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Abesi F. Effect of auto-adaptive metal artifact reduction (aMAR) program in cone-beam computed tomography on assessing pre-implant bone levels. JOURNAL OF ADVANCED PERIODONTOLOGY & IMPLANT DENTISTRY 2024; 16:1-3. [PMID: 39027211 PMCID: PMC11252154 DOI: 10.34172/japid.2024.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 05/18/2024] [Indexed: 07/20/2024]
Abstract
This research aimed to introduce an auto-adaptive metal artifact reduction (aMAR) algorithm in cone-beam computed tomography (CBCT) to assess the levels of the pre-implant alveolar crest. Dental implants as a treatment modality for edentulous patients consist of a titanium alloy, which creates a metal artifact, resulting in a dark dental structure in the CBCT scans. Metallic artifacts are limiting factors for the precise detection in CBCT images. These are related to the dark areas around materials and metallic structures (e.g., restorations, implants, and endodontic instruments). To overcome this problem, the metal artifact reduction (MAR) program has been recommended as a post-procedure stage for CBCT image reconstruction. Recent developments offer CBCT scanners with an aMAR option with a greater dynamic range to help overcome the challenges of peri-implant bone evaluation to reach accurate dental diagnoses.
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Affiliation(s)
- Farida Abesi
- Dental Materials Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
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Henckel J, Ramesh A, Hothi H, Richards R, Di Laura A, Hart A. The accuracy and precision of acetabular implant measurements from CT imaging. Front Bioeng Biotechnol 2023; 11:1150061. [PMID: 37187883 PMCID: PMC10175694 DOI: 10.3389/fbioe.2023.1150061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/17/2023] [Indexed: 05/17/2023] Open
Abstract
The placement of acetabular implant components determines the short- and long-term outcomes of total hip replacement (THR) and a number of tools have been developed to assist the surgeon in achieving cup orientation to match the surgical plan. However, the accuracy and precision of 3D-CT for the measurement of acetabular component position and orientation is yet to be established. To investigate this, we compared measurements of cobalt chrome acetabular components implanted into 2 different bony pelvic models between a coordinate measuring Faro arm and 3 different low dose CT images, including 3D-CT, 2D anterior pelvic plane (APP) referenced CT and 2D scanner referenced (SR) CT. Intra-observer differences were assessed using the Intraclass correlation coefficient (ICC). The effect of imaging the pelvis positioned in 3 different orientations within the CT scanner was also assessed. The measured parameters were the angles of inclination and version. 3D-CT measurements were found to closely match the "true values" of the component position measurements, compared with the 2D-CT methods. ICC analysis also showed good agreement between the coordinate measuring arm (CMA) and 3D-CT but poor agreement between the 2D SR method, in the results from two observers. When using the coordinate system of the CT scanner, the measurements consistently produced the greatest error; this method yielded values up to 34° different from the reference digitising arm. However, the difference between the true inclination and version angles and those measured from 3D APP CT was below half a degree in all cases. We concluded that low radiation dose 3D-CT is a validated reference standard for the measurement of acetabular cup orientation.
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Affiliation(s)
- Johann Henckel
- Royal National Orthopaedic Hospital NHS Trust, Stanmore, United Kingdom
| | - Angelika Ramesh
- Royal National Orthopaedic Hospital NHS Trust, Stanmore, United Kingdom
- Department of Mechanical Engineering, University College London, London, United Kingdom
- *Correspondence: Angelika Ramesh,
| | - Harry Hothi
- Royal National Orthopaedic Hospital NHS Trust, Stanmore, United Kingdom
- Department of Mechanical Engineering, University College London, London, United Kingdom
| | - Robin Richards
- Institute of Orthopaedics and Musculoskeletal Science, University College London, London, United Kingdom
| | - Anna Di Laura
- Royal National Orthopaedic Hospital NHS Trust, Stanmore, United Kingdom
- Department of Mechanical Engineering, University College London, London, United Kingdom
| | - Alister Hart
- Institute of Orthopaedics and Musculoskeletal Science, University College London, London, United Kingdom
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Llopis E, Cerezal L, Auban R, Aguilella L, Piñal FD. Postoperative Imaging of the Wrist and Hand. Magn Reson Imaging Clin N Am 2022; 30:645-671. [DOI: 10.1016/j.mric.2022.03.004] [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]
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Saunders WB, Dejardin LM, Soltys-Niemann EV, Kaulfus CN, Eichelberger BM, Dobson LK, Weeks BR, Kerwin SC, Gregory CA. Angle-stable interlocking nailing in a canine critical-sized femoral defect model for bone regeneration studies: In pursuit of the principle of the 3R’s. Front Bioeng Biotechnol 2022; 10:921486. [PMID: 36118571 PMCID: PMC9479202 DOI: 10.3389/fbioe.2022.921486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 07/19/2022] [Indexed: 11/29/2022] Open
Abstract
Introduction: Critical-sized long bone defects represent a major therapeutic challenge and current treatment strategies are not without complication. Tissue engineering holds much promise for these debilitating injuries; however, these strategies often fail to successfully translate from rodent studies to the clinical setting. The dog represents a strong model for translational orthopedic studies, however such studies should be optimized in pursuit of the Principle of the 3R’s of animal research (replace, reduce, refine). The objective of this study was to refine a canine critical-sized femoral defect model using an angle-stable interlocking nail (AS-ILN) and reduce total animal numbers by performing imaging, biomechanics, and histology on the same cohort of dogs. Methods: Six skeletally mature hounds underwent a 4 cm mid-diaphyseal femoral ostectomy followed by stabilization with an AS-ILN. Dogs were assigned to autograft (n = 3) or negative control (n = 3) treatment groups. At 6, 12, and 18 weeks, healing was quantified by ordinal radiographic scoring and quantified CT. After euthanasia, femurs from the autograft group were mechanically evaluated using an established torsional loading protocol. Femurs were subsequently assessed histologically. Results: Surgery was performed without complication and the AS-ILN provided appropriate fixation for the duration of the study. Dogs assigned to the autograft group achieved radiographic union by 12 weeks, whereas the negative control group experienced non-union. At 18 weeks, median bone and soft tissue callus volume were 9,001 mm3 (range: 4,939–10,061) for the autograft group and 3,469 mm3 (range: 3,085–3,854) for the negative control group. Median torsional stiffness for the operated, autograft treatment group was 0.19 Nm/° (range: 0.19–1.67) and torque at failure was 12.0 Nm (range: 1.7–14.0). Histologically, callus formation and associated endochondral ossification were identified in the autograft treatment group, whereas fibrovascular tissue occupied the critical-sized defect in negative controls. Conclusion: In a canine critical-sized defect model, the AS-ILN and described outcome measures allowed refinement and reduction consistent with the Principle of the 3R’s of ethical animal research. This model is well-suited for future canine translational bone tissue engineering studies.
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Affiliation(s)
- W. B. Saunders
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX, United States
- *Correspondence: W. B. Saunders,
| | - L. M. Dejardin
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - E. V. Soltys-Niemann
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX, United States
| | - C. N. Kaulfus
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX, United States
| | - B. M. Eichelberger
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX, United States
| | - L. K. Dobson
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX, United States
| | - B. R. Weeks
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX, United States
| | - S. C. Kerwin
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX, United States
| | - C. A. Gregory
- Department of Molecular and Cellular Medicine, Institute for Regenerative Medicine, School of Medicine, Texas A & M Health Science Center, College Station, TX, United States
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Reliability and benefits of single-energy projection-based metallic artifact reduction (SEMAR) in the different orthopedic hardware for the hip. Skeletal Radiol 2022; 51:1853-1863. [PMID: 35347404 DOI: 10.1007/s00256-022-04040-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/20/2022] [Accepted: 03/21/2022] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To evaluate the performance and reliability of the single-energy metal artifact reduction (SEMAR) algorithm in patients with different orthopedic hardware at the hips. MATERIALS AND METHODS A total of 153 patients with hip instrumentation who had undergone CT with adaptive iterative dose reduction (AIDR) 3D and SEMAR algorithms between February 2015 and October 2019 were included retrospectively. Patients were divided into 5 groups by the hardware type. Two readers with 21 and 13 years of experience blindly reviewed all image sets and graded the extent of artifacts and imaging quality using 5-point scales. To evaluate reliability, the mean densities and image noises were measured at the urinary bladder, veins, and fat in images with artifacts and the reference images. RESULTS No significant differences were found in the mean densities of the urinary bladder, veins, and fat between the SEMAR images with artifacts (7.57 ± 9.49, 40.29 ± 23.07, 86.78 ± 38.34) and the reference images (7.77 ± 6.2, 40.27 ± 8.66, 89.10 ± 20.70) (P = .860, .994, .392). Image noises of the urinary bladder in the SEMAR images with artifacts (14.25 ± 4.50) and the SEMAR reference images (9.69 ± 1.29) were significantly higher than those in the AIDR 3D reference images (9.11 ± 1.12) (P < .001; P < .001). All AIDR 3D images were non-diagnostic (overall quality ≤ 3) and less than a quarter of the SEMAR images were non-diagnostic (16.7-23.7%), mainly in patients with prostheses [reader 1: 91.7% (22/24); reader 2: 92.6% (25/27)]. CONCLUSION The SEMAR algorithm significantly reduces metal artifacts in CT images, more in patients with internal fixations than in patients with prostheses, and provides reliable attenuation of soft tissues.
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Labrador J, Carrera I, Holdsworth A. Extended Computed Tomography Scale Images Provide a Detailed Assessment of Metal Screws and Are Superior to Standard Computed Tomography Scale Images and Digital Radiography at Detecting Experimentally Induced Screw Fractures In Vitro. Vet Comp Orthop Traumatol 2022; 35:230-238. [PMID: 35705151 DOI: 10.1055/s-0042-1745785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES (1) To compare the ability of standard computed tomography (CT) scale (SCTS) and extended CT scale (ECTS) images, produced using conventional CT technology, to provide detailed assessment of metal screws in vitro. (2) To assess how screw size, type, and orientation relative to the Z-axis of the gantry affect implant assessment. (3) To test the ability of SCTS, ECTS, and radiography to diagnose screw failure when there is negligible screw fragment displacement. STUDY DESIGN Part 1: 12 screws of different size, type, and composition were scanned in three orientations (parallel or 0°; oblique or 45°; and perpendicular or 90°) relative to the Z-axis of the gantry. SCTS and ECTS reconstructions were made for each screw, in each plane, to assess implant shape, structure, and diameter. Part 2: fatigue-failure was induced in four screws commonly used to stabilize canine humeral intracondylar fissures. Screws were then reassembled achieving grossly perfect apposition and alignment of the fragments. Ability to detect implant failure was tested using SCTS, ECTS, and radiography. RESULTS ECTS provided better screw assessment compared with SCTS resulting in clear visualization of the structure in 8/12 versus 0/12 screws and shape in 12/12 versus 11/12 screws; however, results were affected by screw size, type, and orientation. ECTS identified all in vitro screw fractures with negligible screw fragment displacement; however, success was affected by screw orientation: 4/4 fractures identified with a 90° angle, 1/4 for 45°, and 0/4 for 0°. SCTS and radiography did not identify any of them. CONCLUSION The results indicate that ECTS reconstructions are useful for assessment of metal screws and for detection of nondisplaced screw fractures.
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Affiliation(s)
- Jose Labrador
- Diagnostic Imaging Department, Davies Veterinary Specialists, Hitchin, United Kingdom
| | - Ines Carrera
- Willows Referral Centre, Solihull, United Kingdom
| | - Andy Holdsworth
- Diagnostic Imaging Department, Davies Veterinary Specialists, Hitchin, United Kingdom
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Day MA, Ho M, Dibbern K, Rao K, An Q, Anderson DD, Marsh JL. Correlation of 3D Joint Space Width From Weightbearing CT With Outcomes After Intra-articular Calcaneal Fracture. Foot Ankle Int 2020; 41:1106-1116. [PMID: 32648780 PMCID: PMC8162170 DOI: 10.1177/1071100720933891] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Posttraumatic osteoarthritis (PTOA) of the subtalar joint is a serious, disabling, and frequent complication following intra-articular calcaneal fractures (IACFs). Using plain radiographs to assess the subtalar joint for PTOA is imprecise and insensitive, hindering progress toward improving treatment and assessing outcomes. This study explored how low-dose weightbearing computed tomography (WBCT) can be used to provide reliable, quantitative 3D measures of subtalar joint space width (JSW) following IACF and correlated the 3D JSW with clinical outcomes. METHODS After institutional review board approval, 21 patients (15 male; age, 28-70 years) who sustained IACFs and were treated with percutaneous surgical reduction underwent WBCT scans at follow-up visits 2 to 15 years (average, 7.8 years) after surgical treatment. Subtalar joint 3D JSW was computed after a semiautomated protocol was used to segment the talus and calcaneus from the WBCT data. Mean and minimum 3D JSW measurements were calculated and compared with Kellgren-Lawrence (KL) radiographic osteoarthritis grade, RAND-36 Physical (PCS) and Mental (MCS) Component Scores, and visual analog scale (VAS) pain scores. Spearman's rank correlation was used to detect the strength of association between variables, with significance set at P < .05. RESULTS Mean 3D JSW values measured from WBCT for patients with IACFs ranged from 0.9 to 2.5 mm (1.7 ± 0.4 mm) over the entire subtalar joint. Intra- and interrater reliabilities for the WBCT-based JSW measurement technique were 0.95 (95% CI, 0.91-0.97) and 0.97 (95% CI, 0.95-0.98), respectively. Mean and minimum 3D JSW values correlated inversely with VAS pain scores and KL grade (P < .05), particularly in central and posterior subtalar regions. CONCLUSION WBCT-based methods were used to quantify the preservation/loss of JSW in patients with IACFs, enabling more accurate, definitive measurement of subtalar PTOA. The results of this study demonstrate that WBCT can be utilized to objectively assess subtalar PTOA and help us to better understand how arthritic changes affect actual patient experience. LEVEL OF EVIDENCE Level III, prognostic comparative study.
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Affiliation(s)
- Molly A. Day
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA, USA
| | - Michael Ho
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
| | - Kevin Dibbern
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA, USA,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
| | - Karan Rao
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA, USA
| | - Qiang An
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA, USA
| | - Donald D. Anderson
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA, USA,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
| | - J. Lawrence Marsh
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA, USA
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Eriksson T, Maguire GQ, Noz ME, Zeleznik MP, Olivecrona H, Shalabi A, Hänni M. Are low-dose CT scans a satisfactory substitute for stereoradiographs for migration studies? A preclinical test of low-dose CT scanning protocols and their application in a pilot patient. Acta Radiol 2019; 60:1643-1652. [PMID: 31042065 DOI: 10.1177/0284185119844166] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Thomas Eriksson
- Department of Radiology, Centre for Medical Imaging, Uppsala University Hospital, Uppsala, Sweden
| | - Gerald Q Maguire
- School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Kista, Sweden
| | - Marilyn E Noz
- Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Michael P Zeleznik
- School of Computing, College of Engineering, University of Utah, Salt Lake City, UT, USA
| | - Henrik Olivecrona
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Adel Shalabi
- Department of Radiology, Centre for Medical Imaging, Uppsala University Hospital, Uppsala, Sweden
| | - Mari Hänni
- Department of Radiology, Centre for Medical Imaging, Uppsala University Hospital, Uppsala, Sweden
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Baliyan V, Kordbacheh H, Davarpanah AH, Mozafarry A, Sahani DV, Kambadakone A. Orthopedic metallic hardware in routine abdomino-pelvic CT scans: occurrence and clinical significance. Abdom Radiol (NY) 2019; 44:1567-1574. [PMID: 30386880 DOI: 10.1007/s00261-018-1818-3] [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] [Indexed: 11/28/2022]
Abstract
PURPOSE To study the occurrence of orthopedic metallic hardware in routine abdomen/pelvic computed tomography (CT) scans and their impact on image quality (IQ) and diagnostic evaluation. MATERIAL AND METHODS In this retrospective single institution study, we analyzed 3500 consecutive abdomen/pelvis CT scans for occurrence of orthopedic metallic hardware. In the cohort of patients with metallic hardware detected on CT scans, subjective and objective IQ analysis was performed to estimate diagnostic acceptability (DA, 4-point scale), subjective noise (SN, 3-point scale), presence of artifacts (PA, 4-point scale) and objective noise. The clinical significance of metallic hardware was determined by evaluating the impact of artifacts on radiological diagnosis according to the clinical indication and disease type. RESULTS Orthopedic metallic hardware was encountered in 4.97% of abdomino-pelvic CT scans (n = 174/3500), and artifacts related to the hardware in the region of clinical interest were identified in 82% (n = 144/174) of scans. The overall mean DA was 2.66 (n = 174), and it was severely limited (score < 2) in 32% of cases particularly affecting patients with bilateral hip implants (92.6%, n = 25/27). The artifacts due to hardware significantly limited diagnostic evaluation in 58.6% of cases (PA score ≥ 3), and the image noise was unacceptable in 71% of cases (SN score > 2) in the region of clinical interest. CONCLUSION Orthopedic metallic hardware is encountered in nearly 5% of abdomino-pelvic CT scans and causes significant image degradation limiting diagnostic evaluation in the region of clinical interest.
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Affiliation(s)
- Vinit Baliyan
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, White 270, Boston, MA, 02114, USA
| | - Hamed Kordbacheh
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, White 270, Boston, MA, 02114, USA
| | - Amir H Davarpanah
- Department of Radiology and Imaging Sciences, Emory University Hospital, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Amirhossein Mozafarry
- Department of Radiology, Northwestern Memorial Hospital, Northwestern University - Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Dushyant V Sahani
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, White 270, Boston, MA, 02114, USA
| | - Avinash Kambadakone
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, White 270, Boston, MA, 02114, USA.
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Dual-energy CT and ceramic or titanium prostheses material reduce CT artifacts and provide superior image quality of total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2019; 27:1552-1561. [PMID: 29881885 PMCID: PMC6527539 DOI: 10.1007/s00167-018-5001-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Accepted: 05/28/2018] [Indexed: 01/04/2023]
Abstract
PURPOSE To evaluate the influence of different scan parameters for single-energy CT and dual-energy CT, as well as the impact of different material used in a TKA prosthesis on image quality and the extent of metal artifacts. METHODS Eight pairs of TKA prostheses from different vendors were examined in a phantom set-up. Each pair consisted of a conventional CoCr prosthesis and the corresponding anti-allergic prosthesis (full titanium, ceramic, or ceramic-coated) from the same vendor. Nine different (seven dual-energy CT and two single-energy CT) scan protocols with different characteristics were used to determine the most suitable CT protocol for TKA imaging. Quantitative image analysis included assessment of blooming artifacts (metal implants appear thicker on CT than they are, given as virtual growth in mm in this paper) and streak artifacts (thick dark lines around metal). Qualitative image analysis was used to investigate the bone-prosthesis interface. RESULTS The full titanium prosthesis and full ceramic knee showed significantly fewer blooming artifacts compared to the standard CoCr prosthesis (mean virtual growth 0.6-2.2 mm compared to 2.9-4.6 mm, p < 0.001). Dual-energy CT protocols showed less blooming (range 3.3-3.8 mm) compared to single-energy protocols (4.6-5.5 mm). The full titanium and full ceramic prostheses showed significantly fewer streak artifacts (mean standard deviation 77-86 Hounsfield unit (HU)) compared to the standard CoCr prosthesis (277-334 HU, p < 0.001). All dual-energy CT protocols had fewer metal streak artifacts (215-296 HU compared to single-energy CT protocols (392-497 HU)). Full titanium and ceramic prostheses were ranked superior with regard to the image quality at the bone/prosthesis interface compared to a standard CoCr prosthesis, and all dual-energy CT protocols were ranked better than single-energy protocols. CONCLUSIONS Dual-energy CT and ceramic or titanium prostheses reduce CT artifacts and provide superior image quality of total knee arthroplasty at the bone/prosthesis interface. These findings support the use of dual-energy CT as a solid imaging base for clinical decision-making and the use of full-titanium or ceramic prostheses to allow for better CT visualization of the bone-prosthesis interface.
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Eriksson T, Berg P, Olerud C, Shalabi A, Hänni M. Low-dose CT of postoperative pelvic fractures: a comparison with radiography. Acta Radiol 2019; 60:85-91. [PMID: 29665704 DOI: 10.1177/0284185118770919] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Computed tomography (CT) is superior to conventional radiography (CR) for assessing internal fixation of pelvic fractures, but with a higher radiation exposure. Low-dose CT (LDCT) could possibly have a sufficient diagnostic accuracy but with a lower radiation dose. PURPOSE To compare postoperative diagnostic accuracy of LDCT and CR after open reduction and internal fixation of pelvic fracture. MATERIAL AND METHODS Twenty-one patients were examined with LDCT and CR 0-9 days after surgery. The examinations were reviewed by two musculoskeletal radiologists. Hardware, degree of fracture reduction, image quality, and reviewing time were assessed, and effective radiation dose was calculated. Inter-reader agreement was calculated. RESULTS LDCT was significantly better than CR in determining whether hardware positioning was assessable ( P < 0.001). Acetabular congruence was assessable in all fractured patients with LDCT. In 12 of the 32 assessments with CR of patients with an acetabular fracture, joint congruence was not assessable due to overlapping hardware ( P = 0.001). Image quality was significantly higher for LDCT. Median time to review was 240 s for LDCT compared to 180 s for CR. Effective dose was 0.79 mSv for LDCT compared to 0.32 mSv for CR ( P < 0.001). CONCLUSION LDCT is more reliable than CR in assessing hardware position and fracture reduction. Joint congruency is sometimes not possible to assess with CR, due to overlapping hardware. The image quality is higher, but also the effective dose, with LDCT than with CR.
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Affiliation(s)
- Thomas Eriksson
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
| | - Per Berg
- Department of Orthopaedic Surgery, Uppsala University Hospital, Uppsala, Sweden
| | - Claes Olerud
- Department of Orthopaedic Surgery, Uppsala University Hospital, Uppsala, Sweden
| | - Adel Shalabi
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
| | - Mari Hänni
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
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Effect of external fixation rod coupling in computed tomography. Strategies Trauma Limb Reconstr 2018; 13:137-149. [PMID: 30220005 PMCID: PMC6249148 DOI: 10.1007/s11751-018-0318-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022] Open
Abstract
External fixation is a common tool in the treatment of complex fractures, correction of limb deformity, and salvage arthrodesis. These devices typically incorporate radio-opaque metal rods/struts connected at varying distances and orientations between rings. Whilst the predominant imaging modality is plain film radiology, computed tomography (CT) may be performed in order for the surgeon to make a more confident clinical decision (e.g. timing of frame removal, assessment of degree of arthrodesis). We used a fractured sheep leg to systematically assess CT imaging performance with a Discovery CT750 HD CT scanner (GE Healthcare) to show how rod coupling in both traditional Ilizarov and hexapod frames distorts images. We also investigated the role of dual-energy CT (DECT) and metal artefact reduction software (MARS) on the visualisation of the fractured leg. Whilst mechanical reasons predominantly dictate the rod/strut configurations when building a circular frame, rod coupling in CT can be minimised. Firstly, ideally, all or all but one rod can be removed during imaging resulting in no rod coupling. If this is not possible, strategies for configuring the rods to minimise the effect of the rod coupling on the region of interest are demonstrated, e.g., in the case of a four-rod construct, switching the two anterior rods to a more central single one will achieve this goal without particularly jeopardising mechanical strength for a short period. It is also shown that the addition of DECT and MARS results in a reduction of artefacts, but also affects tissue and bone differentiation.
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Application and advantages of monoenergetic reconstruction images for the reduction of metallic artifacts using dual-energy CT in knee and hip prostheses. Radiol Med 2018; 123:593-600. [DOI: 10.1007/s11547-018-0881-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/29/2018] [Indexed: 10/17/2022]
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Queiroz PM, Santaella GM, Groppo FC, Freitas DQ. Metal artifact production and reduction in CBCT with different numbers of basis images. Imaging Sci Dent 2018; 48:41-44. [PMID: 29581948 PMCID: PMC5863018 DOI: 10.5624/isd.2018.48.1.41] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/25/2018] [Accepted: 01/31/2018] [Indexed: 11/18/2022] Open
Abstract
Purpose To evaluate the effect of different numbers of basis images and the use of metal artifact reduction (MAR) on the production and reduction of artifacts in cone-beam computed tomography images. Materials and Methods An acrylic resin phantom with a metal alloy sample was scanned, with 450 or 720 basis images and with or without MAR. Standard deviation values for the test areas (around the metal object) were obtained as a way of measuring artifact production. Two-way analysis of variance was used with a 5% significance level. Results There was no significant difference in artifact production among the images obtained with different numbers of basis images without MAR (P=.985). MAR significantly reduced artifact production in the test areas only in the protocol using 720 basis images (P=.017). The protocol using 450 basis images with MAR showed no significant difference in artifact production when compared to the protocol using 720 basis images with MAR (P=.579). Conclusion Protocols with a smaller number of basis images and with MAR activated are preferable for minimizing artifact production in tomographic images without exposing the patient to a greater radiation dose.
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Affiliation(s)
- Polyane Mazucatto Queiroz
- Department of Oral Diagnosis, Area of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Gustavo Machado Santaella
- Department of Oral Diagnosis, Area of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Francisco Carlos Groppo
- Department of Physiological Sciences, Area of Pharmacology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Deborah Queiroz Freitas
- Department of Oral Diagnosis, Area of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
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Whitmarsh T, Treece GM, Gee AH, Poole KES. An exploratory study into measuring the cortical bone thickness from CT in the presence of metal implants. Int J Comput Assist Radiol Surg 2017; 12:2079-2086. [PMID: 28233167 PMCID: PMC5702383 DOI: 10.1007/s11548-017-1539-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 02/08/2017] [Indexed: 01/30/2023]
Abstract
PURPOSE The aim of this study was to develop and evaluate a method for measuring the cortical bone thickness from computed tomography (CT) scans with metallic implants and to assess the benefits of metal artefact removal software. METHODS A previously validated technique based on the fitting of a cortical model was modified to also model metal structures when required. Cortical thickness measurements were taken over intact bone segments and compared with the corresponding contralateral bone segment. The evaluation dataset includes post-operative CT scans of a unipolar hemi-arthroplasty, a dynamic hip screw fixation, a bipolar hemi-arthroplasty, a fixation with cannulated screws and a total hip arthroplasty. All CT scans were analysed before and after processing with metal artefact removal software. RESULTS Cortical thickness validity and accuracy were improved through the use of a modified metalwork-optimised model and metal artefact removal software. For the proximal femoral segments of the aforementioned cases, the cortical thickness was measured with a mean absolute error of 0.55, 0.39, 0.46, 0.53 and 0.69 mm. The hemi-pelvis produced thickness errors of 0.51, 0.52, 0.52, 0.47 and 0.67 mm, respectively. CONCLUSIONS The proposed method was shown to measure cortical bone thickness in the presence of metalwork at a sub-millimetre accuracy. This new technique might be helpful in assessing fracture healing near implants or fixation devices, and improve the evaluation of periprosthetic bone after hip replacement surgery.
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Affiliation(s)
- Tristan Whitmarsh
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, Cambridgeshire, CB2 1PZ, UK.
| | - Graham M Treece
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, Cambridgeshire, CB2 1PZ, UK
| | - Andrew H Gee
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, Cambridgeshire, CB2 1PZ, UK
| | - Kenneth E S Poole
- Department of Medicine, University of Cambridge, Cambridge, Cambridgeshire, UK
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Alabsi H, Alreshoodi S, Low E, Sultan N, Murray N, Mallinson P, Munk PL, Ouellette HA. Advancements in Dual-Energy CT Applications for Musculoskeletal Imaging. CURRENT RADIOLOGY REPORTS 2017. [DOI: 10.1007/s40134-017-0249-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Behrendt P, Kruse E, Klüter T, Fitschen-Oestern S, Weuster M, Menzdorf L, Finn J, Varoga D, Seekamp A, Müller M, Lippross S. [Fixed angle carbon fiber reinforced polymer composite plate for treatment of distal radius fractures : Pilot study on clinical applications]. Unfallchirurg 2017; 120:139-146. [PMID: 26507986 DOI: 10.1007/s00113-015-0088-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND The clinical implementation of a new carbon-fiber-reinforced polyetheretherketon (PEEK) plate for distal radius fractures might offer advantageous properties over the conventional metallic devices. This includes similar elastic modulus to cortical bone, radiolucency, low artifacts on MRI scans and the lack of metal allergies. OBJECTIVE The aim of this study was to evaluate the clinical results at 6-week and 12-month follow-up using either a new fixed angle (monoaxial) PEEK plate system or a fixed angle (polyaxial) titanium plate. METHODES We included 26 patients (mean age 59.3) with displaced fractures of the distal radius (all AO types). Radiological and functional outcomes were measured prospectively at a 6-week and 12 month follow-up. RESULTS We documented no cases of hardware breakage or significant loss of the surgically achieved fracture reduction with the usage oft the new PEEK device. Operating time was 101.0 min using PEEK versus 109.3 min in titanium plates, recorded times were including preparation, draping, and postoperative processing (ns, p 0.156). At the 6-week follow up the PEEK plate showed a trend for better range of motion and functional results (DASH-score, Mayo-wrist score, VAS) with no statistical significance. Results of 12 month follow up with PEEK showed comparable results with corresponding studies examining titanium plate after this period. CONCLUSION First experience with PEEK plate osteosynthesis demonstrate quick clinical implementation with good clinical outcome and the advantage of excellent postoperative radiological assessment. At early follow-up PEEK even showed a trend for improved functional results.
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Affiliation(s)
- P Behrendt
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland.
| | - E Kruse
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - T Klüter
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - S Fitschen-Oestern
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - M Weuster
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - L Menzdorf
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - J Finn
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - D Varoga
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - A Seekamp
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - M Müller
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
| | - S Lippross
- Klinik für Orthopädie und Unfallchirurgie, UNIVERSITÄTSKLINIKUM Schleswig-Holstein, Campus Kiel, Haus 18, Arnold-Heller-Straße 3, 24105, Kiel, Deutschland
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Sousa Melo SL, Belem MDF, Prieto LT, Tabchoury CPM, Haiter-Neto F. Comparison of cone beam computed tomography and digital intraoral radiography performance in the detection of artificially induced recurrent caries-like lesions. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 124:306-314. [PMID: 28690085 DOI: 10.1016/j.oooo.2017.05.469] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/06/2017] [Accepted: 05/03/2017] [Indexed: 10/19/2022]
Abstract
OBJECTIVES The aim of this study was to compare the performance of cone beam computed tomography (CBCT) and digital radiography in the detection of artificial recurrent caries-like lesions under amalgam and composite fillings. STUDY DESIGN The study included class II cavities in 30 molars that had been filled with amalgam. Fifteen of those molars had the restoration-enamel interface artificially demineralized. Phantoms were prepared, and CBCT images were acquired with 2 units in 3 voxel sizes (K9000, 0.076 mm; i-CAT, 0.2 mm and 0.4 mm). Intraoral radiographs were obtained with 3 systems (Digora, VistaScan, and RVG-6100). Amalgam fillings were then replaced by composite, and new images were obtained. Three examiners assessed all of the images. Sensitivity, specificity, accuracy, and receiver operating characteristic curve were calculated and verified through analysis of variance and the Tukey test. RESULTS There were no significant differences in sensitivity and specificity when the same restorative material was present or when the restorative materials were compared with the imaging technique as a constant. As for accuracy and receiver operating characteristic curve, there were statistically significant differences when the 2 materials were compared, and there were differences in the amalgam group when the imaging modalities were compared. CONCLUSIONS CBCT performed similarly to intraoral radiography in detecting demineralization under restorations. However, the voxel size and the type of restorative material influenced its performance.
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Affiliation(s)
- Saulo Leonardo Sousa Melo
- Clinical Assistant Professor, Department of Oral Pathology, Radiology and Medicine, College of Dentistry, University of Iowa, Iowa City, IA, USA.
| | - Manuella Dias Furtado Belem
- Research Scholar, Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil
| | - Lucia Trazzi Prieto
- Research Scholar, Department of Operative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil
| | - Cinthia Pereira Machado Tabchoury
- Associate Professor, Department of Physiological Sciences, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil
| | - Francisco Haiter-Neto
- Professor, Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil
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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: 125] [Impact Index Per Article: 17.9] [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.
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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
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Osgood GM, Thawait GK, Hafezi-Nejad N, Shakoor D, Shaner A, Yorkston J, Zbijewski WB, Siewerdsen JH, Demehri S. Image quality of cone beam computed tomography for evaluation of extremity fractures in the presence of metal hardware: visual grading characteristics analysis. Br J Radiol 2017; 90:20160539. [PMID: 28281784 DOI: 10.1259/bjr.20160539] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate image quality and interobserver reliability of a novel cone-beam CT (CBCT) scanner in comparison with plain radiography for assessment of fracture healing in the presence of metal hardware. METHODS In this prospective institutional review board-approved Health Insurance Portability and Accountability Act of 1996-complaint study, written informed consent was obtained from 27 patients (10 females and 17 males; mean age 44 years, age range 21-83 years) with either upper or lower extremity fractures, and with metal hardware, who underwent CBCT scans and had a clinical radiograph of the affected part. Images were assessed by two independent observers for quality and interobserver reliability for seven visualization tasks. Visual grading characteristic (VGC) curve analysis determined the differences in image quality between CBCT and plain radiography. Interobserver agreement was calculated using Pearson's correlation coefficient. RESULTS VGC results displayed preference of CBCT images to plain radiographs in terms of visualizing (1) cortical and (2) trabecular bones; (3) fracture line; (4) callus formation; (5) bridging ossification; and (6) screw thread-bone interface and its inferiority to plain radiograph in the visualization of (7) large metallic side plate contour with strong interobserver correlation (p-value < 0.05), except for visualizing large metallic side plate contour. CONCLUSION For evaluation of fracture healing in the presence of metal hardware, CBCT image quality is preferable to plain radiograph for all visualization tasks, except for large metallic side plate contours. Advances in knowledge: CBCT has the potential to be a good diagnostic alternative to plain radiographs in evaluation of fracture healing in the presence of metal hardware.
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Affiliation(s)
- Greg M Osgood
- 1 Department of Orthopedics, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Gaurav K Thawait
- 2 Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Nima Hafezi-Nejad
- 2 Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Delaram Shakoor
- 2 Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Adam Shaner
- 1 Department of Orthopedics, Johns Hopkins Hospital, Baltimore, MD, USA
| | | | - Wojciech B Zbijewski
- 4 Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jeffrey H Siewerdsen
- 4 Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Shadpour Demehri
- 2 Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
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The effects of different restorative materials on the detection of approximal caries in cone-beam computed tomography scans with and without metal artifact reduction mode. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 123:392-400. [DOI: 10.1016/j.oooo.2016.11.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/26/2016] [Accepted: 11/22/2016] [Indexed: 11/20/2022]
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Vasconcelos TV, Bechara BB, McMahan CA, Freitas DQ, Noujeim M. Evaluation of artifacts generated by zirconium implants in cone-beam computed tomography images. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 123:265-272. [DOI: 10.1016/j.oooo.2016.10.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/13/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
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Sandgren B, Skorpil M, Nowik P, Olivecrona H, Crafoord J, Weidenhielm L, Persson A. Assessment of wear and periacetabular osteolysis using dual energy computed tomography on a pig cadaver to identify the lowest acceptable radiation dose. Bone Joint Res 2016; 5:307-13. [PMID: 27445358 PMCID: PMC5005473 DOI: 10.1302/2046-3758.57.2000566] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 03/29/2016] [Indexed: 12/25/2022] Open
Abstract
Objectives Computed tomography (CT) plays an important role in evaluating wear and periacetabular osteolysis (PAO) in total hip replacements. One concern with CT is the high radiation exposure since standard pelvic CT provides approximately 3.5 millisieverts (mSv) of radiation exposure, whereas a planar radiographic examination with three projections totals approximately 0.5 mSv. The objective of this study was to evaluate the lowest acceptable radiation dose for dual-energy CT (DECT) images when measuring wear and periacetabular osteolysis in uncemented metal components. Materials and Methods A porcine pelvis with bilateral uncemented hip prostheses and with known linear wear and acetabular bone defects was examined in a third-generation multidetector DECT scanner. The examinations were performed with four different radiation levels both with and without iterative reconstruction techniques. From the high and low peak kilo voltage acquisitions, polychrmoatic images were created together with virtual monochromatic images of energies 100 kiloelectron volts (keV) and 150 keV. Results We could assess wear and PAO while substantially lowering the effective radiation dose to 0.7 mSv for a total pelvic view with an accuracy of around 0.5 mm for linear wear and 2 mm to 3 mm for PAO. Conclusion CT for detection of prosthetic wear and PAO could be used with clinically acceptable accuracy at a radiation exposure level equal to plain radiographic exposures. Cite this article: B. Sandgren, M. Skorpil, P. Nowik, H. Olivecrona, J. Crafoord, L. Weidenhielm, A. Persson. Assessment of wear and periacetabular osteolysis using dual energy computed tomography on a pig cadaver to identify the lowest acceptable radiation dose. Bone Joint Res 2016;5:307–313. DOI: 10.1302/2046-3758.57.2000566.
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Affiliation(s)
- B Sandgren
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - M Skorpil
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - P Nowik
- Department of Medical Physics, Karolinska University Hospital, Stockholm, Sweden
| | - H Olivecrona
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - J Crafoord
- Department of Radiology, Ersta Hospital, Stockholm, Sweden
| | - L Weidenhielm
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - A Persson
- Center for Medical Image Science and Visualization, Linköping University, Hêlsouniversitetet, Linköping, Sweden
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Metal Artifact Reduction: Added Value of Rapid-Kilovoltage-Switching Dual-Energy CT in Relation to Single-Energy CT in a Piglet Animal Model. AJR Am J Roentgenol 2015; 205:W352-9. [PMID: 26295672 DOI: 10.2214/ajr.14.12547] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE The purpose of this article is to evaluate virtual monochromatic spectral imaging and metal artifact reduction software for reducing metal artifact and to compare it with conventional single-energy CT (SECT) in an animal model. MATERIALS AND METHODS Postmortem juvenile (n = 5) and adult (n = 1) swine specimens were scanned with SECT followed by a dual-energy CT (DECT) pediatric protocol after the insertion of two rods into their paraspinal thoracolumbar regions. Virtual monochromatic spectral images were extrapolated from DECT images at five monoenergetic levels (64, 69, 75, 88, and 105 keV) with and without the use of metal artifact reduction software. Images were evaluated by a 5-point scoring system for the extent of metallic artifacts and image interpretability in soft-tissue and bone windows. The density in the most pronounced artifact was measured. CT dose index was recorded. RESULTS In studies without metal artifact reduction software, higher energy reconstructions resulted in fewer artifacts and better image interpretability in both soft-tissue and bone windows (p < 0.0001). Artifact density decreased from -792 HU at 64 keV to -128 HU at 105 keV without the use of metal artifact reduction software. No difference was noted in attributes' scores or in artifact density in studies using metal artifact reduction software (p > 0.05). DECT studies showed lower scores compared with SECT with regard to all attributes. A new faint perimetallic hypodense halo was seen in all studies with metal artifact reduction software. The CT dose index of DECT was 1.18-3.56 times higher than that of SECT techniques. CONCLUSION DECT at all energy levels with metal artifact reduction software and higher energy extrapolations without metal artifact reduction software reduced metallic artifact and enhanced image interpretability compared with SECT. Radiation dose with DECT could be significantly higher than SECT.
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de Rezende Barbosa GL, Sousa Melo SL, Alencar PNB, Nascimento MCC, Almeida SM. Performance of an artefact reduction algorithm in the diagnosis ofin vitrovertical root fracture in four different root filling conditions on CBCT images. Int Endod J 2015; 49:500-8. [DOI: 10.1111/iej.12477] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 05/26/2015] [Indexed: 11/30/2022]
Affiliation(s)
- G. L. de Rezende Barbosa
- Division of Radiology; Department of Oral Diagnosis; Piracicaba Dental School; University of Campinas; São Paulo Brazil
| | - S. L. Sousa Melo
- Department of Oral Pathology, Radiology and Medicine; University of Iowa College of Dentistry; Iowa City IA USA
| | - P. N. B. Alencar
- Division of Radiology; Department of Oral Diagnosis; Piracicaba Dental School; University of Campinas; São Paulo Brazil
| | - M. C. C. Nascimento
- Division of Radiology; Department of Oral Diagnosis; Piracicaba Dental School; University of Campinas; São Paulo Brazil
| | - S. M. Almeida
- Division of Radiology; Department of Oral Diagnosis; Piracicaba Dental School; University of Campinas; São Paulo Brazil
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Accuracy of fluoroscopy versus computer-assisted navigation for the placement of anterior cervical pedicle screws. Spine (Phila Pa 1976) 2015; 40:E404-10. [PMID: 25599290 DOI: 10.1097/brs.0000000000000786] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Randomized laboratory cadaver study. OBJECTIVE The objective of this study was to determine the accuracy of anterior transpedicular screw placement in the cervical spine using conventional fluoroscopy versus computer-assisted navigation. SUMMARY OF BACKGROUND DATA Traditionally, global cervical instability has required anterior and posterior fixation due to the superior biomechanical stability of circumferential constructs. Anterior transpedicular screws (ATPS) have recently been advocated as a single surgical approach. Current clinical publications report using fluoroscopic guidance for screw placement. Computer-assisted navigation (CAN) systems have demonstrated enhanced accuracy of pedicle screw placement at all spine levels but have not been assessed for ATPS. METHODS The anterior vertebrae of 9 fresh frozen cadaver cervical spines were exposed, preserving the lateral and posterior soft tissue envelope. Nine practicing spine surgeons placed 2.0-mm titanium anterior transpecidular Kirschner wires into the C3-T1 pedicles bilaterally using fluoroscopy or CAN guidance. Specimens were imaged by computed tomography and virtual screws were overlaid on the K-wires. Targeting accuracy was compared between the 2 techniques in all planes using a 5-level grading scale. RESULTS The percentage of acceptable screw placements for fluoroscopy and CAN was 42.6% and 66.7%, respectively (P = 0.012). Catastrophic screw placement (grade 3 or 4) was 33.3% for fluoroscopy and 16.7% for CAN. In the multivariable model, the accuracy rate was 67% lower for fluoroscopy than for CAN after controlling for other factors (odds ratio: 0.33, 95% confidence interval: 0.14-0.79). CONCLUSION The accuracy of CAN-guided placement of K-wires for ATPS was superior to placement under fluoroscopic guidance, demonstrating statistically more acceptable screw placements and significantly less catastrophic virtual screws. However, malposition was still high, with potential for vertebral artery and neurological injury in a clinical setting. Further advancement in current ATPS techniques is warranted prior to widespread implementation in a patient setting. LEVEL OF EVIDENCE N/A.
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Matsuura Y, Kuniyoshi K, Suzuki T, Ogawa Y, Sukegawa K, Rokkaku T, Thoreson AR, An KN, Takahashi K. Accuracy of specimen-specific nonlinear finite element analysis for evaluation of radial diaphysis strength in cadaver material. Comput Methods Biomech Biomed Engin 2014; 18:1811-7. [PMID: 25374112 DOI: 10.1080/10255842.2014.974579] [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] [Indexed: 10/24/2022]
Abstract
The feasibility of a user-specific finite element model for predicting the in situ strength of the radius after implantation of bone plates for open fracture reduction was established. The effect of metal artifact in CT imaging was characterized. The results were verified against biomechanical test data. Fourteen cadaveric radii were divided into two groups: (1) intact radii for evaluating the accuracy of radial diaphysis strength predictions with finite element analysis and (2) radii with a locking plate affixed for evaluating metal artifact. All bones were imaged with CT. In the plated group, radii were first imaged with the plates affixed (for simulating digital plate removal). They were then subsequently imaged with the locking plates and screws removed (actual plate removal). Fracture strength of the radius diaphysis under axial compression was predicted with a three-dimensional, specimen-specific, nonlinear finite element analysis for both the intact and plated bones (bones with and without the plate captured in the scan). Specimens were then loaded to failure using a universal testing machine to verify the actual fracture load. In the intact group, the physical and predicted fracture loads were strongly correlated. For radii with plates affixed, the physical and predicted (simulated plate removal and actual plate removal) fracture loads were strongly correlated. This study demonstrates that our specimen-specific finite element analysis can accurately predict the strength of the radial diaphysis. The metal artifact from CT imaging was shown to produce an overestimate of strength.
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Affiliation(s)
- Yusuke Matsuura
- a Department of Orthopeadic Surgery , Graduate School of Medicine, Chiba University , 1-8-1 Inohana, Chuo-ku , Chiba 260-8670 , Japan
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Spadea MF, Verburg JM, Baroni G, Seco J. The impact of low-Z and high-Z metal implants in IMRT: a Monte Carlo study of dose inaccuracies in commercial dose algorithms. Med Phys 2014; 41:011702. [PMID: 24387494 DOI: 10.1118/1.4829505] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The aim of the study was to evaluate the dosimetric impact of low-Z and high-Z metallic implants on IMRT plans. METHODS Computed tomography (CT) scans of three patients were analyzed to study effects due to the presence of Titanium (low-Z), Platinum and Gold (high-Z) inserts. To eliminate artifacts in CT images, a sinogram-based metal artifact reduction algorithm was applied. IMRT dose calculations were performed on both the uncorrected and corrected images using a commercial planning system (convolution/superposition algorithm) and an in-house Monte Carlo platform. Dose differences between uncorrected and corrected datasets were computed and analyzed using gamma index (Pγ<1) and setting 2 mm and 2% as distance to agreement and dose difference criteria, respectively. Beam specific depth dose profiles across the metal were also examined. RESULTS Dose discrepancies between corrected and uncorrected datasets were not significant for low-Z material. High-Z materials caused under-dosage of 20%-25% in the region surrounding the metal and over dosage of 10%-15% downstream of the hardware. Gamma index test yielded Pγ<1>99% for all low-Z cases; while for high-Z cases it returned 91% < Pγ<1< 99%. Analysis of the depth dose curve of a single beam for low-Z cases revealed that, although the dose attenuation is altered inside the metal, it does not differ downstream of the insert. However, for high-Z metal implants the dose is increased up to 10%-12% around the insert. In addition, Monte Carlo method was more sensitive to the presence of metal inserts than superposition/convolution algorithm. CONCLUSIONS The reduction in terms of dose of metal artifacts in CT images is relevant for high-Z implants. In this case, dose distribution should be calculated using Monte Carlo algorithms, given their superior accuracy in dose modeling in and around the metal. In addition, the knowledge of the composition of metal inserts improves the accuracy of the Monte Carlo dose calculation significantly.
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Affiliation(s)
- Maria Francesca Spadea
- Department of Experimental and Clinical Medicine, University of Magna Graecia, Catanzaro 88100, Italy and Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Joost Mathias Verburg
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Guido Baroni
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, Milano 20133, Italy and Bioengineering Unit, Fondazione CNAO, Pavia 27100, Italy
| | - Joao Seco
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
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Rochkind S, Strauss I, Shlitner Z, Alon M, Reider E, Graif M. Clinical aspects of ballistic peripheral nerve injury: shrapnel versus gunshot. Acta Neurochir (Wien) 2014; 156:1567-75. [PMID: 24898760 DOI: 10.1007/s00701-014-2139-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 05/17/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Ballistic injuries to peripheral nerves pose special challenges in terms of indications, timing and type of surgical intervention. The aim of the present work was to analyze our experience in the surgical treatment of peripheral nerve ballistic injuries with respect to the mechanism of injury (gunshot versus shrapnel), and identify common and dissimilar prognostic factors in both types of injury. METHODS This study was conducted on 42 patients totaling 58 nerves. Twenty-two patients (32 nerves) were injured by gunshot and 20 patients (26 nerves) by shrapnel. Median postoperative follow-up was 33 months (range 12 months to 14 years). RESULTS Overall postoperative outcome appears to be more favorable for gunshot-wound (GSW) patients than shrapnel-injured patients, especially in terms of neuropathic pain relief (75 % vs. 58 % respectively, p < 0.05). Presence of foreign particles in shrapnel injured patients has a negative impact on the surgical outcome in terms of rate of pain improvement (28 % compared to 67 % in patients with and without foreign particles, respectively). Nerve graft reconstruction, rather than neurolysis, seems to be the more beneficial treatment for shrapnel-induced neuropathic pain (100 % vs. 47 % in improvement rate, respectively). Early surgical intervention (median 2 months after injury) significantly relieved neuropathic pain in 83 % of shrapnel-injured patients compared to 58 % in patients operated later. CONCLUSIONS This study suggests that shrapnel injury is more destructive for nerve tissue than gunshot injury. Our impression is that early surgical intervention in shrapnel injuries and split nerve grafting (especially when small fragments are recognized in the nerve) significantly improve the patient's functional activity and quality of life.
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Affiliation(s)
- Shimon Rochkind
- Division of Peripheral Nerve Reconstruction, Tel-Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, 64239, Israel,
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Hirano H. [Current status and future of tomosynthesis: possibilities in orthopedics]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2013; 69:545-546. [PMID: 24046873 DOI: 10.6009/jjrt.2013_jsrt_69.5.545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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Romero-Muñoz LM, Alfonso M, Villas C, Zubieta JL. Effect of brightness in the evaluation of lumbar pedicular screws position: clinical study. Musculoskelet Surg 2013; 97:159-64. [PMID: 23558728 DOI: 10.1007/s12306-013-0248-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 03/13/2013] [Indexed: 11/25/2022]
Abstract
Artifact may lead to confusion when evaluating postoperative CT scans of lumbar pedicle screws. The aim of our study was to develop a specific metal artifact reduction image protocol, in order to reduce metal artifact caused by titanium pedicular screw in patients undergoing lumbar pathology by lumbar fusion. Therefore, the reduction in metal artifacts in lumbar pedicle screws allows surgeons to do an accurate diagnosis of the exact placement of inserted pedicle screws, minimizes false reexploration, and maximizes proper and prompt treatment of misplaced screw. In a first step, we performed a retrospective study of 103 titanium alloy pedicle screws in patients undergoing a lumbar instrumented fusion for treatment for degenerative disease. CT scan was performed postoperatively evaluating the possible overdimension caused by artifact. In a second step, a prospective study was performed using a 64-slice multidetector-row computed tomography (MDCT) in 104 titanium alloy pedicle screws in patients undergoing a lumbar instrumented fusion for treatment for degenerative disease. Our results show that on the group of sequential CT scan, mean overdimension (on each side) due to brightness was 1.045 mm (SD 0.45). On the group of 64-slice multichannel CT, mean overdimension (on each side) due to brightness was 0.005 mm at the proximal part of the screw and 0.025 mm at the distal part of the screw. The results observed suggest that beam-hardening artifacts caused by the screw on CT after lumbar fusion are dramatically reduced by using specific metal artifact reduction image protocol in a 64-slice MDCT.
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Affiliation(s)
- L M Romero-Muñoz
- Department of Orthopedics, University Clinic of Navarra, Avenida de Pio XII, 36, 31008, Pamplona, Navarra, Spain.
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Bechara B, Alex McMahan C, Moore WS, Noujeim M, Teixeira FB, Geha H. Cone beam CT scans with and without artefact reduction in root fracture detection of endodontically treated teeth. Dentomaxillofac Radiol 2013; 42:20120245. [PMID: 23520395 DOI: 10.1259/dmfr.20120245] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Cone beam CT (CBCT) is used widely to depict root fracture (RF) in endodontically treated teeth. Beam hardening and other artefacts due to gutta-percha may increase the time of the diagnosis and result in an incorrect diagnosis. Two CBCT machines, ProMax(®) (Planmeca, Helsinki, Finland) and Master 3D(®) (Vatech, Hwaseong, Republic of Korea), have the option of applying an artefact reduction (AR) algorithm. The aim of this study was to determine whether using an AR algorithm in two CBCT machines enhances the accuracy of detecting RFs in endodontically treated teeth. METHODS 66 roots were collected and decoronated. All roots were treated endodontically using the same technique with gutta-percha and zinc oxide cement. One-half of the roots were randomly selected and fractured using a nail that was tapped gently with a hammer until complete fracture resulted in two root fragments; the two root fragments were glued together with one layer of methyl methacrylate. The roots were placed randomly in eight prepared beef rib fragments. RESULTS The highest accuracy was obtained when the ProMax was used without AR. The lowest accuracy was obtained with the Master 3D when used with AR. For both machines, accuracy was significantly higher without AR than with AR. Both with and without AR, the ProMax machine was significantly more accurate than the Master 3D machine. The same rank ordering was obtained for both sensitivity and specificity. CONCLUSIONS For both machines, AR decreased the accuracy of RF detection in endodontically treated teeth. The highest accuracy was obtained when using the ProMax without AR.
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Affiliation(s)
- B Bechara
- Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
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Lewis M, Reid K, Toms AP. Reducing the effects of metal artefact using high keV monoenergetic reconstruction of dual energy CT (DECT) in hip replacements. Skeletal Radiol 2013; 42:275-82. [PMID: 22684409 DOI: 10.1007/s00256-012-1458-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE The aim of this study was to determine whether high keV monoenergetic reconstruction of dual energy computed tomography (DECT) could be used to overcome the effects of beam hardening artefact that arise from preferential deflection of low energy photons. MATERIALS AND METHODS Two phantoms were used: a Charnley total hip replacement set in gelatine and a Catphan 500. DECT datasets were acquired at 100, 200 and 400 mA (Siemens Definition Flash, 100 and 140 kVp) and reconstructed using a standard combined algorithm (1:1) and then as monoenergetic reconstructions at 10 keV intervals from 40 to 190 keV. Semi-automated segmentation with threshold inpainting was used to obtain the attenuation values and standard deviation (SD) of the streak artefact. High contrast line pair resolution and background noise were assessed using the Catphan 500. RESULTS Streak artefact is progressively reduced with increasing keV monoenergetic reconstructions. Reconstruction of a 400 mA acquisition at 150 keV results in reduction in the volume of streak artefact from 65 cm(3) to 17 cm(3) (74 %). There was a decrease in the contrast to noise ratio (CNR) at higher tube voltages, with the peak CNR seen at 70-80 keV. High contrast spatial resolution was maintained at high keV values. CONCLUSION Monoenergetic reconstruction of dual energy CT at increasing theoretical kilovoltages reduces the streak artefact produced by beam hardening from orthopaedic prostheses, accompanied by a modest increase in heterogeneity of background image attenuation, and decrease in contrast to noise ratio, but no deterioration in high contrast line pair resolution.
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Affiliation(s)
- Mark Lewis
- Norfolk and Norwich University Hospital, Norwich, UK.
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Rodrigues SP, Paiva JM, De Francesco S, Amaral MI, Oliveira FJ, Silva RF. Artifact level produced by different femoral head prostheses in CT imaging: diamond coated silicon nitride as total hip replacement material. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2013; 24:231-239. [PMID: 23053807 DOI: 10.1007/s10856-012-4778-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 09/25/2012] [Indexed: 06/01/2023]
Abstract
Commercial femoral head prostheses (cobalt-chromium alloy, yttria partially stabilized zirconia (Y-PSZ) and alumina) and new silicon nitride ceramic ones (nanocrystalline diamond coated and uncoated) were compared in terms of artifact level production by computed tomography (CT). Pelvis examination by CT allows the correct diagnosis of some pathologies (e.g. prostate and colon cancer) and the evaluation of the prosthesis-bone interface in post-operative joint surgery. Artifact quantification is rarely seen in literature despite having a great potential to grade biomaterials according to their imaging properties. Materials' characteristics (density and effective atomic number), size and geometry of the prostheses can cause more or less artifact. A quantification procedure based on the calculation of four statistical parameters for the Hounsfield pixel values (mean, standard deviation, mean squared error and worst case error) is presented. CT sequential and helical scanning modes were performed. Results prove the artifact reproducibility and indicate that the cobalt-chromium and Y-PSZ are the most artifact-inducing materials, while alumina and silicon nitride (diamond coated and uncoated) ceramic ones present a low level of artifact. Considering the excellent biocompatibility and biotribological behaviour reported in earlier works, combined with the high medical imaging quality here assessed, diamond coated silicon nitride ceramics are arising as new materials for joint replacement.
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Affiliation(s)
- Simone P Rodrigues
- CICECO, Department of Ceramics and Glass Engineering, University of Aveiro, Aveiro, Portugal.
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Ankle post-traumatic osteoarthritis: a CT arthrography study in patients with bi- and trimalleolar fractures. Skeletal Radiol 2012; 41:803-9. [PMID: 22038281 DOI: 10.1007/s00256-011-1292-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 07/09/2011] [Accepted: 09/23/2011] [Indexed: 02/02/2023]
Abstract
PURPOSE To detect radiographically occult cartilage lesions using CT arthrography (CTa) in patients with malleolar fractures treated with open reduction internal fixation and to correlate the lesions with the functional outcome score. MATERIALS AND METHODS Twenty-one patients (13 men and 8 women, mean age 35 years, range 16-55) underwent ankle CTa after a mean postoperative period of 565 days (range 271-756). CTa images were analyzed by two radiologists. Articular surface post-traumatic collapse and subsequent cartilage defects or erosions were recorded in millimeters and in a binary mode (i.e., present if >50% of cartilage thickness) respectively. The functional outcome was assessed using the American Orthopedic Foot and Ankle Society (AOFAS) score by two orthopaedic surgeons. The statistical analysis correlated the AOFAS score with both imaging parameters and was performed with ANOVA using the MedCalc statistical package, version 11.3. RESULTS Of the total of 12 articular surface steps recorded, 2/12 (16.67%) were anterolateral, 4/12 (33.33%) posterolateral, 5/12 (41.67%) anteromedial, and 1/12(8.33%) posteromedial. Of the total of 42 cartilage lesions, 7/42 (16.67%) were anterolateral, 14/42 (33.33%) posterolateral, 12/42 (28.57%) anteromedial, and 9/42 (21.43%) posteromedial. The mean AOFAS score was 8.67 (range 5.95-9.70). There was no statistically significant correlation between the AOFAS score and the post-traumatic internal derangement of the ankle joint (p = 0.524). CONCLUSION CTa detects radiographically silent cartilage lesions in patients with fractures of the ankle joint. There is no correlation of the extent of lesions and the patient's AOFAS score.
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Roth TD, Maertz NA, Parr JA, Buckwalter KA, Choplin RH. CT of the Hip Prosthesis: Appearance of Components, Fixation, and Complications. Radiographics 2012; 32:1089-107. [DOI: 10.1148/rg.324115183] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bechara B, McMahan CA, Geha H, Noujeim M. Evaluation of a cone beam CT artefact reduction algorithm. Dentomaxillofac Radiol 2012; 41:422-8. [PMID: 22362221 DOI: 10.1259/dmfr/43691321] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES An algorithm and software to reduce metal artefact has been developed recently and is available in the Picasso Master 3D® (VATECH, Hwaseong, Republic of Korea), which under visual assessment produces better quality images than were obtainable previously. The objective of this in vitro study was to investigate whether the metal artefact reduction (MAR) algorithm of the Picasso Master 3D machine reduced the incidence of metal artefacts and increased the contrast-to-noise ratio (CNR) while maintaining the same gray value when there was no metallic body present within the scanned volume. METHODS 20 scans with a range of 50-90 kVp were acquired, of which 10 had a metallic bead inserted within a phantom. The images obtained were analysed using public domain software (ImageJ; NIH Image, Bethesda, MD). Area histograms were used to evaluate the mean gray level variation of the epoxy resin-based substitute (ERBS) block and a control area. The CNR was calculated. RESULTS The MAR algorithm increased the CNR when the metallic bead was present; it enhanced the ERBS gray level independently of the presence of the metallic bead. The image quality also improved as peak tube potential was increased. CONCLUSION Improved quality of images and regaining of the control gray values of a phantom were achieved when the MAR algorithm was used in the presence of a metallic bead.
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Affiliation(s)
- B Bechara
- Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
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Bechara BB, Moore WS, McMahan CA, Noujeim M. Metal artefact reduction with cone beam CT: an in vitro study. Dentomaxillofac Radiol 2012; 41:248-53. [PMID: 22241878 DOI: 10.1259/dmfr/80899839] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Metal in a patient's mouth has been shown to cause artefacts that can interfere with the diagnostic quality of cone beam CT. Recently, a manufacturer has made an algorithm and software available which reduces metal streak artefact (Picasso Master 3D® machine; Vatech, Hwaseong, Republic of Korea). OBJECTIVES The purpose of this investigation was to determine whether or not the metal artefact reduction algorithm was effective and enhanced the contrast-to-noise ratio. METHODS A phantom was constructed incorporating three metallic beads and three epoxy resin-based bone substitutes to simulate bone next to metal. The phantom was placed in the centre of the field of view and at the periphery. 10 data sets were acquired at 50-90 kVp. The images obtained were analysed using a public domain software ImageJ (NIH Image, Bethesda, MD). Profile lines were used to evaluate grey level changes and area histograms were used to evaluate contrast. The contrast-to-noise ratio was calculated. RESULTS The metal artefact reduction option reduced grey value variation and increased the contrast-to-noise ratio. The grey value varied least when the phantom was in the middle of the volume and the metal artefact reduction was activated. The image quality improved as the peak kilovoltage increased. CONCLUSION Better images of a phantom were obtained when the metal artefact reduction algorithm was used.
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Affiliation(s)
- B B Bechara
- Department of Oral and Maxilloficial Radiology, University of Texas Health Science Centre at San Antonio, TX, USA.
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Recognition, assessment, and treatment of non-union after surgical fixation of fractures: emphasis on 3D CT. Jpn J Radiol 2011; 30:1-9. [DOI: 10.1007/s11604-011-0006-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 07/31/2011] [Indexed: 02/07/2023]
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Omoumi P, Teixeira P, Lecouvet F, Chung CB. Glenohumeral joint instability. J Magn Reson Imaging 2011; 33:2-16. [PMID: 21182115 DOI: 10.1002/jmri.22343] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Due to the configuration of its bony elements, the glenohumeral joint is the most mobile joint of the body, but also an inherently unstable articulation. Stabilization of the joint is linked to a complex balance between static and dynamic soft tissue stabilizers. Because of complex biomechanics, and the existence of numerous classifications and acronyms to describe shoulder instability lesions, this remains a daunting topic for most radiologists. In this article we provide a brief review of the anatomy of the glenohumeral joint, as well as the classifications and the pathogenesis of shoulder instability. Technical aspects related to the available imaging techniques (including computed tomography [CT] arthrography, magnetic resonance imaging [MRI], and MR arthrography) are reviewed. We then describe the imaging findings related to shoulder instability, focusing on those elements that are important to the clinician.
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Affiliation(s)
- Patrick Omoumi
- Department of Radiology, Cliniques Universitaires Saint Luc, Académie Universitaire de Louvain, Brussels, Belgium
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Amanat N, James NL, McKenzie DR. Welding methods for joining thermoplastic polymers for the hermetic enclosure of medical devices. Med Eng Phys 2010; 32:690-9. [DOI: 10.1016/j.medengphy.2010.04.011] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 02/18/2010] [Accepted: 04/12/2010] [Indexed: 12/01/2022]
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Kataoka ML, Hochman MG, Rodriguez EK, Lin PJP, Kubo S, Raptopolous VD. A Review of Factors That Affect Artifact From Metallic Hardware on Multi-Row Detector Computed Tomography. Curr Probl Diagn Radiol 2010; 39:125-36. [DOI: 10.1067/j.cpradiol.2009.05.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Epidemiology and imaging of the subchondral bone in articular cartilage repair. Knee Surg Sports Traumatol Arthrosc 2010; 18:463-71. [PMID: 20148327 DOI: 10.1007/s00167-010-1053-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Accepted: 01/08/2010] [Indexed: 01/12/2023]
Abstract
Articular cartilage and the subchondral bone act as a functional unit. Following trauma, osteochondritis dissecans, osteonecrosis or osteoarthritis, this intimate connection may become disrupted. Osteochondral defects-the type of defects that extend into the subchondral bone-account for about 5% of all articular cartilage lesions. They are very often caused by trauma, in about one-third of the cases by osteoarthritis and rarely by osteochondritis dissecans. Osteochondral defects are predominantly located on the medial femoral condyle and also on the patella. Frequently, they are associated with lesions of the menisci or the anterior cruciate ligament. Because of the close relationship between the articular cartilage and the subchondral bone, imaging of cartilage defects or cartilage repair should also focus on the subchondral bone. Magnetic resonance imaging is currently considered to be the key modality for the evaluation of cartilage and underlying subchondral bone. However, the choice of imaging technique also depends on the nature of the disease that caused the subchondral bone lesion. For example, radiography is still the golden standard for imaging features of osteoarthritis. Bone scintigraphy is one of the most valuable techniques for early diagnosis of spontaneous osteonecrosis about the knee. A CT scan is a useful technique to rule out a possible depression of the subchondral bone plate, whereas a CT arthrography is highly accurate to evaluate the stability of the osteochondral fragment in osteochondritis dissecans. Particularly for the problem of subchondral bone lesions, image evaluation methods need to be refined for adequate and reproducible analysis. This article highlights recent studies on the epidemiology and imaging of the subchondral bone, with an emphasis on magnetic resonance imaging.
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Abstract
OBJECTIVE The purposes of this retrospective study were to elaborate our experience in postoperative MDCT of tibial plateau fractures, to establish the frequency of these fractures and the indications for MDCT, and to assess the common findings and their clinical importance. MATERIALS AND METHODS A total of 782 knee injuries were imaged with MDCT at a level 1 trauma center over 86 months. A total of 592 knees had a tibial plateau fracture; 381 of these fractures were managed surgically, and postoperative MDCT was performed on 36 of these knees (9%). At postoperative image analysis, an orthopedic surgeon evaluated reduction as good or suboptimal using the first postoperative radiographs. Fracture healing was determined as complete ossification, partial ossification, or nonunion on MDCT images acquired later in follow-up. The MDCT findings were compared with the radiographic findings to assess the usefulness and clinical importance of MDCT. RESULTS The main indications for MDCT were assessment and follow-up of the joint articular surface and evaluation of fracture healing. Orthopedic hardware caused no diagnostic problems at MDCT. Postoperative MDCT revealed additional clinically important information on 29 patients (81%), and 14 patients (39%) underwent reoperation. CONCLUSION Postoperative MDCT of tibial plateau fractures is performed infrequently, even in a large trauma center. When it is performed, however, because of suspicion of increasing articular step-off or fracture nonunion, postoperative MDCT reveals clinically significant information in most cases.
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Value of 3D CT in Defining Skeletal Complications of Orthopedic Hardware in the Postoperative Patient. AJR Am J Roentgenol 2009; 193:1155-63. [DOI: 10.2214/ajr.09.2610] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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von See C, Bormann KH, Schumann P, Goetz F, Gellrich NC, Rücker M. Forensic imaging of projectiles using cone-beam computed tomography. Forensic Sci Int 2009; 190:38-41. [DOI: 10.1016/j.forsciint.2009.05.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 05/08/2009] [Accepted: 05/12/2009] [Indexed: 11/28/2022]
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Abstract
CT arthrography and MR arthrography are accurate methods for the study of surface cartilage lesions and cartilage loss. They also provide information on subchondral bone and marrow changes, and ligaments and meniscal lesions that can be associated with osteoarthritis. Nuclear medicine also offers new insights in the assessment of the disease. This article discusses the strengths and limitations of CT arthrography and MR arthrography. It also highlights nuclear medicine methods that may be relevant to the study of osteoarthritis in research and clinical practice.
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Sabo MT, Pollmann SI, Gurr KR, Bailey CS, Holdsworth DW. Use of co-registered high-resolution computed tomography scans before and after screw insertion as a novel technique for bone mineral density determination along screw trajectory. Bone 2009; 44:1163-8. [PMID: 19233323 DOI: 10.1016/j.bone.2009.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2008] [Revised: 12/24/2008] [Accepted: 02/09/2009] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Bone mineral density (BMD) is an important factor in the examination of the performance of bone instrumentation both in and ex vivo, and until now, there has not existed a reliable technique for determining BMD at the precise location of such hardware. This paper describes such a technique, using cadaveric human sacra as a model. METHODS Nine fresh-frozen sacra had solid and hollow titanium screws placed into the S1 pedicles from a posterior approach. High-resolution micro-computed tomography (CT) was performed on each specimen before and after screw placement. All images were reconstructed with an isotropic spatial resolution of 308 mum, reoriented, and the pre-screw and post-screw scans were registered and transformed using a six-degree rigid-body transformation matrix. Once registered, two points, corresponding to the center of the screw at the cortex and at the screw tip, were determined in each scan. These points were used to generate cylindrical regions of interest (ROI) with the same trajectory and dimensions as the screw. BMD measurements were obtained within each of the ROI in the pre-screw scan. To examine the effect of artefact on BMD measurements around the titanium screws, annular ROI of 1 mm thickness were created expanding from the surface of the screws, and BMD was measured within each in both the pre- and post-screw scans. RESULTS The registration process was accurate to 190 mum, with a precision of 189 mum and error in BMD measurement of +/-2% in repeated scans. BMD values in the cylindrical ROI corresponding to screw trajectories were not statistically different from side to side of each specimen (p=0.23). Metal artefact created significant differences in BMD values (p=0.001) and followed an exponential decay curve as distance from the screws increased, approaching a low value of approximately 20 mg HA cm(-3), but not disappearing completely. SUMMARY CT in the presence of metal creates artefact, making measured BMD values near implants unreliable. This technique is accurate for determination of BMD, non-destructive, and eliminates the problem of this metal artefact through the use of co-registered scans. This technique has applications both in vitro and in vivo.
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Affiliation(s)
- M T Sabo
- Division of Orthopaedics, Department of Surgery, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
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Abul-Kasim K, Overgaard A, Maly P, Ohlin A, Gunnarsson M, Sundgren PC. Low-dose helical computed tomography (CT) in the perioperative workup of adolescent idiopathic scoliosis. Eur Radiol 2008; 19:610-8. [DOI: 10.1007/s00330-008-1178-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 07/13/2008] [Indexed: 10/21/2022]
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