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Ghotra SS, Cottier Y, Bruguier C, Dominguez A, Monnin P, Sá Dos Reis C. A pilot study to identify suitable MRI protocols for preoperative planning of total hip arthroplasty. Eur J Radiol 2024; 178:111620. [PMID: 39029238 DOI: 10.1016/j.ejrad.2024.111620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 06/15/2024] [Accepted: 07/11/2024] [Indexed: 07/21/2024]
Abstract
PURPOSE The purpose of this study is to identify suitable MRI sequences and evaluate the feasibility and performance of MRI for total hip arthroplasty (THA) preoperative planning. METHOD A multicentric pilot study was conducted to evaluate DP TSE and T1 GRE 3D sequences. High-resolution pelvis, hip, knee and ankle images were acquired. Protocols were optimised to enhance image quality (IQ) and reduce acquisition time to fit clinical practice. The final protocol was validated with 19 healthy volunteers with variable BMIs at 1.5 and 3 Tesla. Visual assessment was performed by five radiographers and radiologists using the ViewDEX software. Visual Grading Analysis (VGA), Intraclass Correlation Coefficient (ICC), Prevalence-adjusted and bias-adjusted kappa (PABAK) and Visual Grading Characteristics (VGC) were performed to analyse data. RESULTS VGA scores indicated that the optimised 3D DP TSE and 3D T1 GRE sequences at 3 T, as well as 3D DP TSE sequence at 1.5 T offer adequate IQ and allow a correct visualisation of the anatomy. Overall ICC analysis was moderate to good reliability at 0.749 (95 % CI 0.69-0.79) and increased from good to excellent at 0.846 (95 % CI 0.72-0.91) for DP at 3 T. PABAK shows fair agreement at 0.25 (95 % CI 0.227-0.273). VGC analysis showed that 3D DP TSE sequences performed statistically better than 3D T1 GRE at 1.5 and 3 T (p-value ≤ 0.05). Furthermore, 3 T sequences showed a statistically better performance compared to 1.5 T (p-value ≤ 0.05). CONCLUSIONS According to the results, 3D DP and T1 MRI sequences can be considered for preoperative planning for THA. Further research is required to emphasize the clinical validation of the results.
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Affiliation(s)
- Switinder Singh Ghotra
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne 1011, Switzerland; Department of Radiology, Hospital of Yverdon-les-Bains (eHnv), 1400 Yverdon-les-Bains, Switzerland.
| | - Yann Cottier
- Centre d'Imagerie Diagnostique de Lausanne, Lausanne 1011, Switzerland
| | - Christine Bruguier
- Department of Diagnostic & Interventional Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne 1011, Switzerland; University Center of Legal Medicine Lausanne - Geneva, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne 1011, Switzerland.
| | - Alejandro Dominguez
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne 1011, Switzerland; University Center of Legal Medicine Lausanne - Geneva, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne 1011, Switzerland.
| | - Pascal Monnin
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne 1011, Switzerland.
| | - Cláudia Sá Dos Reis
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne 1011, Switzerland.
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Røhme LAG, Homme THF, Johansen ECK, Schulz A, Aaløkken TM, Johansson E, Johansen S, Mussmann B, Brunborg C, Eikvar LK, Martinsen ACT. Image quality and radiation doses in abdominal CT: A multicenter study. Eur J Radiol 2024; 178:111642. [PMID: 39079322 DOI: 10.1016/j.ejrad.2024.111642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 06/18/2024] [Accepted: 07/22/2024] [Indexed: 08/18/2024]
Abstract
PURPOSE To benchmark image quality and corresponding radiation doses for acute abdominal CT examination across different laboratories and CT manufacturers. METHOD An anthropomorphic phantom was scanned once with local abdominal CT protocols at 40 CT scanners, from four vendors, in thirty-three sites. Quantitative image quality was evaluated by CNR and SNR in the liver and kidney parenchyma. Qualitative image quality was assessed by visual grading analysis performed by three experienced radiologists using a five-point Likert scale to score thirteen image quality criteria. The CTDIvol was recorded for each scan. Pearson's correlation coefficient was calculated for the continuous variables, and the intraclass correlation coefficient was used to investigate interrater reliability between the radiologists. RESULTS CTDIvol ranged from 3.5 to 12 mGy (median 5.3 mGy, third quartile 6.7 mGy). SNR in liver parenchyma ranged from 4.4 to 14.4 (median 8.5), and CNR ranged from 2.7 to 11.2 (median 6.1). A weak correlation was found between CTDIvol and CNR (r = 0.270, p = 0.092). Variations in CNR across scanners at the same dose level CTDIvol were observed. No significant difference in CTDIvol or CNR was found based on scanner installation year. The oldest scanners had a 15 % higher median CTDIvol and a 12 % lower median CNR. The ICC showed acceptable agreement for all dose groups: low (ICC=0.889), medium (ICC=0.767), high (ICC=0.847), and in low (ICC=0.803) and medium (ICC=0.811) CNR groups. CONCLUSION There was large variation in radiation dose and image quality across the different CT scanners. Interestingly, the weak correlation between CTDIvol and CNR indicates that higher doses do not consistently improve CNR, indicating a need for systematic assessment and optimization of image quality and radiation doses for the abdominal CT examination.
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Affiliation(s)
- Linn Andrea Gjerberg Røhme
- Department of Life Sciences and Health, Faculty of Health Science, Oslo Metropolitan University Oslo, Norway.
| | - Tora Hilde Fjeld Homme
- Department of Life Sciences and Health, Faculty of Health Science, Oslo Metropolitan University Oslo, Norway.
| | | | - Anselm Schulz
- Department of Radiology and Nuclear Medicine, Oslo University Hospital, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Trond Mogens Aaløkken
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Radiology and Nuclear Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway.
| | - Ellen Johansson
- Department of Radiology, Drammen Hospital, Vestre Viken Hospital Trust, Norway.
| | - Safora Johansen
- Department of Life Sciences and Health, Faculty of Health Science, Oslo Metropolitan University Oslo, Norway; Department of Cancer Treatment, Oslo University Hospital, Oslo, Norway; Health and Social Science Cluster, Singapore Institute of Technology, Singapore.
| | - Bo Mussmann
- Department of Life Sciences and Health, Faculty of Health Science, Oslo Metropolitan University Oslo, Norway; Department of Radiology, Odense University Hospital, Odense, Denmark; Research and Innovation Unit of Radiology, University of Southern Denmark, Odense, Denmark.
| | - Cathrine Brunborg
- Oslo Centre for Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway.
| | - Lars Kristian Eikvar
- Department of Medicine and Health Services, The South-Eastern Norway Health Authority, Hamar, Norway.
| | - Anne Catrine T Martinsen
- Department of Life Sciences and Health, Faculty of Health Science, Oslo Metropolitan University Oslo, Norway; Centre for Research and Innovation, Sunnaas Rehabilitation Hospital, Bjornemyr, Norway.
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Lorentsson R, Hosseini N, Aurell Y, Collin D, Frösing E, Szaro P, Månsson LG, Båth M. Investigation of the Impact of Defective Ultrasound Transducers on Clinical Image Quality in Grayscale 2-D Still Images. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:2126-2133. [PMID: 37400301 DOI: 10.1016/j.ultrasmedbio.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 05/17/2023] [Accepted: 06/05/2023] [Indexed: 07/05/2023]
Abstract
OBJECTIVE There are several studies that show high defect rates of transducers in clinical use. The purpose of the present study was to investigate whether image quality and the risk for misdiagnosis is affected by using defective transducers. METHODS Four defective transducers with varying degrees of defect severity, still in clinical use, were selected. Forty artifact-affected clinical images from each transducer were compared with images acquired from fully functional transducers, of the same model, in an observer study where four experienced radiologists rated each of the 320 images. The rating tasks included if the artifacts were detectable, if the possible artifacts might affect the diagnosis, how well structural details were reproduced and, finally, an assessment of overall image quality. RESULTS The artifacts in the images were detectable for three of the four transducers (p < 0.05), and in 121 of 640 assessments of the images from the defective transducers the observers were confident that the artifacts could affect the diagnosis. All four faulty transducers were assessed to have decreased ability to resolve structural details (p < 0.05), and three of the four transducers were assessed to have worse overall image quality (p < 0.05). CONCLUSION The present study shows that image quality and the risk of misdiagnosis can be affected by using defective transducers. This highlights the importance of frequent quality control of the transducers to avoid decreased image quality and even misdiagnosis.
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Affiliation(s)
- Robert Lorentsson
- Department of Medical Radiation Sciences, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden.
| | - Nasser Hosseini
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Ylva Aurell
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Radiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - David Collin
- Department of Radiology, Sykehuset Innlandet, Tynset, Norway
| | - Eva Frösing
- Department of Radiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Pawel Szaro
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Radiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Lars Gunnar Månsson
- Department of Medical Radiation Sciences, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Magnus Båth
- Department of Medical Radiation Sciences, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden
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Ludewig E, Rowan C, Schieder K, Frank B. An Overview of Factors Affecting Exposure Level in Digital Detector Systems and their Relevance in Constructing Exposure Tables in Equine Digital Radiography. J Equine Vet Sci 2023; 121:104206. [PMID: 36621702 DOI: 10.1016/j.jevs.2022.104206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
The aim of this review is to describe the steps of constructing exposure tables for use of digital detector systems (DRx) in equine practice. Introductory, selected underlying technical aspects of digital radiography are illustrated. Unlike screen-film radiography (SFR), DRx have a uniform signal response of the detector over a large dose range. This enables generation of diagnostic images from exposures that were previously nondiagnostic on SFR, thus reducing retakes. However, with decreasing detector entrance dose, image noise increasingly hampers the image quality. Conversely, unlike the blackening observed on SFR, overexposures can go visibly undetected by the observer. In DRx the numeric exposure indicator value is the only dose-control tool. In digital radiography the challenge is to reduce the dose and reduce the radiation risk to staff whilst maintaining diagnostic image quality. We provide a stepwise method of developing exposure tables as tools for controlling exposure levels. The identified kVp - mAs combinations in the table are derived from the predefined exposure indicator values of the detector system. Further recommendations are given as to how the exposure indicator can be integrated into routine workflow for rechecking the reliability of the formerly identified settings and how these tables might serve a basis for further reduction of the exposure level. Detector quantum efficiency (DQE) is an important parameter of assessing performance of an imaging system. Detectors with higher DQE can generate diagnostic images with a lower dose, thus having a greater potential for dose reduction than detectors with low DQE.
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Affiliation(s)
- Eberhard Ludewig
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Conor Rowan
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Katrin Schieder
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ben Frank
- Diagnostic Imaging, Department of Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
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Götestrand S, Björkman A, Björkman-Burtscher IM, Ab-Fawaz R, Kristiansson I, Lundin B, Geijer M. Visualization of wrist ligaments with 3D and 2D magnetic resonance imaging at 3 Tesla. Acta Radiol 2022; 63:368-375. [PMID: 33657847 DOI: 10.1177/0284185121994044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Wrist ligaments are challenging to visualize using magnetic resonance imaging (MRI). Injuries involving the scapholunate ligament (SLL), the lunotriquetral ligament (LTL), and the triangular fibrocartilage complex (TFCC) are common and difficult to diagnose, often requiring diagnostic arthroscopy. PURPOSE To compare the visualization of wrist ligaments on a three-dimensional (3D) sequence with two-dimensional (2D) sequences on 3-T MRI. MATERIAL AND METHODS Eighteen healthy volunteers were examined with a 3D SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) sequence and 2D coronal, axial, and sagittal proton density-weighted (PD) sequences. Four musculoskeletal radiologists graded the anatomical visibility of the SLL, LTL, TFCC, and the image quality, using five grades in a visual grading characteristics (VGC) evaluation. After Bonferroni correction, a P value ≤0.005 was considered statistically significant. RESULTS The 3D images were graded significantly better than the 2D images in the visualization of the dorsal and palmar parts of the SLL and the LTL. Regarding the TFCC, the 3D images were graded significantly better for visualization of the foveal attachment. 2D imaging was not found significantly superior to 3D imaging in any aspect. CONCLUSION The 3D SPACE sequence was scored as superior to the 2D sequences at 3 T in the assessment of the SLL, the LTL, and the foveal attachment of the TFCC. Thus, 3D SPACE can replace 2D PD sequences when these ligaments need to be assessed.
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Affiliation(s)
- Simon Götestrand
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
- Department of Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Anders Björkman
- Department of Translational Medicine – Hand Surgery, Skåne University Hospital, Malmö, Sweden
- The Wallenberg Center for Molecular Medicine, Lund University, Sweden
| | - Isabella M Björkman-Burtscher
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Rana Ab-Fawaz
- Department of Radiology, Kristianstad Hospital, Kristianstad, Sweden
- European Telemedicine Clinic, Department of Musculoskeletal Radiology, Barcelona, Spain
| | - Ingvar Kristiansson
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - Björn Lundin
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
- Department of Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Mats Geijer
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Clinical Sciences, Lund University, Lund, Sweden
- Region Västra Götaland, Sahlgrenska University Hospital, Department of Radiology, Gothenburg, Sweden
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Saint J, England A, Ali AM, Bonnett L. The effect of different statistical approaches on image quality data obtained from radiological examinations. Radiography (Lond) 2021; 28:518-523. [PMID: 34848136 DOI: 10.1016/j.radi.2021.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Selection of optimal image acquisition protocols in medical imaging remains a grey area, the superimposed use of the Likert scale in radiological image quality evaluations creates an additional challenge for the statistical analysis of image quality data. Using a simulation study, we have trialled a novel approach to analysing radiological image quality Likert scale data. METHODS A simulation study was undertaken where simulated datasets were generated based on the distribution of Likert scale values according to varying image acquisition protocols from a real dataset. Simulated Likert scale values were pooled in four different ways; the mean, median, mode and the summation of patient Likert scale values of which the total was assigned a categorical Likert scale value. Estimates of bias, MAPE and RMSPE were then calculated for all four pooling approaches to determine which method most accurately represented an expert's opinion. RESULTS When compared to an expert's opinion, the method of summation and categorisation of Likert scale values was most accurate 49 times out of the 114 (43.0%) tests. The mean 28 times out of 114 (24.6%), the median 23 times out of 114 (20.2%) and the mode 17 times out of 114 (14.9%). CONCLUSION We conclude that our method of summation and categorisation of Likert scale values is most often the best representation of the simulated data compared to the expert's opinion. IMPLICATIONS FOR PRACTICE There is scope to reproduce this simulation study with multiple observers to reflect clinical reality more accurately with the dynamic nature of multiple observers. This also prompts future investigation into other anatomical areas, to see if the same methods produce similar results.
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Affiliation(s)
- J Saint
- Department of Biostatistics, University of Liverpool, United Kingdom.
| | - A England
- Directorate of Radiography, University of Salford, United Kingdom
| | - A M Ali
- Directorate of Radiography, University of Salford, United Kingdom
| | - L Bonnett
- Department of Biostatistics, University of Liverpool, United Kingdom
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Nocum DJ, Robinson J, Halaki M, Båth M, Mekiš N, Liang E, Thompson N, Moscova M, Reed W. UTERINE ARTERY EMBOLISATION: CONTINUOUS QUALITY IMPROVEMENT REDUCES RADIATION DOSE WHILE MAINTAINING IMAGE QUALITY. RADIATION PROTECTION DOSIMETRY 2021; 196:159-166. [PMID: 34595527 DOI: 10.1093/rpd/ncab145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/01/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
The purpose of this study was to introduce a continuous quality improvement (CQI) program for radiation dose optimisation during uterine artery embolisation (UAE) and assess its impact on dose reduction and image quality. The CQI program investigated the effects of optimising radiation dose parameters on the kerma-area product (KAP) and image quality when comparing a 'CQI intervention' group (n = 50) and 'Control' group (n = 50). Visual grading characteristics (VGC) analysis was used to assess image quality, using the 'Control' group as a reference. A significant reduction in KAP by 17% (P = 0.041, d = 0.2) and reference air kerma (Ka, r) by 20% (P = 0.027, d = 0.2) was shown between the two groups. The VGC analysis resulted in an area under the VGC curve (AUCVGC) of 0.54, indicating no significant difference in image quality between the two groups (P = 0.670). The implementation of the CQI program and optimisation of radiation dose parameters improved the UAE radiation dose practices at our centre. The dose reduction demonstrated no detrimental effects on image quality.
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Affiliation(s)
- Don J Nocum
- San Radiology & Nuclear Medicine, Sydney Adventist Hospital, Wahroonga, NSW, Australia
- Discipline of Medical Imaging Science, Sydney School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - John Robinson
- Discipline of Medical Imaging Science, Sydney School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
- Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Imaging Science, Sydney School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Mark Halaki
- Discipline of Exercise and Sports Science, Sydney School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Magnus Båth
- Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, SE-413 45 Gothenburg, Sweden
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Nejc Mekiš
- Medical Imaging and Radiotherapy Department, Faculty of Health Sciences, University of Ljubljana, Ljubljana, Slovenia
| | - Eisen Liang
- San Radiology & Nuclear Medicine, Sydney Adventist Hospital, Wahroonga, NSW, Australia
- Sydney Adventist Hospital Clinical School, Faculty of Medicine and Health, University of Sydney, Wahroonga, NSW, Australia
| | - Nadine Thompson
- San Radiology & Nuclear Medicine, Sydney Adventist Hospital, Wahroonga, NSW, Australia
- Sydney Adventist Hospital Clinical School, Faculty of Medicine and Health, University of Sydney, Wahroonga, NSW, Australia
| | - Michelle Moscova
- School of Medical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW, Australia
| | - Warren Reed
- Discipline of Medical Imaging Science, Sydney School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
- Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Imaging Science, Sydney School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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Hettinger E, Aurumskjöld ML, Sartor H, Holmquist F, Svärd D, Timberg P. EVALUATION OF MODEL-BASED ITERATIVE RECONSTRUCTION IN ABDOMINAL COMPUTED TOMOGRAPHY IMAGING AT TWO DIFFERENT DOSE LEVELS. RADIATION PROTECTION DOSIMETRY 2021; 195:205-211. [PMID: 33683328 DOI: 10.1093/rpd/ncab010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/04/2021] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
The purpose of this study was to qualitatively evaluate recently introduced Model-based iterative reconstruction method (IMR) and routinely used iterative reconstruction algorithm iDose4 to investigate future dose reduction possibilities for abdominal CT exams. The study contained data from 34 patients who underwent abdominal CT in SkåneUniversityHospital Lund, Sweden. A low-dose scan (CTDIvol3.4 mGy) reconstructed with both iDose4 and IMR and a standard-dose scan (CTDIvol 5.3 mG) reconstructed with iDose4 alone were visually graded in ViewDEX v2.0 by four radiologists using modified EU image criteria. The visual grading characteristics analysis for the evaluation comparing iDose4 standard dose with IMR low dose did not show any statistically significant difference in five of six criteria. In one of the criteria, iDose4 was superior to IMR. The result show promising possibilities are introduced for substantial radiation dose reduction (35%) in abdominal CT imaging when replacing iDose4 with IMR. Still, care should be taken when considering the reproduction of adrenal glands.
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Affiliation(s)
- E Hettinger
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - M-L Aurumskjöld
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - H Sartor
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
- Diagnostic Radiology, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - F Holmquist
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - D Svärd
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - P Timberg
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
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Sanderink WBG, Teuwen J, Appelman L, Moy L, Heacock L, Weiland E, Sechopoulos I, Mann RM. Diffusion weighted imaging for evaluation of breast lesions: Comparison between high b-value single-shot and routine readout-segmented sequences at 3 T. Magn Reson Imaging 2021; 84:35-40. [PMID: 34560230 DOI: 10.1016/j.mri.2021.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/10/2021] [Accepted: 09/16/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE In this study, we compare readout-segmented echo-planar imaging (rs-EPI) Diffusion Weighted Imaging (DWI) to a work-in-progress single-shot EPI with modified Inversion Recovery Background Suppression (ss-EPI-mIRBS) sequence at 3 T using a b-value of 2000 s/mm2 on image quality, lesion visibility and evaluation time. METHOD From September 2017 to December 2018, 23 women (one case used for training) with known breast cancer were included in this study, after providing signed informed consent. Women were scanned with the conventional rs-EPI sequence and the work-in-progress ss-EPI-mIRBS during the same examination. Four breast radiologists (4-13 years of experience) independently scored both series for overall image quality (1: extremely poor to 9: excellent). All lesions (47 in total, 36 malignant, and 11 benign and high-risk) were evaluated for visibility (1: not visible, 2: visible if location is given, 3: visible) and probability of malignancy (BI-RADS 1 to 5). ADC values were determined by measuring signal intensity in the lesions using dynamic contrast-enhanced (DCE) images for reference. Evaluation times for all assessments were automatically recorded. Results were analyzed using the visual grading characteristics (VGC) and the resulting area under the curve (AUCVGC) method. Statistical analysis was performed in SPSS, with McNemar tests, and paired t-tests used for comparison. RESULTS No significant differences were detected between the two sequences in image quality (AUCVGC: 0.398, p = 0.087) and lesion visibility (AUCVGC: 0.534, p = 0.336) scores. Lesion characteristics (e.g benign and high-risk, versus malignant; small (≤10 mm) vs. larger (>10 mm)) did not result in different image quality or lesion visibility between sequences. Sensitivity (rs-EPI: 72.2% vs. ss-EPImIRBS: 78.5%, p = 0.108) and specificity (70.5% vs. 56.8%, p = 0.210, respectively) were comparable. In both sequences the mean ADC value was higher for benign and high-risk lesions than for malignant lesions (ss-EPI-mIRBS: p = 0.022 and rs-EPI: p = 0.055). On average, ss-EPI-mIRBS resulted in decreased overall reading time by 7.7 s/case (p = 0.067); a reduction of 17%. For malignant lesions, average reading time was significantly shorter using ss-EPI-mIRBS compared to rs-EPI (64.0 s/lesion vs. 75.9 s/lesion, respectively, p = 0.039). CONCLUSION Based on this study, the ss-EPI sequence using a b-value of 2000 s/mm2 enables for a mIRBS acquisition with quality and lesion conspicuity that is comparable to conventional rs-EPI, but with a decreased reading time.
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Affiliation(s)
- Wendelien B G Sanderink
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA Nijmegen, the Netherlands.
| | - Jonas Teuwen
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA Nijmegen, the Netherlands; Department of Radiology, the Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066, CX, Amsterdam, the Netherlands
| | - Linda Appelman
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA Nijmegen, the Netherlands
| | - Linda Moy
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, 4(th) floor, New York, NY 10016, United States
| | - Laura Heacock
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, 4(th) floor, New York, NY 10016, United States
| | - Elisabeth Weiland
- MR Application Predevelopment, Siemens Healthcare, Allee am Roethelheimpark 2, 91052 Erlangen, Germany
| | - Ioannis Sechopoulos
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA Nijmegen, the Netherlands
| | - Ritse M Mann
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA Nijmegen, the Netherlands; Department of Radiology, the Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066, CX, Amsterdam, the Netherlands
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10
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Boita J, van Engen RE, Mackenzie A, Tingberg A, Bosmans H, Bolejko A, Zackrisson S, Wallis MG, Ikeda DM, van Ongeval C, Pijnappel R, Broeders M, Sechopoulos I. Validation of a candidate instrument to assess image quality in digital mammography using ROC analysis. Eur J Radiol 2021; 139:109686. [PMID: 33819803 DOI: 10.1016/j.ejrad.2021.109686] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE To validate a candidate instrument, to be used by different professionals to assess image quality in digital mammography (DM), against detection performance results. METHODS A receiver operating characteristics (ROC) study was conducted to assess the detection performance in DM images with four different image quality levels due to different quality issues. Fourteen expert breast radiologists from five countries assessed a set of 80 DM cases, containing 60 lesions (40 cancers, 20 benign findings) and 20 normal cases. A visual grading analysis (VGA) study using a previously-described candidate instrument was conducted to evaluate a subset of 25 of the images used in the ROC study. Eight radiologists that had participated in the ROC study, and seven expert breast-imaging physicists, evaluated this subset. The VGA score (VGAS) and the ROC and visual grading characteristics (VGC) areas under the curve (AUCROC and AUCVGC) were compared. RESULTS No large differences in image quality among the four levels were detected by either ROC or VGA studies. However, the ranking of the four levels was consistent: level 1 (partial AUCROC: 0.070, VGAS: 6.77) performed better than levels 2 (0.066, 6.15), 3 (0.061, 5.82), and 4 (0.062, 5.37). Similarity between radiologists' and physicists' assessments was found (average VGAS difference of 10 %). CONCLUSIONS The results from the candidate instrument were found to correlate with those from ROC analysis, when used by either observer group. Therefore, it may be used by different professionals, such as radiologists, radiographers, and physicists, to assess clinically-relevant image quality variations in DM.
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Affiliation(s)
- Joana Boita
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands; Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands
| | - Ruben E van Engen
- Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands
| | - Alistair Mackenzie
- National Coordinating Centre for the Physics of Mammography, Royal Surrey NHS Foundation Trust, Guildford, GU2 7XX, UK
| | - Anders Tingberg
- Department of Medical Radiation Physics, Translational Medicine Malmö, Lund University, Skåne University Hospital, Carl Bertil Laurells gata 9, SE-20502 Malmö, Sweden
| | - Hilde Bosmans
- Department of Imaging and Pathology, Radiology, KUL, Herestraat 49, Leuven B-3000, Belgium; Department of Radiology, Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000, Belgium
| | - Anetta Bolejko
- Department of Medical Imaging and Physiology, Translational Medicine Malmö, Lund University, Skåne University Hospital, Carl Bertil Laurells gata 9, SE-20502 Malmö, Sweden
| | - Sophia Zackrisson
- Department of Medical Imaging and Physiology, Translational Medicine Malmö, Lund University, Skåne University Hospital, Carl Bertil Laurells gata 9, SE-20502 Malmö, Sweden
| | - Matthew G Wallis
- Cambridge Breast Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge & NIHR Cambridge Biomedical Research Centre, Cambridge, CB2 0QQ, UK
| | - Debra M Ikeda
- Department of Radiology, Stanford University School of Medicine, 875 Blake Wilbur Dr, Stanford, CA, 94305, USA
| | - Chantal van Ongeval
- Department of Radiology, Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000, Belgium
| | - Ruud Pijnappel
- Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands; Department of Radiology, University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, Utrecht University, the Netherlands
| | - Mireille Broeders
- Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands; Department for Health Evidence, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands
| | - Ioannis Sechopoulos
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands; Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands.
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11
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Sanderink WBG, Teuwen J, Appelman L, Moy L, Heacock L, Weiland E, Karssemeijer N, Baltzer PAT, Sechopoulos I, Mann RM. Comparison of simultaneous multi-slice single-shot DWI to readout-segmented DWI for evaluation of breast lesions at 3T MRI. Eur J Radiol 2021; 138:109626. [PMID: 33711569 DOI: 10.1016/j.ejrad.2021.109626] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/15/2021] [Accepted: 03/01/2021] [Indexed: 01/09/2023]
Abstract
PURPOSE To compare diffusion-weighted imaging of the breast performed with a conventional readout-segmented echo-planar imaging (rs-EPI) sequence to when using a prototype simultaneous multi-slice single-shot EPI (SMS-ss-EPI) acquisition. METHOD From September 2017 to December 2018, 26 women with histologically proven breast cancer were scanned with the conventional rs-EPI and the SMS-ss-EPI at 3 T during the same imaging examination. Four breast radiologists (4-13 years of experience) independently scored both acquired series of 25 women (one case was used for training) for overall image quality (1: extremely poor to 9: excellent) and artifacts (1: very disturbing to 5: not present). All lesions (n = 52; 40 malignant, 12 benign) were also evaluated for visibility (1: not visible, 2: visible if location is given, 3: visible). In addition, lesion characteristics were rated, and a BI-RADS score was given. Results were analyzed using visual grading characteristics and the resulting area under the curve (AUCVGC), weighted kappa, McNemar test, and dependent-samples t-test when appropriate. RESULTS Overall, radiologists significantly preferred the image quality in rs-EPI over that of SMS-ss-EPI (AUCVGC: 0.698, P = 0.002). Infolding and ghosting, and distortion artifacts were significantly less apparent in the rs-EPI (AUCVGC: 0.660, P = 0.022 and AUCVGC: 0.700 P = 0.002, respectively). Lesions were, however, significantly better visible on the SMS-ss-EPI images (AUCVGC: 0.427, P = 0.016). Malignant lesions had significantly higher visibility with SMS-ss-EPI (P = 0.035). Sensitivity and specificity were comparable between both sequences (P = 0.760 and P = 0.549, respectively). CONCLUSIONS Despite the perceived lower image quality and the increased presence of artifacts in the SMS-ss-EPI sequence, malignant lesions are better visualized using this sequence.
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Affiliation(s)
- Wendelien B G Sanderink
- Medical Imaging, Radboud University Medical Centre, Geert Grooteplein Zuid 10, Nijmegen, 6525GA, the Netherlands.
| | - Jonas Teuwen
- Medical Imaging, Radboud University Medical Centre, Geert Grooteplein Zuid 10, Nijmegen, 6525GA, the Netherlands
| | - Linda Appelman
- Medical Imaging, Radboud University Medical Centre, Geert Grooteplein Zuid 10, Nijmegen, 6525GA, the Netherlands
| | - Linda Moy
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, 4(th) Floor, New York, NY, 10016, United States
| | - Laura Heacock
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, 4(th) Floor, New York, NY, 10016, United States
| | - Elisabeth Weiland
- MR Application Predevelopment, Siemens Healthcare, Allee am Roethelheimpark 2, Erlangen, 91052, Germany
| | - Nico Karssemeijer
- Medical Imaging, Radboud University Medical Centre, Geert Grooteplein Zuid 10, Nijmegen, 6525GA, the Netherlands
| | - Pascal A T Baltzer
- Department of Biomedical Imaging and Image-guided Therapy, Vienna General Hospital, Währinger Gürtel 18-20, Vienna, 1090, Austria
| | - Ioannis Sechopoulos
- Medical Imaging, Radboud University Medical Centre, Geert Grooteplein Zuid 10, Nijmegen, 6525GA, the Netherlands
| | - Ritse M Mann
- Medical Imaging, Radboud University Medical Centre, Geert Grooteplein Zuid 10, Nijmegen, 6525GA, the Netherlands
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Hossein M, Reza SM, Jamshid SN. Image quality and dose assessment of collimator slit width effect in SLOT-SCAN X-ray imaging system. Appl Radiat Isot 2021; 171:109642. [PMID: 33631503 DOI: 10.1016/j.apradiso.2021.109642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/07/2021] [Accepted: 02/11/2021] [Indexed: 11/30/2022]
Abstract
The effect of collimator slit width on patient absorbed dose and image quality is evaluated in the SLOT-SCAN imaging system. For this purpose, GATE Monte-Carlo code was used for simulation. To determine contrast to noise ratio (CNR), copper filters with different thicknesses were used and a 2mm lead filter was applied for the determination of the Modulation Transfer Function (MTF) and Detective Quantum Efficiency (DQE). Spatial resolution was determined by using line-pairs per millimeter test. In addition, the anthropomorphic digital Zubal phantom was used to estimate the patient absorbed dose. As the results showed, the CNR shows 77% reduction by decreasing the collimator slit width from 4 mm to 0.4 mm. Other parameters such as DQE and spatial resolution showed to be constant. Finally, whole-body patient absorbed dose estimation resulted in reduction of 14 times using the 0.4 mm collimator slit. The results showed that decreasing the slit width reduced the patient absorbed dose without any significant change in the image quality.
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Affiliation(s)
- Mohammadi Hossein
- Department of Physics, Shahrood University of Technology, Shahrood, Iran.
| | | | - Soltani-Nabipour Jamshid
- Department of Physics, Faculty of Computer and IT, Islamic Azad University Parand Branch, Parand, Iran
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13
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Boita J, Bolejko A, Zackrisson S, Wallis MG, Ikeda DM, Van Ongeval C, van Engen RE, Mackenzie A, Tingberg A, Bosmans H, Pijnappel R, Sechopoulos I, Broeders M. Development and content validity evaluation of a candidate instrument to assess image quality in digital mammography: A mixed-method study. Eur J Radiol 2021; 134:109464. [PMID: 33307458 DOI: 10.1016/j.ejrad.2020.109464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 10/22/2022]
Abstract
PURPOSE To develop a candidate instrument to assess image quality in digital mammography, by identifying clinically relevant features in images that are affected by lower image quality. METHODS Interviews with fifteen expert breast radiologists from five countries were conducted and analysed by using adapted directed content analysis. During these interviews, 45 mammographic cases, containing 44 lesions (30 cancers, 14 benign findings), and 5 normal cases, were shown with varying image quality. The interviews were performed to identify the structures from breast tissue and lesions relevant for image interpretation, and to investigate how image quality affected the visibility of those structures. The interview findings were used to develop tentative items, which were evaluated in terms of wording, understandability, and ambiguity with expert breast radiologists. The relevance of the tentative items was evaluated using the content validity index (CVI) and modified kappa index (k*). RESULTS Twelve content areas, representing the content of image quality in digital mammography, emerged from the interviews and were converted into 29 tentative items. Fourteen of these items demonstrated excellent CVI ≥ 0.78 (k* > 0.74), one showed good CVI < 0.78 (0.60 ≤ k* ≤ 0.74), while fourteen were of fair or poor CVI < 0.78 (k* ≤ 0.59). In total, nine items were deleted and five were revised or combined resulting in 18 items. CONCLUSIONS By following a mixed-method methodology, a candidate instrument was developed that may be used to characterise the clinically-relevant impact that image quality variations can have on digital mammography.
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Affiliation(s)
- Joana Boita
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands; Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands
| | - Anetta Bolejko
- Department of Medical Imaging and Physiology, Translational Medicine Malmö, Lund University, Skåne University Hospital, Carl Bertil Laurells gata 9, SE-20502, Malmö, Sweden
| | - Sophia Zackrisson
- Department of Medical Imaging and Physiology, Translational Medicine Malmö, Lund University, Skåne University Hospital, Carl Bertil Laurells gata 9, SE-20502, Malmö, Sweden
| | - Matthew G Wallis
- Cambridge Breast Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge & NIHR Cambridge Biomedical Research Centre, Cambridge, CB2 0QQ, UK
| | - Debra M Ikeda
- Department of Radiology, Stanford University School of Medicine, 875 Blake Wilbur Dr. Stanford, CA, 94305, USA
| | - Chantal Van Ongeval
- Department of Radiology, Radiology, UZ Gasthuisberg, Herestraat 49, Leuven, B-3000, Belgium
| | - Ruben E van Engen
- Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands
| | - Alistair Mackenzie
- National Coordinating Centre for the Physics of Mammography, Royal Surrey NHS Foundation Trust, Guildford, GU2 7XX, UK
| | - Anders Tingberg
- Department of Medical Radiation Physics, Translational Medicine Malmö, Lund University, Skåne University Hospital, Carl Bertil Laurells gata 9, SE-20502, Malmö, Sweden
| | - Hilde Bosmans
- Department of Radiology, Radiology, UZ Gasthuisberg, Herestraat 49, Leuven, B-3000, Belgium; Department of Imaging and Pathology, Radiology, KUL, Herestraat 49, Leuven, B-3000, Belgium
| | - Ruud Pijnappel
- Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands; Department of Radiology, University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, Utrecht University, the Netherlands
| | - Ioannis Sechopoulos
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands; Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands
| | - Mireille Broeders
- Dutch Expert Centre for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, the Netherlands; Department for Health Evidence, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
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14
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Grob D, Oostveen LJ, Jacobs C, Scholten E, Prokop M, Schaefer-Prokop CM, Sechopoulos I, Brink M. Pulmonary nodule enhancement in subtraction CT and dual-energy CT: A comparison study. Eur J Radiol 2020; 134:109443. [PMID: 33310553 DOI: 10.1016/j.ejrad.2020.109443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/10/2020] [Accepted: 11/25/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To compare nodule enhancement on subtraction CT iodine maps to that on dual-energy CT iodine maps using CT datasets acquired simultaneously. METHODS A previously-acquired set of lung subtraction and dual-energy CT maps consisting of thirty patients with 95 solid pulmonary nodules (≥4 mm diameter) was used. Nodules were annotated and segmented on CT angiography, and mean nodule enhancement in the iodine maps calculated. Three radiologists scored nodule visibility with both techniques on a 4-point scale. RESULTS Mean nodule enhancement was higher (p < 0.001) at subtraction CT (34.9 ± 12.9 HU) than at dual-energy CT (25.4 ± 21.0 HU). Nodule enhancement at subtraction CT was judged more often to be "highly visible" for each observers (p < 0.001) with an area under the curve of 0.81. CONCLUSIONS Subtraction CT is able to depict iodine enhancement in pulmonary nodules better than dual-energy CT.
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Affiliation(s)
- Dagmar Grob
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
| | - Luuk J Oostveen
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
| | - Colin Jacobs
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
| | - Ernst Scholten
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
| | - Mathias Prokop
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
| | - Cornelia M Schaefer-Prokop
- Department of Radiology and Nuclear Medicine, Meander Medical Centre, Maatweg 3, 3813 TZ, Amersfoort, the Netherlands.
| | - Ioannis Sechopoulos
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
| | - Monique Brink
- Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, the Netherlands.
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Enevoldsen S, Kusk MW. Image quality of bedside chest radiographs in intensive care beds with integrated detector tray: A phantom study. Radiography (Lond) 2020; 27:453-458. [PMID: 33158751 DOI: 10.1016/j.radi.2020.10.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/18/2020] [Accepted: 10/19/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Vendors offer intensive care beds with integrated detector trays for bedside radiography, promoting better ergonomics and patient comfort. However, no documentation of the effects on diagnostic image quality has been located. This study examines measured and subjective image quality of supine bedside chest radiographs with and without use of such a detector tray. METHODS A contrast-detail phantom (CDRAD 2.0) was exposed using standard supine chest exposure parameters. Plexiglass plates of 16 and 21 cm were placed in front to simulate patient attenuation for standard and adipose patients. Exposures were repeated with the detector placed in tray and directly in bed. Images were analysed using dedicated software giving a figure-of-merit IQFinv. Results were compared using ANOVA. Then an anthropomorphic chest phantom (Lungman) was exposed using the same parameters, and the same placements of the detector. Exposures were done with and without extra conformal tissue to simulate varying patient sizes, and with and without added typical intensive care equipment. Images were analysed by two radiologists using a three-point scale, on five image quality criteria. Radiologist also stated whether the images were sufficient for diagnosis. Results were compared using Visual Grading Characteristics, using dedicated software, resulting in Areas Under the Curve (AUC-VGC) for each combination and criteria. Inter- and intra-rater reliability were assessed with kappa statistics. Composite Visual Grading Analysis (VGAS) scores were calculated for each image. Both IQFinv and were normalized and compared. RESULTS For all criteria both IQFinv and AUC-VGC was significantly better when exposing the detector directly in bed, than with the detector placed in the tray across all exposures. When stratified into thin and adipose patients, IQFinv decreased significantly for thin patients, while VGAS-scores did not. For adipose patients, both figures were significantly lower with the detector in the tray. CONCLUSION Use of detector tray for bedside chest imaging decreases image quality. IMPLICATIONS FOR PRACTICE Radiographers should critically evaluate image quality and experimentally determine optimal exposure factors, when taking equipment with integrated trays into use.
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Affiliation(s)
- S Enevoldsen
- University Hospital Southwest Denmark, Department of Radiology and Nuclear Medicine, Finsensgade 35, 6700 Esbjerg, Denmark.
| | - M W Kusk
- University Hospital Southwest Denmark, Department of Radiology and Nuclear Medicine, Finsensgade 35, 6700 Esbjerg, Denmark.
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Nitrosi A, Bertolini M, Chendi A, Trojani V, Canovi L, Pattacini P, Iori M. Physical characterization of a novel wireless DRX Plus 3543C using both a carbon nano tube (CNT) mobile x-ray system and a traditional x-ray system. Phys Med Biol 2020; 65:11NT02. [PMID: 32311679 DOI: 10.1088/1361-6560/ab8afb] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work aims to characterize the novel DRX Plus 3543C detector in terms of detective quantum efficiency (DQE) using both a mobile x-ray system called Carestream DRX Revolution Nano and a traditional x-ray system (Carestream DRX Evolution). We used the commercial system DRX Revolution Nano, equipped with a new x-ray source based on CNT technology and field emission (FE) as the electron emitter (cathode). An innovative aspect of this device is its intrinsic selection of the focal spot size. We tested the system using three IEC-specified beam qualities (RQA3, 5 and 7) in terms of modulation transfer function (MTF), normalized noise power spectra (NNPS) and DQE as defined in the IEC 62220-1-1:2015. We compared the results obtained using DRX Revolution Nano and DRX Evolution with correlation and with Bland-Altman plots to study their agreement. RQA3 MTF is slightly lower than the RQA5 and 7 curves between 0.5 and 2.5 cycles mm-1. We measured MTF values of about 0.6 at 1 lp mm-1 and about 0.28 lp mm-1 at 2 lp mm-1. The NNPS curves show a decreasing trend with the energy regarding the DRX Revolution Nano. On the other hand, the DRX Evolution NNPS curve at RQA3 is greater than the one at RQA5, but the one at RQA5 is less than the one at RQA7. The DQE(0) ranged between about 0.82 (DRX Evolution at RQA3) and 0.54 (DRX Evolution at RQA7). As expected, the squared Pearson's correlation coefficients between the two x-ray tubes were always in an optimal agreement, and Bland-Altman plots confirmed a substantial equivalence between the two physical characterizations of the wireless detector. In conclusion, we can show that the dynamic focal selection of the system equipped with CNT does not play a substantial role in image quality compared to a traditional system in terms of physical characterisation of the detector in our measurement conditions.
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Affiliation(s)
- A Nitrosi
- Servizio di Fisica Medica, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
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Lisson CG, Lisson CS, Vogele D, Strauss B, Schuetze K, Cintean R, Beer M, Schmidt SA. Improvement of image quality applying iterative scatter correction for grid-less skeletal radiography in trauma room setting. Acta Radiol 2020; 61:768-775. [PMID: 31569948 DOI: 10.1177/0284185119878348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Iterative reconstruction is well established for CT. Plain radiography also takes advantage of iterative algorithms to reduce scatter radiation and improve image quality. First applications have been described for bedside chest X-ray. A recent experimental approach also provided proof of principle for skeletal imaging. PURPOSE To examine clinical applicability of iterative scatter correction for skeletal imaging in the trauma setting. MATERIAL AND METHODS In this retrospective single-center study, 209 grid-less radiographs were routinely acquired in the trauma room for 12 months, with imaging of the chest (n = 31), knee (n = 111), pelvis (n = 14), shoulder (n = 24), and other regions close to the trunk (n = 29). Radiographs were postprocessed with iterative scatter correction, doubling the number of images. The radiographs were then independently evaluated by three radiologists and three surgeons. A five-step rating scale and visual grading characteristics analysis were used. The area under the VGC curve (AUCVGC) quantified differences in image quality. RESULTS Images with iterative scatter correction were generally rated significantly better (AUCVGC = 0.59, P < 0.01). This included both radiologists (AUCVGC = 0.61, P < 0.01) and surgeons (AUCVGC = 0.56, P < 0.01). The image-improving effect was significant for all body regions; in detail: chest (AUCVGC = 0.64, P < 0.01), knee (AUCVGC = 0.61, P < 0.01), pelvis (AUCVGC = 0.60, P = 0.01), shoulder (AUCVGC = 0.59, P = 0.02), and others close to the trunk (AUCVGC = 0.59, P < 0.01). CONCLUSION Iterative scatter correction improves the image quality of grid-less skeletal radiography in the clinical setting for a wide range of body regions. Therefore, iterative scatter correction may be the future method of choice for free exposure imaging when an anti-scatter grid is omitted due to high risk of tube-detector misalignment.
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Affiliation(s)
- Christoph G Lisson
- Department of Diagnostic and Interventional Radiology, Ulm University Medical Center, Ulm, Germany
| | - Catharina S Lisson
- Department of Diagnostic and Interventional Radiology, Ulm University Medical Center, Ulm, Germany
| | - Daniel Vogele
- Department of Diagnostic and Interventional Radiology, Ulm University Medical Center, Ulm, Germany
| | - Beatrice Strauss
- Department of Orthopedic Trauma, Hand, Plastic and Reconstructive Surgery, Ulm University Medical Center, Ulm, Germany
| | - Konrad Schuetze
- Department of Orthopedic Trauma, Hand, Plastic and Reconstructive Surgery, Ulm University Medical Center, Ulm, Germany
| | - Raffael Cintean
- Department of Orthopedic Trauma, Hand, Plastic and Reconstructive Surgery, Ulm University Medical Center, Ulm, Germany
| | - Meinrad Beer
- Department of Diagnostic and Interventional Radiology, Ulm University Medical Center, Ulm, Germany
| | - Stefan A Schmidt
- Department of Diagnostic and Interventional Radiology, Ulm University Medical Center, Ulm, Germany
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Wilson S, Thompson JD. Comparison of two Meglumine-Diatrizoate based bowel preparations for computed tomography colonography: Comparison of patient symptoms and bowel preparation quality. Radiography (Lond) 2020; 26:e290-e296. [PMID: 32376192 DOI: 10.1016/j.radi.2020.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 02/06/2023]
Abstract
INTRODUCTION To investigate the impact of two Meglumine-Diatrizoate based bowel preparation regimes for computed tomography colonography (CTC) on the patient experience and image quality. METHODS 100 patients consumed Meglumine-Diatrizoate at 24 h and 12 h prior to the CTC examination. 50 patients followed regime 1 (50:50), 50 ml of Meglumine-Diatrizoate at both 24 and 12 h prior to the examination. 50 patients followed regime 2 (75:25), 75 ml of Meglumine-Diatrizoate at 24 h prior to the examination and 25 ml of Meglumine-Diatrizoate at 12 h prior to the examination. All patients completed a questionnaire to indicate the time of onset of adverse effects and when they were most severe. Five advanced practitioners assessed the image quality in a visual grading study. Visual grading characteristic (VGC) analysis was applied with regime 1 as the reference condition and regime 2 and test condition; test alpha was set at 0.05. RESULTS Image quality was assessed with successful bowel cleansing as the scoring criteria for the visual grading study. The bowel cleansing as provided by the two Meglumine-Diatrizoate regimes was revealed not to be statistically different, with the area under the VGC curve and 95% confidence intervals 0.487 (0.287, 0.701), p = 0.887. Patients taking the 75:25 bowel preparation experienced a shorter median time to the onset of adverse effects. CONCLUSION There was no observed difference in Image quality criteria score for the two Meglumine-Diatrizoate based bowel preparation with more predictable adverse effects of Meglumine-Diatrizoate with the 75:25 preparation. IMPLICATIONS FOR PRACTICE Providing patients with a higher contrast burden 24 h prior to CTC may have a positive impact on the patient experience without compromising image quality.
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Affiliation(s)
- S Wilson
- North West Anglia NHS Foundation Trust, North West Anglia NHS Foundation Trust, Peterborough, PE3 9GZ, UK.
| | - J D Thompson
- University of Salford, University of Salford, Manchester, M6 6PU, UK.
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The impact of gonad shielding in anteroposterior (AP) pelvis projections in an adult: A phantom study utilising digital radiography (DR). Radiography (Lond) 2020; 26:240-247. [PMID: 32089492 DOI: 10.1016/j.radi.2020.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/12/2020] [Accepted: 01/17/2020] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Positioning relative to the lateral automatic exposure control (AEC) chambers (cranial/caudal orientation) optimises dose and image quality in pelvic radiography. In the cranial orientation introducing gonad shielding (GS) in females may increase radiation dose. The aim of this study was to fully optimise the combination of pelvis orientation and use of GS in both male and females. METHODS An anthropomorphic pelvis phantom was exposed, with dose area product (DAP) recorded, in both orientations without GS and four conditions with GS: cranial orientation (female/male), caudal orientation (female/male). A 4 cm × 4 cm grid incorporating thirteen positions for the GS resulted in 52 experimental settings. Blind image quality assessment, utilising a modified scale, was undertaken by two experienced observers. RESULTS Comparing no GS (caudal orientation) to female GS, no significant change in DAP was seen (3.97 v 4.03 dGy*cm2; Mann-Whitney p = 0.060). Comparing no GS (cranial orientation) to male GS no significant change in DAP was seen (8.66 v 8.77 dGy*cm2; Mann-Whitney; p = 0.210). DAP increased significantly with introduction of female GS in the cranial orientation (23%: 8.66 v 10.65 dGy*cm2, Mann-Whitney; p < 0.001) and male GS in the caudal orientation (22.8%: 3.97 v 4.87 dGy*cm2, Mann-Whitney; p < 0.001). Significantly higher repeat rates (Chi-squared test; p < 0.001) were seen for GS in female (85-100%) compared to male (30.8%). CONCLUSION The use of gonad shielding can increase DAP and lead to repeats being required, with more required for female GS usage, suggesting the utility of GS for pelvis examinations is questionable. IMPLICATIONS FOR PRACTICE Optimisation of radiation dose in pelvic radiographic examinations utilising AEC terminated exposures requires consideration of AEC chamber position and GS usage.
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Mohammed Ali A, Hogg P, England A. Dose optimisation in paediatric radiography – Using regression models to investigate the relative impact of acquisition factors on image quality and radiation dose. Phys Med 2019; 68:61-68. [DOI: 10.1016/j.ejmp.2019.10.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 10/20/2019] [Accepted: 10/21/2019] [Indexed: 11/27/2022] Open
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Svenson B, Båth M, Karlsson R, Persson B. A comparison of perceived diagnostic image quality in direct digital panoramic images between standard and advanced external GOP image processing. Acta Odontol Scand 2019; 77:560-565. [PMID: 31146623 DOI: 10.1080/00016357.2019.1618912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Objective: The objective of the present study was to study the effect of adaptive image processing (GOP processing) on the visibility of anatomical structures in direct digital panoramic images. Material and methods: The study comprised panoramic images of 50 consecutive adult individuals aged 18-60 years. Nine dentists working with dental radiology compared the structural image quality of all standard-processed and GOP-processed panoramic images for six anatomical structures, using a six-point scale for visual grading characteristics analysis. Results: For all anatomic structures a statistically significant difference in favour of the GOP was found. Conclusions: The present study shows that it is possible to improve perceived diagnostic image quality of direct digital panoramic radiography using GOP technology compared to the manufacturers' standard processing. Manufacturers' image-processing programs can be further developed, as there is a possibility of improving the perceived diagnostic content of an image with external processing.
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Affiliation(s)
- Björn Svenson
- Department of Dental Research, Postgraduate Dental Education Center, Örebro, Sweden
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden
| | - Magnus Båth
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Radiation Physics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Reet Karlsson
- Department of Radiology, Skaraborg Hospital Skövde, Skövde, Sweden
| | - Bo Persson
- Department of Radiology, Skaraborg Hospital Skövde, Skövde, Sweden
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Mohammed Ali A, Hogg P, Abuzaid M, England A. Impact of acquisition parameters on dose and image quality optimisation in paediatric pelvis radiography-A phantom study. Eur J Radiol 2019; 118:130-137. [PMID: 31439232 DOI: 10.1016/j.ejrad.2019.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 05/25/2019] [Accepted: 07/13/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE Within paediatric pelvis imaging there is a lack of systematic dose optimisation studies which consider age and size variations. This paper presents data from dose optimisation studies using digital radiography and pelvis phantoms representing 1 and 5-year-old children. MATERIAL AND METHOD Dose optimisation included assessments of image quality and radiation dose. Systematic variations using a factorial design for acquisition factors (kVp, mAs, source-detector distance [SDD] and filtration) were undertaken to acquire AP pelvis X-ray images. Perceptual image quality was assessed using a relative and absolute visual grading assessment (VGA) method. Radiation doses were measured by placing a dosimeter at the radiographic centring point on the surface of each phantom. Statistical analyses for determining the optimised parameters included main effects analysis. RESULTS Optimised techniques, with diagnostically acceptable image quality, for each paediatric age were: 1-year-old; 65 kVp, 2 mAs and 115 cm SDD, while, 5-year-old; 62 kVp, 8 mAs and 130 cm SDD both included 1 mm Al +0.1 mm Cu additional filtration. The main effect analysis identified situations in which image quality and radiation dose increased or decreased, except for kVp which showed peak image quality when exposure factors were increased. A set of minimum mAs values for producing diagnostic image quality were identified. Increasing SDD, unlike the other exposure factors, showed no trends for producing non-diagnostic images. CONCLUSION The factorial design provided an opportunity to identify suitable acquisition factors. This study provided a method for investigating the combined effect of multiple acquisition parameters on image quality and radiation dose for children.
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Affiliation(s)
- Ali Mohammed Ali
- School of Health Sciences, University of Salford, Salford, M6 6PU, United Kingdom.
| | - Peter Hogg
- School of Health Sciences, University of Salford, Salford, M6 6PU, United Kingdom.
| | - Mohamed Abuzaid
- College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.
| | - Andrew England
- School of Health Sciences, University of Salford, Salford, M6 6PU, United Kingdom.
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Precht H, Hansson J, Outzen C, Hogg P, Tingberg A. Radiographers' perspectives' on Visual Grading Analysis as a scientific method to evaluate image quality. Radiography (Lond) 2019; 25 Suppl 1:S14-S18. [PMID: 31481182 DOI: 10.1016/j.radi.2019.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Radiographers routinely undertake many initiatives to balance image quality with radiation dose (optimisation). For optimisation studies to be successful image quality needs to be carefully evaluated. Purpose was to 1) discuss the strengths and limitations of a Visual Grading Analysis (VGA) method for image quality evaluation and 2) to outline the method from a radiographer's perspective. METHODS A possible method for investigating and discussing the relationship between radiographic image quality parameters and the interpretation and perception of X-ray images is the VGA method. VGA has a number of advantages such as being low cost and a detailed image quality assessment, although it is limited to ensure the images convey the relevant clinical information and relate the task based radiography. RESULTS Comparing the experience of using VGA and Receiver Operating Characteristic (ROC) it is obviously that less papers are published on VGA (Pubmed n=1.384) compared to ROC (Pubmed n=122.686). Hereby the scientific experience of the VGA method is limited compared to the use of ROC. VGA is, however, a much newer method and it is slowly gaining more and more attention. CONCLUSION The success of VGA requires a number of steps to be completed, such as defining the VGA criteria, choosing the VGA method (absolute or relative), including observers, finding the best image display platforms, training observers and selecting the best statistical method for the study purpose should be thoroughly considered. IMPLICATION FOR PRACTICE Detailed evaluation of image quality for optimisation studies related to technical definition of image quality.
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Affiliation(s)
- H Precht
- Conrad Research Programme, University College Lillebelt, Niels Bohrs Alle 1, 5230, Odense M, Denmark; Medical Research Department, Odense University Hospital, Baagøes Àlle 15, 5700, Svendborg, Denmark; Department of Clinical Research, University of Southern Denmark, Winsløwsparken, 5000, Odense C, Denmark.
| | - J Hansson
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45, Gothenburg, Sweden; Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - C Outzen
- Conrad Research Programme, University College Lillebelt, Niels Bohrs Alle 1, 5230, Odense M, Denmark
| | - P Hogg
- School of Health and Society, University of Salford, Manchester, UK
| | - A Tingberg
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Sweden; Skåne University Hospital, 205 02, Malmö, Sweden
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Bergamino C, Hoey S, Waller K, Skelly C. Comparison of T1wFLAIR and T1wTSE sequences in imaging the brain of small animals using high-field MRI. Ir Vet J 2019; 72:6. [PMID: 31312432 PMCID: PMC6612133 DOI: 10.1186/s13620-019-0145-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/01/2019] [Indexed: 11/14/2022] Open
Abstract
Background T1w turbo spin echo (TSE) represents a fundamental sequence in magnetic resonance imaging (MRI) protocols investigating the brain. Recent human literature has reported T1w Fluid Attenuated Inversion Recovery’s (FLAIR’s), superiority to T1wTSE in relation to tissue contrast for grey-to-white matter (GM-WM) and lesion-to-WM, although conflicting results are reported concerning lesion detection. To the author’s knowledge, T1wFLAIR has not been investigated in veterinary medicine. The aim of this prospective study was to determine quantitatively and qualitatively which sequence provides better overall better image quality both pre- and post-gadolinium. Results Twenty-eight animals underwent MRI of the brain with T1wTSE and T1wFLAIR sequences performed with equivalent mean acquisition times. Quantitative assessment of the sequences was undertaken using contrast-to-noise (CNR) and signal-to-noise (SNR) ratios from predefined locations. T1wFLAIR provided a better CNR compared to T1wTSE, while T1wTSE provided better SNR due to the higher noise levels of T1wFLAIR images. Qualitative assessment of the sequences was performed using Visual Grading Analysis Scoring (VGAS) for a number of criteria by three observers on two separate occasions. T1wFLAIR performed better for cerebrospinal fluid (CSF) suppression, white-to-grey matter (WM-GM) and white matter-to-CSF (WM-to-CSF) definition in both pre- and post-contrast images whereas the T1wTSE sequence was less affected by noise levels. The individual parameter for overall image quality found no significant difference between the two sequences. However, the composite VGAS favored T1wFLAIR as the preferred sequence. Although case numbers were insufficient for statistical analysis, comparison of the sequences indicates that lesion definition and margination was better in T1wFLAIR pre-contrast images, however post-contrast lesion detection was almost equivalent between sequences with slightly better margination in the T1wTSE sequence. Conclusions T1wFLAIR provides better CNR with better WM-GM and WM-CSF definition both pre- and post-contrast compared to T1wTSE albeit with a higher degree of noise; this was confirmed both quantitatively and qualitatively. Our results also suggest that T1wFLAIR is better for lesion detection and margination pre-contrast administration and sequences are relatively equivocal post-gadolinium administration although further research is required to determine the benefit that inversion recovery sequences make when investigating brain lesions in small animal MRI.
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Affiliation(s)
- Chiara Bergamino
- 1School of Veterinary Medicine Teaching Hospital, University College Dublin, Belfield, Dublin Ireland
| | - Séamus Hoey
- 1School of Veterinary Medicine Teaching Hospital, University College Dublin, Belfield, Dublin Ireland
| | - Kenneth Waller
- 2Department of Surgical Sciences, University of Wisconsin, Madison, WI 53706 USA
| | - Cliona Skelly
- 1School of Veterinary Medicine Teaching Hospital, University College Dublin, Belfield, Dublin Ireland
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Svenson B, Båth M, Karlsson R. Can adaptive post-processing of storage phosphor plate panoramic radiographs provide better image quality? A comparison of anatomical image quality of panoramic radiographs before and after adaptive processing. Acta Odontol Scand 2019; 77:328-333. [PMID: 30623704 DOI: 10.1080/00016357.2018.1556801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE The objective of the present study was to study the effect of adaptive image processing on the visibility of anatomical structures in storage phosphor plate (SPP) panoramic images. MATERIALS AND METHODS Three hundred SPP panoramic X-ray radiographs of children and adolescents were used. The radiographs were post-processed using general operator processor (GOP) technology, resulting in both a standard-processed and a GOP-processed radiograph. Four specialists in dental radiology compared the structural image quality of all standard-processed and GOP-processed panorama images for six anatomical structures, using a six-point scale for visual grading characteristics (VGC) analysis. RESULTS For three of the anatomic structures - the root canal space of the mandibular left first premolar, mandibular canal left side and periodontal ligament space of the mandibular right first molar - there was a statistically significant difference to the GOP's advantage. For the three remaining structures - dentino-enamel junction of the maxillary right first molar, crista alveolaris of the mandibular left molar area and floor of maxillary sinus right side - no significant difference between standard processing and GOP processing was obtained. CONCLUSIONS The study demonstrates that it is possible to improve the quality of SPP radiographs and the visibility of anatomical structures by using the GOP technique. Manufacturers' image-processing programs can be further developed, as there is a possibility of improving the diagnostic content of an image with external processing.
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Affiliation(s)
- Björn Svenson
- Dental Research Department, Postgraduate Dental Education Center, Örebro, Sweden
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden
| | - Magnus Båth
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Radiation Physics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Reet Karlsson
- Department of Radiology, Skaraborg Hospital, Skövde, Sweden
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Konst B, Weedon-Fekjaer H, Båth M. Image quality and radiation dose in planar imaging - Image quality figure of merits from the CDRAD phantom. J Appl Clin Med Phys 2019; 20:151-159. [PMID: 31152576 PMCID: PMC6612684 DOI: 10.1002/acm2.12649] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 03/25/2019] [Accepted: 05/04/2019] [Indexed: 12/24/2022] Open
Abstract
Purpose A contrast‐detail phantom such as CDRAD is frequently used for quality assurance, optimization of image quality, and several other purposes. However, it is often used without considering the uncertainty of the results. The aim of this study was to assess two figure of merits (FOM) originating from CDRAD regarding the variations of the FOMs by dose utilized to create the x‐ray image. The probability of overlapping (assessing an image acquired at a lower dose as better than an image acquired at a higher dose) was determined. Methods The CDRAD phantom located underneath 12, 20, and 26 cm PMMA was imaged 16 times at five dose levels using an x‐ray system with a flat‐panel detector. All images were analyzed by CDRAD Analyser, version 1.1, which calculated the FOM inverse image quality figure (IQFinv) and gave contrast detail curves for each image. Inherent properties of the CDRAD phantom were used to derive a new FOM h, which describes the size of the hole with the same diameter and depth that is just visible. Data were analyzed using heteroscedastic regression of mean and variance by dose. To ease interpretation, probabilities for overlaps were calculated assuming normal distribution, with associated bootstrap confidence intervals. Results The proportion of total variability in IQFinv, explained by the dose (R2), was 91%, 85%, and 93% for 12, 20, and 26 cm PMMA. Corresponding results for h were 91%, 89%, and 95%. The overlap probability for different mAs levels was 1% for 0.8 vs 1.2 mAs, 5% for 1.2 vs 1.6 mAs, 10% for 1.6 vs 2.0 mAs, and 10% for 2.0 mAs vs 2.5 mAs for 12 cm PMMA. For 20 cm PMMA, it was 0.5% for 10 vs 16 mAs, 13% for 16 vs 20 mAs, 14% for 20 vs 25 mAs, and 14% for 25 vs 32 mAs. For 26 cm PMMA, the probability varied from 0% to 6% for various mAs levels. Even though the estimated probability for overlap was small, the 95% confidence interval (CI) showed relatively large uncertainties. For 12 cm PMMA, the associated CI for 0.8 vs 1.2 mAs was 0.1–3.2%, and the CI for 1.2 vs 1.6 mAs was 2.1–7.8%. Conclusions Inverse image quality figure and h are about equally related to dose level. The FOM h, which describes the size of a hole that should be seen in the image, may be a more intuitive FOM than IQFinv. However, considering the probabilities for overlap and their confidence intervals, the FOMs deduced from the CDRAD phantom are not sensitive to dose. Hence, CDRAD may not be an optimal phantom to differentiate between images acquired at different dose levels.
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Affiliation(s)
- Bente Konst
- Department of Radiology, Vestfold Hospital Trust, Tønsberg, Norway
| | - Harald Weedon-Fekjaer
- Oslo Center for Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway
| | - Magnus Båth
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
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Lisson CG, Lisson CS, Kleiner S, Regier M, Beer M, Schmidt SA. Iterative scatter correction for grid-less skeletal radiography allows improved image quality equal to an antiscatter grid in adjunct with dose reduction: a visual grading study of 20 body donors. Acta Radiol 2019; 60:735-741. [PMID: 30149748 DOI: 10.1177/0284185118796668] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Iterative scatter correction (ISC) is a new technique applicable to plain radiography; comparable to iterative reconstruction for computed tomography, it promises dose reduction and image quality improvement. ISC for bedside chest X-rays has been applied and evaluated for some time and has recently been commercially offered for plain skeletal radiography. PURPOSE To analyze the potential of ISC for plain skeletal radiography with regard to image quality improvement, dose reduction, and replacement for an antiscatter grid. MATERIAL AND METHODS A total of 385 radiographs with different imaging protocols of the pelvis and cervical spine were acquired from 20 body donors. Radiographs were rated by four radiologists. Ratings were analyzed with visual grading characteristics (VGC) analysis. The area under the VGC curve was used as a measure of difference in image quality. RESULTS Without ISC, the grid-less images were rated significantly worse than their grid-based counterparts (0.389, P = 0.005); adding ISC made image quality equal (0.498; P = 0.963). In grid-less imaging, reduction of dose by 50% led to significant image quality impairment (0.415, P = 0.001); this was fully counterbalanced when ISC was added (0.512; P = 0.588). CONCLUSION ISC for plain skeletal radiography has the ability to replace the antiscatter grid without image quality impairment, to improve image quality in grid-less imaging, and to reduce patient radiation dose by 50% without substantial loss in image quality.
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Affiliation(s)
- Christoph G Lisson
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Ulm, Germany
| | - Catharina S Lisson
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Ulm, Germany
| | - Sebastian Kleiner
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Ulm, Germany
| | - Marc Regier
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Meinrad Beer
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Ulm, Germany
| | - Stefan A Schmidt
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Ulm, Germany
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Söderman C, Johnsson ÅA, Vikgren J, Norrlund RR, Molnar D, Mirzai M, Svalkvist A, Månsson LG, Båth M. Detection of Pulmonary Nodule Growth with Chest Tomosynthesis: A Human Observer Study Using Simulated Nodules. Acad Radiol 2019; 26:508-518. [PMID: 29903641 DOI: 10.1016/j.acra.2018.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/08/2018] [Accepted: 05/13/2018] [Indexed: 12/20/2022]
Abstract
RATIONALE AND OBJECTIVES Chest tomosynthesis has been suggested as a suitable alternative to CT for follow-up of pulmonary nodules. The aim of the present study was to investigate the possibility of detecting pulmonary nodule growth using chest tomosynthesis. MATERIALS AND METHODS Simulated nodules with volumes of approximately 100 mm3 and 300 mm3 as well as additional versions with increasing volumes were created. The nodules were inserted into images from pairs of chest tomosynthesis examinations, simulating cases where the nodule had either remained stable in size or increased in size between the two imaging occasions. Nodule volume growths ranging from 11% to 252% were included. A simulated dose reduction was applied to a subset of the cases. Cases differing in terms of nodule size, dose level, and nodule position relative to the plane of image reconstruction were included. Observers rated their confidence that the nodules were stable in size or not. The rating data for the nodules that were stable in size was compared to the rating data for the nodules simulated to have increased in size using ROC analysis. RESULTS Area under the curve values ranging from 0.65 to 1 were found. The lowest area under the curve values were found when there was a mismatch in nodule position relative to the reconstructed image plane between the two examinations. Nodule size and dose level affected the results. CONCLUSION The study indicates that chest tomosynthesis can be used to detect pulmonary nodule growth. Nodule size, dose level, and mismatch in position relative to the image reconstruction plane in the baseline and follow-up examination may affect the precision.
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Bergamino C, Hoey SE, de Swarte M, Skelly C. Improved visualization of the lumbar spine nerve roots in dogs using water excitation (ProSet) as opposed to short tau inversion recovery: A retrospective study of two fat suppression MRI sequences. Vet Radiol Ultrasound 2019; 60:323-329. [PMID: 30656772 DOI: 10.1111/vru.12714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/01/2018] [Accepted: 11/01/2018] [Indexed: 12/30/2022] Open
Abstract
Magnetic resonance imaging fat suppression techniques are commonly used for diagnosis of canine spinal disease, however, studies comparing different techniques are currently lacking. This retrospective, methods comparison study aimed to evaluate water excitation and STIR MRI pulse sequences for visualization of canine lumbar spinal nerve roots. For inclusion, all dogs had to have dorsal planar MRI studies of the lumbar spine using both sequences. Visual grading analysis was used for scoring the following five criteria: degree of fat suppression; nerve root visualization; subjective tissue contrast; presence of noise; and overall better image quality. Scores were independently recorded by three board-certified veterinary radiologists on two separate occasions, 3-6 weeks apart. A total of 90 dogs were sampled. A two-tailed t-test showed that there were significant differences in all scored parameters (P < 0.00001), with the exception of noise (P = 0.47343), and that the water excitation sequence scored higher in all cases excluding noise. A Gwets AC kappa for intraobserver and interobserver reliability showed "almost perfect" agreement for the nerve roots in both tests (intra: k = 0.88; inter: k = 0.90). Intraobserver agreement was "substantial" for the degree of fat suppression (k = 0.68), subjective tissue contrast (k = 0.75), and overall better image quality (k = 0.76) and it was "fair" for the noise (k = 0.46). Interobserver agreement was "moderate" for the degree of fat suppression (k = 0.53), subjective tissue contrast (k = 0.63), and overall better image quality (k = 0.66) and "slight" for noise (k = 0.25). These findings supported using the water excitation pulse sequence for fat-suppressed MRI of canine lumbar spinal nerve roots.
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Affiliation(s)
- Chiara Bergamino
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Séamus E Hoey
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Marie de Swarte
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, 37996
| | - Cliona Skelly
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
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Al-Murshedi S, Hogg P, Lanca L, England A. A novel method for comparing radiation dose and image quality, between and within different x-ray units in a series of hospitals. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2018; 38:1344-1358. [PMID: 30251707 DOI: 10.1088/1361-6498/aae3fa] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
OBJECTIVES To develop a novel method for comparing radiation dose and image quality (IQ) to evaluate adult chest x-ray (CXR) imaging among several hospitals. METHODS CDRAD 2.0 phantom was used to acquire images in eight hospitals (17 digital x-ray units) using local adult CXR protocols. IQ was represented by image quality figure inverse (IQFinv), measured using CDRAD analyser software. Signal to noise ratio, contrast to noise ratio and conspicuity index were calculated as additional measures of IQ. Incident air kerma (IAK) was measured using a solid-state dosimeter for each acquisition. Figure of merit (FOM) was calculated to provide a single estimation of IQ and radiation dose. RESULTS IQ, radiation dose and FOM varied considerably between hospitals and x-ray units. For IQFinv, the mean (range) between and within the hospitals were 1.42 (0.83-2.18) and 1.87 (1.52-2.18), respectively. For IAK, the mean (range) between and within the hospitals were 93.56 (17.26-239.15) μGy and 180.85 (122.58-239.15) μGy, respectively. For FOM, the mean (range) between and within hospitals were 0.05 (0.01-0.14) and 0.03 (0.02-0.05), respectively. CONCLUSIONS The suggested method for comparing IQ and dose using FOM concept along with the new proposed FOM, is a valid, reliable and effective approach for monitoring and comparing IQ and dose between and within hospitals. It is also can be beneficial for the optimisation of x-ray units in clinical practice. Further optimisation for the hospitals/x-ray units with low FOM are required to minimise radiation dose without degrading IQ.
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Affiliation(s)
- Sadeq Al-Murshedi
- School of Health Sciences, University of Salford, Salford M6 6PU, United Kingdom
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Alzyoud K, Hogg P, Snaith B, Flintham K, England A. Impact of body part thickness on AP pelvis radiographic image quality and effective dose. Radiography (Lond) 2018; 25:e11-e17. [PMID: 30599841 DOI: 10.1016/j.radi.2018.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 09/04/2018] [Accepted: 09/06/2018] [Indexed: 10/28/2022]
Abstract
INTRODUCTION Within medical imaging variations in patient size can generate challenges, especially when selecting appropriate acquisition parameters. This experiment sought to evaluate the impact of increasing body part thickness on image quality (IQ) and effective dose (E) and identify optimum exposure parameters. METHODS An anthropomorphic pelvis phantom was imaged with additional layers (1-15 cm) of animal fat as a proxy for increasing body thickness. Acquisitions used the automatic exposure control (AEC), 100 cm source to image distance (SID) and a range of tube potentials (70-110 kVp). IQ was evaluated physically and perceptually. E was estimated using PCXMC software. RESULTS For all tube potentials, signal to noise ratio (SNR) and contrast to noise ratio (CNR) deceased as body part thickness increased. 70 kVp produced the highest SNR (46.6-22.6); CNR (42.8-17.6). Visual grading showed that the highest IQ scores were achieved using 70 and 75 kVp. As thickness increases, E increased exponentially (r = 0.96; p < 0.001). Correlations were found between visual and physical IQ (SNR r = 0.97, p < 0.001; CNR r = 0.98, p < 0.001). CONCLUSION To achieve an optimal IQ across the range of thicknesses, lower kVp settings were most effective. This is at variance with professional practice as there is a tendency for radiographers to increase kVp as thickness increases. Dose reductions were experienced at higher kVp settings and are a valid method for optimisation when imaging larger patients.
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Affiliation(s)
- K Alzyoud
- School of Health Sciences, University of Salford, Salford M6 6PU, United Kingdom; Faculty of Allied Health Sciences, Hashemite University, Zarqa, Jordan.
| | - P Hogg
- School of Health Sciences, University of Salford, Salford M6 6PU, United Kingdom.
| | - B Snaith
- The Mid Yorkshire Hospitals NHS Trust, Wakefield WF1 4DG, United Kingdom; University of Bradford, Bradford BD7 1DP, United Kingdom.
| | - K Flintham
- The Mid Yorkshire Hospitals NHS Trust, Wakefield WF1 4DG, United Kingdom.
| | - A England
- School of Health Sciences, University of Salford, Salford M6 6PU, United Kingdom.
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Aurumskjöld ML, Söderberg M, Stålhammar F, von Steyern KV, Tingberg A, Ydström K. Evaluation of an iterative model-based reconstruction of pediatric abdominal CT with regard to image quality and radiation dose. Acta Radiol 2018; 59:740-747. [PMID: 28825319 DOI: 10.1177/0284185117728415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Background In pediatric patients, computed tomography (CT) is important in the medical chain of diagnosing and monitoring various diseases. Because children are more radiosensitive than adults, they require minimal radiation exposure. One way to achieve this goal is to implement new technical solutions, like iterative reconstruction. Purpose To evaluate the potential of a new, iterative, model-based method for reconstructing (IMR) pediatric abdominal CT at a low radiation dose and determine whether it maintains or improves image quality, compared to the current reconstruction method. Material and Methods Forty pediatric patients underwent abdominal CT. Twenty patients were examined with the standard dose settings and 20 patients were examined with a 32% lower radiation dose. Images from the standard examination were reconstructed with a hybrid iterative reconstruction method (iDose4), and images from the low-dose examinations were reconstructed with both iDose4 and IMR. Image quality was evaluated subjectively by three observers, according to modified EU image quality criteria, and evaluated objectively based on the noise observed in liver images. Results Visual grading characteristics analyses showed no difference in image quality between the standard dose examination reconstructed with iDose4 and the low dose examination reconstructed with IMR. IMR showed lower image noise in the liver compared to iDose4 images. Inter- and intra-observer variance was low: the intraclass coefficient was 0.66 (95% confidence interval = 0.60-0.71) for the three observers. Conclusion IMR provided image quality equivalent or superior to the standard iDose4 method for evaluating pediatric abdominal CT, even with a 32% dose reduction.
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Affiliation(s)
- Marie-Louise Aurumskjöld
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Marcus Söderberg
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Fredrik Stålhammar
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | | | - Anders Tingberg
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Kristina Ydström
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
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Jadidi M, Båth M, Nyrén S. Dependency of image quality on acquisition protocol and image processing in chest tomosynthesis-a visual grading study based on clinical data. Br J Radiol 2018; 91:20170683. [PMID: 29565673 DOI: 10.1259/bjr.20170683] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE To compare the quality of images obtained with two different protocols with different acquisition time and the influence from image post processing in a chest digital tomosynthesis (DTS) system. METHODS 20 patients with suspected lung cancer were imaged with a chest X-ray equipment with tomosynthesis option. Two examination protocols with different acquisition times (6.3 and 12 s) were performed on each patient. Both protocols were presented with two different image post-processing (standard DTS processing and more advanced processing optimised for chest radiography). Thus, 4 series from each patient, altogether 80 series, were presented anonymously and in a random order. Five observers rated the quality of the reconstructed section images according to predefined quality criteria in three different classes. Visual grading characteristics (VGC) was used to analyse the data and the area under the VGC curve (AUCVGC) was used as figure-of-merit. The 12 s protocol and the standard DTS processing were used as references in the analyses. RESULTS The protocol with 6.3 s acquisition time had a statistically significant advantage over the vendor-recommended protocol with 12 s acquisition time for the classes of criteria, Demarcation (AUCVGC = 0.56, p = 0.009) and Disturbance (AUCVGC = 0.58, p < 0.001). A similar value of AUCVGC was found also for the class Structure (definition of bone structures in the spine) (0.56) but it could not be statistically separated from 0.5 (p = 0.21). For the image processing, the VGC analysis showed a small but statistically significant advantage for the standard DTS processing over the more advanced processing for the classes of criteria Demarcation (AUCVGC = 0.45, p = 0.017) and Disturbance (AUCVGC = 0.43, p = 0.005). A similar value of AUCVGC was found also for the class Structure (0.46), but it could not be statistically separated from 0.5 (p = 0.31). CONCLUSION The study indicates that the protocol with 6.3 s acquisition time yields slightly better image quality than the vender-recommended protocol with acquisition time 12 s for several anatomical structures. Furthermore, the standard gradation processing (the vendor-recommended post-processing for DTS), yields to some extent advantage over the gradation processing/multiobjective frequency processing/flexible noise control processing in terms of image quality for all classes of criteria. Advances in knowledge: The study proves that the image quality may be strongly affected by the selection of DTS protocol and that the vendor-recommended protocol may not always be the optimal choice.
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Affiliation(s)
- Masoud Jadidi
- 1 Departments of Clinical Science, Intervention and Technology, Karolinska Institutet , Stockholm , Sweden
| | - Magnus Båth
- 2 Department of Radiation Physics, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden.,3 Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital , Gothenburg , Sweden
| | - Sven Nyrén
- 4 Molecular medicine and surgery, Karolinska intitutet , Stockholm , Sweden.,5 Department of Thoracic radiology, Karolinska University Hospital , Stockholm , Sweden
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Lowered dose full-spine radiography in pediatric patients with idiopathic scoliosis. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2018; 27:1089-1095. [PMID: 29589171 DOI: 10.1007/s00586-018-5561-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 03/08/2018] [Accepted: 03/22/2018] [Indexed: 10/17/2022]
Abstract
PURPOSE To optimize our standard full-spine radiography with respect to diagnostic quality and dose. METHODS A phantom study was performed to establish an optimal posterior-anterior view (PA) full spine protocol having the lowest dose with non-inferior quality compared to standard. We then applied this protocol in 40 pediatric patients (group B). The radiographs were scored on six criteria by a pediatric radiologist and orthopedist and compared to the scores of 40 PA full spine radiographs performed in 2013 with standard protocol (group A). Radiation dose was assessed by dose area product (DAP) and effective dose (E). Statistical analysis included independent samples t test, Mann-Whitney U test and intra-class correlation coefficient (ICC). RESULTS An optimized protocol was defined (0.2 mm Cu filter, 0.87 relative exposure, with grid). Mean age was 13.3 ± 1.6 years for group A and 13.4 ± 1.7 years for group B. For group B, the mean DAP was 47.0 µGy m2 with an E of 0.13 mSv. For group A, the mean DAP was 85.3 µGy m2 with an E of 0.24 mSv. This represents a dose reduction of 45%. Mean image quality scores for group A (27.9 ± 2.4) and group B (28.1 ± 2.3) were similar (p = 0.612). Interobserver agreement was observed to be excellent (ICC 0.92). CONCLUSION This study demonstrates that a low-dose full-spine radiograph can be performed in patients with idiopathic scoliosis without loss of image quality. These slides can be retrieved under Electronic Supplementary Material.
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Smet MH, Breysem L, Mussen E, Bosmans H, Marshall NW, Cockmartin L. Visual grading analysis of digital neonatal chest phantom X-ray images: Impact of detector type, dose and image processing on image quality. Eur Radiol 2018; 28:2951-2959. [PMID: 29460076 DOI: 10.1007/s00330-017-5301-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/13/2017] [Accepted: 12/29/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To evaluate the impact of digital detector, dose level and post-processing on neonatal chest phantom X-ray image quality (IQ). METHODS A neonatal phantom was imaged using four different detectors: a CR powder phosphor (PIP), a CR needle phosphor (NIP) and two wireless CsI DR detectors (DXD and DRX). Five different dose levels were studied for each detector and two post-processing algorithms evaluated for each vendor. Three paediatric radiologists scored the images using European quality criteria plus additional questions on vascular lines, noise and disease simulation. Visual grading characteristics and ordinal regression statistics were used to evaluate the effect of detector type, post-processing and dose on VGA score (VGAS). RESULTS No significant differences were found between the NIP, DXD and CRX detectors (p>0.05) whereas the PIP detector had significantly lower VGAS (p< 0.0001). Processing did not influence VGAS (p=0.819). Increasing dose resulted in significantly higher VGAS (p<0.0001). Visual grading analysis (VGA) identified a detector air kerma/image (DAK/image) of ~2.4 μGy as an ideal working point for NIP, DXD and DRX detectors. CONCLUSIONS VGAS tracked IQ differences between detectors and dose levels but not image post-processing changes. VGA showed a DAK/image value above which perceived IQ did not improve, potentially useful for commissioning. KEY POINTS • A VGA study detects IQ differences between detectors and dose levels. • The NIP detector matched the VGAS of the CsI DR detectors. • VGA data are useful in setting initial detector air kerma level. • Differences in NNPS were consistent with changes in VGAS.
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Affiliation(s)
- M H Smet
- Department of Radiology, University Hospital Leuven, Herestraat, 49, 3000 - Leuven, Louvain, Belgium.
| | - L Breysem
- Department of Radiology, University Hospital Leuven, Herestraat, 49, 3000 - Leuven, Louvain, Belgium
| | - E Mussen
- Department of Radiology, University Hospital Leuven, Herestraat, 49, 3000 - Leuven, Louvain, Belgium
| | - H Bosmans
- Department of Radiology, University Hospital Leuven, Herestraat, 49, 3000 - Leuven, Louvain, Belgium.,Medical Imaging Research Center, Medical Physics and Quality Assessment, Katholieke Universiteit Leuven, 3000 - Leuven, Louvain, Belgium
| | - N W Marshall
- Department of Radiology, University Hospital Leuven, Herestraat, 49, 3000 - Leuven, Louvain, Belgium.,Medical Imaging Research Center, Medical Physics and Quality Assessment, Katholieke Universiteit Leuven, 3000 - Leuven, Louvain, Belgium
| | - L Cockmartin
- Department of Radiology, University Hospital Leuven, Herestraat, 49, 3000 - Leuven, Louvain, Belgium
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Geso M, Alghamdi SS, Shanahan M, Alghamdi S, Mineo R, Aldhafery B. Information Loss Via Visual Assessment of Radiologic Images Using Modified Version of the Low-Contrast Detailed Phantom at Direct DR System. J Med Imaging Radiat Sci 2017; 48:137-143. [DOI: 10.1016/j.jmir.2017.02.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 01/21/2017] [Accepted: 02/14/2017] [Indexed: 11/29/2022]
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Gislason-Lee AJ, Keeble C, Egleston D, Bexon J, Kengyelics SM, Davies AG. Comprehensive assessment of patient image quality and radiation dose in latest generation cardiac x-ray equipment for percutaneous coronary interventions. J Med Imaging (Bellingham) 2017; 4:025501. [PMID: 28491907 PMCID: PMC5412945 DOI: 10.1117/1.jmi.4.2.025501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 04/14/2017] [Indexed: 11/14/2022] Open
Abstract
This study aimed to determine whether a reduction in radiation dose was found for percutaneous coronary interventional (PCI) patients using a cardiac interventional x-ray system with state-of-the-art image enhancement and x-ray optimization, compared to the current generation x-ray system, and to determine the corresponding impact on clinical image quality. Patient procedure dose area product (DAP) and fluoroscopy duration of 131 PCI patient cases from each x-ray system were compared using a Wilcoxon test on median values. Significant reductions in patient dose ([Formula: see text]) were found for the new system with no significant change in fluoroscopy duration ([Formula: see text]); procedure DAP reduced by 64%, fluoroscopy DAP by 51%, and "cine" acquisition DAP by 76%. The image quality of 15 patient angiograms from each x-ray system (30 total) was scored by 75 clinical professionals on a continuous scale for the ability to determine the presence and severity of stenotic lesions; image quality scores were analyzed using a two-sample [Formula: see text]-test. Image quality was reduced by 9% ([Formula: see text]) for the new x-ray system. This demonstrates a substantial reduction in patient dose, from acquisition more than fluoroscopy imaging, with slightly reduced image quality, for the new x-ray system compared to the current generation system.
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Affiliation(s)
| | - Claire Keeble
- University of Leeds, Division of Epidemiology and Biostatistics, Leeds, United Kingdom
| | - Daniel Egleston
- University of Leeds, Division of Biomedical Imaging, Leeds, United Kingdom
| | - Josephine Bexon
- University of Leeds, Division of Biomedical Imaging, Leeds, United Kingdom
| | | | - Andrew G. Davies
- University of Leeds, Division of Biomedical Imaging, Leeds, United Kingdom
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Kember SA, Hansen VN, Fast MF, Nill S, McDonald F, Ahmed M, Thomas K, McNair HA. Evaluation of three presets for four-dimensional cone beam CT in lung radiotherapy verification by visual grading analysis. Br J Radiol 2016; 89:20150933. [PMID: 27109735 PMCID: PMC5257304 DOI: 10.1259/bjr.20150933] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 03/27/2016] [Accepted: 04/20/2016] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To evaluate three image acquisition presets for four-dimensional cone beam CT (CBCT) to identify an optimal preset for lung tumour image quality while minimizing dose and acquisition time. METHODS Nine patients undergoing radical conventionally fractionated radiotherapy for lung cancer had verification CBCTs acquired using three presets: Preset 1 on Day 1 (11 mGy dose, 240 s acquisition time), Preset 2 on Day 2 (9 mGy dose, 133 s acquisition time) and Preset 3 on Day 3 (9 mGy dose, 67 s acquisition time). The clarity of the tumour and other thoracic structures, and the acceptability of the match, were retrospectively graded by visual grading analysis (VGA). Logistic regression was used to identify the most appropriate preset and any factors that might influence the result. RESULTS Presets 1 and 2 met a clinical requirement of 75% of structures to be rated "Clear" or above and 75% of matches to be rated "Acceptable" or above. Clarity is significantly affected by preset, patient, observer and structure. Match acceptability is significantly affected by preset. CONCLUSION The application of VGA in this initial study enabled a provisional selection of an optimal preset (Preset 2) to be made. ADVANCES IN KNOWLEDGE This was the first application of VGA to the investigation of presets for CBCT.
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Affiliation(s)
| | - Vibeke N Hansen
- Royal Marsden NHS Foundation Trust, London, UK
- The Institute of Cancer Research, London, UK
| | - Martin F Fast
- Royal Marsden NHS Foundation Trust, London, UK
- The Institute of Cancer Research, London, UK
| | - Simeon Nill
- Royal Marsden NHS Foundation Trust, London, UK
- The Institute of Cancer Research, London, UK
| | - Fiona McDonald
- Royal Marsden NHS Foundation Trust, London, UK
- The Institute of Cancer Research, London, UK
| | | | | | - Helen A McNair
- Royal Marsden NHS Foundation Trust, London, UK
- The Institute of Cancer Research, London, UK
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Keeble C, Baxter PD, Gislason-Lee AJ, Treadgold LA, Davies AG. Methods for the analysis of ordinal response data in medical image quality assessment. Br J Radiol 2016; 89:20160094. [PMID: 26975497 PMCID: PMC5257322 DOI: 10.1259/bjr.20160094] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/02/2016] [Accepted: 03/10/2016] [Indexed: 01/10/2023] Open
Abstract
The assessment of image quality in medical imaging often requires observers to rate images for some metric or detectability task. These subjective results are used in optimization, radiation dose reduction or system comparison studies and may be compared to objective measures from a computer vision algorithm performing the same task. One popular scoring approach is to use a Likert scale, then assign consecutive numbers to the categories. The mean of these response values is then taken and used for comparison with the objective or second subjective response. Agreement is often assessed using correlation coefficients. We highlight a number of weaknesses in this common approach, including inappropriate analyses of ordinal data and the inability to properly account for correlations caused by repeated images or observers. We suggest alternative data collection and analysis techniques such as amendments to the scale and multilevel proportional odds models. We detail the suitability of each approach depending upon the data structure and demonstrate each method using a medical imaging example. Whilst others have raised some of these issues, we evaluated the entire study from data collection to analysis, suggested sources for software and further reading, and provided a checklist plus flowchart for use with any ordinal data. We hope that raised awareness of the limitations of the current approaches will encourage greater method consideration and the utilization of a more appropriate analysis. More accurate comparisons between measures in medical imaging will lead to a more robust contribution to the imaging literature and ultimately improved patient care.
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Affiliation(s)
- Claire Keeble
- Division of Epidemiology and Biostatistics, University of Leeds, Leeds, UK
- Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | - Paul D Baxter
- Division of Epidemiology and Biostatistics, University of Leeds, Leeds, UK
| | | | | | - Andrew G Davies
- Division of Biomedical Imaging, University of Leeds, Leeds, UK
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Hansson J, Månsson LG, Båth M. THE VALIDITY OF USING ROC SOFTWARE FOR ANALYSING VISUAL GRADING CHARACTERISTICS DATA: AN INVESTIGATION BASED ON THE NOVEL SOFTWARE VGC ANALYZER. RADIATION PROTECTION DOSIMETRY 2016; 169:54-59. [PMID: 26979808 DOI: 10.1093/rpd/ncw035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The purpose of the present work was to investigate the validity of using single-reader-adapted receiver operating characteristics (ROC) software for analysis of visual grading characteristics (VGC) data. VGC data from four published VGC studies on optimisation of X-ray examinations, previously analysed using ROCFIT, were reanalysed using a recently developed software dedicated to VGC analysis (VGC Analyzer), and the outcomes [the mean and 95 % confidence interval (CI) of the area under the VGC curve (AUCVGC) and the p-value] were compared. The studies included both paired and non-paired data and were reanalysed both for the fixed-reader and the random-reader situations. The results showed good agreement between the softwares for the mean AUCVGC For non-paired data, wider CIs were obtained with VGC Analyzer than previously reported, whereas for paired data, the previously reported CIs were similar or even broader. Similar observations were made for the p-values. The results indicate that the use of single-reader-adapted ROC software such as ROCFIT for analysing non-paired VGC data may lead to an increased risk of committing Type I errors, especially in the random-reader situation. On the other hand, the use of ROC software for analysis of paired VGC data may lead to an increased risk of committing Type II errors, especially in the fixed-reader situation.
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Affiliation(s)
- Jonny Hansson
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Radiation Physics, Institute of Clinical Sciences, the Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Lars Gunnar Månsson
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Radiation Physics, Institute of Clinical Sciences, the Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Magnus Båth
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Radiation Physics, Institute of Clinical Sciences, the Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
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Båth M, Hansson J. VGC ANALYZER: A SOFTWARE FOR STATISTICAL ANALYSIS OF FULLY CROSSED MULTIPLE-READER MULTIPLE-CASE VISUAL GRADING CHARACTERISTICS STUDIES. RADIATION PROTECTION DOSIMETRY 2016; 169:46-53. [PMID: 26769908 DOI: 10.1093/rpd/ncv542] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Visual grading characteristics (VGC) analysis is a non-parametric rank-invariant method for analysis of visual grading data. In VGC analysis, image quality ratings for two different conditions are compared by producing a VGC curve, similar to how the ratings for normal and abnormal cases in receiver operating characteristic (ROC) analysis are used to create an ROC curve. The use of established ROC software for the analysis of VGC data has therefore previously been proposed. However, the ROC analysis is based on the assumption of independence between normal and abnormal cases. In VGC analysis, this independence cannot always be assumed, e.g. if the ratings are based on the same patients imaged under both conditions. A dedicated software intended for analysis of VGC studies, which takes possible dependencies between ratings into account in the statistical analysis of a VGC study, has therefore been developed. The software-VGC Analyzer-determines the area under the VGC curve and its uncertainty using non-parametric resampling techniques. This article gives an introduction to VGC Analyzer, describes the types of analyses that can be performed and instructs the user about the input and output data.
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Affiliation(s)
- Magnus Båth
- Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Jonny Hansson
- Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
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Svalkvist A, Söderman C, Båth M. EFFECTIVE DOSE TO PATIENTS FROM THORACIC SPINE EXAMINATIONS WITH TOMOSYNTHESIS. RADIATION PROTECTION DOSIMETRY 2016; 169:274-280. [PMID: 26675145 DOI: 10.1093/rpd/ncv498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The purposes of the present work were to calculate the average effective dose to patients from lateral tomosynthesis examinations of the thoracic spine, compare the results with the corresponding conventional examination and to determine a conversion factor between dose-area product (DAP) and effective dose for the tomosynthesis examination. Thoracic spine examinations from 17 patients were included in the study. The registered DAP and information about the field size for each projection radiograph were, together with patient height and mass, used to calculate the effective dose for each projection radiograph. The total effective doses for the tomosynthesis examinations were obtained by adding the effective doses from the 60 projection radiographs included in the examination. The mean effective dose was 0.47 mSv (range 0.24-0.81 mSv) for the tomosynthesis examinations and 0.20 mSv (range 0.07-0.29 mSv) for the corresponding conventional examinations (anteroposterior + left lateral projection). For the tomosynthesis examinations, a conversion factor between total DAP and effective dose of 0.092 mSv Gycm(-2) was obtained.
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Affiliation(s)
- Angelica Svalkvist
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Christina Söderman
- Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Magnus Båth
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
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Ceder E, Danielson B, Kovàč P, Fogel H, Svalkvist A, Vikgren J, Båth M. THORACIC SPINE IMAGING: A COMPARISON BETWEEN RADIOGRAPHY AND TOMOSYNTHESIS USING VISUAL GRADING CHARACTERISTICS. RADIATION PROTECTION DOSIMETRY 2016; 169:204-210. [PMID: 26868012 DOI: 10.1093/rpd/ncv559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The aim of the present study was to evaluate digital tomosynthesis (DTS) in thoracic spine imaging, comparing the reproduction of anatomical structures with that achieved using digital radiography (DR). In a prospective visual grading study, 23 patients referred in 2014 for elective radiographic examination of the thoracic spine were examined using lateral DR and DTS. The DR image and the DTS section images were read in random order by four radiologists, evaluating the ability of the modalities to present a clear reproduction of nine specific relevant structures of the thoracic vertebrae 3, 6 and 9 (T3, T6 and T9). The data were analysed using visual grading characteristics (VGC) analysis. The VGC analysis revealed a statistically significant difference in favour of DTS for all evaluated structures, except for the anterior vertebral edges and lower end plate surfaces of T6 and T9 and the cancellous bone of T9. The difference was most striking in T3 and for posterior structures. For no structure in any vertebra was the reproduction rated significantly better for DR. In conclusion, DTS of the thoracic spine appears to be a promising alternative to DR, especially in areas where the problem of overlaying anatomy is accentuated, such as posterior and upper thoracic structures.
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Affiliation(s)
- Erik Ceder
- Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Barbro Danielson
- Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Peter Kovàč
- Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Hanna Fogel
- Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Angelica Svalkvist
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Jenny Vikgren
- Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Magnus Båth
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
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Meltzer C, Båth M, Kheddache S, Ásgeirsdóttir H, Gilljam M, Johnsson ÅA. VISIBILITY OF STRUCTURES OF RELEVANCE FOR PATIENTS WITH CYSTIC FIBROSIS IN CHEST TOMOSYNTHESIS: INFLUENCE OF ANATOMICAL LOCATION AND OBSERVER EXPERIENCE. RADIATION PROTECTION DOSIMETRY 2016; 169:177-87. [PMID: 26842827 PMCID: PMC4911964 DOI: 10.1093/rpd/ncv556] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The aims of this study were to assess the visibility of pulmonary structures in patients with cystic fibrosis (CF) in digital tomosynthesis (DTS) using computed tomography (CT) as reference and to investigate the dependency on anatomical location and observer experience. Anatomical structures in predefined regions of CT images from 21 patients were identified. Three observers with different levels of experience rated the visibility of the structures in DTS by performing a head-to-head comparison with visibility in CT. Visibility of the structures in DTS was reported as equal to CT in 34 %, inferior in 52 % and superior in 14 % of the ratings. Central and peripheral lateral structures received higher visibility ratings compared with peripheral structures anteriorly, posteriorly and surrounding the diaphragm (p ≤ 0.001). Reported visibility was significantly higher for the most experienced observer (p ≤ 0.01). The results indicate that minor pathology can be difficult to visualise with DTS depending on location and observer experience. Central and peripheral lateral structures are generally well depicted.
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Affiliation(s)
- Carin Meltzer
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Magnus Båth
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Susanne Kheddache
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
| | - Helga Ásgeirsdóttir
- Gothenburg CF-Center, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Respiratory Medicine, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Marita Gilljam
- Gothenburg CF-Center, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden Department of Respiratory Medicine, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Åse Allansdotter Johnsson
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, SE-413 45 Gothenburg, Sweden Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
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Davidsson A, Olsson E, Engvall J, Gustafsson A. Influence of reconstruction algorithms on image quality in SPECT myocardial perfusion imaging. Clin Physiol Funct Imaging 2016; 37:655-662. [PMID: 26991110 DOI: 10.1111/cpf.12354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 01/22/2016] [Indexed: 11/30/2022]
Abstract
INTRODUCTION We investigated if image- and diagnostic quality in SPECT MPI could be maintained despite a reduced acquisition time adding Depth Dependent Resolution Recovery (DDRR) for image reconstruction. Images were compared with filtered back projection (FBP) and iterative reconstruction using Ordered Subsets Expectation Maximization with (IRAC) and without (IRNC) attenuation correction (AC). MATERIALS AND METHODS Stress- and rest imaging for 15 min was performed on 21 subjects with a dual head gamma camera (Infinia Hawkeye; GE Healthcare), ECG-gating with 8 frames/cardiac cycle and a low-dose CT-scan. A 9 min acquisition was generated using five instead of eight gated frames and was reconstructed with DDRR, with (IRACRR) and without AC (IRNCRR) as well as with FBP. Three experienced nuclear medicine specialists visually assessed anonymized images according to eight criteria on a four point scale, three related to image quality and five to diagnostic confidence. Statistical analysis was performed using Visual Grading Regression (VGR). RESULTS Observer confidence in statements on image quality was highest for the images that were reconstructed using DDRR (P<0·01 compared to FBP). Iterative reconstruction without DDRR was not superior to FBP. Interobserver variability was significant for statements on image quality (P<0·05) but lower in the diagnostic statements on ischemia and scar. The confidence in assessing ischemia and scar was not different between the reconstruction techniques (P = n.s.). CONCLUSION SPECT MPI collected in 9 min, reconstructed with DDRR and AC, produced better image quality than the standard procedure. The observers expressed the highest diagnostic confidence in the DDRR reconstruction.
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Affiliation(s)
- Anette Davidsson
- Department of Clinical Physiology, Department of Medical and Health Sciences/Cardiovascular Medicine, Regionostergotland, Linköping University, Linköping, Sweden
| | - Eva Olsson
- Department of Clinical Physiology, Department of Medical and Health Sciences/Cardiovascular Medicine, Regionostergotland, Linköping University, Linköping, Sweden
| | - Jan Engvall
- Department of Clinical Physiology, Department of Medical and Health Sciences/Cardiovascular Medicine, Regionostergotland, Linköping University, Linköping, Sweden
| | - Agnetha Gustafsson
- Department of Medical Physics, Karolinska University Hospital, Huddinge, Stockholm, Sweden
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Mraity HAAB, England A, Cassidy S, Eachus P, Dominguez A, Hogg P. Development and validation of a visual grading scale for assessing image quality of AP pelvis radiographic images. Br J Radiol 2016; 89:20150430. [PMID: 26943836 PMCID: PMC4985444 DOI: 10.1259/bjr.20150430] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 02/22/2016] [Accepted: 03/02/2016] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The aim of this article was to apply psychometric theory to develop and validate a visual grading scale for assessing the visual perception of digital image quality anteroposterior (AP) pelvis. METHODS Psychometric theory was used to guide scale development. Seven phantom and seven cadaver images of visually and objectively predetermined quality were used to help assess scale reliability and validity. 151 volunteers scored phantom images, and 184 volunteers scored cadaver images. Factor analysis and Cronbach's alpha were used to assess scale validity and reliability. RESULTS A 24-item scale was produced. Aggregated mean volunteer scores for each image correlated with the rank order of the visually and objectively predetermined image qualities. Scale items had good interitem correlation (≥0.2) and high factor loadings (≥0.3). Cronbach's alpha (reliability) revealed that the scale has acceptable levels of internal reliability for both phantom and cadaver images (α = 0.8 and 0.9, respectively). Factor analysis suggested that the scale is multidimensional (assessing multiple quality themes). CONCLUSION This study represents the first full development and validation of a visual image quality scale using psychometric theory. It is likely that this scale will have clinical, training and research applications. ADVANCES IN KNOWLEDGE This article presents data to create and validate visual grading scales for radiographic examinations. The visual grading scale, for AP pelvis examinations, can act as a validated tool for future research, teaching and clinical evaluations of image quality.
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Affiliation(s)
- Hussien A A B Mraity
- Department of Physics, Faculty of Science, University of Kufa, Najaf, Iraq
- School of Health Sciences, University of Salford, Salford, UK
| | - Andrew England
- School of Health Sciences, University of Salford, Salford, UK
| | - Simon Cassidy
- School of Health Sciences, University of Salford, Salford, UK
| | - Peter Eachus
- School of Health Sciences, University of Salford, Salford, UK
| | - Alejandro Dominguez
- Haute Ecole de Sante Vaud, University of Applied Sciences and Arts Western Switzerland, Lausanne, Switzerland
- School of Health Sciences, University Center of Legal Medecine, Lausanne, Switzerland
| | - Peter Hogg
- School of Health Sciences, University of Salford, Salford, UK
- Department of Radiography, Karolinska Institute, Stockholm, Sweden
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Perks TD, Dendere R, Irving B, Hartley T, Scholtz P, Lawson A, Trauernicht C, Steiner S, Douglas TS. Filtration to reduce paediatric dose for a linear slot-scanning digital X-ray machine. RADIATION PROTECTION DOSIMETRY 2015; 167:552-561. [PMID: 25433049 DOI: 10.1093/rpd/ncu339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 10/29/2014] [Indexed: 06/04/2023]
Abstract
This paper describes modelling, application and validation of a filtration technique for a linear slot-scanning digital X-ray system to reduce radiation dose to paediatric patients while preserving diagnostic image quality. A dose prediction model was implemented, which calculates patient entrance doses using variable input parameters. Effective dose is calculated using a Monte Carlo simulation. An added filter of 1.8-mm aluminium was predicted to lower the radiation dose significantly. An objective image quality study was conducted using detective quantum efficiency (DQE). The PTW Normi 4FLU test phantom was used for quantitative assessment, showing that image contrast and spatial resolution were maintained with the proposed filter. A paediatric cadaver full-body imaging trial assessed the diagnostic quality of the images and measured the dose reduction using a 1.8-mm aluminium filter. Assessment by radiologists indicated that diagnostic quality was maintained with the added filtration, despite a reduction in DQE. A new filtration technique for full-body paediatric scanning on the Lodox Statscan has been validated, reducing entrance dose for paediatric patients by 36 % on average and effective dose by 27 % on average, while maintaining image quality.
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Affiliation(s)
- T D Perks
- MRC/UCT Medical Imaging Research Unit and Biomedical Engineering Programme, University of Cape Town, Cape Town, South Africa
| | - R Dendere
- MRC/UCT Medical Imaging Research Unit and Biomedical Engineering Programme, University of Cape Town, Cape Town, South Africa
| | - B Irving
- MRC/UCT Medical Imaging Research Unit and Biomedical Engineering Programme, University of Cape Town, Cape Town, South Africa University of Oxford, Oxford, UK
| | - T Hartley
- Groote Schuur Hospital, Observatory, Cape Town, South Africa
| | - P Scholtz
- Groote Schuur Hospital, Observatory, Cape Town, South Africa
| | - A Lawson
- Red Cross War Memorial Children's Hospital, Mowbray, Cape Town, South Africa
| | - C Trauernicht
- Department of Medical Physics, University of Cape Town, Cape Town, South Africa
| | - S Steiner
- MRC/UCT Medical Imaging Research Unit and Biomedical Engineering Programme, University of Cape Town, Cape Town, South Africa Lodox Systems, Johannesburg, South Africa
| | - T S Douglas
- MRC/UCT Medical Imaging Research Unit and Biomedical Engineering Programme, University of Cape Town, Cape Town, South Africa
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Svenson B, Larsson L, Båth M. Optimization of exposure in panoramic radiography while maintaining image quality using adaptive filtering. Acta Odontol Scand 2015; 74:229-35. [PMID: 26478956 DOI: 10.3109/00016357.2015.1100752] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Objective The purpose of the present study was to investigate the potential of using advanced external adaptive image processing for maintaining image quality while reducing exposure in dental panoramic storage phosphor plate (SPP) radiography. Materials and methods Thirty-seven SPP radiographs of a skull phantom were acquired using a Scanora panoramic X-ray machine with various tube load, tube voltage, SPP sensitivity and filtration settings. The radiographs were processed using General Operator Processor (GOP) technology. Fifteen dentists, all within the dental radiology field, compared the structural image quality of each radiograph with a reference image on a 5-point rating scale in a visual grading characteristics (VGC) study. The reference image was acquired with the acquisition parameters commonly used in daily operation (70 kVp, 150 mAs and sensitivity class 200) and processed using the standard process parameters supplied by the modality vendor. Results All GOP-processed images with similar (or higher) dose as the reference image resulted in higher image quality than the reference. All GOP-processed images with similar image quality as the reference image were acquired at a lower dose than the reference. This indicates that the external image processing improved the image quality compared with the standard processing. Regarding acquisition parameters, no strong dependency of the image quality on the radiation quality was seen and the image quality was mainly affected by the dose. Conclusions The present study indicates that advanced external adaptive image processing may be beneficial in panoramic radiography for increasing the image quality of SPP radiographs or for reducing the exposure while maintaining image quality.
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MESH Headings
- Filtration/instrumentation
- Humans
- Image Processing, Computer-Assisted/methods
- Image Processing, Computer-Assisted/standards
- Phantoms, Imaging
- Radiation Dosage
- Radiographic Image Enhancement/methods
- Radiography, Dental, Digital/methods
- Radiography, Dental, Digital/standards
- Radiography, Panoramic/methods
- Radiography, Panoramic/standards
- Skull/diagnostic imaging
- Technology, Radiologic/methods
- X-Ray Intensifying Screens
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Affiliation(s)
- Björn Svenson
- a Department of Oral Radiology , Postgraduate Dental Education Center , Örebro , Sweden
- b Faculty of Medicine and Health , School of Health and Medical Sciences, Örebro University , Örebro , Sweden
- c Department of Radiology , Skaraborg Hospital Skövde , Skövde , Sweden
| | - Lars Larsson
- c Department of Radiology , Skaraborg Hospital Skövde , Skövde , Sweden
| | - Magnus Båth
- d Department of Medical Physics and Biomedical Engineering , Sahlgrenska University Hospital , Gothenburg , Sweden
- e Department of Radiation Physics , Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden
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De Crop A, Smeets P, Van Hoof T, Vergauwen M, Dewaele T, Van Borsel M, Achten E, Verstraete K, D'Herde K, Thierens H, Bacher K. Correlation of clinical and physical-technical image quality in chest CT: a human cadaver study applied on iterative reconstruction. BMC Med Imaging 2015; 15:32. [PMID: 26286596 PMCID: PMC4541737 DOI: 10.1186/s12880-015-0075-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 08/10/2015] [Indexed: 12/14/2022] Open
Abstract
Background The first aim of this study was to evaluate the correlation between clinical and physical-technical image quality applied to different strengths of iterative reconstruction in chest CT images using Thiel cadaver acquisitions and Catphan images. The second aim was to determine the potential dose reduction of iterative reconstruction compared to conventional filtered back projection based on different clinical and physical-technical image quality parameters. Methods Clinical image quality was assessed using three Thiel embalmed human cadavers. A Catphan phantom was used to assess physical-technical image quality parameters such as noise, contrast-detail and contrast-to-noise ratio (CNR). Both Catphan and chest Thiel CT images were acquired on a multislice CT scanner at 120 kVp and 0.9 pitch. Six different refmAs settings were applied (12, 30, 60, 90, 120 and 150refmAs) and each scan was reconstructed using filtered back projection (FBP) and iterative reconstruction (SAFIRE) algorithms (1,3 and 5 strengths) using a sharp kernel, resulting in 24 image series. Four radiologists assessed the clinical image quality, using a visual grading analysis (VGA) technique based on the European Quality Criteria for Chest CT. Results Correlation coefficients between clinical and physical-technical image quality varied from 0.88 to 0.92, depending on the selected physical-technical parameter. Depending on the strength of SAFIRE, the potential dose reduction based on noise, CNR and the inverse image quality figure (IQFinv) varied from 14.0 to 67.8 %, 16.0 to 71.5 % and 22.7 to 50.6 % respectively. Potential dose reduction based on clinical image quality varied from 27 to 37.4 %, depending on the strength of SAFIRE. Conclusion Our results demonstrate that noise assessments in a uniform phantom overestimate the potential dose reduction for the SAFIRE IR algorithm. Since the IQFinv based dose reduction is quite consistent with the clinical based dose reduction, an optimised contrast-detail phantom could improve the use of contrast-detail analysis for image quality assessment in chest CT imaging. In conclusion, one should be cautious to evaluate the performance of CT equipment taking into account only physical-technical parameters as noise and CNR, as this might give an incomplete representation of the actual clinical image quality performance.
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Affiliation(s)
- An De Crop
- Department of Basic Medical Sciences, Ghent University, Proeftuinstraat 86, B-9000, Ghent, Belgium.
| | - Peter Smeets
- Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
| | - Tom Van Hoof
- Department of Basic Medical Sciences, Ghent University, Proeftuinstraat 86, B-9000, Ghent, Belgium.
| | - Merel Vergauwen
- Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
| | - Tom Dewaele
- Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
| | - Mathias Van Borsel
- Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
| | - Eric Achten
- Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
| | - Koenraad Verstraete
- Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
| | - Katharina D'Herde
- Department of Basic Medical Sciences, Ghent University, Proeftuinstraat 86, B-9000, Ghent, Belgium.
| | - Hubert Thierens
- Department of Basic Medical Sciences, Ghent University, Proeftuinstraat 86, B-9000, Ghent, Belgium.
| | - Klaus Bacher
- Department of Basic Medical Sciences, Ghent University, Proeftuinstraat 86, B-9000, Ghent, Belgium.
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Gislason-Lee AJ, Tunstall CM, Kengyelics SK, Cowen AR, Davies AG. Technical Note: Impact on detective quantum efficiency of edge angle determination method by International Electrotechnical Commission methodology for cardiac x-ray image detectors. Med Phys 2015; 42:4423-7. [PMID: 26233172 DOI: 10.1118/1.4923178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Cardiac x-ray detectors are used to acquire moving images in real-time for angiography and interventional procedures. Detective quantum efficiency (DQE) is not generally measured on these dynamic detectors; the required "for processing" image data and control of x-ray settings have not been accessible. By 2016, USA hospital physicists will have the ability to measure DQE and will likely utilize the International Electrotechnical Commission (IEC) standard for measuring DQE of dynamic x-ray imaging devices. The current IEC standard requires an image of a tilted tungsten edge test object to obtain modulation transfer function (MTF) for DQE calculation. It specifies the range of edge angles to use; however, it does not specify a preferred method to determine this angle for image analysis. The study aimed to answer the question "will my choice in method impact my results?" Four different established edge angle determination methods were compared to investigate the impact on DQE. METHODS Following the IEC standard, edge and flat field images were acquired on a cardiac flat-panel detector to calculate MTF and noise power spectrum, respectively, to determine DQE. Accuracy of the methods in determining the correct angle was ascertained using a simulated edge image with known angulations. Precision of the methods was ascertained using variability of MTF and DQE, calculated via bootstrapping. RESULTS Three methods provided near equal angles and the same MTF while the fourth, with an angular difference of 6%, had a MTF lower by 3% at 1.5 mm(-1) spatial frequency and 8% at 2.5 mm(-1); corresponding DQE differences were 6% at 1.5 mm(-1) and 17% at 2.5 mm(-1); differences were greater than standard deviations in the measurements. CONCLUSIONS DQE measurements may vary by a significant amount, depending on the method used to determine the edge angle when following the IEC standard methodology for a cardiac x-ray detector. The most accurate and precise methods are recommended for absolute assessments and reproducible measurements, respectively.
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Affiliation(s)
- Amber J Gislason-Lee
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Clare M Tunstall
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Stephen K Kengyelics
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Arnold R Cowen
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Andrew G Davies
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
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