = 15 for Sparse-SEMAC and SES = 9 for Standard-SEMAC using high spatial resolution Proton Density (PD) and lower-resolution STIR acquisitions. Two expert musculoskeletal (MSK) radiologists performed a consensus reading to score image-quality parameters. RESULTS Sparse-SEMAC enables up to eight-fold acceleration of data acquisition that results in two-fold scan time reductions, compared with Standard-SEMAC, with improved metal artifact correction for patients with hip implants without degrading spatial resolution. CONCLUSION The high acceleration enabled by Sparse-SEMAC would enable clinically feasible examination times with improved correction of metal distortion. Magn Reson Med 78:79-87, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Ricardo Otazo
- Department of Radiology, NYU School of Medicine, New York, New York, USA
| | | | - Mary Bruno
- Department of Radiology, NYU School of Medicine, New York, New York, USA
| | | | | | | | - Michael Recht
- Department of Radiology, NYU School of Medicine, New York, New York, USA
| | - Leon Rybak
- Department of Radiology, NYU School of Medicine, New York, New York, USA
| |
Collapse
|
35
|
Wiens CN, Artz NS, Jang H, McMillan AB, Reeder SB. Externally calibrated parallel imaging for 3D multispectral imaging near metallic implants using broadband ultrashort echo time imaging. Magn Reson Med 2016; 77:2303-2309. [PMID: 27403613 DOI: 10.1002/mrm.26327] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 01/23/2023]
Abstract
PURPOSE To develop an externally calibrated parallel imaging technique for three-dimensional multispectral imaging (3D-MSI) in the presence of metallic implants. THEORY AND METHODS A fast, ultrashort echo time (UTE) calibration acquisition is proposed to enable externally calibrated parallel imaging techniques near metallic implants. The proposed calibration acquisition uses a broadband radiofrequency (RF) pulse to excite the off-resonance induced by the metallic implant, fully phase-encoded imaging to prevent in-plane distortions, and UTE to capture rapidly decaying signal. The performance of the externally calibrated parallel imaging reconstructions was assessed using phantoms and in vivo examples. RESULTS Phantom and in vivo comparisons to self-calibrated parallel imaging acquisitions show that significant reductions in acquisition times can be achieved using externally calibrated parallel imaging with comparable image quality. Acquisition time reductions are particularly large for fully phase-encoded methods such as spectrally resolved fully phase-encoded three-dimensional (3D) fast spin-echo (SR-FPE), in which scan time reductions of up to 8 min were obtained. CONCLUSION A fully phase-encoded acquisition with broadband excitation and UTE enabled externally calibrated parallel imaging for 3D-MSI, eliminating the need for repeated calibration regions at each frequency offset. Significant reductions in acquisition time can be achieved, particularly for fully phase-encoded methods like SR-FPE. Magn Reson Med 77:2303-2309, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Curtis N Wiens
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
| | - Nathan S Artz
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.,Department of Diagnostic Imaging, St. Jude Children's St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Hyungseok Jang
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.,Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin, USA
| | - Alan B McMillan
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
| | - Scott B Reeder
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.,Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.,Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, USA.,Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA.,Dept. of Emergency Medicine, University of Wisconsin, Madison, Wisconsin, USA
| |
Collapse
|
36
|
Dillenseger JP, Molière S, Choquet P, Goetz C, Ehlinger M, Bierry G. An illustrative review to understand and manage metal-induced artifacts in musculoskeletal MRI: a primer and updates. Skeletal Radiol 2016; 45:677-88. [PMID: 26837388 DOI: 10.1007/s00256-016-2338-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 01/13/2016] [Accepted: 01/17/2016] [Indexed: 02/02/2023]
Abstract
This article reviews and explains the basic physical principles of metal-induced MRI artifacts, describes simple ways to reduce them, and presents specific reduction solutions. Artifacts include signal loss, pile-up artifacts, geometric distortion, and failure of fat suppression. Their nature and origins are reviewed and explained though schematic representations that ease the understanding. Then, optimization of simple acquisition parameters is detailed. Lastly, dedicated sequences and options specifically developed to reduce metal artifacts (VAT, SEMAC, and MAVRIC) are explained.
Collapse
Affiliation(s)
- J P Dillenseger
- Medical imaging department, University Hospital of Strasbourg, 10 Av. Molière, F- 67098, Strasbourg, France.,Icube, CNRS, University of Strasbourg, Strasbourg, France.,Translational Medicine Research Federation, Strasbourg Medical School, University of Strasbourg, Strasbourg, France
| | - S Molière
- Medical imaging department, University Hospital of Strasbourg, 10 Av. Molière, F- 67098, Strasbourg, France
| | - P Choquet
- Medical imaging department, University Hospital of Strasbourg, 10 Av. Molière, F- 67098, Strasbourg, France.,Icube, CNRS, University of Strasbourg, Strasbourg, France.,Translational Medicine Research Federation, Strasbourg Medical School, University of Strasbourg, Strasbourg, France
| | - C Goetz
- Medical imaging department, University Hospital of Strasbourg, 10 Av. Molière, F- 67098, Strasbourg, France.,Icube, CNRS, University of Strasbourg, Strasbourg, France.,Translational Medicine Research Federation, Strasbourg Medical School, University of Strasbourg, Strasbourg, France
| | - M Ehlinger
- Icube, CNRS, University of Strasbourg, Strasbourg, France.,Translational Medicine Research Federation, Strasbourg Medical School, University of Strasbourg, Strasbourg, France.,Department of orthopedic surgery, University Hospital of Strasbourg, Strasbourg, France
| | - G Bierry
- Medical imaging department, University Hospital of Strasbourg, 10 Av. Molière, F- 67098, Strasbourg, France. .,Icube, CNRS, University of Strasbourg, Strasbourg, France. .,Translational Medicine Research Federation, Strasbourg Medical School, University of Strasbourg, Strasbourg, France.
| |
Collapse
|
37
|
Roth E, Hoff M, Richardson ML, Ha AS, Porrino J. Artifacts Affecting Musculoskeletal Magnetic Resonance Imaging: Their Origins and Solutions. Curr Probl Diagn Radiol 2016; 45:340-6. [PMID: 26948320 DOI: 10.1067/j.cpradiol.2016.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/25/2016] [Indexed: 11/22/2022]
Abstract
Among articles within the radiology literature, few present the manifestations of magnetic resonance imaging artifacts in a clinically oriented manner. Recognizing such artifacts is imperative given the increasing clinical use of magnetic resonance imaging and the emphasis by the American Board of Radiology on practical physics applications. The purpose of this article is to present magnetic resonance physics principles visually and conceptually in the context of common musculoskeletal radiology artifacts and their solutions, described using nonmathematical explanations.
Collapse
Affiliation(s)
- Eira Roth
- Irving Radiological Associates, Irving, TX
| | - Michael Hoff
- Department of Radiology, University of Washington, Seattle, WA
| | | | - Alice S Ha
- Department of Radiology, University of Washington, Seattle, WA
| | - Jack Porrino
- Department of Radiology, University of Washington, Seattle, WA.
| |
Collapse
|
38
|
Kaushik SS, Marszalkowski C, Koch KM. External calibration of the spectral coverage for three-dimensional multispectral MRI. Magn Reson Med 2015; 76:1494-1503. [PMID: 26745139 DOI: 10.1002/mrm.26065] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 01/18/2023]
Abstract
PURPOSE By combining images created at distinct frequency offsets from the Larmor frequency, three-dimensional (3D) multispectral imaging (3D-MSI) sequences help overcome the large spatial frequency dispersion caused by metal implants. This frequency dispersion, however, varies with the implant size, orientation, and composition. Using a MAVRIC 3D-MSI acquisition, we sought to prospectively calibrate the spectral coverage needed for 3D-MSI scans. This calibration should offer a significant improvement to image quality, and reduce the scan time. METHODS The 24 spectral bins from the calibration scan were used to generate a map of frequency offsets around the implant. The magnitude image was used to remove any outliers in the associated frequency offset map, and this processed map was used to determine the cutoff frequency offset and, hence, number of spectral bins. This approach was tested in 13 subjects, by retrospectively reconstructing MAVRIC-SL images with fewer spectral bins. Subsequently, the spectral coverage for MAVRIC-SL images was prospectively calibrated in six subjects, and based on the cutoff frequency offset, these images were acquired with fewer spectral bins. RESULTS With fewer spectral bins, both retrospectively and prospectively calibrated MAVRIC-SL images adequately delineated the implant boundary. CONCLUSION Incorporating this calibration procedure into future 3D-MSI exams will help improve image signal-to-noise ratio, reduce scan time, and significantly improve clinical workflow when imaging near orthopedic implants. Magn Reson Med 76:1494-1503, 2016. © 2015 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- S Sivaram Kaushik
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
| | - Cathy Marszalkowski
- Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Kevin M Koch
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| |
Collapse
|
39
|
Usefulness of metal artifact reduction with WARP technique at 1.5 and 3T MRI in imaging metal-on-metal hip resurfacings. Skeletal Radiol 2015; 44:941-51. [PMID: 25805436 DOI: 10.1007/s00256-015-2128-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/19/2015] [Accepted: 02/22/2015] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To evaluate the usefulness of the metal artifact reduction technique "WARP" in the assessment of metal-on-metal hip resurfacings at 1.5 and 3T in the context of image quality and imaging speed. MATERIALS AND METHODS Nineteen patients (25 hip resurfacings) were randomized for 1.5 and 3T MRI, both including T1 and T2 turbo spin-echo as well as turbo inversion recovery magnitude sequences with and without view angle tilting and high bandwidth. Additional 3T sequences were acquired with a reduced number of averages and using the parallel acquisition technique for accelerating imaging speed. Artifact size (diameter, area), image quality (5-point scale) and delineation of anatomical structures were compared among the techniques, sequences and field strengths using the Wilcoxon sign-rank and paired t-test with Bonferroni correction. RESULTS At both field strengths, WARP showed significant superiority over standard sequences regarding image quality, artifact size and delineation of anatomical structures. At 3T, artifacts were larger compared to 1.5T without affecting diagnostic quality, and scanning time could be reduced by up to 64 % without quality degradation. CONCLUSION WARP proved useful in imaging metal-on-metal hip resurfacings at 1.5T as well as 3T with better image quality surrounding the implants. At 3T imaging could be considerably accelerated without losing diagnostic quality.
Collapse
|
40
|
Ladefoged CN, Hansen AE, Keller SH, Fischer BM, Rasmussen JH, Law I, Kjær A, Højgaard L, Lauze F, Beyer T, Andersen FL. Dental artifacts in the head and neck region: implications for Dixon-based attenuation correction in PET/MR. EJNMMI Phys 2015; 2:8. [PMID: 26501810 PMCID: PMC4546019 DOI: 10.1186/s40658-015-0112-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/05/2015] [Indexed: 12/18/2022] Open
Abstract
Background In the absence of CT or traditional transmission sources in combined clinical positron emission tomography/magnetic resonance (PET/MR) systems, MR images are used for MR-based attenuation correction (MR-AC). The susceptibility effects due to metal implants challenge MR-AC in the neck region of patients with dental implants. The purpose of this study was to assess the frequency and magnitude of subsequent PET image distortions following MR-AC. Methods A total of 148 PET/MR patients with clear visual signal voids on the attenuation map in the dental region were included in this study. Patients were injected with [18F]-FDG, [11C]-PiB, [18F]-FET, or [64Cu]-DOTATATE. The PET/MR data were acquired over a single-bed position of 25.8 cm covering the head and neck. MR-AC was based on either standard MR-ACDIXON or MR-ACINPAINTED where the susceptibility-induced signal voids were substituted with soft tissue information. Our inpainting algorithm delineates the outer contour of signal voids breaching the anatomical volume using the non-attenuation-corrected PET image and classifies the inner air regions based on an aligned template of likely dental artifact areas. The reconstructed PET images were evaluated visually and quantitatively using regions of interests in reference regions. The volume of the artifacts and the computed relative differences in mean and max standardized uptake value (SUV) between the two PET images are reported. Results The MR-based volume of the susceptibility-induced signal voids on the MR-AC attenuation maps was between 1.6 and 520.8 mL. The corresponding/resulting bias of the reconstructed tracer distribution was localized mainly in the area of the signal void. The mean and maximum SUVs averaged across all patients increased after inpainting by 52% (± 11%) and 28% (± 11%), respectively, in the corrected region. SUV underestimation decreased with the distance to the signal void and correlated with the volume of the susceptibility artifact on the MR-AC attenuation map. Conclusions Metallic dental work may cause severe MR signal voids. The resulting PET/MR artifacts may exceed the actual volume of the dental fillings. The subsequent bias in PET is severe in regions in and near the signal voids and may affect the conspicuity of lesions in the mandibular region. Electronic supplementary material The online version of this article (doi:10.1186/s40658-015-0112-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Claes N Ladefoged
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Adam E Hansen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Sune H Keller
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Barbara M Fischer
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Jacob H Rasmussen
- Department of Oncology, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Ian Law
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Andreas Kjær
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Liselotte Højgaard
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| | - Francois Lauze
- Department of Computer Science, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen East, Denmark.
| | - Thomas Beyer
- Centre for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4L, Vienna, A-1090, Austria.
| | - Flemming L Andersen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen East, Denmark.
| |
Collapse
|
41
|
MR imaging near metallic implants using MAVRIC SL: initial clinical experience at 3T. Acad Radiol 2015; 22:370-9. [PMID: 25435186 DOI: 10.1016/j.acra.2014.09.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 09/10/2014] [Accepted: 09/23/2014] [Indexed: 11/23/2022]
Abstract
RATIONALE AND OBJECTIVES To compare the effectiveness of multiacquisition with variable resonance image combination selective (MAVRIC SL) with conventional two-dimensional fast spin-echo (2D-FSE) magnetic resonance (MR) techniques at 3T in imaging patients with a variety of metallic implants. MATERIALS AND METHODS Twenty-one 3T MR studies were obtained in 19 patients with different types of metal implants. Paired MAVRIC SL and 2D-FSE sequences were reviewed by two radiologists and compared for in-plane and through-plane metal artifact, visualization of the bone implant interface and surrounding soft tissues, blurring, and overall image quality using a two-tailed Wilcoxon signed rank test. The area of artifact on paired images was measured and compared using a paired Wilcoxon signed rank test. Changes in patient management resulting from MAVRIC SL imaging were documented. RESULTS Significantly less in-plane and through-plane artifact was seen with MAVRIC SL, with improved visualization of the bone-implant interface and surrounding soft tissues, and superior overall image quality (P = .0001). Increased blurring was seen with MAVRIC SL (P = .0016). MAVRIC SL significantly decreased the image artifact compared to 2D-FSE (P = .0001). Inclusion of MAVRIC SL to the imaging protocol determined the need for surgery or type of surgery in five patients and ruled out the need for surgery in 13 patients. In three patients, the area of interest was well seen on both MAVRIC SL and 2D-FSE images, so the addition of MAVRIC had no effect on patient management. CONCLUSIONS Imaging around metal implants with MAVRIC SL at 3T significantly improved image quality and decreased image artifact compared to conventional 2D-FSE imaging techniques and directly impacted patient management.
Collapse
|
42
|
Metal artifact reduction: standard and advanced magnetic resonance and computed tomography techniques. Radiol Clin North Am 2015; 53:531-47. [PMID: 25953288 DOI: 10.1016/j.rcl.2014.12.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An increasing number of joint replacements are being performed in the United States. Patients undergoing these procedures can have various complications. Imaging is one of the primary means of diagnosing these complications. Cross-sectional imaging techniques, such as computed tomography (CT) and MR imaging, are more sensitive than radiographs for evaluating complications. The use of CT and MR imaging in patients with metallic implants is limited by the presence of artifacts. This review discusses the causes of metal artifacts on MR imaging and CT, contributing factors, and conventional and novel methods to reduce the effects of these artifacts on scans.
Collapse
|
43
|
Månsson S, Müller GM, Wellman F, Nittka M, Lundin B. Phantom based qualitative and quantitative evaluation of artifacts in MR images of metallic hip prostheses. Phys Med 2014; 31:173-8. [PMID: 25555906 DOI: 10.1016/j.ejmp.2014.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/05/2014] [Accepted: 12/08/2014] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To develop methods for qualitative and quantitative evaluation of MRI artifacts near metallic prostheses, and to compare the efficiency of different artifact suppression techniques with different types of hip prostheses. METHODS Three hip prostheses of cobalt-chromium, stainless steel, and titanium were embedded in agarose gel together with a rectilinear grid. Coronal MR images of the prostheses were acquired on a 1.5T scanner. Three pulse sequences were evaluated; TSE: a high-bandwidth turbo spin echo; VAT: TSE with view angle tilting, SEMAC: TSE with both VAT and slice distortion correction (6, 10 or 16 z-phase-encoding steps). Through-plane distortions were assessed as the length of visible gridlines, in-plane artifacts as the artifact area, and total artifacts by subtraction of an ideal, undistorted image from the actual image. RESULTS VAT reduced in-plane artifacts by up to 50% compared to TSE, but did not reduce through-plane artifacts. SEMAC reduced through-plane artifacts by 60-80% compared to TSE and VAT. SEMAC in-plane artifacts were from 20% higher (6 encoding steps) to 50% lower (16 steps) than VAT. Total artifacts were reduced by 60-80% in the best sequence (SEMAC, 16 steps) compared to the worst (TSE). The titanium prosthesis produced 3-4 times lower artifact scores than the other prostheses. CONCLUSIONS A rectilinear grid phantom is useful for qualitative and quantitative evaluation of artifacts provoked by different MRI protocols and prosthesis models. VAT and SEMAC were superior to TSE with high bandwidth. A proper number of z-encoding steps in SEMAC was critical. The titanium prosthesis caused least artifacts.
Collapse
Affiliation(s)
- Sven Månsson
- Medical Radiation Physics, Dept. of Clinical Sciences Malmö, Lund University, Skåne University Hospital Malmö, Sweden.
| | - Gunilla M Müller
- Radiology, Dept. of Clinical Sciences Malmö, Lund University, Skåne University Hospital Malmö, Sweden
| | - Fredrik Wellman
- Medical Radiation Physics, Dept. of Clinical Sciences Malmö, Lund University, Skåne University Hospital Malmö, Sweden
| | - Mathias Nittka
- Siemens AG, Healthcare Sector, Imaging & Therapy Division, Erlangen, Germany
| | - Björn Lundin
- Diagnostic Radiology, Dept. of Clinical Sciences Lund, Lund University, Skåne University Hospital Lund, Sweden
| |
Collapse
|
44
|
Koch KM, Koff MF, Shah PH, Kanwischer A, Gui D, Potter HG. Flexible longitudinal magnetization contrast in spectrally overlapped 3D-MSI metal artifact reduction sequences: Technical considerations and clinical impact. Magn Reson Med 2014; 74:1349-55. [PMID: 25365957 DOI: 10.1002/mrm.25518] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 11/07/2022]
Abstract
PURPOSE It has previously been demonstrated that increased overlap of spectral bins in three-dimensional multispectral imaging techniques (3D-MSI) can aid in reducing residual artifacts near metal implants. However, increasing spectral overlap also necessitates consideration of saturation effects for species with long T1 values. Here, an interleaved spectral bin acquisition strategy is presented for overlapping 3D-MSI that allows for flexible choice of repetition times while simultaneously addressing these cross talk concerns. METHODS A phantom imaging experiment is used to illustrate the amplified effect of cross talk on 3D-MSI acquisitions. A methodological approach to address cross talk across a variety of prescribed repetition times is then described. Using the presented principles, a clinical subject with a total hip replacement was imaged to generate T1, proton density, and short-tau inversion recovery contrasts. In addition, a fracture instrumentation case was imaged pre- and postcontrast using T1-weighted spectrally overlapped 3D-MSI. RESULTS Phantom results demonstrate that conventional spectral interleaving approaches can generate unwanted signal characteristics in heavily overlapped 3D-MSI. Clinical images using the presented methods successfully demonstrate T1, proton density, and inversion recovery image contrasts using heavily overlapped 3D-MSI. CONCLUSIONS Through automated management of spectral bin distributions across multiple interleaves, a variety of longitudinal magnetization contrasts can efficiently be acquired without any clinically relevant cross-talk impact using heavily overlapped 3D-MSI.
Collapse
Affiliation(s)
- Kevin M Koch
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Matthew F Koff
- Hospital for Special Surgery, Magnetic Resonance Imaging, New York, New York, USA
| | - Parina H Shah
- Hospital for Special Surgery, Magnetic Resonance Imaging, New York, New York, USA
| | | | - Dawei Gui
- GE Healthcare, Milwaukee, Wisconsin, USA
| | - Hollis G Potter
- Hospital for Special Surgery, Magnetic Resonance Imaging, New York, New York, USA
| |
Collapse
|
45
|
|
46
|
Bachschmidt TJ, Sutter R, Jakob PM, Pfirrmann CWA, Nittka M. Knee implant imaging at 3 Tesla using high-bandwidth radiofrequency pulses. J Magn Reson Imaging 2014; 41:1570-80. [PMID: 25155582 DOI: 10.1002/jmri.24729] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 08/04/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND To investigate the impact of high-bandwidth radiofrequency (RF) pulses used in turbo spin echo (TSE) sequences or combined with slice encoding for metal artifact correction (SEMAC) on artifact reduction at 3 Tesla in the knee in the presence of metal. METHODS Local transmit/receive coils feature increased maximum B1 amplitude, reduced SAR exposition and thus enable the application of high-bandwidth RF pulses. Susceptibility-induced through-plane distortion scales inversely with the RF bandwidth and the view angle, hence blurring, increases for higher RF bandwidths, when SEMAC is used. These effects were assessed for a phantom containing a total knee arthroplasty. TSE and SEMAC sequences with conventional and high RF bandwidths and different contrasts were tested on eight patients with different types of implants. To realize scan times of 7 to 9 min, SEMAC was always applied with eight slice-encoding steps and distortion was rated by two radiologists. RESULTS A local transmit/receive knee coil enables the use of an RF bandwidth of 4 kHz compared with 850 Hz in conventional sequences. Phantom scans confirm the relation of RF bandwidth and through-plane distortion, which can be reduced up to 79%, and demonstrate the increased blurring for high-bandwidth RF pulses. In average, artifacts in this RF mode are rated hardly visible for patients with joint arthroplasties, when eight SEMAC slice-encoding steps are applied, and for patients with titanium fixtures, when TSE is used. CONCLUSION The application of high-bandwidth RF pulses by local transmit coils substantially reduces through-plane distortion artifacts at 3 Tesla.
Collapse
Affiliation(s)
- Theresa J Bachschmidt
- Department of Experimental Physics 5, University of Wuerzburg, Wuerzburg, Germany.,Magnetic Resonance, Siemens AG, Erlangen, Germany
| | - Reto Sutter
- Department of Radiology, Orthopedic University Hospital Balgrist, Zurich, Switzerland.,University of Zurich, Faculty of Medicine, Zurich, Switzerland
| | - Peter M Jakob
- Department of Experimental Physics 5, University of Wuerzburg, Wuerzburg, Germany
| | - Christian W A Pfirrmann
- Department of Radiology, Orthopedic University Hospital Balgrist, Zurich, Switzerland.,University of Zurich, Faculty of Medicine, Zurich, Switzerland
| | | |
Collapse
|
47
|
Friedrich B, Wostrack M, Ringel F, Ryang YM, Förschler A, Waldt S, Zimmer C, Nittka M, Preibisch C. Novel Metal Artifact Reduction Techniques with Use of Slice-Encoding Metal Artifact Correction and View-Angle Tilting MR Imaging for Improved Visualization of Brain Tissue near Intracranial Aneurysm Clips. Clin Neuroradiol 2014; 26:31-7. [PMID: 25081235 DOI: 10.1007/s00062-014-0324-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 07/17/2014] [Indexed: 11/24/2022]
Abstract
PURPOSE The MR image quality after intracranial aneurysm clipping is often impaired because of artifacts induced by metal implants. The purpose of the present study was to evaluate the benefit of a new WARP sequence with slice-encoding metal artifact correction (SEMAC) and view-angle tilting (VAT) MR imaging as novel artifact reduction techniques. MATERIALS AND METHODS A new WARP TSE (a work-in-progress software package provided by Siemens Healthcare) sequence was implemented for cranial applications based on a turbo spin echo (TSE) sequence. T1- and T2-weighted images with standard and WARP TSE sequences were acquired from 6 patients with 11 clipping sites, and the images were compared based on artifact size and general image quality. RESULTS T2- and T1-weighted WARP TSE sequences resulted in a highly significant reduction of metal artifacts compared with standard sequences (T2w- WARP TSE: 89.8 ± 1.4 %; T1w- WARP TSE: 84.9 ± 2.9 %; p < 0.001) without a substantial loss of image quality. CONCLUSION The use of a new WARP TSE sequence after aneurysm clipping is highly beneficial for increasing the diagnostic MR image quality due to a striking reduction of metal artifacts.
Collapse
Affiliation(s)
- B Friedrich
- Department of Neuroradiology, Klinikum rechts der Isar, Ismaningerstr. 22, 81675, Munich, Germany. .,Department of diagnostic and interventional Radiology, University Hospital Leipzig, Leipzig, Germany.
| | - M Wostrack
- Department of Neurosurgery, Klinikum rechts der Isar, Munich, Germany
| | - F Ringel
- Department of Neurosurgery, Klinikum rechts der Isar, Munich, Germany
| | - Y-M Ryang
- Department of Neurosurgery, Klinikum rechts der Isar, Munich, Germany
| | - A Förschler
- Department of Neuroradiology, Klinikum rechts der Isar, Ismaningerstr. 22, 81675, Munich, Germany
| | - S Waldt
- Department of Radiology, Klinikum rechts der Isar, Munich, Germany
| | - C Zimmer
- Department of Neuroradiology, Klinikum rechts der Isar, Ismaningerstr. 22, 81675, Munich, Germany
| | - M Nittka
- Siemens Healthcare, Erlangen, Germany
| | - C Preibisch
- Department of Neuroradiology, Klinikum rechts der Isar, Ismaningerstr. 22, 81675, Munich, Germany
| |
Collapse
|
48
|
Liebl H, Heilmeier U, Lee S, Nardo L, Patsch J, Schuppert C, Han M, Rondak IC, Banerjee S, Koch K, Link TM, Krug R. In vitro assessment of knee MRI in the presence of metal implants comparing MAVRIC-SL and conventional fast spin echo sequences at 1.5 and 3 T field strength. J Magn Reson Imaging 2014; 41:1291-9. [PMID: 24912802 DOI: 10.1002/jmri.24668] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 05/02/2014] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To assess lesion detection and artifact size reduction of a multiacquisition variable-resonance image combination, slice encoding for metal artifact correction (MAVRIC-SEMAC) hybrid sequence (MAVRIC-SL) compared to standard sequences at 1.5T and 3T in porcine knee specimens with metal hardware. MATERIALS AND METHODS Artificial cartilage and bone lesions of defined size were created in the proximity of titanium and steel screws with 2.5 mm diameter in 12 porcine knee specimens and were imaged at 1.5T and 3T magnetic resonance imaging (MRI) with MAVRIC-SL PD and short T1 inversion recovery (STIR), standard fast spin echo (FSE) T2 PD, and STIR and fat-saturated T2 FSE sequences. Three radiologists blinded to the lesion locations assessed lesion detection rates on randomized images for each sequence using receiver operating characteristic (ROC). Artifact length and width were measured. RESULTS Metal artifact sizes were largest in the presence of steel screws at 3T (FSE T2 FS: 28.7 cm(2) ) and 1.5T (16.03 cm(2) ). MAVRIC-SL PD and STIR reduced artifact sizes at both 3T (1.43 cm(2) ; 2.46 cm(2) ) and 1.5T (1.16 cm(2) ; 1.59 cm(2) ) compared to FS T2 FSE sequences (27.57 cm(2) ; 13.20 cm(2) ). At 3T, ROC-derived AUC values using MAVRIC-SL sequences were significantly higher compared to standard sequences (MAVRIC-PD: 0.87, versus FSE-T2 -FS: 0.73 [P = 0.025]; MAVRIC-STIR: 0.9 vs. T2 -STIR: 0.78 [P = 0.001] and vs. FSE-T2 -FS: 0.73 [P = 0.026]). Similar values were observed at 1.5T. Comparison of 3T and 1.5T showed no significant differences (MAVRIC-SL PD: P = 0.382; MAVRIC-SL STIR: P = 0.071). CONCLUSION MAVRIC-SL sequences provided superior lesion detection and reduced metal artifact size at both 1.5T and 3T compared to conventionally used FSE sequences. No significant disadvantage was found comparing MAVRIC-SL at 3T and 1.5T, although metal artifacts at 3T were larger. J. Magn. Reson. Imaging 2015;41:1291-1299. © 2014 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Hans Liebl
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA; Institut fuer diagnostische und interventionelle Radiologie, Technische Universitaet Muenchen, Munich, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Sveinsson B, Worters PW, Gold GE, Hargreaves BA. Hexagonal undersampling for faster MRI near metallic implants. Magn Reson Med 2014; 73:662-8. [PMID: 24549782 DOI: 10.1002/mrm.25132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 12/20/2013] [Accepted: 12/21/2013] [Indexed: 12/22/2022]
Abstract
PURPOSE Slice encoding for metal artifact correction acquires a three-dimensional image of each excited slice with view-angle tilting to reduce slice and readout direction artifacts respectively, but requires additional imaging time. The purpose of this study was to provide a technique for faster imaging around metallic implants by undersampling k-space. METHODS Assuming that areas of slice distortion are localized, hexagonal sampling can reduce imaging time by 50% compared with conventional scans. This work demonstrates this technique by comparisons of fully sampled images with undersampled images, either from simulations from fully acquired data or from data actually undersampled during acquisition, in patients and phantoms. Hexagonal sampling is also shown to be compatible with parallel imaging and partial Fourier acquisitions. Image quality was evaluated using a structural similarity (SSIM) index. RESULTS Images acquired with hexagonal undersampling had no visible difference in artifact suppression from fully sampled images. The SSIM index indicated high similarity to fully sampled images in all cases. CONCLUSION The study demonstrates the ability to reduce scan time by undersampling without compromising image quality.
Collapse
Affiliation(s)
- Bragi Sveinsson
- Department of Radiology, Stanford University, Stanford, California, USA; Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | | | | | | |
Collapse
|
50
|
den Harder JC, van Yperen GH, Blume UA, Bos C. Ripple artifact reduction using slice overlap in slice encoding for metal artifact correction. Magn Reson Med 2014; 73:318-24. [PMID: 24488701 DOI: 10.1002/mrm.25127] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/18/2013] [Accepted: 12/19/2013] [Indexed: 12/15/2022]
Abstract
PURPOSE Multispectral imaging (MSI) significantly reduces metal artifacts. Yet, especially in techniques that use gradient selection, such as slice encoding for metal artifact correction (SEMAC), a residual ripple artifact may be prominent. Here, an analysis is presented of the ripple artifact and of slice overlap as an approach to reduce the artifact. METHODS The ripple artifact was analyzed theoretically to clarify its cause. Slice overlap, conceptually similar to spectral bin overlap in multi-acquisition with variable resonances image combination (MAVRIC), was achieved by reducing the selection gradient and, thus, increasing the slice profile width. Time domain simulations and phantom experiments were performed to validate the analyses and proposed solution. RESULTS Discontinuities between slices are aggravated by signal displacement in the frequency encoding direction in areas with deviating B0. Specifically, it was demonstrated that ripple artifacts appear only where B0 varies both in-plane and through-plane. Simulations and phantom studies of metal implants confirmed the efficacy of slice overlap to reduce the artifact. CONCLUSION The ripple artifact is an important limitation of gradient selection based MSI techniques, and can be understood using the presented simulations. At a scan-time penalty, slice overlap effectively addressed the artifact, thereby improving image quality near metal implants.
Collapse
Affiliation(s)
- J Chiel den Harder
- Medical Physics Department, Reinier de Graaf Groep, Delft, the Netherlands
| | - Gert H van Yperen
- MRI Technology Development Department, Philips Healthcare, Best, the Netherlands
| | - Ulrike A Blume
- Imaging Systems Department, Philips Healthcare, Hamburg, Germany
| | - Clemens Bos
- Imaging Division, University Medical Center Utrecht, Utrecht, the Netherlands
| |
Collapse
|