101
|
Richards CE, Obaid DR. Low-Dose Radiation Advances in Coronary Computed Tomography Angiography in the Diagnosis of Coronary Artery Disease. Curr Cardiol Rev 2019; 15:304-315. [PMID: 30806322 PMCID: PMC8142354 DOI: 10.2174/1573403x15666190222163737] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/24/2018] [Accepted: 12/26/2018] [Indexed: 01/16/2023] Open
Abstract
Background
Coronary computed tomography angiography (CCTA) is now widely used in the diagnosis of coronary artery disease since it is a rapid, minimally invasive test with a diagnostic accuracy comparable to coronary angiography. However, to meet demands for increasing spatial and temporal resolution, higher x-ray radiation doses are required to circumvent the resulting increase in image noise. Exposure to high doses of ionizing radiation with CT imaging is a major health concern due to the potential risk of radiation-associated malignancy. Given its increasing use, a number of dose saving algorithms have been implemented to CCTA to minimize radiation exposure to “as low as reasonably achievable (ALARA)” without compromising diagnostic image quality. Objective
The purpose of this review is to outline the most recent advances and current status of dose saving techniques in CCTA. Method
PubMed, Medline, EMBASE and Scholar databases were searched to identify feasibility studies, clinical trials, and technology guidelines on the technical advances in CT scanner hardware and reconstruction software. Results
Sub-millisievert (mSv) radiation doses have been reported for CCTA due to a combination of strategies such as prospective electrocardiogram-gating, high-pitch helical acquisition, tube current modulation, tube voltage reduction, heart rate reduction, and the most recent novel adaptive iterative reconstruction algorithms. Conclusion
Advances in radiation dose reduction without loss of image quality justify the use of CCTA as a non-invasive alternative to coronary catheterization in the diagnosis of coronary artery disease.
Collapse
Affiliation(s)
- Caryl E Richards
- Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Swansea, SA6 6NL, United Kingdom
| | - Daniel R Obaid
- Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Swansea, SA6 6NL, United Kingdom.,Swansea University Medical School, Swansea University, Grove Building, Singleton Park, Sketty, Swansea SA2 8PP, United Kingdom
| |
Collapse
|
102
|
Beak P, Gabbott B, Williamson M, Hing CB. Four years of experience as a major trauma centre results in no improvement in patient selection for whole-body CT scans following blunt trauma. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2019; 30:473-477. [PMID: 31705403 DOI: 10.1007/s00590-019-02592-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 11/02/2019] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Management of major trauma patients with evidence of polytrauma involves the use of immediate whole-body CT (WBCT). Identification of patients appropriate for immediate WBCT remains challenging. Our study aimed to assess for improvement in patient selection for WBCT over time as a major trauma centre (MTC). METHODS We conducted a retrospective study of patients who presented to our MTC during distinct two-month periods, one in 2013 and the other in 2017. Patients over 18 years of age who presented primarily following blunt trauma and activated a major trauma call were included. All patients underwent either immediate WBCT or standard ATLS workup. Those undergoing WBCT had the results of their scan recorded as positive or negative. RESULTS A total of 516 patients were included, 232 from 2 months in 2013 and 284 from 2 months in 2017. There was no significant difference in the proportion of patients undergoing WBCT (61.6% vs 59.5%), selective CT (31.9% vs 32.4%) or no CT (6.5% vs 8.1%) between the cohorts. There was no improvement in the rate of negative WBCT observed between 2013 and 2017 (47.6% vs 39.6%, p = 0.17). CONCLUSION There was no improvement in patient selection for WBCT following trauma at our institution over a three-year period. Optimal patient selection presents an ongoing clinical challenge, with 39-47% of patients undergoing a scan demonstrating no injuries.
Collapse
Affiliation(s)
- Philip Beak
- Department of Trauma and Orthopaedics, St George's Hospital, St George's University Hospitals NHS Foundation Trust, London, UK.
| | - Ben Gabbott
- Department of Trauma and Orthopaedics, St George's Hospital, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Michael Williamson
- Department of Trauma and Orthopaedics, St George's Hospital, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Caroline B Hing
- Department of Trauma and Orthopaedics, St George's Hospital, St George's University Hospitals NHS Foundation Trust, London, UK
| |
Collapse
|
103
|
Raslau FD, Escott EJ, Smiley J, Adams C, Feigal D, Ganesh H, Wang C, Zhang J. Dose Reduction While Preserving Diagnostic Quality in Head CT: Advancing the Application of Iterative Reconstruction Using a Live Animal Model. AJNR Am J Neuroradiol 2019; 40:1864-1870. [PMID: 31601574 DOI: 10.3174/ajnr.a6258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/21/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Iterative reconstruction has promise in lowering the radiation dose without compromising image quality, but its full potential has not yet been realized. While phantom studies cannot fully approximate the subjective effects on image quality, live animal models afford this assessment. We characterize dose reduction in head CT by applying advanced modeled iterative reconstruction (ADMIRE) in a live ovine model while evaluating preservation of gray-white matter detectability and image texture compared with filtered back-projection. MATERIALS AND METHODS A live sheep was scanned on a Force CT scanner (Siemens) at 12 dose levels (82-982 effective mAs). Images were reconstructed with filtered back-projection and ADMIRE (strengths, 1-5). A total of 72 combinations (12 doses × 6 reconstructions) were evaluated qualitatively for resemblance to the reference image (highest dose with filtered back-projection) using 2 metrics: detectability of gray-white matter differentiation and noise-versus-smoothness in image texture. Quantitative analysis for noise, SNR, and contrast-to-noise was also performed across all dose-strength combinations. RESULTS Both qualitative and quantitative results confirm that gray-white matter differentiation suffers at a lower dose but recovers when complemented by higher iterative reconstruction strength, and image texture acquires excessive smoothness with a higher iterative reconstruction strength but recovers when complemented by dose reduction. Image quality equivalent to the reference image is achieved by a 58% dose reduction with ADMIRE-5. CONCLUSIONS An approximately 60% dose reduction may be possible while preserving diagnostic quality with the appropriate dose-strength combination. This in vivo study can serve as a useful guide for translating the full implementation of iterative reconstruction in clinical practice.
Collapse
Affiliation(s)
- F D Raslau
- From the Departments of Radiology (F.D.R., E.J.E., C.A., D.F., H.G., J.Z.) .,Neurology (F.D.R.).,Neurosurgery (F.D.R.)
| | - E J Escott
- From the Departments of Radiology (F.D.R., E.J.E., C.A., D.F., H.G., J.Z.).,Otolaryngology-Head and Neck Surgery (E.J.E.)
| | - J Smiley
- Laboratory Animal Resources (J.S.)
| | - C Adams
- From the Departments of Radiology (F.D.R., E.J.E., C.A., D.F., H.G., J.Z.)
| | - D Feigal
- From the Departments of Radiology (F.D.R., E.J.E., C.A., D.F., H.G., J.Z.)
| | - H Ganesh
- From the Departments of Radiology (F.D.R., E.J.E., C.A., D.F., H.G., J.Z.)
| | - C Wang
- Biostatistics (C.W.), University of Kentucky, Lexington, Kentucky
| | - J Zhang
- From the Departments of Radiology (F.D.R., E.J.E., C.A., D.F., H.G., J.Z.)
| |
Collapse
|
104
|
Wang T, Lei Y, Tian Z, Dong X, Liu Y, Jiang X, Curran WJ, Liu T, Shu HK, Yang X. Deep learning-based image quality improvement for low-dose computed tomography simulation in radiation therapy. J Med Imaging (Bellingham) 2019; 6:043504. [PMID: 31673567 PMCID: PMC6811730 DOI: 10.1117/1.jmi.6.4.043504] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/03/2019] [Indexed: 01/02/2023] Open
Abstract
Low-dose computed tomography (CT) is desirable for treatment planning and simulation in radiation therapy. Multiple rescanning and replanning during the treatment course with a smaller amount of dose than a single conventional full-dose CT simulation is a crucial step in adaptive radiation therapy. We developed a machine learning-based method to improve image quality of low-dose CT for radiation therapy treatment simulation. We used a residual block concept and a self-attention strategy with a cycle-consistent adversarial network framework. A fully convolution neural network with residual blocks and attention gates (AGs) was used in the generator to enable end-to-end transformation. We have collected CT images from 30 patients treated with frameless brain stereotactic radiosurgery (SRS) for this study. These full-dose images were used to generate projection data, which were then added with noise to simulate the low-mAs scanning scenario. Low-dose CT images were reconstructed from this noise-contaminated projection data and were fed into our network along with the original full-dose CT images for training. The performance of our network was evaluated by quantitatively comparing the high-quality CT images generated by our method with the original full-dose images. When mAs is reduced to 0.5% of the original CT scan, the mean square error of the CT images obtained by our method is ∼ 1.6 % , with respect to the original full-dose images. The proposed method successfully improved the noise, contract-to-noise ratio, and nonuniformity level to be close to those of full-dose CT images and outperforms a state-of-the-art iterative reconstruction method. Dosimetric studies show that the average differences of dose-volume histogram metrics are < 0.1 Gy ( p > 0.05 ). These quantitative results strongly indicate that the denoised low-dose CT images using our method maintains image accuracy and quality and are accurate enough for dose calculation in current CT simulation of brain SRS treatment. We also demonstrate the great potential for low-dose CT in the process of simulation and treatment planning.
Collapse
Affiliation(s)
- Tonghe Wang
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Yang Lei
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Zhen Tian
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Xue Dong
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Yingzi Liu
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Xiaojun Jiang
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Walter J. Curran
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Tian Liu
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Hui-Kuo Shu
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Xiaofeng Yang
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| |
Collapse
|
105
|
Feasibility of Submillisievert CT of the Skeletal Pelvis Using Iterative Reconstruction: A Human Cadaver Study. AJR Am J Roentgenol 2019; 213:903-911. [PMID: 31287726 DOI: 10.2214/ajr.18.20933] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
106
|
Baliyan V, Shaqdan K, Hedgire S, Ghoshhajra B. Vascular computed tomography angiography technique and indications. Cardiovasc Diagn Ther 2019; 9:S14-S27. [PMID: 31559151 DOI: 10.21037/cdt.2019.07.04] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Non-invasive cross-sectional imaging techniques play a crucial role in the assessment of the vascular disease processes. Computed tomography angiography (CTA) is an imaging method of choice for a wide range of vascular diseases that span across different vascular territories. A diagnostic quality CTA requires a robust imaging protocol tailored according to the physiologic state and vascular area of interest. This review article is aimed to provide an overview of the technical considerations and clinical applications of CTA.
Collapse
Affiliation(s)
- Vinit Baliyan
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Khalid Shaqdan
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Sandeep Hedgire
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Brian Ghoshhajra
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
107
|
Chen CW, Chen PA, Chou CC, Fu JH, Wang PC, Hsu SH, Lai PH. Combination of Adaptive Statistical Iterative Reconstruction-V and Lower Tube Voltage During Craniocervical Computed Tomographic Angiography Yields Better Image Quality with a Reduced Radiation Dose. Acad Radiol 2019; 26:e233-e240. [PMID: 30195416 DOI: 10.1016/j.acra.2018.07.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/24/2018] [Accepted: 07/27/2018] [Indexed: 02/06/2023]
Abstract
RATIONALE AND OBJECTIVES To evaluate image quality and radiation exposure when using the adaptive statistical iterative reconstruction-V (ASIR-V) algorithm for reconstructing craniocervical computed tomographic angiography images acquired at 100 kVp. MATERIALS AND METHODS We randomly divided 121 patients into three groups: group A (conventional protocol), 120 kVp with filtered back projection; group B, 120 kVp with 50% ASIR-V; and group C, 100 kVp with 50% ASIR-V. All patients underwent scans in a 256-slice computed tomography (CT) scanner. Radiation dose (volume CT dose index), dose-length product, and effective dose, objective parameters such as arterial attenuation value, signal-to-noise ratio, contrast-to-noise ratio, and noise obtained at head, neck, and shoulder levels were compared among the groups. Subjective image quality was independently assessed by two radiologists, and interobserver reliability was assessed using kappa analysis. RESULTS The radiation dose in group C was the lowest (p < 0.01) with a 40% reduction in volume CT dose index, dose-length product, and effective dose values compared to group A, and group C showed higher arterial attenuation than either group A or B (p < 0.01). Additionally, signal-to-noise ratio and contrast-to-noise ratio were higher and noise was lower in groups B and C than group A. Group C had better subjective image quality than groups A and B (p < 0.05), and the interobserver reliability between the two radiologists was high (k = 0.783). CONCLUSION Compared to the conventional protocol, using 50% ASIR-V and the 100 kVp protocol during craniocervical computed tomographic angiography yields better objective and subjective image quality at lower radiation doses.
Collapse
|
108
|
Abstract
CLINICAL/METHODICAL ISSUE Computed tomography (CT) acquisition should be performed following the ALARA principle: keeping patient radiation exposure as low as reasonably achievable. STANDARD RADIOLOGICAL METHODS Reconstruction with filtered backprojection is still the standard in CT. METHODICAL INNOVATIONS Recently, iterative reconstruction techniques have become available, using a different approach for image reconstruction. A similar approach is used for iterative metal artifact reduction. PERFORMANCE Compared to filtered backprojection, iterative reconstruction yields improvements in image quality and reduces image noise. ACHIEVEMENTS Using iterative reconstruction allows the reduction of patient radiation exposure by up to 80%, depending on the used algorithm and the clinical task at hand. With the help of iterative metal artifact reduction, images of diagnostic quality can be acquired despite metal implants. PRACTICAL RECOMMENDATIONS Iterative reconstruction should be used to reduce patient radiation exposure in accordance with the clinical requirements. The use of iterative metal artifact reduction is recommended.
Collapse
|
109
|
You SK, Choi YH, Cheon JE, Kim WS, Kim IO, Lee SM, Cho HH. Effect of low tube voltage and low iodine concentration abdominal CT on image quality and radiation dose in children: preliminary study. Abdom Radiol (NY) 2019; 44:1928-1935. [PMID: 30683980 DOI: 10.1007/s00261-019-01896-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE To evaluate the image quality of a double-low protocol (low tube voltage and low iodine concentration) for abdominal CT in children. MATERIALS AND METHODS The double-low protocol was compared to the conventional protocol in pediatric patients weighing less than 40 kg from May 2016 to December 2016. Double-low protocol (Group A, n = 18): tube voltage, 70 kVp; and iodine concentration,: 250 mgI/mL versus Conventional protocol (Group B, n = 13): tube voltage, 80-100 kVp; and iodine concentration, 350 mgI/mL. Mean attenuation, noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were compared between the two groups. Image contrast, noise, beam-hardening artifacts, and overall image quality were subjectively scored. Reader performance for correctly differentiating two groups by visual assessment was evaluated. Radiation dose and total iodine load were recorded. RESULTS The mean attenuations of the portal vein and liver and the mean image noise in Group A were higher than in Group B (p = 0.04, 0.03, 0.004, respectively). The mean SNR and CNR of the main portal vein and liver were lower in Group A without any statistically significant difference. There were no statistically significant differences between the two groups in qualitative analysis (image contrast, image noise, and overall image quality) with substantial agreement between the reviewers (weighted kappa values; 0.59-0.76). Significantly diminished radiation dose and iodine load were observed in Group A compared with Group B (25.0%, 36.8% reduction; p = 0.007, 0.006, respectively). CONCLUSION The double-low protocol was feasible for pediatric abdominal CT and reduced both radiation dose and iodine load, while maintaining image quality.
Collapse
|
110
|
Hamamura T, Hayashida Y, Takeshita Y, Sugimoto K, Ueda I, Futatsuya K, Kakeda S, Aoki T, Korogi Y. The usefulness of full-iterative reconstruction algorithm for the visualization of cystic artery on CT angiography. Jpn J Radiol 2019; 37:526-533. [PMID: 31041661 DOI: 10.1007/s11604-019-00839-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/08/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate the potential of full-iterative reconstruction (IR) for improving image quality of the cystic artery on CT angiography and to assess observer performance. METHODS Thirty patients who underwent both liver dynamic CT and conventional angiography were included in this retrospective study. All CT data were reconstructed through filtered back projection (FBP), adaptive iterative dose reduction 3D (AIDR3D), and forward-projected, model-based, iterative reconstruction solution (FIRST), respectively. In objective study, we analyzed mean ΔCT numbers (the difference between the HU peak of the vessel and the background) and full-width at tenth-maximum (FWTM) of three parts of the cystic artery by profile curve method comparing the three reconstructions. Subjectively, visualization was evaluated using a four-point scale performed by two blinded observers. ANOVA was used for statistical analysis. RESULTS In all parts of the cystic artery, the mean ΔCT number of FIRST was shown to be significantly better than that of FBP and AIDR3D (p < 0.05). FWTM in FIRST was the smallest in all of the vessels. The mean visualization score was significantly better with FIRST than with other CT reconstructions (p < 0.05). CONCLUSIONS The FIRST algorithm led to improved CTA visualization of the cystic artery.
Collapse
Affiliation(s)
- Toshihiko Hamamura
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan.
| | - Yoshiko Hayashida
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| | - Yohei Takeshita
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| | - Koichiro Sugimoto
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| | - Issei Ueda
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| | - Koichiro Futatsuya
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| | - Shingo Kakeda
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| | - Takatoshi Aoki
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| | - Yukunori Korogi
- Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan
| |
Collapse
|
111
|
Southard RN, Bardo DME, Temkit MH, Thorkelson MA, Augustyn RA, Martinot CA. Comparison of Iterative Model Reconstruction versus Filtered Back-Projection in Pediatric Emergency Head CT: Dose, Image Quality, and Image-Reconstruction Times. AJNR Am J Neuroradiol 2019; 40:866-871. [PMID: 30975652 DOI: 10.3174/ajnr.a6034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 02/27/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Noncontrast CT of the head is the initial imaging test for traumatic brain injury, stroke, or suspected nonaccidental trauma. Low-dose head CT protocols using filtered back-projection are susceptible to increased noise and decreased image quality. Iterative reconstruction noise suppression allows the use of lower-dose techniques with maintained image quality. We review our experience with children undergoing emergency head CT examinations reconstructed using knowledge-based iterative model reconstruction versus standard filtered back-projection, comparing reconstruction times, radiation dose, and objective and subjective image quality. MATERIALS AND METHODS This was a retrospective study comparing 173 children scanned using standard age-based noncontrast head CT protocols reconstructed with filtered back-projection with 190 children scanned using low-dose protocols reconstructed with iterative model reconstruction. ROIs placed on the frontal white matter and thalamus yielded signal-to-noise and contrast-to-noise ratios. Volume CT dose index and study reconstruction times were recorded. Random subgroups of patients were selected for subjective image-quality review. RESULTS The volume CT dose index was significantly reduced in studies reconstructed with iterative model reconstruction compared with filtered back-projection, (mean, 24.4 ± 3.1 mGy versus 31.1 ± 6.0 mGy, P < .001), while the SNR and contrast-to-noise ratios improved 2-fold (P < .001). Radiologists graded iterative model reconstruction images as superior to filtered back-projection images for gray-white matter differentiation and anatomic detail (P < .001). The average reconstruction time of the filtered back-projection studies was 101 seconds, and with iterative model reconstruction, it was 147 seconds (P < .001), without a practical effect on work flow. CONCLUSIONS In children referred for emergency noncontrast head CT, optimized low-dose protocols with iterative model reconstruction allowed us to significantly reduce the relative dose, on average, 22% compared with filtered back-projection, with significantly improved objective and subjective image quality.
Collapse
Affiliation(s)
- R N Southard
- From the Departments of Medical Imaging (R.N.S., D.M.E.B., M.A.T., R.A.A., C.A.M.)
| | - D M E Bardo
- From the Departments of Medical Imaging (R.N.S., D.M.E.B., M.A.T., R.A.A., C.A.M.)
| | - M H Temkit
- Clinical Research (M.H.T.), Phoenix Children's Hospital, Phoenix Arizona
| | - M A Thorkelson
- From the Departments of Medical Imaging (R.N.S., D.M.E.B., M.A.T., R.A.A., C.A.M.)
| | - R A Augustyn
- From the Departments of Medical Imaging (R.N.S., D.M.E.B., M.A.T., R.A.A., C.A.M.)
| | - C A Martinot
- From the Departments of Medical Imaging (R.N.S., D.M.E.B., M.A.T., R.A.A., C.A.M.)
| |
Collapse
|
112
|
Afzelius P, Nielsen OL, Schønheyder HC, Alstrup A, Hansen SB. An untapped potential for imaging of peripheral osteomyelitis in paediatrics using [ 18F]FDG PET/CT -the inference from a juvenile porcine model. EJNMMI Res 2019; 9:29. [PMID: 30903403 PMCID: PMC6430261 DOI: 10.1186/s13550-019-0498-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 03/11/2019] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To examine parameters affecting the detection of osteomyelitis (OM) by [18F]FDG PET/CT and to reduce tracer activity in a pig model. BACKGROUND [18F]FDG PET/CT is recommended for the diagnosis of OM in the axial skeleton of adults. In children, OM has a tendency to become chronic or recurrent, especially in low-income countries. Early diagnosis and initiation of therapy are therefore essential. We have previously demonstrated that [18F]FDG PET/CT is promising in juvenile Staphylococcus aureus (S. aureus) OM of peripheral bones in a pig model, not failing even small lesions. When using imaging in children, radiation exposure should be balanced against fast diagnostics in the individual case. METHODS Twenty juvenile pigs were inoculated with S. aureus. One week after inoculation, the pigs were [18F]FDG PET/CT scanned. PET list-mode acquired data of a subgroup were retrospectively processed in order to simulate and examine the image quality obtainable with an injected activity of 132 MBq, 44 MBq, 13.2 MBq, and 4.4 MBq, respectively. RESULTS All lesions were detected by [18F]FDG PET and CT. Some lesions were very small (0.01 cm3), and others were larger (4.18 cm3). SUVmax was higher when sequesters (p = 0.023) and fistulas were formed (p < 0.0001). The simulated data demonstrated that it was possible to reduce the activity to 4.4 MBq without compromising image quality in pigs. CONCLUSIONS [18F]FDG PET/CT localized even small OM lesions in peripheral bones. It was possible to reduce the injected activity considerably without compromising image quality, impacting the applicability of PET/CT in peripheral OM in children.
Collapse
Affiliation(s)
- P. Afzelius
- Department of Diagnostic Imaging, Section of Clinical Physiology and Nuclear Medicine, North Zealand Hospital, Dyrehavevej 29, 3400 Hillerod, Denmark
- Department of Nuclear Medicine, Aalborg University Hospital, Aalborg, Denmark
| | - O. L. Nielsen
- Department of Veterinary and Animal Science, University of Copenhagen, Copenhagen, Denmark
| | - H. C. Schønheyder
- Department of Clinical Microbiology, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - A.K.O. Alstrup
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| | - S. B. Hansen
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| |
Collapse
|
113
|
Zhang L, Li Z, Meng J, Xie X, Zhang H. Airway quantification using adaptive statistical iterative reconstruction-V on wide-detector low-dose CT: a validation study on lung specimen. Jpn J Radiol 2019; 37:390-398. [PMID: 30820822 DOI: 10.1007/s11604-019-00818-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 01/31/2019] [Indexed: 12/31/2022]
Abstract
PURPOSE To evaluate the accuracy of airway quantification of adaptive statistical iterative reconstruction (ASIR)-V on low-dose CT using a human lung specimen. METHOD A lung specimen was scanned on Revolution CT with low-dose settings (20 mAs, 40 mAs and 60 mAs/100 kV) and standard-dose setting (100 mAs/120 kV). CT images were reconstructed using lung kernel with eleven ASIR-V levels from 0 to 100% with 10% interval. ASIR-V level from 0 to 100% with 10% interval was reconstructed on lung kernel. Wall area percentage (%WA) and wall thickness (WT) were measured. RESULTS Radiation dose of 20 mAs, 40 mAs and 60 mAs low-dose settings reduced by 87.6%, 75.2% and 62.8% compared to that on standard dose, respectively. Low-dose settings significantly decreased image SNR (p < 0.05) and increased noise (p < 0.001). ASIR-V level exponentially improved image SNR and linearly decreased image noise (all p < 0.001). The mean airway measurement ratios of low-dose to standard-dose were within 2% variation for %WA and within 3% variation for WT. Most %WA and WT values showed no obvious correlation with ASIR-V levels. CONCLUSION ASIR-V showed to improve image quality in low radiation dose. However, low-dose settings and ASIR-V strength did not significantly influence airway quantification values, although variation in measurements slightly increased with dose reduction.
Collapse
Affiliation(s)
- Lin Zhang
- Department of Radiology, Shanghai General Hospital of Nanjing Medical University, No. 100 Haining Road, Shanghai, 200080, People's Republic of China
| | - Zhengyu Li
- Department of Radiology, Shanghai General Hospital of Nanjing Medical University, No. 100 Haining Road, Shanghai, 200080, People's Republic of China
| | - Jie Meng
- Department of Radiology, Shanghai General Hospital of Nanjing Medical University, No. 100 Haining Road, Shanghai, 200080, People's Republic of China
| | - Xueqian Xie
- Department of Radiology, Shanghai General Hospital of Nanjing Medical University, No. 100 Haining Road, Shanghai, 200080, People's Republic of China.
| | - Hao Zhang
- Department of Radiology, Shanghai General Hospital of Nanjing Medical University, No. 100 Haining Road, Shanghai, 200080, People's Republic of China.
| |
Collapse
|
114
|
Evaluation of Adaptive Statistical Iterative Reconstruction-V Reconstruction Algorithm vs Filtered Back Projection in the Detection of Hypodense Liver Lesions: Reader Performance and Preferences. J Comput Assist Tomogr 2019; 43:200-205. [PMID: 30762652 DOI: 10.1097/rct.0000000000000830] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of the study was to evaluate diagnostic accuracy and readers' experience in the detection of focal liver lesions on computed tomography with Adaptive Statistical Iterative Reconstruction-V (ASIR-V) reconstruction compared with filtered back projection (FBP) scans. METHODS Fifty-five patients with liver lesions had FBP and ASIR-V scans. Two radiologists independently reviewed both sets of computed tomography scans, identifying and characterizing liver lesions. RESULTS Adaptive Statistical Iterative Reconstruction-V scans had a reduction in dose length product (P < 0.0001) with no difference in image contrast (P = 0.1805); image noise was less for the ASIR-V scans (P < 0.0001) and contrast-to-noise ratio was better for ASIR-V (P = 0.0002). Both readers found more hypodense liver lesions on the FBP (P = 0.01) scans. Multiple subjective imaging scores were significantly less for the ASIR-V scans for both readers. CONCLUSIONS Although ASIR-V scans were objectively better, our readers performed worse in lesion detection on them, suggesting a need for better education/experience with this technology during implementation.
Collapse
|
115
|
Saltybaeva N, Krauss A, Alkadhi H. Technical Note: Radiation dose reduction from computed tomography localizer radiographs using a tin spectral shaping filter. Med Phys 2019; 46:544-549. [DOI: 10.1002/mp.13353] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 12/04/2018] [Accepted: 12/06/2018] [Indexed: 01/30/2023] Open
Affiliation(s)
- Natalia Saltybaeva
- Institute for Diagnostic and Interventional Radiology University Hospital Zurich Zurich Switzerland
| | - Andreas Krauss
- Computed Tomography Division Siemens Healthineers Forchheim Germany
| | - Hatem Alkadhi
- Institute for Diagnostic and Interventional Radiology University Hospital Zurich Zurich Switzerland
| |
Collapse
|
116
|
Accuracy of Pulmonary Nodule Volumetry at Different Exposure Parameters in Low-Dose Computed Tomography. J Comput Assist Tomogr 2019; 43:926-930. [DOI: 10.1097/rct.0000000000000908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
117
|
Comparison of Metal Artifact Reduction in Dual- and Single-Source CT: A Vertebral Phantom Study. AJR Am J Roentgenol 2018; 211:1298-1305. [DOI: 10.2214/ajr.17.19397] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
118
|
Richards CE, Dorman S, John P, Davies A, Evans S, Ninan T, Martin D, Kannoly S, Roberts-Davies G, Ramsey M, Obaid DR. Low-radiation and high image quality coronary computed tomography angiography in “real-world” unselected patients. World J Radiol 2018; 10:135-142. [PMID: 30386498 PMCID: PMC6205842 DOI: 10.4329/wjr.v10.i10.135] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/14/2018] [Accepted: 10/08/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To determine the radiation dose and image quality in coronary computed tomography angiography (CCTA) using state-of-the-art dose reduction methods in unselected “real world” patients.
METHODS In this single-centre study, consecutive patients in sinus rhythm underwent CCTA for suspected coronary artery disease (CAD) using a 320-row detector CT scanner. All patients underwent the standard CT acquisition protocol at our institute (Morriston Hospital) a combination of dose saving advances including prospective electrocardiogram-gating, automated tube current modulation, tube voltage reduction, heart rate reduction, and the most recent novel adaptive iterative dose reconstruction 3D (AIDR3D) algorithm. The cohort comprised real-world patients for routine CCTA who were not selected on age, body mass index, or heart rate. Subjective image quality was graded on a 4-point scale (4 = excellent, 1 = non-diagnostic).
RESULTS A total of 543 patients were included in the study with a mean body weight of 81 ± 18 kg and a pre-scan mean heart rate of 70 ± 11 beats per minute (bpm). When indicated, patients received rate-limiting medication with an oral beta-blocker followed by additional intravenous beta-blocker to achieve a heart rate below 65 bpm. The median effective radiation dose was 0.88 mSv (IQR, 0.6-1.4 mSv) derived from a Dose Length Product of 61.45 mGy.cm (IQR, 42.86-100.00 mGy.cm). This also includes what we believe to be the lowest ever-reported radiation dose for a routine clinical CCTA (0.18 mSv). The mean image quality (± SD) was 3.65 ± 0.61, with a subjective image quality score of 3 (“good”) or above for 93% of patient CCTAs.
CONCLUSION Combining a low-dose scan protocol and AIDR3D with a 320-detector row CT scanner can provide high quality images at exceptionally low radiation dose in unselected patients being investigated for CAD.
Collapse
Affiliation(s)
- Caryl Elizabeth Richards
- Swansea University Medical School, Swansea University, Grove Building, Singleton Park, Sketty, Swansea SA2 8PP, United Kingdom
| | - Stephen Dorman
- Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
| | - Patricia John
- Department of Radiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
| | - Anthony Davies
- Department of Radiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
| | - Sharon Evans
- Department of Radiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
| | - Tishi Ninan
- Department of Radiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
| | - David Martin
- Department of Radiology, Singleton Hospital, Sketty Ln, Sketty, Swansea SA2 8QA, United Kingdom
| | - Sriranj Kannoly
- Department of Cardiology, Singleton Hospital, Sketty Ln, Sketty, Swansea SA2 8QA, United Kingdom
| | - Gail Roberts-Davies
- Department of Radiology, Singleton Hospital, Sketty Ln, Sketty, Swansea SA2 8QA, United Kingdom
| | - Mark Ramsey
- Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
| | - Daniel Rhys Obaid
- Swansea University Medical School, Swansea University, Grove Building, Singleton Park, Sketty, Swansea SA2 8PP, United Kingdom
- Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
| |
Collapse
|
119
|
Kim DJ, Kim C, Shin C, Lee SK, Ko CS, Lee KY. Impact of Model-Based Iterative Reconstruction on the Correlation between Computed Tomography Quantification of a Low Lung Attenuation Area and Airway Measurements and Pulmonary Function Test Results in Normal Subjects. Korean J Radiol 2018; 19:1187-1195. [PMID: 30386150 PMCID: PMC6201968 DOI: 10.3348/kjr.2018.19.6.1187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/28/2018] [Indexed: 12/11/2022] Open
Abstract
Objective To compare correlations between pulmonary function test (PFT) results and different reconstruction algorithms and to suggest the optimal reconstruction protocol for computed tomography (CT) quantification of low lung attenuation areas and airways in healthy individuals. Materials and Methods A total of 259 subjects with normal PFT and chest CT results were included. CT scans were reconstructed using filtered back projection, hybrid-iterative reconstruction, and model-based IR (MIR). For quantitative analysis, the emphysema index (EI) and wall area percentage (WA%) were determined. Subgroup analysis according to smoking history was also performed. Results The EIs of all the reconstruction algorithms correlated significantly with the forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) (all p < 0.001). The EI of MIR showed the strongest correlation with FEV1/FVC (r = -0.437). WA% showed a significant correlation with FEV1 in all the reconstruction algorithms (all p < 0.05) correlated significantly with FEV1/FVC for MIR only (p < 0.001). The WA% of MIR showed the strongest correlations with FEV1 (r = -0.205) and FEV1/FVC (r = -0.250). In subgroup analysis, the EI of MIR had the strongest correlation with PFT in both ever-smoker and never-smoker subgroups, although there was no significant difference in the EI between the reconstruction algorithms. WA% of MIR showed a significantly thinner airway thickness than the other algorithms (49.7 ± 7.6 in ever-smokers and 49.5 ± 7.5 in never-smokers, all p < 0.001), and also showed the strongest correlation with PFT in both ever-smoker and never-smoker subgroups. Conclusion CT quantification of low lung attenuation areas and airways by means of MIR showed the strongest correlation with PFT results among the algorithms used, in normal subjects.
Collapse
Affiliation(s)
- Da Jung Kim
- Department of Radiology, Korea University College of Medicine, Korea University Ansan Hospital, Ansan 15355, Korea
| | - Cherry Kim
- Department of Radiology, Korea University College of Medicine, Korea University Ansan Hospital, Ansan 15355, Korea
| | - Chol Shin
- Department of Pulmonology, Korea University College of Medicine, Korea University Ansan Hospital, Ansan 15355, Korea
| | - Seung Ku Lee
- Institute for Human Genomic Study, Korea University College of Medicine, Korea University Ansan Hospital, Ansan 15355, Korea
| | - Chang Sub Ko
- Department of Radiology, Korea University College of Medicine, Korea University Ansan Hospital, Ansan 15355, Korea
| | - Ki Yeol Lee
- Department of Radiology, Korea University College of Medicine, Korea University Ansan Hospital, Ansan 15355, Korea
| |
Collapse
|
120
|
Quantifying Decreased Radiation Exposure From Modern CT Scan Technology and Surveillance Programs of Germ Cell Tumors. Am J Clin Oncol 2018; 41:949-952. [DOI: 10.1097/coc.0000000000000399] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
121
|
State-of-the-Art Imaging for the Evaluation of Pulmonary Embolism. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2018; 20:71. [DOI: 10.1007/s11936-018-0671-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
122
|
Hong SG, Kang EJ, Park JH, Choi WJ, Lee KN, Kwon HJ, Ha DH, Kim DW, Kim SH, Jo JH, Lee J. Effect of Hybrid Kernel and Iterative Reconstruction on Objective and Subjective Analysis of Lung Nodule Calcification in Low-Dose Chest CT. Korean J Radiol 2018; 19:888-896. [PMID: 30174478 PMCID: PMC6082754 DOI: 10.3348/kjr.2018.19.5.888] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 03/02/2018] [Indexed: 12/30/2022] Open
Abstract
Objective To evaluate the differences in subjective calcification detection rates and objective calcium volumes in lung nodules according to different reconstruction methods using hybrid kernel (FC13-H) and iterative reconstruction (IR). Materials and Methods Overall, 35 patients with small (< 4 mm) calcified pulmonary nodules on chest CT were included. Raw data were reconstructed using filtered back projection (FBP) or IR algorithm (AIDR-3D; Canon Medical Systems Corporation), with three types of reconstruction kernel: conventional lung kernel (FC55), FC13-H and conventional soft tissue kernel (FC13). The calcium volumes of pulmonary nodules were quantified using the modified Agatston scoring method. Two radiologists independently interpreted the role of each nodule calcification on the six types of reconstructed images (FC55/FBP, FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D). Results Seventy-eight calcified nodules detected on FC55/FBP images were regarded as reference standards. The calcium detection rates of FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D protocols were 80.7%, 15.4%, 6.4%, 52.6%, and 28.2%, respectively, and FC13-H/AIDR-3D showed the smallest calcium detection rate. The calcium volume varied significantly with reconstruction protocols and FC13/AIDR-3D showed the smallest calcium volume (0.04 ± 0.22 mm3), followed by FC13-H/AIDR-3D. Conclusion Hybrid kernel and IR influence subjective detection and objective measurement of calcium in lung nodules, particularly when both techniques (FC13-H/AIDR-3D) are combined.
Collapse
Affiliation(s)
- Seul Gi Hong
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Eun-Ju Kang
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Jae Hyung Park
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Won Jin Choi
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Ki-Nam Lee
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Hee Jin Kwon
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Dong-Ho Ha
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Dong Won Kim
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Sang Hyeon Kim
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Jeong-Hyun Jo
- Department of Radiology, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Jongmin Lee
- Department of Radiology, College of Medicine, Kyungpook National University, Daegu 41944, Korea
| |
Collapse
|
123
|
Berenguer R, Pastor-Juan MDR, Canales-Vázquez J, Castro-García M, Villas MV, Mansilla Legorburo F, Sabater S. Radiomics of CT Features May Be Nonreproducible and Redundant: Influence of CT Acquisition Parameters. Radiology 2018; 288:407-415. [PMID: 29688159 DOI: 10.1148/radiol.2018172361] [Citation(s) in RCA: 422] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Purpose To identify the reproducible and nonredundant radiomics features (RFs) for computed tomography (CT). Materials and Methods Two phantoms were used to test RF reproducibility by using test-retest analysis, by changing the CT acquisition parameters (hereafter, intra-CT analysis), and by comparing five different scanners with the same CT parameters (hereafter, inter-CT analysis). Reproducible RFs were selected by using the concordance correlation coefficient (as a measure of the agreement between variables) and the coefficient of variation (defined as the ratio of the standard deviation to the mean). Redundant features were grouped by using hierarchical cluster analysis. Results A total of 177 RFs including intensity, shape, and texture features were evaluated. The test-retest analysis showed that 91% (161 of 177) of the RFs were reproducible according to concordance correlation coefficient. Reproducibility of intra-CT RFs, based on coefficient of variation, ranged from 89.3% (151 of 177) to 43.1% (76 of 177) where the pitch factor and the reconstruction kernel were modified, respectively. Reproducibility of inter-CT RFs, based on coefficient of variation, also showed large material differences, from 85.3% (151 of 177; wood) to only 15.8% (28 of 177; polyurethane). Ten clusters were identified after the hierarchical cluster analysis and one RF per cluster was chosen as representative. Conclusion Many RFs were redundant and nonreproducible. If all the CT parameters are fixed except field of view, tube voltage, and milliamperage, then the information provided by the analyzed RFs can be summarized in only 10 RFs (each representing a cluster) because of redundancy.
Collapse
Affiliation(s)
- Roberto Berenguer
- From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.)
| | - María Del Rosario Pastor-Juan
- From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.)
| | - Jesús Canales-Vázquez
- From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.)
| | - Miguel Castro-García
- From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.)
| | - María Victoria Villas
- From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.)
| | - Francisco Mansilla Legorburo
- From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.)
| | - Sebastià Sabater
- From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.)
| |
Collapse
|
124
|
Kim CR, Jeon JY. Radiation dose and image conspicuity comparison between conventional 120 kVp and 150 kVp with spectral beam shaping for temporal bone CT. Eur J Radiol 2018; 102:68-73. [PMID: 29685547 DOI: 10.1016/j.ejrad.2018.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/09/2018] [Accepted: 03/03/2018] [Indexed: 11/15/2022]
Abstract
OBJECTIVE The purpose of this article is to compare radiation doses and conspicuity of anatomic landmarks of the temporal bone between the CT technique using spectral beam shaping at 150 kVp with a dedicated tin filter (150 kVp-Sn) and the conventional protocol at 120 kVp. METHODS 25 patients (mean age, 46.8 ± 21.2 years) were examined using the 150-kVp Sn protocol (200 reference mAs using automated tube current modulation, 64 × 0.6 mm collimation, 0.6 mm slice thickness, pitch 0.8), whereas 30 patients (mean age, 54.5 ± 17.8 years) underwent the 120-kVp protocol (180 mAs, 128 × 0.6 mm collimation, 0.6 mm slice thickness, pitch 0.8). Radiation doses were compared between the two acquisition techniques, and dosimetric data from the literature were reviewed for comparison of radiation dose reduction. Subjective conspicuity of 23 anatomic landmarks of the temporal bone, expressed by 5-point rating scale and objective conspicuity by signal-to-noise ratio (SNR) which measured in 4 different regions of interest (ROI), were compared between 150-kVp Sn and 120-kVp acquisitions. RESULTS The mean dose-length-product (DLP) and effective dose were significantly lower for the 150-kVp Sn scans (0.26 ± 0.26 mSv) compared with the 120-kVp scans (0.92 ± 0.10 mSv, p < 0.001). The lowest effective dose from the literature-based protocols was 0.31 ± 0.12 mSv, which proposed as a low-dose protocol in the setting of spiral multislice temporal bone CT. SNR was slightly superior for 120-kVp images, however analyzability of the 23 anatomic structures did not differ significantly between 150-kVp Sn and 120-kVp scans. CONCLUSION Temporal bone CT performed at 150 kVp with an additional tin filter for spectral shaping markedly reduced radiation exposure when compared with conventional temporal bone CT at 120 kVp while maintaining anatomic conspicuity. The decreased radiation dose of the 150-kVp Sn was also lower in comparison to the previous literature-based low-dose temporal bone CT protocol.
Collapse
Affiliation(s)
- Chang Rae Kim
- Department of Radiology, Gachon University, Gil Medical Center, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, 21565, Republic of Korea.
| | - Ji Young Jeon
- Department of Radiology, Gachon University, Gil Medical Center, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, 21565, Republic of Korea.
| |
Collapse
|
125
|
Low-Dose CT for Evaluation of Suspected Urolithiasis: Diagnostic Yield for Assessment of Alternative Diagnoses. AJR Am J Roentgenol 2018; 210:557-563. [DOI: 10.2214/ajr.17.18552] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
126
|
Widmann G, Al-Ekrish AA. Ultralow Dose MSCT Imaging in Dental Implantology. Open Dent J 2018; 12:87-93. [PMID: 29492174 PMCID: PMC5814940 DOI: 10.2174/1874210601812010087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 12/20/2017] [Accepted: 01/05/2018] [Indexed: 01/18/2023] Open
Abstract
INTRODUCTION The Council Directive 2013/59 Euratom has a clear commitment for keeping medical radiation exposure as low as reasonably achievable and demands a regular review and use of diagnostic reference levels. METHODS In dental implantology, the range of effective doses for cone beam computed tomography (CBCT) shows a broad overlap with multislice computed tomography (MSCT). More recently, ultralow dose imaging with new generations of MSCT scanners may impart radiation doses equal to or lower than CBCT. Dose reductions in MSCT have been further facilitated by the introduction of iterative image reconstruction technology (IRT), which provides substantial noise reduction over the current standard of filtered backward projection (FBP). AIM The aim of this article is to review the available literature on ultralow dose CT imaging and IRTs in dental implantology imaging and to summarize their influence on spatial and contrast resolution, image noise, tissue density measurements, and validity of linear measurements of the jaws. CONCLUSION Application of ultralow dose MSCT with IRT technology in dental implantology offers the potential for very large dose reductions compared with standard dose imaging. Yet, evaluation of various diagnostic tasks related to dental implantology is still needed to confirm the results obtained with various IRTs and ultra-low doses so far.
Collapse
Affiliation(s)
- Gerlig Widmann
- Department of Radiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Asma'a A. Al-Ekrish
- Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| |
Collapse
|
127
|
Experience With Iterative Reconstruction Techniques for Abdominopelvic Computed Tomography in Morbidly and Super Obese Patients. J Comput Assist Tomogr 2018; 42:124-132. [PMID: 28786906 DOI: 10.1097/rct.0000000000000656] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE The aim of this study was to investigate the diagnostic performance of abdominopelvic computed tomography (CT) images reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) algorithms in morbidly and super obese patients. MATERIALS AND METHODS One hundred eighty-seven abdominopelvic CT examinations in portal venous phase were performed between February 2015 and February 2016 in 182 patients (mean age = 52 years, mean body mass index = 45.5). One hundred fourteen of 187 examinations were reconstructed using IR and 73 examinations were processed using FBP. Patients were further stratified based on body mass index. Sixty CT scans were reviewed by a single reader for image quality, image noise, and artifacts. Objective noise and attenuation were also determined. Size-specific dose estimate and CT dose index volume were compared and statistically analyzed. RESULTS A diagnostic interpretation was rendered for all 187 examinations. A single-reader review of 60 cases showed greater diagnostic acceptability for IR when compared with FBP (image quality = 4.2 and 3.8 [P = 0.035], noise = 1.5 and 1.6 [P = 0.692], artifact = 1.4 and 1.5 [P = 0.759], respectively). For all examinations, the IR group had lower objective image noise (IR = 9.3 and FBP = 14.3; P < 0.001) and higher contrast-to-noise ratio (IR = 17.2 and FBP = 11.7; P < 0.001) without increase in radiation dose (size-specific dose estimate [IR = 15.1, FBP = 16.5 mGy; P = 0.045] and CT dose index volume [IR = 17.6, FBP = 18 mGy; P = 0.62]). CONCLUSIONS In morbidly and super obese patients, diagnostic quality images could be reliably generated with minimal artifacts and noise using newer generation scanners integrated with IR without increasing radiation dose.
Collapse
|
128
|
Adaptive Statistical Iterative Reconstruction–V Versus Adaptive Statistical Iterative Reconstruction. J Comput Assist Tomogr 2018; 42:191-196. [PMID: 28937493 DOI: 10.1097/rct.0000000000000677] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
129
|
Johnson RP. Review of medical radiography and tomography with proton beams. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:016701. [PMID: 28884707 DOI: 10.1088/1361-6633/aa8b1d] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The use of hadron beams, especially proton beams, in cancer radiotherapy has expanded rapidly in the past two decades. To fully realize the advantages of hadron therapy over traditional x-ray and gamma-ray therapy requires accurate positioning of the Bragg peak throughout the tumor being treated. A half century ago, suggestions had already been made to use protons themselves to develop images of tumors and surrounding tissue, to be used for treatment planning. The recent global expansion of hadron therapy, coupled with modern advances in computation and particle detection, has led several collaborations around the world to develop prototype detector systems and associated reconstruction codes for proton computed tomography (pCT), as well as more simple proton radiography, with the ultimate intent to use such systems in clinical treatment planning and verification. Recent imaging results of phantoms in hospital proton beams are encouraging, but many technical and programmatic challenges remain to be overcome before pCT scanners will be introduced into clinics. This review introduces hadron therapy and the perceived advantages of pCT and proton radiography for treatment planning, reviews its historical development, and discusses the physics related to proton imaging, the associated experimental and computation issues, the technologies used to attack the problem, contemporary efforts in detector and computational development, and the current status and outlook.
Collapse
Affiliation(s)
- Robert P Johnson
- Department of Physics, University of California Santa Cruz, 1156 High St., Santa Cruz, CA 95064, United States of America
| |
Collapse
|
130
|
Gavrielides MA, Berman BP, Supanich M, Schultz K, Li Q, Petrick N, Zeng R, Siegelman J. Quantitative assessment of nonsolid pulmonary nodule volume with computed tomography in a phantom study. Quant Imaging Med Surg 2017; 7:623-635. [PMID: 29312867 DOI: 10.21037/qims.2017.12.07] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background To assess the volumetric measurement of small (≤1 cm) nonsolid nodules with computed tomography (CT), focusing on the interaction of state of the art iterative reconstruction (IR) methods and dose with nodule densities, sizes, and shapes. Methods Twelve synthetic nodules [5 and 10 mm in diameter, densities of -800, -630 and -10 Hounsfield units (HU), spherical and spiculated shapes] were scanned within an anthropomorphic phantom. Dose [computed tomography scan dose index (CTDIvol)] ranged from standard (4.1 mGy) to below screening levels (0.3 mGy). Data was reconstructed using filtered back-projection and two state-of-the-art IR methods (adaptive and model-based). Measurements were extracted with a previously validated matched filter-based estimator. Analysis of accuracy and precision was based on evaluation of percent bias (PB) and the repeatability coefficient (RC) respectively. Results Density had the most important effect on measurement error followed by the interaction of density with nodule size. The nonsolid -630 HU nodules had high accuracy and precision at levels comparable to solid (-10 HU) nonsolid, regardless of reconstruction method and with CTDIvol as low as 0.6 mGy. PB was <5% and <11% for the 10- and 5-mm in nominal diameter -630 HU nodules respectively, and RC was <5% and <12% for the same nodules. For nonsolid -800 HU nodules, PB increased to <11% and <30% for the 10- and 5-mm nodules respectively, whereas RC increased slightly overall but varied widely across dose and reconstruction algorithms for the 5-mm nodules. Model-based IR improved measurement accuracy for the 5-mm, low-density (-800, -630 HU) nodules. For other nodules the effect of reconstruction method was small. Dose did not affect volumetric accuracy and only affected slightly the precision of 5-mm nonsolid nodules. Conclusions Reasonable values of both accuracy and precision were achieved for volumetric measurements of all 10-mm nonsolid nodules, and for the 5-mm nodules with -630 HU or higher density, when derived from scans acquired with below screening dose levels as low as 0.6 mGy and regardless of reconstruction algorithm.
Collapse
Affiliation(s)
- Marios A Gavrielides
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Laboratories, , Office of In Vitro Diagnostics and Radiological Health, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Benjamin P Berman
- Division of Radiological Health, Office of In Vitro Diagnostics and Radiological Health, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Mark Supanich
- Department of Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center, Chicago, Illinois, USA
| | - Kurt Schultz
- Toshiba Medical Research Institute USA, Inc., Center for Medical Research and Development, Illinois, USA
| | - Qin Li
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Laboratories, , Office of In Vitro Diagnostics and Radiological Health, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Nicholas Petrick
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Laboratories, , Office of In Vitro Diagnostics and Radiological Health, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Rongping Zeng
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Laboratories, , Office of In Vitro Diagnostics and Radiological Health, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Jenifer Siegelman
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachussetts, USA
| |
Collapse
|
131
|
Abstract
This study investigates the radiation dose and image quality of patients not receiving β-blockers for cardiac CT angiography (CCTA) with or without the optimization of electrocardiographic (ECG) pulsing window. The differences in patient characteristics are also characterized.Normal-weight and obese patients (n = 154) with heart rates between 65 and 80 beats per minutes (bpm) during the prospective axial scanning were enrolled retrospectively. The ECG pulsing windows were set at 50% to 75% (Group A) or 60% to 75% (Group B) of the R-R interval for patients with heart rate variability higher than or not exceeding ±5 bpm, respectively. The effective doses of individual patient were estimated from the dose length product of the CCTA scan. Two radiologists independently reviewed the images and applied a 4-point Likert scale for image quality assessment. The patients' characteristics were compared along with the patients' effective doses between groups.The optimized pulsing window significantly reduced the average radiation dose for normal-weight and obese patients by 33% and 27%, respectively. The CCTA image quality of patients in Group A was not different overall from those obtained from Group B. Nondiabetic obese patients were more likely to be accepted for the use of the optimized pulsing window. Unlike obese patients, normal-weight patients revealed no characteristic difference between Groups A and B.This study indicates an equivalent efficacy of using optimized pulsing windows for reducing the radiation dose for patients without β-blocker administration between different body weight groups. Nevertheless, gender and diabetic status became prominent characteristics in the obese group when matching up with the optimized pulsing window.
Collapse
Affiliation(s)
- Yuan-Hao Lee
- Department of Radiology, Wan Fang Hospital, Taipei Medical University
| | - Po-Yen Chang
- Department of Radiology, Wan Fang Hospital, Taipei Medical University
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, Republic of China
| | - Shee Yen Tay
- Department of Radiology, Wan Fang Hospital, Taipei Medical University
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, Republic of China
| | - Cheng-Yu Tsai
- Department of Radiology, Wan Fang Hospital, Taipei Medical University
| | - Po-Hsin Cheng
- Department of Radiology, Wan Fang Hospital, Taipei Medical University
| | - Wilson T. Lao
- Department of Radiology, Wan Fang Hospital, Taipei Medical University
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, Republic of China
| | - Wing P. Chan
- Department of Radiology, Wan Fang Hospital, Taipei Medical University
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, Republic of China
| |
Collapse
|
132
|
Weis M, Henzler T, Nance JW, Haubenreisser H, Meyer M, Sudarski S, Schoenberg SO, Neff KW, Hagelstein C. Radiation Dose Comparison Between 70 kVp and 100 kVp With Spectral Beam Shaping for Non-Contrast-Enhanced Pediatric Chest Computed Tomography: A Prospective Randomized Controlled Study. Invest Radiol 2017; 52:155-162. [PMID: 27662576 DOI: 10.1097/rli.0000000000000325] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of this prospective randomized controlled study was to compare 2 techniques for radiation dose reduction in non-contrast-enhanced pediatric chest computed tomography (CT): low peak kilovoltage imaging at 70 kVp and spectral beam shaping at 100 kVp using a dedicated tin filter (100-kVp Sn). MATERIALS AND METHODS All chest CT examinations were performed on a third-generation dual-source CT system (SOMATOM Force; Siemens Healthineers, Germany). Fifty children (mean age, 6.8 ± 5.1 years) were examined using the 100-kVp Sn protocol, whereas 25 children received the 70-kVp protocol (mean age, 5.7 ± 5.2 years; 2:1 randomization scheme). Radiation metrics and organ doses were compared between acquisition techniques using commercially available radiation dose analysis software (Radimetrics Inc, Bayer AG, Toronto, Ontario, Canada). Objective image quality, expressed by signal-to-noise ratio and subjective image quality based on a 4-point scale (1, best; 4, worst image quality), were compared. RESULTS Volume CT dose index and size-specific dose estimate were significantly lower in the 100-kVp Sn group compared with the 70-kVp group (0.19 ± 0.12 mGy vs 0.81 ± 0.70 mGy and 0.34 ± 0.13 mGy vs 1.48 ± 1.11 mGy; P < 0.0001 for both). Accordingly, mean effective dose was significantly lower for the 100-kVp Sn examinations (0.21 ± 0.10 mSv) compared with the 70-kVp examinations (0.83 ± 0.49 mSv; P < 0.0001). Calculated organ doses were also significantly lower using the 100-kVp Sn protocol when compared with the 70-kVp protocol; for example, breast dose was reduced by a factor of 4.3. Signal-to-noise ratio was slightly superior for 70-kVp images while lung image quality of the 100-kVp Sn protocol was preferred in subjective analysis (P = 0.0004). CONCLUSIONS Pediatric chest CT performed at 100 kVp with an additional tin filter for spectral shaping significantly reduces radiation dose when compared with low peak kilovoltage imaging at 70 kVp and therefore should be preferred in non-contrast-enhanced pediatric chest CT examinations, particularly (given the improved subjective image quality) when the main focus is evaluation of the lung parenchyma.
Collapse
Affiliation(s)
- Meike Weis
- From the *Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; and †Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC
| | | | | | | | | | | | | | | | | |
Collapse
|
133
|
Multi-detector CT: Liver protocol and recent developments. Eur J Radiol 2017; 97:101-109. [PMID: 29153359 DOI: 10.1016/j.ejrad.2017.10.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/18/2017] [Accepted: 10/26/2017] [Indexed: 02/07/2023]
Abstract
Multi-detector computed tomography is today the workhorse in the evaluation of the vast majority of patients with known or suspected liver disease. Reasons for that include widespread availability, robustness and repeatability of the technique, time-efficient image acquisitions of large body volumes, high temporal and spatial resolution as well as multiple post-processing capabilities. However, as the technique employs ionizing radiation and intravenous iodine-based contrast media, the associated potential risks have to be taken into account. In this review article, liver protocols in clinical practice are discussed with emphasis on optimisation strategies. Furthermore, recent developments such as perfusion CT and dual-energy CT and their applications are presented.
Collapse
|
134
|
Bellesi L, Wyttenbach R, Gaudino D, Colleoni P, Pupillo F, Carrara M, Braghetti A, Puligheddu C, Presilla S. A simple method for low-contrast detectability, image quality and dose optimisation with CT iterative reconstruction algorithms and model observers. Eur Radiol Exp 2017; 1:18. [PMID: 29708194 PMCID: PMC5909349 DOI: 10.1186/s41747-017-0023-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/21/2017] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The aim of this work was to evaluate detection of low-contrast objects and image quality in computed tomography (CT) phantom images acquired at different tube loadings (i.e. mAs) and reconstructed with different algorithms, in order to find appropriate settings to reduce the dose to the patient without any image detriment. METHODS Images of supraslice low-contrast objects of a CT phantom were acquired using different mAs values. Images were reconstructed using filtered back projection (FBP), hybrid and iterative model-based methods. Image quality parameters were evaluated in terms of modulation transfer function; noise, and uniformity using two software resources. For the definition of low-contrast detectability, studies based on both human (i.e. four-alternative forced-choice test) and model observers were performed across the various images. RESULTS Compared to FBP, image quality parameters were improved by using iterative reconstruction (IR) algorithms. In particular, IR model-based methods provided a 60% noise reduction and a 70% dose reduction, preserving image quality and low-contrast detectability for human radiological evaluation. According to the model observer, the diameters of the minimum detectable detail were around 2 mm (up to 100 mAs). Below 100 mAs, the model observer was unable to provide a result. CONCLUSION IR methods improve CT protocol quality, providing a potential dose reduction while maintaining a good image detectability. Model observer can in principle be useful to assist human performance in CT low-contrast detection tasks and in dose optimisation.
Collapse
Affiliation(s)
- Luca Bellesi
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Rolf Wyttenbach
- Department of Radiology, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, Switzerland
- University of Bern, Bern, Switzerland
| | - Diego Gaudino
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Paolo Colleoni
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Francesco Pupillo
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Mauro Carrara
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Antonio Braghetti
- Department of Radiology, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, Switzerland
| | - Carla Puligheddu
- Department of Radiology, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, Switzerland
| | - Stefano Presilla
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| |
Collapse
|
135
|
Favazza CP, Ferrero A, Yu L, Leng S, McMillan KL, McCollough CH. Use of a channelized Hotelling observer to assess CT image quality and optimize dose reduction for iteratively reconstructed images. J Med Imaging (Bellingham) 2017; 4:031213. [PMID: 28983493 DOI: 10.1117/1.jmi.4.3.031213] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/18/2017] [Indexed: 11/14/2022] Open
Abstract
The use of iterative reconstruction (IR) algorithms in CT generally decreases image noise and enables dose reduction. However, the amount of dose reduction possible using IR without sacrificing diagnostic performance is difficult to assess with conventional image quality metrics. Through this investigation, achievable dose reduction using a commercially available IR algorithm without loss of low contrast spatial resolution was determined with a channelized Hotelling observer (CHO) model and used to optimize a clinical abdomen/pelvis exam protocol. A phantom containing 21 low contrast disks-three different contrast levels and seven different diameters-was imaged at different dose levels. Images were created with filtered backprojection (FBP) and IR. The CHO was tasked with detecting the low contrast disks. CHO performance indicated dose could be reduced by 22% to 25% without compromising low contrast detectability (as compared to full-dose FBP images) whereas 50% or more dose reduction significantly reduced detection performance. Importantly, default settings for the scanner and protocol investigated reduced dose by upward of 75%. Subsequently, CHO-based protocol changes to the default protocol yielded images of higher quality and doses more consistent with values from a larger, dose-optimized scanner fleet. CHO assessment provided objective data to successfully optimize a clinical CT acquisition protocol.
Collapse
Affiliation(s)
| | - Andrea Ferrero
- Mayo Clinic, Department of Radiology, Rochester, Minnesota, United States
| | - Lifeng Yu
- Mayo Clinic, Department of Radiology, Rochester, Minnesota, United States
| | - Shuai Leng
- Mayo Clinic, Department of Radiology, Rochester, Minnesota, United States
| | - Kyle L McMillan
- Mayo Clinic, Department of Radiology, Rochester, Minnesota, United States
| | | |
Collapse
|
136
|
A review of GPU-based medical image reconstruction. Phys Med 2017; 42:76-92. [PMID: 29173924 DOI: 10.1016/j.ejmp.2017.07.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/06/2017] [Accepted: 07/30/2017] [Indexed: 11/20/2022] Open
Abstract
Tomographic image reconstruction is a computationally demanding task, even more so when advanced models are used to describe a more complete and accurate picture of the image formation process. Such advanced modeling and reconstruction algorithms can lead to better images, often with less dose, but at the price of long calculation times that are hardly compatible with clinical workflows. Fortunately, reconstruction tasks can often be executed advantageously on Graphics Processing Units (GPUs), which are exploited as massively parallel computational engines. This review paper focuses on recent developments made in GPU-based medical image reconstruction, from a CT, PET, SPECT, MRI and US perspective. Strategies and approaches to get the most out of GPUs in image reconstruction are presented as well as innovative applications arising from an increased computing capacity. The future of GPU-based image reconstruction is also envisioned, based on current trends in high-performance computing.
Collapse
|
137
|
Iterative Reconstructions in Reduced-Dose CT: Which Type Ensures Diagnostic Image Quality in Young Oncology Patients? Acad Radiol 2017; 24:1114-1124. [PMID: 28365232 DOI: 10.1016/j.acra.2017.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 02/24/2017] [Accepted: 02/24/2017] [Indexed: 12/11/2022]
Abstract
RATIONALE AND OBJECTIVES To compare adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms for reduced-dose computed tomography (CT). MATERIALS AND METHODS Forty-four young oncology patients (mean age 30 ± 9 years) were included. After routine thoraco-abdominal CT (dose 100%, average CTDIvol 9.1 ± 2.4 mGy, range 4.4-16.9 mGy), follow-up CT was acquired at 50% (average CTDIvol 4.5 ± 1.2 mGy, range 2.2-8.4 mGy) in 29 patients additionally at 20% dose (average CTDIvol 1.9 ± 0.5 mGy, range 0.9-3.4 mGy). Each reduced-dose CT was reconstructed using both ASIR and MBIR. Four radiologists (two juniors and two seniors) blinded to dose and technique read each set of CT images regarding objective and subjective image qualities (high- or low-contrast structures), subjective noise or pixilated appearance, diagnostic confidence, and lesion detection. RESULTS At all dose levels, objective image noise was significantly lower with MBIR than with ASIR (P < 0.001). The subjective image quality for low-contrast structures was significantly higher with MBIR than with ASIR (P < 0.001). Reduced-dose abdominal CT images of patients with higher body mass index (BMI) were read with significantly higher diagnostic confidence than images of slimmer patients (P < 0.001) and had higher subjective image quality, regardless of technique. Although MBIR images appeared significantly more pixilated than ASIR images, they were read with higher diagnostic confidence, especially by juniors (P < 0.001). CONCLUSIONS Reduced-dose CT during the follow-up of young oncology patients should be reconstructed with MBIR to ensure diagnostic quality. Elevated body mass index does not hamper the quality of reduced-dose CT.
Collapse
|
138
|
Hedgire SS, Baliyan V, Ghoshhajra BB, Kalra MK. Recent advances in cardiac computed tomography dose reduction strategies: a review of scientific evidence and technical developments. J Med Imaging (Bellingham) 2017; 4:031211. [PMID: 28894760 DOI: 10.1117/1.jmi.4.3.031211] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 07/28/2017] [Indexed: 12/24/2022] Open
Abstract
Cardiac imagers worldwide are bracing for increased utilization of cardiac computed tomography (CT) in clinical practice. This expanding opportunity brings along a responsibility to produce diagnostic quality images with optimized radiation dose. The following review aims to address the dose reduction strategies in cardiac CT in light of recent scientific evidence and technical developments.
Collapse
Affiliation(s)
- Sandeep S Hedgire
- Massachusetts General Hospital, Department of Imaging, Division of Cardiovascular Imaging, Boston, Massachusetts, United States
| | - Vinit Baliyan
- Massachusetts General Hospital, Department of Imaging, Division of Cardiovascular Imaging, Boston, Massachusetts, United States
| | - Brian B Ghoshhajra
- Massachusetts General Hospital, Department of Imaging, Division of Cardiovascular Imaging, Boston, Massachusetts, United States
| | - Mannudeep K Kalra
- Massachusetts General Hospital, Department of Imaging, Division of Cardiovascular Imaging, Boston, Massachusetts, United States
| |
Collapse
|
139
|
Widmann G, Juranek D, Waldenberger F, Schullian P, Dennhardt A, Hoermann R, Steurer M, Gassner EM, Puelacher W. Influence of Ultra-Low-Dose and Iterative Reconstructions on the Visualization of Orbital Soft Tissues on Maxillofacial CT. AJNR Am J Neuroradiol 2017; 38:1630-1635. [PMID: 28596194 PMCID: PMC7960431 DOI: 10.3174/ajnr.a5239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/19/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Dose reduction on CT scans for surgical planning and postoperative evaluation of midface and orbital fractures is an important concern. The purpose of this study was to evaluate the variability of various low-dose and iterative reconstruction techniques on the visualization of orbital soft tissues. MATERIALS AND METHODS Contrast-to-noise ratios of the optic nerve and inferior rectus muscle and subjective scores of a human cadaver were calculated from CT with a reference dose protocol (CT dose index volume = 36.69 mGy) and a subsequent series of low-dose protocols (LDPs I-4: CT dose index volume = 4.18, 2.64, 0.99, and 0.53 mGy) with filtered back-projection (FBP) and adaptive statistical iterative reconstruction (ASIR)-50, ASIR-100, and model-based iterative reconstruction. The Dunn Multiple Comparison Test was used to compare each combination of protocols (α = .05). RESULTS Compared with the reference dose protocol with FBP, the following statistically significant differences in contrast-to-noise ratios were shown (all, P ≤ .012) for the following: 1) optic nerve: LDP-I with FBP; LDP-II with FBP and ASIR-50; LDP-III with FBP, ASIR-50, and ASIR-100; and LDP-IV with FBP, ASIR-50, and ASIR-100; and 2) inferior rectus muscle: LDP-II with FBP, LDP-III with FBP and ASIR-50, and LDP-IV with FBP, ASIR-50, and ASIR-100. Model-based iterative reconstruction showed the best contrast-to-noise ratio in all images and provided similar subjective scores for LDP-II. ASIR-50 had no remarkable effect, and ASIR-100, a small effect on subjective scores. CONCLUSIONS Compared with a reference dose protocol with FBP, model-based iterative reconstruction may show similar diagnostic visibility of orbital soft tissues at a CT dose index volume of 2.64 mGy. Low-dose technology and iterative reconstruction technology may redefine current reference dose levels in maxillofacial CT.
Collapse
Affiliation(s)
- G Widmann
- From the Departments of Radiology (G.W., P.S., M.S., E.-M.G.)
| | - D Juranek
- Craniomaxillofacial Surgery (D.J., F.W., A.D., W.P.)
| | | | - P Schullian
- From the Departments of Radiology (G.W., P.S., M.S., E.-M.G.)
| | - A Dennhardt
- Craniomaxillofacial Surgery (D.J., F.W., A.D., W.P.)
| | - R Hoermann
- Division of Functional and Clinical Anatomy (R.H.), Innsbruck Medical University, Innsbruck, Austria
| | - M Steurer
- From the Departments of Radiology (G.W., P.S., M.S., E.-M.G.)
| | - E-M Gassner
- From the Departments of Radiology (G.W., P.S., M.S., E.-M.G.)
| | - W Puelacher
- Craniomaxillofacial Surgery (D.J., F.W., A.D., W.P.)
| |
Collapse
|
140
|
Case JA, deKemp RA, Slomka PJ, Smith MF, Heller GV, Cerqueira MD. Status of cardiovascular PET radiation exposure and strategies for reduction: An Information Statement from the Cardiovascular PET Task Force. J Nucl Cardiol 2017; 24:1427-1439. [PMID: 28512722 DOI: 10.1007/s12350-017-0897-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 03/23/2017] [Indexed: 11/29/2022]
Abstract
Cardiovascular positron emission tomography (PET) imaging provides high-quality visual and quantitative myocardial perfusion and function images. In addition, cardiovascular PET can assess myocardial viability, myocardial inflammatory disorders such as cardiac sarcoid, and infections of implanted devices including pacemakers, ventricular assist devices, and prosthetic heart valves. As with all nuclear cardiology procedures, the benefits need to be considered in relation to the risks of exposure to radiation. When performed properly, these assessments can be obtained while simultaneously minimizing radiation exposure. The purpose of this information statement is to present current concepts to minimize patient and staff radiation exposure while ensuring high image quality.
Collapse
Affiliation(s)
- James A Case
- Cardiovascular Imaging Technologies, L.L.C, Kansas City, MO, USA.
| | | | | | | | - Gary V Heller
- Gagnon Cardiovascular Institute, Morristown Medical Center, Morristown, NJ, USA
| | | |
Collapse
|
141
|
McDermott S, Kalra MK. Low-Dose Computed Tomography for Lung Cancer Screening: The Protocol and The Dose. Semin Roentgenol 2017; 52:132-136. [DOI: 10.1053/j.ro.2017.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
142
|
Wang T, Zhu L. Pixel-wise estimation of noise statistics on iterative CT reconstruction from a single scan. Med Phys 2017; 44:3525-3533. [PMID: 28444799 DOI: 10.1002/mp.12302] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 04/06/2017] [Accepted: 04/19/2017] [Indexed: 01/03/2023] Open
Abstract
PURPOSE As iterative CT reconstruction continues to advance, the spatial distribution of noise standard deviation (STD) and accurate noise power spectrum (NPS) on the reconstructed CT images become important for method evaluation as well as optimization of algorithm parameters. Using a single CT scan, we propose a practical method for pixel-wise calculation of noise statistics on an iteratively reconstructed CT image, which enables accurate calculation of noise STD for each pixel and NPS. METHOD We first derive the noise propagation from measured projections to an iteratively reconstructed CT image provided that the projection noise is known. We then show that the model of noise propagation remains approximately unchanged for extra simulated noise added on the measured projections. To compute the noise STD map and the NPS map on an iteratively reconstructed CT image from a single scan, we first iteratively reconstruct the CT image from the measured projections using an existing reconstruction algorithm. The same measured projections are added by different sets (a total of 32 sets in our implementation) of projection noise simulated from an estimated projection noise model, and are then used to iteratively reconstruct different CT images. The calculations of the noise STD map and the NPS map are finally performed on the entire stack of these different reconstruction images. RESULTS We evaluate our method on an anthropomorphic head phantom, and demonstrate the clinical utility on a set of head and neck patient CT data, using two iterative CT reconstruction algorithms: the penalized weighted least-square (PWLS) algorithm and the total-variation (TV) regularization. In the head phantom case, repeated scans are acquired to generate the ground truths of noise STD and NPS maps. Using only one single scan, the proposed method accurately calculates the noise STD maps with a root-mean-square error (RMSE) of less than 5HU. In the NPS map estimation, we compare the result of our proposed method with that of the conventional method which calculates the NPS maps on a uniform region of interest on one CT image. Our method outperforms the conventional method on the NPS map estimation with RMSE reduced by 92%. The implementation of the proposed method on the patient data successfully provides the noise STD values around complex structures and a high-quality NPS map. CONCLUSION The proposed method accurately calculates noise STD for each pixel and NPS on an iteratively reconstructed CT image, with no requirement of repeated CT scans. It provides a detailed evaluation of imaging performance of different iterative reconstruction methods on the same CT dataset.
Collapse
Affiliation(s)
- Tonghe Wang
- Nuclear and Radiological Engineering and Medical Physics Programs, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA
| | - Lei Zhu
- Nuclear and Radiological Engineering and Medical Physics Programs, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA.,Department of Modern Physics, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
| |
Collapse
|
143
|
Park HR, Park SB, Lee ES, Park HJ, Lee JB, Kim YS. Unenhanced computed tomography for normal appendix detection: comparison of low-dose with statistical iterative reconstruction and regular-dose with filtered back projection. Clin Imaging 2017; 43:117-121. [PMID: 28282598 DOI: 10.1016/j.clinimag.2017.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/09/2017] [Accepted: 02/24/2017] [Indexed: 01/07/2023]
Abstract
PURPOSE To evaluate the differences in visualization of a normal appendix between regular-dose (RD) and low-dose (LD) unenhanced CT. MATERIAL AND METHODS 179 patients underwent both RDCT and LDCT for urolithiasis. Two reviewers evaluated the appendiceal visualization on a three-point scale. Sensitivities and interobserver agreement were measured. RESULTS There were no significant differences between RDCT and LDCT in sensitivity, regardless of the reviewer. Interobserver agreement was excellent in both RDCT and LDCT. CONCLUSION Unenhanced LDCT is a good tool for detecting a normal appendix and is also useful for less experienced interpreters who are unfamiliar with using LDCT images.
Collapse
Affiliation(s)
- Hwi Ryong Park
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul 06973, Republic of Korea
| | - Sung Bin Park
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul 06973, Republic of Korea.
| | - Eun Sun Lee
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul 06973, Republic of Korea
| | - Hyun Jeong Park
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul 06973, Republic of Korea
| | - Jong Beum Lee
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul 06973, Republic of Korea
| | - Yang Soo Kim
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul 06973, Republic of Korea
| |
Collapse
|
144
|
Sung CK, Moon MH, Son H, Oh S, Lee MS, Woo H. Standard vs. reduced-radiation-dose CT in the tracing of the ureter. Abdom Radiol (NY) 2017; 42:900-907. [PMID: 27730329 DOI: 10.1007/s00261-016-0929-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE To assess the effectiveness of reduced-radiation-dose computed tomography (CT) protocols in the tracing of the ureter in patients with suspected renal colic. METHODS The study was approved by our institutional review board, and informed consent was obtained from the participants. From July 2012 to April 2014, 310 consecutive patients with suspected urolithiasis were recruited to undergo unenhanced CT at 280 (n = 62), 200 (n = 62), 140 (n = 62), 100 (n = 62), and 70 (n = 62) reference mA seconds (mAs) while keeping other imaging parameters constant. Images were independently and randomly reviewed by two radiologists blinded to the study to determine the tracing rates of the ureter and the acceptable rates of image quality according to different tube charge settings. RESULTS A significant linear association was noted between tube charge settings, the rates for tracing of the ureter, and the acceptability of image quality (linear-by-linear association; p = 0.000 in all rates for both readers). The 140 reference mAs is the point at which the tracing rates deteriorate rapidly, with the tracing rate of 41.5% (95% CI 32.6%-51.0%) in reader 1 and 51.9% (95% CI 42.5%-61.2%) in reader 2, and with the acceptable rate of 82.3% (95% CI 70.8%-90.0%) in reader 1 and 96.8% (95% CI 88.3%-99.8%) in reader 2. CONCLUSION Decreasing the tube charge settings from 280 to 70 reference mAs resulted in a significant reduction in the tracing rate of the ureter, with 140 reference mAs being the breaking point.
Collapse
Affiliation(s)
- Chang Kyu Sung
- Department of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, 41, Boramae-Gil, Dongjak-Gu, Seoul, 156-707, Korea
| | - Min Hoan Moon
- Department of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, 41, Boramae-Gil, Dongjak-Gu, Seoul, 156-707, Korea.
| | - Hwancheol Son
- Department of Urology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
| | - Sohee Oh
- Department of Biostatistics, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
| | - Myoung Seok Lee
- Department of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, 41, Boramae-Gil, Dongjak-Gu, Seoul, 156-707, Korea
| | - Hyunsik Woo
- Department of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, 41, Boramae-Gil, Dongjak-Gu, Seoul, 156-707, Korea
| |
Collapse
|
145
|
Neuroimaging of Children With Surgically Treated Hydrocephalus: A Practical Approach. AJR Am J Roentgenol 2017; 208:413-419. [DOI: 10.2214/ajr.16.16870] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
146
|
Author's response to: "The screening criteria for whole-body computed tomography in trauma patients is required". Am J Emerg Med 2017; 35:1016. [PMID: 28139310 DOI: 10.1016/j.ajem.2017.01.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 01/21/2017] [Indexed: 11/21/2022] Open
|
147
|
Abstract
Idiopathic interstitial pneumonias are a heterogeneous group of diffuse lung diseases characterized by distinct clinicopathologic entities with the usual interstitial pneumonia (UIP) being the most common. The pattern of UIP can be seen in idiopathic pulmonary fibrosis (IPF) as well as in secondary causes, most commonly in connective tissue diseases. IPF is usually progressive and associated with a very poor prognosis, and newer therapies pose a risk of serious complications; therefore, diagnostic certainty is crucial. This article reviews the radiologic findings in UIP with clinical correlation and histopathologic features along with its significance for prognosis and patients monitoring.
Collapse
Affiliation(s)
- Joanna E Kusmirek
- Department of Radiology, Virginia Commonwealth University, 1250 East Marshall Street, Richmond, VA 23298, USA.
| | - Maria Daniela Martin
- Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792-3252, USA
| | - Jeffrey P Kanne
- Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792-3252, USA
| |
Collapse
|
148
|
Comparison of the effects of model-based iterative reconstruction and filtered back projection algorithms on software measurements in pulmonary subsolid nodules. Eur Radiol 2017; 27:3266-3274. [DOI: 10.1007/s00330-016-4716-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 11/01/2016] [Accepted: 12/16/2016] [Indexed: 01/06/2023]
|
149
|
Rohr A, Wick J, Hill J, Walter C, Irani N, Best S, Miller K, Ash R. Reducing radiation exposure with iterative reconstruction: an inter- and intra-scanner analysis. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2017; 37:N42-N48. [PMID: 28936988 DOI: 10.1088/1361-6498/aa8e54] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Our purpose in this study was to compare delivered radiation exposure via computed tomography dose index volume (CTDIvol) and dose length production (DLP) measurements from computed tomography (CT) examinations performed on scanners with and without image-quality enhancing iterative reconstruction (IR) software. A retrospective analysis was conducted on randomly selected chest, abdomen, and/or pelvis CT examinations from three different scanners from 1 January 2013 to 31 December 2013. CTDIvol and DLP measurements were obtained from two CT scanners with and one CT scanner without IR software. To evaluate inter-scanner variability, we compared measurements from the same model CT scanners, one with and one without IR software. To evaluate intra-scanner variability, we compared measurements between two scanners with IR software from different manufacturers. CT scanners with IR software aided in the overall reduction in radiation exposure, measured as CTDIvol by 30% and DLP by 39% when compared to a scanner without IR. There was no significant difference in CTDlvol or DLP measurements across different manufacturers with IR software. As a result, IR software significantly decreased the radiation exposure to patients, but there were no differences in radiation measurements across CT manufacturers with IR software.
Collapse
Affiliation(s)
- Aaron Rohr
- University of Kansas Medical Center, Department of Radiology, 3901 Rainbow Boulevard, Mail Stop 4032, Kansas City, KS 66160, United States of America
| | | | | | | | | | | | | | | |
Collapse
|
150
|
An audit of patient radiation in low-dose CT pulmonary angiography. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2016. [DOI: 10.1016/j.ejrnm.2016.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|