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Tian X, Chang Z, Dilixiati S, Haimiti Y, Wang S, Sun J. Optimizing image quality and minimizing radiation dose in pediatric abdominal multiphase contrast-enhanced computed tomography: a study on CARE kV and CARE Dose 4D. Quant Imaging Med Surg 2024; 14:1985-1993. [PMID: 38415123 PMCID: PMC10895141 DOI: 10.21037/qims-23-1181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 12/14/2023] [Indexed: 02/29/2024]
Abstract
Background Multiphase contrast-enhanced computed tomography (CECT) is a commonly used modality in pediatric computed tomography (CT) scans. However, the purposes and focus of each phase, such as CT angiography (CTA), and parenchymal phase, are different. In routine practice, the same scanning parameters are used for all phases, resulting in unnecessary radiation exposure for children. Accurately and rapidly adjusting the scanning parameters for each phase of CECT is challenging in clinical settings. This retrospective cross-sectional study was designed to investigate the feasibility of using both CARE kV and CARE Dose 4D to reduce the radiation dose while maintaining diagnostic quality in multiphase CECT scans of children. Methods Overall, 57 children (33 males and 24 females) who underwent multiphase abdominal CECT in Xinjiang Hospital of Beijing Children's Hospital with an average age of 6.52±4.30 years (range, 0.1-15 years), were enrolled. The tube voltage was automatically modulated using CARE kV. The tube current was automatically modulated using CARE Dose 4D. Different dose saving optimization indices (DI) were used for the three phases: a DI value of 3 was used for the unenhanced CT phase, a DI value of 12 was used for the CTA phase, and a DI value of 7 was used for the parenchymal phase. The tube voltage and volume CT dose index (CTDIvol) were recorded for each phase. Two reviewers subjectively evaluated the overall image quality and noise level of the three phases using a 5-point Likert scale (1-2 points: unqualified, 3 points: qualified, 4 points: better, 5 points: best). The CT and noise values of the descending aorta, liver, and back muscle were measured objectively. The voltage distribution and the image quality and CTDIvol in each phase were compared. Results The most selected tube voltage in the unenhanced CT, CTA, and parenchymal phases was 100 kV (49/57, 85.96%), 70 kV (36/57, 63.16%), and 80 kV (32/57, 56.14%), respectively. The differences between the three phases were statistically significant (P<0.001). The CTDIvol values of the three phases were 3.99±1.99, 2.02±1.71, and 3.18±2.10 mGy, respectively, with a significant difference between the three phases (P<0.001). The CTDIvol decreased linearly as the DI value increased. All images met the diagnostic requirements. The overall quality scores for the three phases were 4.24±0.42, 4.41±0.49, and 4.50±0.45, respectively, with no significant linear relationship with the change in the DI. Conclusions The combined use of CARE Dose 4D and CARE kV could effectively reduce the radiation dose in children during multiphase abdominal CECT without compromising the diagnostic image quality.
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Affiliation(s)
- Xinyu Tian
- Medical Imaging Department, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Urumqi, China
| | - Zhenjiang Chang
- Medical Imaging Department, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Urumqi, China
| | - Subinuer Dilixiati
- Medical Imaging Department, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Urumqi, China
| | - Yilisuyaer Haimiti
- Medical Imaging Department, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Urumqi, China
| | - Shui Wang
- Medical Imaging Department, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Urumqi, China
| | - Jihang Sun
- Medical Imaging Department, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Urumqi, China
- Department of Radiology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
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Thomas SP, Jaffe TA. CT Versus MR Enterography: Point-CT Enterography Remains Essential to Imaging Patients With Inflammatory Bowel Disease in the Acute Setting. AJR Am J Roentgenol 2023; 220:787-788. [PMID: 36416394 DOI: 10.2214/ajr.22.28716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Sarah P Thomas
- Department of Radiology, Duke University, 2301 Erwin Rd, DUMC Box 3808, Durham, NC 27710
| | - Tracy A Jaffe
- Department of Radiology, Duke University, 2301 Erwin Rd, DUMC Box 3808, Durham, NC 27710
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The why, who, how, and what of communicating CT radiation risks to patients and healthcare providers. ABDOMINAL RADIOLOGY (NEW YORK) 2023; 48:1514-1525. [PMID: 36799998 DOI: 10.1007/s00261-022-03778-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 02/18/2023]
Abstract
Computed tomography (CT) has witnessed tremendous growth in utilization. Despite its immense benefits, there is a growing concern from the general public and the medical community about the detrimental consequences of ionizing radiation from CT. Anxiety from the perceived risks associated with CT can deter referring physicians from ordering clinically indicated CT scans and patients from undergoing medically necessary exams. This article discusses various strategies for educating patients and healthcare providers on the benefits and risks of CT scanning and salient techniques for effective communication.
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LIN CHIHSHENG, CHEN YUNGFU, DENG JIE, YANG DENGHO, CHEN MINGHSIANG, LIN YAHUI, PAN LUNGKWANG. TAGUCHI-BASED OPTIMIZATION OF HEAD AND NECK CT ANGIOGRAPHY: IN-VIVO ENHANCED TRIGGERED TIMING FOR 600 PATIENTS. J MECH MED BIOL 2021. [DOI: 10.1142/s0219519421400418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Taguchi-based optimization of head and neck CT angiography (CTA) using in-vivo enhanced triggered timing for 600 patients was accomplished in this study. A total of 600 patients were categorized into three (test, verification, and implementation groups with 360, 120, and 120 patients, respectively). The patients in the test group were randomly assigned into 18 sub-groups according to Taguchi L[Formula: see text](2[Formula: see text]) orthogonal array for optimizing factor combinations of head and neck CTA. The signal-to-noise ratio was defined as a high LRA/US ratio (both left and right arterial pressure divided by upper sinuses’ one) and low stdev. The seven factors of CTA were: (A) left- or right-hand injection; (B) tube current, mA; (C) kilovoltage peak, kVp; (D) contrast media concentration; (E) FOV; (F) flow rate of contrast media; and (G) rotation time for one CTA loop. With the Taguchi unique organization, 18 sub-groups (each containing 20 patients’ real LRA/US ratios) could cover 1458 cases and provide the appropriate reliability. The optimal factor combination was identified as follows: (A) left-hand injection, (B) tube current of 280[Formula: see text]mA, (C) 100[Formula: see text]kVp, (D) contrast media concentration of 60%, (E) FOV of 250[Formula: see text]mm, (F) contrast media flow rate of 4.0[Formula: see text]ml/s, and (G) rotation time for one CTA loop of 0.9[Formula: see text]s. The optimal suggestion was validated in the verification group with 120 patients and applied to the implementation group with 120 patients. The successful factor combination is instrumental in defining a standard protocol for medical staff in deriving the maximal LRA/US value ([Formula: see text]) of head and neck CTA.
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Affiliation(s)
- CHIH-SHENG LIN
- Department of Radiology, BenQ Medical Center, The Affiliated BenQ Hospital of the Nanjing Medical University, Nanjing Jiangsu, P. R. China
- Department of Medical Imaging and Radiological Science, Central Taiwan University of Science and Technology, Takun Taichung 406, Taiwan, ROC
| | - YUNG-FU CHEN
- Department of Dental Technology & Materials Science, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan, ROC
| | - JIE DENG
- Department of Radiology, BenQ Medical Center, The Affiliated BenQ Hospital of the Nanjing Medical University, Nanjing Jiangsu, P. R. China
| | - DENG-HO YANG
- Division of Rheumatology/Immunology/Allergy, Department of Internal Medicine, Taichung Armed-Forces General Hospital Taichung, Taiwan, ROC
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung Taiwan, ROC
- Division of Rheumatology/Immunology/Allergy, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC
| | - MING-HSIANG CHEN
- Department of Logistics Support Division, BenQ Medical Center, The Affiliated BenQ Hospital of the Nanjing Medical University, Nanjing, Jiangsu, P. R. China
| | - YA-HUI LIN
- College of Nursing, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan, ROC
- Department of Clinical Pharmacy, Taichung Armed Forces General Hospital, Taichung 406, Taiwan, ROC
| | - LUNG-KWANG PAN
- Department of Medical Imaging and Radiological Science, Central Taiwan University of Science and Technology, Takun Taichung 406, Taiwan, ROC
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Mohammadinejad P, Mileto A, Yu L, Leng S, Guimaraes LS, Missert AD, Jensen CT, Gong H, McCollough CH, Fletcher JG. CT Noise-Reduction Methods for Lower-Dose Scanning: Strengths and Weaknesses of Iterative Reconstruction Algorithms and New Techniques. Radiographics 2021; 41:1493-1508. [PMID: 34469209 DOI: 10.1148/rg.2021200196] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Iterative reconstruction (IR) algorithms are the most widely used CT noise-reduction method to improve image quality and have greatly facilitated radiation dose reduction within the radiology community. Various IR methods have different strengths and limitations. Because IR algorithms are typically nonlinear, they can modify spatial resolution and image noise texture in different regions of the CT image; hence traditional image-quality metrics are not appropriate to assess the ability of IR to preserve diagnostic accuracy, especially for low-contrast diagnostic tasks. In this review, the authors highlight emerging IR algorithms and CT noise-reduction techniques and summarize how these techniques can be evaluated to help determine the appropriate radiation dose levels for different diagnostic tasks in CT. In addition to advanced IR techniques, we describe novel CT noise-reduction methods based on convolutional neural networks (CNNs). CNN-based noise-reduction techniques may offer the ability to reduce image noise while maintaining high levels of image detail but may have unique drawbacks. Other novel CT noise-reduction methods are being developed to leverage spatial and/or spectral redundancy in multiphase or multienergy CT. Radiologists and medical physicists should be familiar with these different alternatives to adapt available CT technology for different diagnostic tasks. The scope of this article is (a) to review the clinical applications of IR algorithms as well as their strengths, weaknesses, and methods of assessment and (b) to explore new CT image reconstruction and noise-reduction techniques that promise to facilitate radiation dose reduction. ©RSNA, 2021.
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Affiliation(s)
- Payam Mohammadinejad
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Achille Mileto
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Lifeng Yu
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Shuai Leng
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Luis S Guimaraes
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Andrew D Missert
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Corey T Jensen
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Hao Gong
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Cynthia H McCollough
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Joel G Fletcher
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
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Reader Performance as a Function of Patient Size for the Detection of Hepatic Metastases. J Comput Assist Tomogr 2021; 45:812-819. [PMID: 34347711 DOI: 10.1097/rct.0000000000001200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate reader performance as a function of patient size for the detection of hepatic metastases when an automatic exposure control (AEC) system is used, which varies image noise as a function of patient size. METHODS Abdominal computed tomograhy examinations across 100, 120, 160, and 200 quality reference tube current-time product were collected, involving a cohort of 83 patients. Three radiologists identified hepatic metastases across all dose levels. Partial Spearman rank correlation and multivariate logistic regression were used to evaluate correlations between reader performance and patient size and lesion size/contrast while accounting for potential confounding effects. Analyses were repeated on an emulated less-variable noise AEC. RESULTS No statistically significant correlation was observed between patient size and radiologist performance (for variable-noise AEC: range of partial Spearman ρ, -0.157 to -0.035]; range of adjusted odds ratios, 0.987, 1.006). CONCLUSIONS Reader performance was independent of patient size, suggesting that variable-noise AEC provides better modulation for larger patients than constant-noise AEC.
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Ria F, Fu W, Chalian H, Abadi E, Segars PW, Fricks R, Khoshpouri P, Samei E. A comparison of COVID-19 and imaging radiation risk in clinical patient populations. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2020; 40:10.1088/1361-6498/abbf3b. [PMID: 33027775 PMCID: PMC9757494 DOI: 10.1088/1361-6498/abbf3b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
The outbreak of coronavirus SARS-COV2 affected more than 180 countries necessitating fast and accurate diagnostic tools. Reverse transcriptase polymerase chain reaction (RT-PCR) has been identified as a gold standard test with Chest CT and Chest Radiography showing promising results as well. However, radiological solutions have not been used extensively for the diagnosis of COVID-19 disease, partly due to radiation risk. This study aimed to provide quantitative comparison of imaging radiation risk versus COVID risk. The analysis was performed in terms of mortality rate per age group. COVID-19 mortality was extracted from epidemiological data across 299, 004 patients published by ISS-Integrated surveillance of COVID-19 in Italy. For radiological risk, the study considered 659 Chest CT performed in adult patients. Organ doses were estimated using a Monte Carlo method and then used to calculate Risk Index that was converted into an upper bound for related mortality rate following NCI-SEER data. COVID-19 mortality showed a rapid rise for ages >30 years old (min: 0.30%; max: 30.20%), whereas only four deaths were reported in the analysed patient cohort for ages <20 years old. The rates decreased for radiation risk across age groups. The median mortality rate across all ages for Chest-CT and Chest-Radiography were 0.007% (min: 0.005%; max: 0.011%) and 0.0003% (min: 0.0002%; max: 0.0004%), respectively. COVID-19, Chest Radiography, and Chest CT mortality rates showed different magnitudes and trends across age groups. In higher ages, the risk of COVID-19 far outweighs that of radiological exams. Based on risk comparison alone, Chest Radiography and CT for COVID-19 care is justified for patients older than 20 and 30 years old, respectively. Notwithstanding other aspects of diagnosis, the present results capture a component of risk consideration associated with the use of imaging for COVID. Once integrated with other diagnostic factors, they may help inform better management of the pandemic.
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Affiliation(s)
- Francesco Ria
- Carl E. Ravin Advanced Imaging Labs and Clinical Imaging Physics Group, Duke University Health System, 2424 Erwin Road, Suite 302, Durham, NC 27710, United States of America
| | - Wanyi Fu
- Carl E. Ravin Advanced Imaging Labs, Duke University Health System, 2424 Erwin Road, Suite 302, Durham, NC 27710, United States of America
| | - Hamid Chalian
- Radiology Department, Duke University Health System, 2301 Erwin Road, Durham, NC 27710, United States of America
| | - Ehsan Abadi
- Carl E. Ravin Advanced Imaging Labs, Duke University Health System, 2424 Erwin Road, Suite 302, Durham, NC 27710, United States of America
| | - Paul W Segars
- Carl E. Ravin Advanced Imaging Labs, Duke University Health System, 2424 Erwin Road, Suite 302, Durham, NC 27710, United States of America
| | - Rafael Fricks
- Carl E. Ravin Advanced Imaging Labs, Duke University Health System, 2424 Erwin Road, Suite 302, Durham, NC 27710, United States of America
- Department of Veterans Affairs, 508 Fulton St, Durham, NC 27705, United States of America
| | - Pegah Khoshpouri
- Radiology Department, Duke University Health System, 2301 Erwin Road, Durham, NC 27710, United States of America
| | - Ehsan Samei
- Carl E. Ravin Advanced Imaging Labs, Clinical Imaging Physics Group, Medical Physics Graduate Program, Departments of Radiology, Physics, Biomedical Engineering, and Electrical and Computer Engineering, Duke University, 2424 Erwin Road, Suite 302, Durham, NC 27710, United States of America
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Yurt A, Özsoykal İ, Kandemir R, Ada E. LOCAL STUDY OF DIAGNOSTIC REFERENCE LEVELS FOR COMPUTED TOMOGRAPHY EXAMINATIONS OF ADULT PATIENTS IN İZMIR, TURKEY. RADIATION PROTECTION DOSIMETRY 2020; 190:446-451. [PMID: 32947621 DOI: 10.1093/rpd/ncaa121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 06/11/2023]
Abstract
PURPOSE This study aims to develop local diagnostic reference levels (DRLs) for the most common computed tomography (CT) examinations carried out around Izmir, Turkey. METHODS Five common CT examinations (head, neck, chest, abdomen-pelvis (AP), chest-abdomen-pelvis (CAP)) from four different radiology centres have been included in the study. CT dose index-volume (CTDIvol) and dose length product (DLP) values were recorded for 50 patients per exam in each centre. Third quartiles of CTDIvol and DLP values were determined as DRLs and compared with international findings. RESULTS 51.3% of the patients were male and 48.7% were female, with a mean age of 57 (between 18 and 93). DRLs for CTDIvol were recorded as 70, 16, 15, 23 and 16 for head, neck, chest, AP and CAP examinations, respectively, while the corresponding DLPs were 1385, 604, 567, 998 and 1180 mGy.cm. CONCLUSION Results are mostly comparable to the latest international data, except for the head examinations, which were observed to slightly exceed the DRLs established by other countries.
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Affiliation(s)
- Ayşegül Yurt
- Department of Medical Physics, The Health Sciences Institute, Dokuz Eylül University, Balçova, İzmir, Turkey
- The Vocational School of Health Services, Dokuz Eylül University, Balçova, İzmir, Turkey
| | - İsmail Özsoykal
- Department of Medical Physics, The Health Sciences Institute, Dokuz Eylül University, Balçova, İzmir, Turkey
| | - Recep Kandemir
- Department of Medical Physics, The Health Sciences Institute, Dokuz Eylül University, Balçova, İzmir, Turkey
| | - Emel Ada
- Department of Radiology, Faculty of Medicine, Dokuz Eylül University, Balçova, İzmir, Turkey
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Abuelhia E, Alghamdi A. Evaluation of arising exposure of ionizing radiation from computed tomography and the associated health concerns. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2020. [DOI: 10.1080/16878507.2020.1728962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Elfatih Abuelhia
- Department of Radiological Sciences, College of Applied Medical Science, Imam Abdulrahman Bin Faisal University, Dammam, KSA
| | - Ali Alghamdi
- Department of Radiological Sciences, College of Applied Medical Science, Imam Abdulrahman Bin Faisal University, Dammam, KSA
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Mohammadinejad P, Ehman EC, Vasconcelos RN, Venkatesh SK, Hough DM, Lowe R, Lee YS, Nehra A, Dirks S, Holmes DR, Carter RE, Schmidt B, Halaweish AF, McCollough CH, Fletcher JG. Prior iterative reconstruction (PIR) to lower radiation dose and preserve radiologist performance for multiphase liver CT: a multi-reader pilot study. Abdom Radiol (NY) 2020; 45:45-54. [PMID: 31705250 DOI: 10.1007/s00261-019-02280-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE Prior iterative reconstruction (PIR) spatially registers CT image data from multiple phases of enhancement to reduce image noise. We evaluated PIR in contrast-enhanced multiphase liver CT. METHODS Patients with archived projection CT data with proven malignant or benign liver lesions, or without lesions, by reference criteria were included. Lower-dose PIR images were reconstructed using validated noise insertion from multiphase CT exams (50% dose in 2 phases, 25% dose in 1 phase). The phase of enhancement most relevant to the diagnostic task was selected for evaluation. Four radiologists reviewed routine-dose and lower-dose PIR images, circumscribing liver lesions and rating confidence for malignancy (0 to 100) and image quality. JAFROC Figures of Merit (FOM) were calculated. RESULTS 31 patients had 60 liver lesions (28 primary hepatic malignancies, 6 hepatic metastases, 26 benign lesions). Pooled JAFROC FOM for malignancy for routine-dose CT was 0.615 (95% CI 0.464, 0.767) compared to 0.662 for PIR (95% CI 0.527, 0.797). The estimated FOM difference between the routine-dose and lower-dose PIR images was + 0.047 (95% CI - 0.023, + 0.116). Pooled sensitivity/specificity for routine-dose images was 70%/68% compared to 73%/66% for lower-dose PIR. Lower-dose PIR had lower diagnostic image quality (mean 3.8 vs. 4.2, p = 0.0009) and sharpness (mean 2.3 vs. 2.0, p = 0.0071). CONCLUSIONS PIR is a promising method to reduce radiation dose for multiphase abdominal CT, preserving observer performance despite small reductions in image quality. Further work is warranted.
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PENG BINGRU, KITTIPAYAK SAMRIT, PAN LUNGFA, PAN LUNGKWANG. OPTIMIZING THE MINIMUM DETECTABLE DIFFERENCE OF COMPUTED TOMOGRAPHY SCANNED IMAGES VIA THE TAGUCHI ANALYSIS: A FEASIBILITY STUDY WITH AN INDIGENOUS HEPATIC PHANTOM AND A LINE GROUP GAUGE. J MECH MED BIOL 2019. [DOI: 10.1142/s0219519419400487] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Objective: The minimum detectable difference (MDD) of computed tomography (CT) scanned images was quantified and optimized according to an indigenous hepatic phantom, line group gauge and Taguchi [Formula: see text] optimization analysis in this work. Methods: Optimal combinations of CT scan factors in every group with the level organization were judged using the Taguchi analysis, in which every factor was organized into only 18 groups, creating evaluated outcomes with the same confidence as if every factor was analyzed independently. The five practical factors of the CT scan were (1) kVp, (2) mAs, (3) pitch increment, (4) field of view (FOV) and (5) rotation time for one loop of CT scan. Insofar as each factor had two or three levels, the total number of 162 (i.e., [Formula: see text]) combinations was considered. Results: The optimal setting was 120[Formula: see text]kVp, 300[Formula: see text]mAs, 0.641 pitch, 320[Formula: see text]mm FOV and 1.0[Formula: see text]s of rotation time of CT scan. The minimal MDD was 2.65[Formula: see text]mm under 0.39[Formula: see text]mm of the slit depth from the revised Student’s [Formula: see text]-test with a 95% confidence level. In contrast, the MDD of conventional and the best one (no. 7) among all original 18 groups were 3.27[Formula: see text]mm and 2.93[Formula: see text]mm for 0.43[Formula: see text]mm and 0.41[Formula: see text]mm slit depths, respectively. Conclusion: The Taguchi analysis was found very lucrative for the design of imaging analysis in practical diagnosis. The indigenous line group gauge and hepatic phantom also proved to be suitable in simulating the human body in real hepatic carcinoma examination.
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Affiliation(s)
- BING-RU PENG
- Graduate Institute of Radiological Science, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan, ROC
- Department of Radiology Taichung, Armed Forces General Hospital, Taichung 411, Taiwan, ROC
| | - SAMRIT KITTIPAYAK
- Department of Radiological Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - LUNG-FA PAN
- Graduate Institute of Radiological Science, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan, ROC
- Department of Cardiology, Taichung Armed Forces, General Hospital, Taichung 411, Taiwan, ROC
| | - LUNG-KWANG PAN
- Graduate Institute of Radiological Science, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan, ROC
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Mileto A, Guimaraes LS, McCollough CH, Fletcher JG, Yu L. State of the Art in Abdominal CT: The Limits of Iterative Reconstruction Algorithms. Radiology 2019; 293:491-503. [DOI: 10.1148/radiol.2019191422] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Achille Mileto
- From the Department of Radiology, University of Washington School of Medicine, Seattle, Wash (A.M.); Joint Department of Medical Imaging, Sinai Health System, University of Toronto, Toronto, Ontario, Canada (L.S.G.); and Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (C.H.M., J.G.F., L.Y.)
| | - Luis S. Guimaraes
- From the Department of Radiology, University of Washington School of Medicine, Seattle, Wash (A.M.); Joint Department of Medical Imaging, Sinai Health System, University of Toronto, Toronto, Ontario, Canada (L.S.G.); and Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (C.H.M., J.G.F., L.Y.)
| | - Cynthia H. McCollough
- From the Department of Radiology, University of Washington School of Medicine, Seattle, Wash (A.M.); Joint Department of Medical Imaging, Sinai Health System, University of Toronto, Toronto, Ontario, Canada (L.S.G.); and Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (C.H.M., J.G.F., L.Y.)
| | - Joel G. Fletcher
- From the Department of Radiology, University of Washington School of Medicine, Seattle, Wash (A.M.); Joint Department of Medical Imaging, Sinai Health System, University of Toronto, Toronto, Ontario, Canada (L.S.G.); and Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (C.H.M., J.G.F., L.Y.)
| | - Lifeng Yu
- From the Department of Radiology, University of Washington School of Medicine, Seattle, Wash (A.M.); Joint Department of Medical Imaging, Sinai Health System, University of Toronto, Toronto, Ontario, Canada (L.S.G.); and Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (C.H.M., J.G.F., L.Y.)
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Qurashi AA, Rainford LA, Alshamrani KM, Foley SJ. THE IMPACT OF OBESITY ON ABDOMINAL CT RADIATION DOSE AND IMAGE QUALITY. RADIATION PROTECTION DOSIMETRY 2019; 185:17-26. [PMID: 30508172 DOI: 10.1093/rpd/ncy212] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/02/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
The aim of this study was to evaluate how iterative reconstruction can compensate for the noise increase in low radiation dose abdominal computed tomography (CT) technique for large size patients and the general impact of obesity on abdominal organ doses and image quality in CT. An anthropomorphic phantom layered with either none or a single layer of 3-cm- thick circumferential animal fat packs to simulate obese patients was imaged using a 128MDCT scanner. Abdominal protocols (n = 12) were applied using automatic tube current modulation (ATCM) with various quality reference mAs (150, 200, 250 and 300). kVs of 100, 120 and 140 were used for each mAs selection. Metal oxide semiconductor field effect transistor dosimeters (MOSFET) measured internal organ dose. All images produced were reconstructed with filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE) (3, 4 and 5) and objective noise was measured within three regions of interest at the level of L4-L5. Organ doses varied from 0.12 to 41.9 mGy, the spleen received the highest doses for both phantom sizes. Compared to the phantom simulating average size, the obese phantom was associated with up to twofold increase in delivered mAs, dose length product (DLP) and computed tomography dose index (CTDIvol) for the matched mAs selection (p < 0.05). However, organ dose increased by 50% only. The use of 100 kV resulted in a 40% lower dose (p < 0.05) compared to 120 kV and the associated noise increase was improved by SAFIRE (5) use, which resulted in 60% noise reduction compared to FBP (p < 0.05). When combined with iterative reconstruction, low kV is feasible for obese patients to optimise radiation dose and maintain objective image quality.
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Affiliation(s)
- Abdulaziz A Qurashi
- Department of Diagnostic Radiologic Technology, College of Applied Medical Sciences, Taibah University, Madinah, Saudi Arabia
| | - Louise A Rainford
- Radiography & Diagnostic Imaging, School of Medicine, University College Dublin, Dublin, Ireland
| | - Khalid M Alshamrani
- Radiological Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Shane J Foley
- Radiography & Diagnostic Imaging, School of Medicine, University College Dublin, Dublin, Ireland
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14
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Fletcher JG, DeLone DR, Kotsenas AL, Campeau NG, Lehman VT, Yu L, Leng S, Holmes DR, Edwards PK, Johnson MP, Michalak GJ, Carter RE, McCollough CH. Evaluation of Lower-Dose Spiral Head CT for Detection of Intracranial Findings Causing Neurologic Deficits. AJNR Am J Neuroradiol 2019; 40:1855-1863. [PMID: 31649155 DOI: 10.3174/ajnr.a6251] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/21/2019] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND PURPOSE Despite the frequent use of unenhanced head CT for the detection of acute neurologic deficit, the radiation dose for this exam varies widely. Our aim was to evaluate the performance of lower-dose head CT for detection of intracranial findings resulting in acute neurologic deficit. MATERIALS AND METHODS Projection data from 83 patients undergoing unenhanced spiral head CT for suspected neurologic deficits were collected. Cases positive for infarction, intra-axial hemorrhage, mass, or extra-axial hemorrhage required confirmation by histopathology, surgery, progression of findings, or corresponding neurologic deficit; cases negative for these target diagnoses required negative assessments by two neuroradiologists and a clinical neurologist. A routine dose head CT was obtained using 250 effective mAs and iterative reconstruction. Lower-dose configurations were reconstructed (25-effective mAs iterative reconstruction, 50-effective mAs filtered back-projection and iterative reconstruction, 100-effective mAs filtered back-projection and iterative reconstruction, 200-effective mAs filtered back-projection). Three neuroradiologists circled findings, indicating diagnosis, confidence (0-100), and image quality. The difference between the jackknife alternative free-response receiver operating characteristic figure of merit at routine and lower-dose configurations was estimated. A lower 95% CI estimate of the difference greater than -0.10 indicated noninferiority. RESULTS Forty-two of 83 patients had 70 intracranial findings (29 infarcts, 25 masses, 10 extra- and 6 intra-axial hemorrhages) at routine head CT (CT dose index = 38.3 mGy). The routine-dose jackknife alternative free-response receiver operating characteristic figure of merit was 0.87 (95% CI, 0.81-0.93). Noninferiority was shown for 100-effective mAs iterative reconstruction (figure of merit difference, -0.04; 95% CI, -0.08 to 0.004) and 200-effective mAs filtered back-projection (-0.02; 95% CI, -0.06 to 0.02) but not for 100-effective mAs filtered back-projection (-0.06; 95% CI, -0.10 to -0.02) or lower-dose levels. Image quality was better at higher-dose levels and with iterative reconstruction (P < .05). CONCLUSIONS Observer performance for dose levels using 100-200 eff mAs was noninferior to that observed at 250 effective mAs with iterative reconstruction, with iterative reconstruction preserving noninferiority at a mean CT dose index of 15.2 mGy.
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Affiliation(s)
- J G Fletcher
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - D R DeLone
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - A L Kotsenas
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - N G Campeau
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - V T Lehman
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - L Yu
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - S Leng
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - D R Holmes
- Biomedical Imaging Resource (D.R.H., P.E.)
| | | | - M P Johnson
- Biomedical Statistics and Informatics (M.P.J.), Mayo Clinic, Rochester, Minnesota
| | - G J Michalak
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
| | - R E Carter
- Health Sciences Research (R.E.C.), Mayo Clinic, Jacksonville, Florida
| | - C H McCollough
- From the Departments of Radiology (J.G.F., D.R.D., A.L.K., N.G.C., V.T.L., L.Y., S.L., G.J.M., C.H.M.)
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Whole-body computed tomography: a new point of view in a hospital check-up unit? Our experience in 6516 patients. Radiol Med 2019; 124:1199-1211. [PMID: 31407223 DOI: 10.1007/s11547-019-01068-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 08/06/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND There is a growing awareness that prevention and early diagnosis may reduce the high mortality associated with cancer, cardiovascular and other diseases. The role of whole-body computed tomography (WB-CT) in self-referred and asymptomatic patients has been debated. AIM To determine frequency and spectrum of WB-CT findings in average-risk subjects derived from a Medical-Check-Up-Unit, to evaluate recommendations reported and distribution according to sex and age-groups. MATERIALS AND METHODS We retrospectively reviewed 6516 subjects who underwent WB-CT (June 2004/February 2015). All were > 40 years and referred by Medical-Check-Up-Unit of our hospital. The main findings were categorized and classified as normal or not. Its distribution according to sex and age-groups was evaluated using Chi-square test and linear-by-linear association test, respectively. Number of recommendations, type and interval of follow-up were recorded. Descriptive statistics were used. RESULTS WB-CT performed in 6516 patients (69% men, 31% women, mean age = 58.4 years) revealed chest (81.4%), abdominal (93.06%) and spine (65.39%) abnormalities. Only 1.60% had completely normal exploration. Abnormal WB-CT in men was significantly higher than women (98.64% vs. 97.87%; p = 0.021), with significant increase as age was higher (40-49 years: 95.65%; 50-59 years: 98.33%; 60-69 years: 99.47%; > 69 years: 99.89%) (p < 0.001). Although most findings were benign, we detected 1.47% primary tumors (96, mainly 35 kidneys and 15 lungs). 17.39% of patients received at least one recommendation predominantly in chest (78.19%) and follow-up imaging (69.89%). CONCLUSION The most common WB-CT findings in asymptomatic subjects are benign. However, this examination allows identifying an important number of relevant and precocious findings that significantly increase with age, involving changes in lifestyle and precocious treatment.
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CT in Crohn's Disease Is Beneficial for Patient Care and Should Not Be Feared. Dig Dis Sci 2019; 64:2056-2058. [PMID: 31123974 DOI: 10.1007/s10620-019-05678-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/04/2019] [Indexed: 12/09/2022]
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17
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Improving image quality with model-based iterative reconstruction algorithm for chest CT in children with reduced contrast concentration. Radiol Med 2019; 124:595-601. [PMID: 30739289 DOI: 10.1007/s11547-019-00995-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/24/2019] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To evaluate model-based iterative reconstruction (MBIR) in improving the image quality of chest CT in children with reduced concentration contrast medium (CM). METHODS Fifty-six children (median age of 4 years) who received low-dose enhanced chest CT were enrolled as the study group and compared with the control group of 56 children. Both groups used the automatic tube current modulation to achieve age-based noise index values of 11-15 HU. The study group used 100 kVp and reduced CM concentration of 270 mgI/ml, and the images in this group were reconstructed with 50% adaptive statistical iterative reconstruction (ASIR) and MBIR. The control group used 120 kV and standard CM of 320 mgI/ml, and the images in this group were reconstructed with ASIR only. Subjective image quality and objective image quality of the three image sets were evaluated. The subjective quality included overall image noise, enhancement degree, lesion (including mediastinum mass, pulmonary space-occupying lesions, and parenchymal infiltrative lesions) conspicuity, and beam-hardening artifacts. The objective quality included the measurement of noise in the left ventricle and back muscle to calculate signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of ventricle. RESULTS There was no difference in radiation dose between the study (CTDIvol of 1.79 ± 1.45 mGy) and control (1.68 ± 0.92 mGy) groups (p = 0.65). However, the study group used 19.7% lower CM dose than the control group (5.84 ± 2.69 vs. 7.27 ± 3.80 gI), and the enhancement in all images met the diagnostic requirements. MBIR reduced image noise by 58.6% and increased SNR and CNR by 143.6% and 165.7%, respectively, compared to ASIR images in the control group. The two ASIR image sets had similar image quality. CONCLUSION MBIR improved the image quality of low-radiation-dose chest CT in children at 19.3% reduced CM dose.
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18
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Fletcher JG, Fidler JL, Venkatesh SK, Hough DM, Takahashi N, Yu L, Johnson M, Leng S, Holmes DR, Carter R, McCollough CH. Observer Performance with Varying Radiation Dose and Reconstruction Methods for Detection of Hepatic Metastases. Radiology 2018; 289:455-464. [PMID: 30204077 DOI: 10.1148/radiol.2018180125] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To estimate the ability of lower dose levels and iterative reconstruction (IR) to display hepatic metastases that can be detected by radiologists. Materials and Methods Projection data from 83 contrast agent-enhanced CT examinations were collected. Metastases were defined by histopathologic analysis or progression and regression. Lower radiation dose configurations were reconstructed at five dose levels with filtered back projection (FBP) and IR (automatic exposure control settings: 80, 100, 120, 160, and 200 quality reference mAs [QRM]). Three abdominal radiologists circumscribed metastases, indicating confidence (confidence range, 0-100) and image quality. Noninferiority was assessed by using jackknife alternative free-response receiver operating characteristic (JAFROC) analysis (noninferiority limit, -0.10) and reader agreement rules, which required identification of metastases identified at routine dose, and no nonlesion localizations in patients negative for metastases, in 71 or more patient CT examinations (of 83), for each configuration. Results There were 123 hepatic metastases (mean size, 1.4 cm; median volume CT dose index and size-specific dose estimate, 11.0 and 13.4 mGy, respectively). By using JAFROC figure of merit, 100 QRM FBP did not meet noninferiority criteria and had estimated performance difference from routine dose of -0.08 (95% confidence interval: -0.11, -0.04). Preset reader agreement rules were not met for 100 QRM IR or 80 QRM IR, but were met for doses 120 QRM or higher (ie, size-specific dose estimate ≥ 8.0 mGy). IR improved image quality (P < .05) but not reader performance. Other than 160 QRM IR, lower dose levels were associated with reduced confidence in metastasis detection (P < .001). Conclusion For detection of hepatic metastases by using contrast-enhanced CT, dose levels that corresponded to 120 quality reference mAs (size-specific dose estimate, 8.0 mGy) and higher performed similarly to 200 quality reference mAs with filtered back projection. © RSNA, 2018 Online supplemental material is available for this article.
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Affiliation(s)
- Joel G Fletcher
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Jeff L Fidler
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Sudhakar K Venkatesh
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - David M Hough
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Naoki Takahashi
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Lifeng Yu
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Matthew Johnson
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Shuai Leng
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - David R Holmes
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Rickey Carter
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Cynthia H McCollough
- From the Departments of Radiology (J.G.F., J.L.F., S.K.V., D.M.H., N.T., L.Y., S.L., C.H.M.), Health Sciences Research (M.J., R.C.), and Physiology and Biomedical Research (D.R.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
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Krishnan S, Moghekar A, Duggal A, Yella J, Narechania S, Ramachandran V, Mehta A, Adhi F, Vijayan AKC, Han X, Wang X, Dong F, Martin C, Guzman J. Radiation Exposure in the Medical ICU: Predictors and Characteristics. Chest 2018; 153:1160-1168. [PMID: 29391140 DOI: 10.1016/j.chest.2018.01.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 11/21/2017] [Accepted: 01/02/2018] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Patients admitted to the medical ICU (MICU) are often subjected to multiple radiologic studies. We hypothesized that some endure radiation dose exposure (cumulative effective dose [CED]) in excess of annual US federal occupational health standard limits (CED ≥ 50 mSv) and 5-year cumulative limit (CED ≥ 100 mSv). We also evaluated the correlation of CED with Acute Physiology and Chronic Health Evaluation (APACHE) III score and other clinical variables. METHODS Retrospective observational study conducted in an academic medical center involving all adult admissions (N = 4,155) to the MICU between January 2013 and December 2013. Radiation doses from ionizing radiologic studies were calculated from reference values to determine the CED. RESULTS Three percent of admissions (n = 131) accrued CED ≥ 50 mSv (1% [n = 47] accrued CED ≥ 100 mSv). The median CED was 0.72 mSv (interquartile range, 0.02-5.23 mSv), with a range of 0.00 to 323 mSv. Higher APACHE III scores (P = .003), longer length of MICU stay (P < .0001), sepsis (P = .03), and gastrointestinal disorders and bleeding (P < .0001) predicted higher CED in a multivariable linear regression model. Patients with gastrointestinal bleeding and disorders had an odds ratio of 21.05 (95% CI, 13.54-32.72; P < .0001) and 6.94 (95% CI, 3.88-12.38; P < .0001), respectively, of accruing CED ≥ 50 mSv in a multivariable logistic regression model. CT scan and interventional radiology accounted for 49% and 38% of the total CED, respectively. CONCLUSIONS Patients in the MICU are exposed to radiation doses that can be substantial, exceeding federal annual occupational limits, and in a select subset, are > 100 mSv. Efforts to justify, restrict, and optimize the use of radiologic resources when feasible are warranted.
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Affiliation(s)
| | | | | | | | | | | | - Atul Mehta
- Cleveland Clinic Foundation, Cleveland, OH
| | - Fatima Adhi
- New York University School of Medicine, New York, NY
| | | | | | | | - Frank Dong
- Cleveland Clinic Foundation, Cleveland, OH
| | | | - Jorge Guzman
- Cleveland Clinic Abu Dhabi, Al Maryah Island, Abu Dhabi, United Arab Emirates
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Comparison of Radiation Dose and Image Quality of Abdominopelvic CT Using Iterative (AIDR 3D) and Conventional Reconstructions. AJR Am J Roentgenol 2018; 210:127-133. [DOI: 10.2214/ajr.17.18025] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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21
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Bretas EAS, Torres US, Torres LR, Bekhor D, Saito Filho CF, Racy DJ, Faggioni L, D'Ippolito G. Is liver perfusion CT reproducible? A study on intra- and interobserver agreement of normal hepatic haemodynamic parameters obtained with two different software packages. Br J Radiol 2017; 90:20170214. [PMID: 28830195 DOI: 10.1259/bjr.20170214] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To evaluate the agreement between the measurements of perfusion CT parameters in normal livers by using two different software packages. METHODS This retrospective study was based on 78 liver perfusion CT examinations acquired for detecting suspected liver metastasis. Patients with any morphological or functional hepatic abnormalities were excluded. The final analysis included 37 patients (59.7 ± 14.9 y). Two readers (1 and 2) independently measured perfusion parameters using different software packages from two major manufacturers (A and B). Arterial perfusion (AP) and portal perfusion (PP) were determined using the dual-input vascular one-compartmental model. Inter-reader agreement for each package and intrareader agreement between both packages were assessed with intraclass correlation coefficients (ICC) and Bland-Altman statistics. RESULTS Inter-reader agreement was substantial for AP using software A (ICC = 0.82) and B (ICC = 0.85-0.86), fair for PP using software A (ICC = 0.44) and fair to moderate for PP using software B (ICC = 0.56-0.77). Intrareader agreement between software A and B ranged from slight to moderate (ICC = 0.32-0.62) for readers 1 and 2 considering the AP parameters, and from fair to moderate (ICC = 0.40-0.69) for readers 1 and 2 considering the PP parameters. CONCLUSION At best there was only moderate agreement between both software packages, resulting in some uncertainty and suboptimal reproducibility. Advances in knowledge: Software-dependent factors may contribute to variance in perfusion measurements, demanding further technical improvements. AP measurements seem to be the most reproducible parameter to be adopted when evaluating liver perfusion CT.
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Affiliation(s)
- Elisa Almeida Sathler Bretas
- 1 Department of Imaging, Universidade Federal de São Paulo, São Paulo, Brazil.,2 Department of Radiology, Grupo Fleury, São Paulo, Brazil
| | | | - Lucas Rios Torres
- 2 Department of Radiology, Grupo Fleury, São Paulo, Brazil.,3 Department of Imaging, Hospital Beneficência Portuguesa, São Paulo, Brazil
| | - Daniel Bekhor
- 1 Department of Imaging, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Douglas Jorge Racy
- 3 Department of Imaging, Hospital Beneficência Portuguesa, São Paulo, Brazil
| | - Lorenzo Faggioni
- 4 Department of Diagnostic and Interventional Radiology, University Hospital of Pisa, Pisa, Italy
| | - Giuseppe D'Ippolito
- 1 Department of Imaging, Universidade Federal de São Paulo, São Paulo, Brazil.,2 Department of Radiology, Grupo Fleury, São Paulo, Brazil
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Estimation of Observer Performance for Reduced Radiation Dose Levels in CT: Eliminating Reduced Dose Levels That Are Too Low Is the First Step. Acad Radiol 2017; 24:876-890. [PMID: 28262519 DOI: 10.1016/j.acra.2016.12.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/23/2016] [Accepted: 12/26/2016] [Indexed: 12/20/2022]
Abstract
RATIONALE AND OBJECTIVES This study aims to estimate observer performance for a range of dose levels for common computed tomography (CT) examinations (detection of liver metastases or pulmonary nodules, and cause of neurologic deficit) to prioritize noninferior dose levels for further analysis. MATERIALS AND METHODS Using CT data from 131 examinations (abdominal CT, 44; chest CT, 44; head CT, 43), CT images corresponding to 4%-100% of the routine clinical dose were reconstructed with filtered back projection or iterative reconstruction. Radiologists evaluated CT images, marking specified targets, providing confidence scores, and grading image quality. Noninferiority was assessed using reference standards, reader agreement rules, and jackknife alternative free-response receiver operating characteristic figures of merit. Reader agreement required that a majority of readers at lower dose identify target lesions seen by the majority of readers at routine dose. RESULTS Reader agreement identified dose levels lower than 50% and 4% to have inadequate performance for detection of hepatic metastases and pulmonary nodules, respectively, but could not exclude any low dose levels for head CT. Estimated differences in jackknife alternative free-response receiver operating characteristic figures of merit between routine and lower dose configurations found that only the lowest dose configurations tested (ie, 30%, 4%, and 10% of routine dose levels for abdominal, chest, and head CT examinations, respectively) did not meet criteria for noninferiority. At lower doses, subjective image quality declined before observer performance. Iterative reconstruction was only beneficial when filtered back projection did not result in noninferior performance. CONCLUSION Opportunity exists for substantial radiation dose reduction using existing CT technology for common diagnostic tasks.
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Introduction of a pan-scan protocol for blunt trauma activations: what are the consequences? Am J Emerg Med 2017; 35:13-19. [DOI: 10.1016/j.ajem.2016.09.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/13/2016] [Accepted: 09/14/2016] [Indexed: 11/18/2022] Open
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Zarb F, Foley S, Holm S, Toomey R, Evanoff MG, Rainford L. AN INVESTIGATION INTO CT RADIATION DOSE VARIATIONS FOR HEAD EXAMINATIONS ON MATCHED EQUIPMENT. RADIATION PROTECTION DOSIMETRY 2016; 172:466-474. [PMID: 26822422 DOI: 10.1093/rpd/ncv549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/08/2015] [Accepted: 12/09/2015] [Indexed: 06/05/2023]
Abstract
This study investigated radiation dose and image quality differences for computed tomography (CT) head examinations across centres with matched CT equipment. Radiation dose records and imaging protocols currently employed across three European university teaching hospitals were collated, compared and coded as Centres A, B and C from specification matched CT equipment models. Patient scans (n = 40) obtained from Centres A and C were evaluated for image quality, based on the visualisation of Commission of European Community (CEC) image quality criteria using visual grading characteristic (VGC) analysis, where American Board of Radiology examiners (n = 11) stated their confidence in identifying anatomical criteria. Mean doses in terms of CT dose index (CTDIvol-mGy) and dose length product (DLP-mGy cm) were as follows: Centre A-33.12 mGy and 461.45 mGy cm; Centre B -101 mGy (base)/32 mGy (cerebrum) and 762 mGy cm and Centre C-71.98 mGy and 1047.26 mGy cm, showing a significant difference (p ≤ 0.05) in DLP across centres. VGC analysis indicated better visualisation of CEC criteria on Centre C images (VGCAUC 0.225). All three imaging protocols are routinely used clinically, and image quality is acceptable in each centre. Clinical centres with identical model CT scanners have variously customised their protocols achieving a range of dose savings and still resulting in clinically acceptable image quality.
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Affiliation(s)
- Francis Zarb
- Faculty of Health Sciences, Department of Radiography, University of Malta, Msida, Malta
| | - Shane Foley
- Diagnostic Imaging, School of Medicine, University College Dublin, Belfield Dublin 4, Ireland
| | - Susanne Holm
- CONRAD-Radiographic Research Center, University College Lillebaelt, Blangstedgaardsvej 4, 5220 Odense, Denmark
| | - Rachel Toomey
- Diagnostic Imaging, School of Medicine, University College Dublin, Belfield Dublin 4, Ireland
| | - Michael G Evanoff
- American Board of Radiology, 5441 East Williams Boulevard, Suite 200, Tucson, AZ, USA
| | - Louise Rainford
- Diagnostic Imaging, School of Medicine, University College Dublin, Belfield Dublin 4, Ireland
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Optimizing CT technique to reduce radiation dose: effect of changes in kVp, iterative reconstruction, and noise index on dose and noise in a human cadaver. Radiol Phys Technol 2016; 10:180-188. [DOI: 10.1007/s12194-016-0382-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/21/2016] [Accepted: 09/25/2016] [Indexed: 10/20/2022]
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Parakh A, Kortesniemi M, Schindera ST. CT Radiation Dose Management: A Comprehensive Optimization Process for Improving Patient Safety. Radiology 2016; 280:663-73. [DOI: 10.1148/radiol.2016151173] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Irving B, Leswick DA, Fladeland D, Lim HJ, Bryce R. Knowing the Enemy: Health Care Provider Knowledge of Computed Tomography Radiation Dose and Associated Risks. J Med Imaging Radiat Sci 2016; 47:243-250. [PMID: 31047289 DOI: 10.1016/j.jmir.2016.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 04/25/2016] [Accepted: 05/09/2016] [Indexed: 10/24/2022]
Abstract
BACKGROUND There is ionizing radiation and associated risk from many medical imaging examinations, especially computed tomography (CT). Unfortunately, health care providers often have limited knowledge regarding radiation dose levels and potential risk. RESEARCH OBJECTIVES To assess knowledge of dose levels and risk among referring physicians, imaging technologists, and radiologists in Saskatoon, Saskatchewan, and to identify potential differences between and within those groups. MATERIALS AND METHODS A survey was designed and administered to health care professionals. RESULTS A total of 308 of 328 surveys were completed (91% response rate). Overall 73% of physicians, 97% of radiologists, and 76% of technologists correctly believed that there is a risk for cancer from an abdomen-pelvic CT scan. Although only 18% of physicians, 28% of radiologists, and 22% of technologists selected the most appropriate estimate of abdominal-pelvic CT dose in terms of chest x-ray equivalents, this is similar to other reported studies. Physicians and technologists who use CT were more likely to select the correct dose than those who do not. Most respondents (91% of physicians, 100% of radiologists, and 100% of technologists) felt that pregnant patients should always be informed about radiation dose as a risk. Although frequency of discussing risk decreased with increasing patient age, technologists were more likely to discuss risk at any age. A total of 93% of respondents expressed interest in receiving dose feedback from medical imaging procedures. CONCLUSIONS Radiologists and technologists generally showed better knowledge than referring physicians. Among physicians and technologists, knowledge was better in those who use CT than those who do not.
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Affiliation(s)
- Breanne Irving
- Department of Academic Family Medicine, University of Saskatchewan, Swift Current, Saskatchewan, Canada.
| | - David A Leswick
- Department of Radiology, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Derek Fladeland
- Department of Radiology, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Hyun Ja Lim
- Department of Community Health & Epidemiology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Rhonda Bryce
- Department of Community Health & Epidemiology, Clinical Research Support Unit, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Gang GJ, Siewerdsen JH, Stayman JW. Task-Based Design of Fluence Field Modulation in CT for Model-Based Iterative Reconstruction. CONFERENCE PROCEEDINGS. INTERNATIONAL CONFERENCE ON IMAGE FORMATION IN X-RAY COMPUTED TOMOGRAPHY 2016; 2016:407-410. [PMID: 28066840 PMCID: PMC5217752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A task-driven imaging framework for prospective fluence field modulation (FFM) is developed in this paper. The design approach uses a system model that includes a parameterized FFM acquisition and model-based iterative reconstruction (MBIR) for image formation. Using prior anatomical knowledge (e.g. from a low-dose 3D scout image), accurate predictions of spatial resolution and noise as a function of FFM are integrated into a task-based objective function. Specifically, detectability index (d'), a common metric for task-based image quality assessment, is computed for a specific formulation of the imaging task. To optimize imaging performance in across an image volume, a maximin objective function was adopted to maximize the minimum detectability index for many locations sampled throughout the volume. To reduce the dimensionality, FFM patterns were represented using wavelet bases, the coefficients of which were optimized using the covariance matrix adaptation evolutionary strategy (CMA-ES) algorithm. The optimization was performed for a mid-frequency discrimination task involving a cluster of micro-calcifications in an abdomen phantom. The task-driven design yielded FFM patterns that were significantly different from traditional strategies proposed for FBP reconstruction. In addition to a higher minimum d' consistent with the objective function, the task-driven approach also improved d' to a greater extent over a larger area of the phantom. Results from this work suggests that FFM strategies suitable for FBP reconstruction need to be reevaluated in the context of MBIR and that a task-driven imaging framework provides a promising approach for such optimization.
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Affiliation(s)
- Grace J Gang
- G. J. Gang, J. W. Stayman, and J. H. Siewerdsen are with the Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205 USA
| | - Jeffrey H Siewerdsen
- G. J. Gang, J. W. Stayman, and J. H. Siewerdsen are with the Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205 USA
| | - J Webster Stayman
- G. J. Gang, J. W. Stayman, and J. H. Siewerdsen are with the Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205 USA
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Jansen JTM, Shrimpton PC. Development of Monte Carlo simulations to provide scanner-specific organ dose coefficients for contemporary CT. Phys Med Biol 2016; 61:5356-77. [DOI: 10.1088/0031-9155/61/14/5356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Magro F, Coelho R, Guimarães LS, Silva M, Peixoto A, Lopes S, Macedo G. Ionizing radiation exposure is still increasing in Crohn's disease: Who should be blamed? Scand J Gastroenterol 2016; 50:1214-25. [PMID: 25881793 DOI: 10.3109/00365521.2015.1037344] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIM Crohn's disease (CD) patients undergo many radiological studies employing ionizing radiation for diagnosis and management purposes. Our aim was to assess the total radiation exposure of our patients over the years, to estimate the risk factors for exposure to high doses, and to correlate radiation exposure to immunosuppression. METHODS The cumulative effective dose of radiation (CEDR) was calculated multiplying the number of imaging studies by the effective dose of each examination. RESULTS A total of 451 patients with CD (226 female) were followed during 11.0 years (interquartile range [IQR]: 6.0-16.0), with 52.1% of the patients being classified with penetrating (B3) and 38.6% being steroid-dependent. About 16% were exposed to high-radiation dose levels (CEDR >50 mSv) and 4% were exposed to CEDR >100 mSv. The mean CEDR between age 26 and 35 years was 12.539 mSv and a significant dose of radiation (over 50 mSv) was achieved at a median age of 40 (IQR: 29.0-47.0). Abdominal-pelvic computed tomography scan was the examination that contributed the most for CEDR. Patients with B3 phenotype, previous surgery, azathioprine, and anti-tumor necrosis factor (TNF)-α therapy were exposed earlier on the course of the disease to CEDR >50 mSv (p < 0.001). The value of CEDR in the patients under immunosuppression mainly increased in the first year of immunosuppression. CONCLUSION Penetrating phenotype, abdominal surgery, steroid resistance or steroid dependence, and treatment with anti-TNF-α and azathioprine were predictive factors for high CEDR. It was also demonstrated that immunosuppression and anti-TNF-α treatment were followed by a sustained increment of radiation exposure and that a significant dose of radiation was achieved <40 years of age.
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Affiliation(s)
- Fernando Magro
- Gastroenterology Department, Faculty of Medicine, Centro Hospitalar São João , Oporto , Portugal
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Alshamari M, Geijer M, Norrman E, Lidén M, Krauss W, Wilamowski F, Geijer H. Low dose CT of the lumbar spine compared with radiography: a study on image quality with implications for clinical practice. Acta Radiol 2016. [PMID: 26221055 DOI: 10.1177/0284185115595667] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Lumbar spine radiography is often performed instead of CT for radiation dose concerns. PURPOSE To compare image quality and diagnostic information from low dose lumbar spine CT at an effective dose of about 1 mSv with lumbar spine radiography. MATERIAL AND METHODS Fifty-one patients were examined by both methods. Five reviewers scored all examinations on eight image quality criteria using a five-graded scale and also assessed three common pathologic changes. RESULTS Low dose CT scored better than radiography on the following: sharp reproduction of disc profile and vertebral end-plates (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.3-2.5), intervertebral foramina and pedicles (OR, 4.3; 95% CI, 3.1-5.9), intervertebral joints (OR, 139; 95% CI, 59-326), spinous and transverse processes (OR, 7.0; 95% CI, 4.3-11.2), sacro-iliac joints (OR, 4.2; 95% CI, 3.2-5.7), reproduction of the adjacent soft tissues (OR, 2.9; 95% CI, 2.1-4.0), and absence of any obscuring superimposed gastrointestinal gas and contents (OR, 188; 95% CI, 66-539). Radiography scored better on sharp reproduction of cortical and trabecular bone (OR, 0.3; 95% CI, 0.2-0.4). The reviewers visualized disk degeneration, spondylosis/diffuse idiopathic skeletal hyperostosis (DISH) and intervertebral joint osteoarthritis more clearly and were more certain with low dose CT. Mean time to review low dose CT was 204 s (95% CI, 194-214 s.), radiography 152 s (95% CI, 146-158 s.). The effective dose for low dose CT was 1.0-1.1 mSv, for radiography 0.7 mSv. CONCLUSION Low dose lumbar spine CT at about 1 mSv has superior image quality to lumbar spine radiography with more anatomical and diagnostic information.
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Affiliation(s)
- Muhammed Alshamari
- Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Mats Geijer
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Lund University, Sweden
| | - Eva Norrman
- Department of Medical Physics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Mats Lidén
- Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Wolfgang Krauss
- Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Franciszek Wilamowski
- Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Håkan Geijer
- Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
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Kim M, Lee JH, Kim SE, Kang SS, Tae G. Nanosized Ultrasound Enhanced-Contrast Agent for in Vivo Tumor Imaging via Intravenous Injection. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8409-8418. [PMID: 27010717 DOI: 10.1021/acsami.6b02115] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
To enhance the detection limit of ultrasound (US) imaging, ultrasound enhanced-contrast agents (UECAs) that can go preferentially to the target tissue such as a tumor and amplify the US signal have been developed. However, nanosized UECAs among various UECAs developed are very limited to clearly demonstrate proper ability for selective tumor detection by US imaging upon their intravenous injection. In this study, we prepared CaCO3 nanoparticles that were formed inside a flexible and biocompatible pluronic-based nanocarrier. This nanosized UECA was stable in serum-containing media and generated CO2, more preferentially at low pH; thus, it could be detected by US imaging. After intravenous injection into tumor-bearing mice, this nanosized UECA showed a significant US contrast enhancement at the tumor site in 1 h, in contrast to no change in the liver, followed by a rapid clearance from the body in 24 h. Therefore, the present nanosized UECA could be applied as an effective diagnostic modality for in vivo tumor imaging by ultrasonography.
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Affiliation(s)
- Manse Kim
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology , Gwangju 61005, Republic of Korea
| | - Jong Hyun Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology , Gwangju 61005, Republic of Korea
| | - Se Eun Kim
- College of Veterinary Medicine, Chonnam National University , Gwangju 61186, Republic of Korea
| | - Seong Soo Kang
- College of Veterinary Medicine, Chonnam National University , Gwangju 61186, Republic of Korea
| | - Giyoong Tae
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology , Gwangju 61005, Republic of Korea
- Center for Theragnosis, Biomedical Research Institute, KIST , Seoul 02792, Republic of Korea
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Tian X, Yin Z, De Man B, Samei E. Estimation of Radiation Dose in CT Based on Projection Data. J Digit Imaging 2016; 29:615-21. [PMID: 26893140 DOI: 10.1007/s10278-016-9869-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Managing and optimizing radiation dose has become a core problem for the CT community. As a fundamental step for dose optimization, accurate and computationally efficient dose estimates are crucial. The purpose of this study was to devise a computationally efficient projection-based dose metric. The absorbed energy and object mass were individually modeled using the projection data. The absorbed energy was estimated using the difference between intensity of the primary photon and the exit photon. The mass was estimated using the volume under the attenuation profile. The feasibility of the approach was evaluated across phantoms with a broad size range, various kVp settings, and two bowtie filters, using a simulation tool, the Computer Assisted Tomography SIMulator (CATSIM) software. The accuracy of projection-based dose estimation was validated against Monte Carlo (MC) simulations. The relationship between projection-based dose metric and MC dose estimate was evaluated using regression models. The projection-based dose metric showed a strong correlation with Monte Carlo dose estimates (R (2) > 0.94). The prediction errors for the projection-based dose metric were all below 15 %. This study demonstrated the feasibility of computationally efficient dose estimation requiring only the projection data.
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Affiliation(s)
- Xiaoyu Tian
- Department of Biomedical Engineering, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, 2424 Erwin Road, Suite 302, Durham, NC, 27705, USA
| | - Zhye Yin
- CT Systems and Applications Laboratory, GE Global Research, Niskayuna, NY, 12309, USA
| | - Bruno De Man
- CT Systems and Applications Laboratory, GE Global Research, Niskayuna, NY, 12309, USA
| | - Ehsan Samei
- Department of Biomedical Engineering, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, 2424 Erwin Road, Suite 302, Durham, NC, 27705, USA. .,Medical Physics Graduate Program, Departments of Radiology, Electrical and Computer Engineering, and Physics, Duke University Medical Center, Durham, NC, 27705, USA.
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Geyer LL, Körner M, Harrieder A, Mueck FG, Deak Z, Wirth S, Linsenmaier U. Dose reduction in 64-row whole-body CT in multiple trauma: an optimized CT protocol with iterative image reconstruction on a gemstone-based scintillator. Br J Radiol 2016; 89:20160003. [PMID: 26853510 DOI: 10.1259/bjr.20160003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Evaluation of potential dose savings by implementing adaptive statistical iterative reconstruction (ASiR) on a gemstone-based scintillator in a clinical 64-row whole-body CT (WBCT) protocol after multiple trauma. METHODS Dose reports of 152 WBCT scans were analysed for two 64-row multidetector CT scanners (Scanners A and B); the main scanning parameters were kept constant. ASiR and a gemstone-based scintillator were used in Scanner B, and the noise index was adjusted (head: 5.2 vs 6.0; thorax/abdomen: 29.0 vs 46.0). The scan length, CT dose index (CTDI) and dose-length product (DLP) were analysed. The estimated mean effective dose was calculated using normalized conversion factors. Student's t-test was used for statistics. RESULTS Both the mean CTDI (mGy) (Scanner A: 53.8 ± 2.0, 10.3 ± 2.5, 14.4 ± 3.7; Scanner B: 48.7 ± 2.2, 7.1 ± 2.3, 9.1 ± 3.6; p < 0.001, respectively) and the mean DLP (mGy cm) (Scanner A: 1318.9 ± 167.8, 509.3 ± 134.7, 848.8 ± 254.0; Scanner B: 1190.6 ± 172.6, 354.6 ± 128.3, 561.0 ± 246.7; p < 0.001, respectively) for the head, thorax and abdomen were significantly reduced with Scanner B. There was no relevant difference in scan length. The total mean effective dose (mSv) was significantly decreased with Scanner B (24.4 ± 6.0, 17.2 ± 5.8; p < 0.001). CONCLUSION The implementation of ASiR and a gemstone-based scintillator allows for significant dose savings in a clinical WBCT protocol. ADVANCES IN KNOWLEDGE Recent technical developments can significantly reduce radiation dose of WBCT in multiple trauma. Dose reductions of 10-34% can be achieved.
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Affiliation(s)
- Lucas L Geyer
- 1 Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | | | - Andreas Harrieder
- 1 Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Fabian G Mueck
- 1 Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Zsuzsanna Deak
- 1 Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Stefan Wirth
- 1 Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Ulrich Linsenmaier
- 3 Institute for Diagnostic and Interventional Radiology, HELIOS Klinikum Munich West and Munich Perlach, Munich, Germany
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Tian X, Samei E. Accurate assessment and prediction of noise in clinical CT images. Med Phys 2015; 43:475. [DOI: 10.1118/1.4938588] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Tian X, Li X, Segars WP, Frush DP, Samei E. Prospective estimation of organ dose in CT under tube current modulation. Med Phys 2015; 42:1575-85. [PMID: 25832048 DOI: 10.1118/1.4907955] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Computed tomography (CT) has been widely used worldwide as a tool for medical diagnosis and imaging. However, despite its significant clinical benefits, CT radiation dose at the population level has become a subject of public attention and concern. In this light, optimizing radiation dose has become a core responsibility for the CT community. As a fundamental step to manage and optimize dose, it may be beneficial to have accurate and prospective knowledge about the radiation dose for an individual patient. In this study, the authors developed a framework to prospectively estimate organ dose for chest and abdominopelvic CT exams under tube current modulation (TCM). METHODS The organ dose is mainly dependent on two key factors: patient anatomy and irradiation field. A prediction process was developed to accurately model both factors. To model the anatomical diversity and complexity in the patient population, the authors used a previously developed library of computational phantoms with broad distributions of sizes, ages, and genders. A selected clinical patient, represented by a computational phantom in the study, was optimally matched with another computational phantom in the library to obtain a representation of the patient's anatomy. To model the irradiation field, a previously validated Monte Carlo program was used to model CT scanner systems. The tube current profiles were modeled using a ray-tracing program as previously reported that theoretically emulated the variability of modulation profiles from major CT machine manufacturers Li et al., [Phys. Med. Biol. 59, 4525-4548 (2014)]. The prediction of organ dose was achieved using the following process: (1) CTDIvol-normalized-organ dose coefficients (horgan) for fixed tube current were first estimated as the prediction basis for the computational phantoms; (2) each computation phantom, regarded as a clinical patient, was optimally matched with one computational phantom in the library; (3) to account for the effect of the TCM scheme, a weighted organ-specific CTDIvol [denoted as CTDIvol organ,weighted] was computed for each organ based on the TCM profile and the anatomy of the "matched" phantom; (4) the organ dose was predicted by multiplying the weighted organ-specific CTDIvol with the organ dose coefficients (horgan). To quantify the prediction accuracy, each predicted organ dose was compared with the corresponding organ dose simulated from the Monte Carlo program with the TCM profile explicitly modeled. RESULTS The predicted organ dose showed good agreements with the simulated organ dose across all organs and modulation profiles. The average percentage error in organ dose estimation was generally within 20% across all organs and modulation profiles, except for organs located in the pelvic and shoulder regions. For an average CTDIvol of a CT exam of 10 mGy, the average error at full modulation strength (α = 1) across all organs was 0.91 mGy for chest exams, and 0.82 mGy for abdominopelvic exams. CONCLUSIONS This study developed a quantitative model to predict organ dose for clinical chest and abdominopelvic scans. Such information may aid in the design of optimized CT protocols in relation to a targeted level of image quality.
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Affiliation(s)
- Xiaoyu Tian
- Department of Biomedical Engineering, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University, Durham, North Carolina 27705
| | - Xiang Li
- Department of Physics, Cleveland State University, Cleveland, Ohio 44115
| | - W Paul Segars
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705
| | - Donald P Frush
- Division of Pediatric Radiology, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710
| | - Ehsan Samei
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Departments of Physics and Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27705
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Gomes M, Matias A, Macedo F. Risks to the fetus from diagnostic imaging during pregnancy: review and proposal of a clinical protocol. Pediatr Radiol 2015; 45:1916-29. [PMID: 26271622 DOI: 10.1007/s00247-015-3403-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 04/25/2015] [Accepted: 06/01/2015] [Indexed: 11/25/2022]
Abstract
Every day, medical practitioners face the dilemma of exposing pregnant or possibly pregnant patients to radiation from diagnostic examinations. Both doctors and patients often have questions about the risks of radiation. The most vulnerable period is between the 8th and 15th weeks of gestation. Deterministic effects like pregnancy loss, congenital malformations, growth retardation and neurobehavioral abnormalities have threshold doses above 100-200 mGy. The risk is considered negligible at 50 mGy and in reality no diagnostic examination exceeds this limit. The risk of carcinogenesis is slightly higher than in the general population. Intravenous iodinated contrast is discouraged, except in highly selected patients. Considering all the possible noxious effects of radiation exposure, measures to diminish radiation are essential and affect the fetal outcome. Nonionizing procedures should be considered whenever possible and every radiology center should have its own data analysis on fetal radiation exposure. In this review, we analyze existing literature on fetal risks due to radiation exposure, producing a clinical protocol to guide safe radiation use in a clinical setting.
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Affiliation(s)
- Mafalda Gomes
- Faculty of Medicine, University of Porto, Praça de Gomes Teixeira, 4099-002, Porto, Portugal.
| | - Alexandra Matias
- Faculty of Medicine, University of Porto, Praça de Gomes Teixeira, 4099-002, Porto, Portugal
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Ehman EC, Yu L, Manduca A, Hara AK, Shiung MM, Jondal D, Lake DS, Paden RG, Blezek DJ, Bruesewitz MR, McCollough CH, Hough DM, Fletcher JG. Methods for clinical evaluation of noise reduction techniques in abdominopelvic CT. Radiographics 2015; 34:849-62. [PMID: 25019428 DOI: 10.1148/rg.344135128] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Most noise reduction methods involve nonlinear processes, and objective evaluation of image quality can be challenging, since image noise cannot be fully characterized on the sole basis of the noise level at computed tomography (CT). Noise spatial correlation (or noise texture) is closely related to the detection and characterization of low-contrast objects and may be quantified by analyzing the noise power spectrum. High-contrast spatial resolution can be measured using the modulation transfer function and section sensitivity profile and is generally unaffected by noise reduction. Detectability of low-contrast lesions can be evaluated subjectively at varying dose levels using phantoms containing low-contrast objects. Clinical applications with inherent high-contrast abnormalities (eg, CT for renal calculi, CT enterography) permit larger dose reductions with denoising techniques. In low-contrast tasks such as detection of metastases in solid organs, dose reduction is substantially more limited by loss of lesion conspicuity due to loss of low-contrast spatial resolution and coarsening of noise texture. Existing noise reduction strategies for dose reduction have a substantial impact on lowering the radiation dose at CT. To preserve the diagnostic benefit of CT examination, thoughtful utilization of these strategies must be based on the inherent lesion-to-background contrast and the anatomy of interest. The authors provide an overview of existing noise reduction strategies for low-dose abdominopelvic CT, including analytic reconstruction, image and projection space denoising, and iterative reconstruction; review qualitative and quantitative tools for evaluating these strategies; and discuss the strengths and limitations of individual noise reduction methods.
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Affiliation(s)
- Eric C Ehman
- From the Departments of Radiology (E.C.E., L.Y., A.M., M.M.S., D.J., M.R.B., C.H.M., D.M.H., J.G.F.) and Biomedical Engineering (D.S.L., D.J.B.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H., R.G.P.)
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Communicating Potential Radiation-Induced Cancer Risks From Medical Imaging Directly to Patients. AJR Am J Roentgenol 2015; 205:962-70. [DOI: 10.2214/ajr.15.15057] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Chang K, Heisler M, Mahesh M, Baird G, Mayo-Smith W. CT colonography at low tube potential: using iterative reconstruction to decrease noise. Clin Radiol 2015; 70:981-8. [DOI: 10.1016/j.crad.2015.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 03/24/2015] [Accepted: 05/12/2015] [Indexed: 01/15/2023]
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Automatic exposure control systems designed to maintain constant image noise: effects on computed tomography dose and noise relative to clinically accepted technique charts. J Comput Assist Tomogr 2015; 39:437-42. [PMID: 25938214 DOI: 10.1097/rct.0000000000000221] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare computed tomography dose and noise arising from use of an automatic exposure control (AEC) system designed to maintain constant image noise as patient size varies with clinically accepted technique charts and AEC systems designed to vary image noise. MATERIALS AND METHODS A model was developed to describe tube current modulation as a function of patient thickness. Relative dose and noise values were calculated as patient width varied for AEC settings designed to yield constant or variable noise levels and were compared to empirically derived values used by our clinical practice. Phantom experiments were performed in which tube current was measured as a function of thickness using a constant-noise-based AEC system and the results were compared with clinical technique charts. RESULTS For 12-, 20-, 28-, 44-, and 50-cm patient widths, the requirement of constant noise across patient size yielded relative doses of 5%, 14%, 38%, 260%, and 549% and relative noises of 435%, 267%, 163%, 61%, and 42%, respectively, as compared with our clinically used technique chart settings at each respective width. Experimental measurements showed that a constant noise-based AEC system yielded 175% relative noise for a 30-cm phantom and 206% relative dose for a 40-cm phantom compared with our clinical technique chart. CONCLUSIONS Automatic exposure control systems that prescribe constant noise as patient size varies can yield excessive noise in small patients and excessive dose in obese patients compared with clinically accepted technique charts. Use of noise-level technique charts and tube current limits can mitigate these effects.
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Iterative Reconstruction Techniques in Abdominopelvic CT: Technical Concepts and Clinical Implementation. AJR Am J Roentgenol 2015; 205:W19-31. [PMID: 26102414 DOI: 10.2214/ajr.14.13402] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Fletcher JG, Yu L, Li Z, Manduca A, Blezek DJ, Hough DM, Venkatesh SK, Brickner GC, Cernigliaro JC, Hara AK, Fidler JL, Lake DS, Shiung M, Lewis D, Leng S, Augustine KE, Carter RE, Holmes DR, McCollough CH. Observer Performance in the Detection and Classification of Malignant Hepatic Nodules and Masses with CT Image-Space Denoising and Iterative Reconstruction. Radiology 2015; 276:465-78. [PMID: 26020436 DOI: 10.1148/radiol.2015141991] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE To determine if lower-dose computed tomographic (CT) scans obtained with adaptive image-based noise reduction (adaptive nonlocal means [ANLM]) or iterative reconstruction (sinogram-affirmed iterative reconstruction [SAFIRE]) result in reduced observer performance in the detection of malignant hepatic nodules and masses compared with routine-dose scans obtained with filtered back projection (FBP). MATERIALS AND METHODS This study was approved by the institutional review board and was compliant with HIPAA. Informed consent was obtained from patients for the retrospective use of medical records for research purposes. CT projection data from 33 abdominal and 27 liver or pancreas CT examinations were collected (median volume CT dose index, 13.8 and 24.0 mGy, respectively). Hepatic malignancy was defined by progression or regression or with histopathologic findings. Lower-dose data were created by using a validated noise insertion method (10.4 mGy for abdominal CT and 14.6 mGy for liver or pancreas CT) and images reconstructed with FBP, ANLM, and SAFIRE. Four readers evaluated routine-dose FBP images and all lower-dose images, circumscribing liver lesions and selecting diagnosis. The jackknife free-response receiver operating characteristic figure of merit (FOM) was calculated on a per-malignant nodule or per-mass basis. Noninferiority was defined by the lower limit of the 95% confidence interval (CI) of the difference between lower-dose and routine-dose FOMs being less than -0.10. RESULTS Twenty-nine patients had 62 malignant hepatic nodules and masses. Estimated FOM differences between lower-dose FBP and lower-dose ANLM versus routine-dose FBP were noninferior (difference: -0.041 [95% CI: -0.090, 0.009] and -0.003 [95% CI: -0.052, 0.047], respectively). In patients with dedicated liver scans, lower-dose ANLM images were noninferior (difference: +0.015 [95% CI: -0.077, 0.106]), whereas lower-dose FBP images were not (difference -0.049 [95% CI: -0.140, 0.043]). In 37 patients with SAFIRE reconstructions, the three lower-dose alternatives were found to be noninferior to the routine-dose FBP. CONCLUSION At moderate levels of dose reduction, lower-dose FBP images without ANLM or SAFIRE were noninferior to routine-dose images for abdominal CT but not for liver or pancreas CT.
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Affiliation(s)
- Joel G Fletcher
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Lifeng Yu
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Zhoubo Li
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Armando Manduca
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Daniel J Blezek
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - David M Hough
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Sudhakar K Venkatesh
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Gregory C Brickner
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Joseph C Cernigliaro
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Amy K Hara
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Jeff L Fidler
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - David S Lake
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Maria Shiung
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - David Lewis
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Shuai Leng
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Kurt E Augustine
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Rickey E Carter
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - David R Holmes
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
| | - Cynthia H McCollough
- From the Departments of Radiology (J.G.F., L.Y., Z.L., D.M.H., S.K.V., J.L.F., M.S., D.L., S.L., C.H.M.), Physiology and Biomedical Engineering (A.M., D.S.L., K.E.A., D.R.H.), Information Technology (D.J.B.), and Biomedical Statistics and Informatics (R.E.C.), Mayo Clinic, 200 First St SW, Rochester, MN 55905; Department of Radiology, Mayo Clinic, Eau Claire, Wis (G.C.B.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (J.C.C.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (A.K.H.)
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Cohen MD. ALARA, image gently and CT-induced cancer. Pediatr Radiol 2015; 45:465-70. [PMID: 25680877 DOI: 10.1007/s00247-014-3198-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 09/28/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Mervyn D Cohen
- Department of Radiology, Indiana University School of Medicine,Riley Hospital for Children, 520 W. Cedar St, Zionsville, IN, 46077, USA,
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Meinel FG, Nance JW, Harris BS, De Cecco CN, Costello P, Schoepf UJ. Radiation risks from cardiovascular imaging tests. Circulation 2015; 130:442-5. [PMID: 25070551 DOI: 10.1161/circulationaha.113.005340] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Felix G Meinel
- From the Department of Radiology and Radiological Science (F.G.M., J.W.N., B.S.H., C.N.D.C., P.C., U.J.S.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, Charleston; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (F.G.M.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (J.W.N.); and Departments of Radiological Sciences, Oncology, and Pathology, University of Rome "Sapienza"--Polo Pontino, Latina, Italy (C.N.D.C.)
| | - John W Nance
- From the Department of Radiology and Radiological Science (F.G.M., J.W.N., B.S.H., C.N.D.C., P.C., U.J.S.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, Charleston; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (F.G.M.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (J.W.N.); and Departments of Radiological Sciences, Oncology, and Pathology, University of Rome "Sapienza"--Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Brett S Harris
- From the Department of Radiology and Radiological Science (F.G.M., J.W.N., B.S.H., C.N.D.C., P.C., U.J.S.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, Charleston; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (F.G.M.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (J.W.N.); and Departments of Radiological Sciences, Oncology, and Pathology, University of Rome "Sapienza"--Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Carlo N De Cecco
- From the Department of Radiology and Radiological Science (F.G.M., J.W.N., B.S.H., C.N.D.C., P.C., U.J.S.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, Charleston; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (F.G.M.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (J.W.N.); and Departments of Radiological Sciences, Oncology, and Pathology, University of Rome "Sapienza"--Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Philip Costello
- From the Department of Radiology and Radiological Science (F.G.M., J.W.N., B.S.H., C.N.D.C., P.C., U.J.S.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, Charleston; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (F.G.M.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (J.W.N.); and Departments of Radiological Sciences, Oncology, and Pathology, University of Rome "Sapienza"--Polo Pontino, Latina, Italy (C.N.D.C.)
| | - U Joseph Schoepf
- From the Department of Radiology and Radiological Science (F.G.M., J.W.N., B.S.H., C.N.D.C., P.C., U.J.S.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, Charleston; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (F.G.M.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (J.W.N.); and Departments of Radiological Sciences, Oncology, and Pathology, University of Rome "Sapienza"--Polo Pontino, Latina, Italy (C.N.D.C.).
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Hwang IK, Lee YS, Kim J, Lee YJ, Park JH, Hwang JH. Do we really need additional contrast-enhanced abdominal computed tomography for differential diagnosis in triage of middle-aged subjects with suspected biliary pain. Medicine (Baltimore) 2015; 94:e546. [PMID: 25700321 PMCID: PMC4554168 DOI: 10.1097/md.0000000000000546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
Abstract
Enhanced computed tomography (CT) is widely used for evaluating acute biliary pain in the emergency department (ED). However, concern about radiation exposure from CT has also increased. We investigated the usefulness of pre-contrast CT for differential diagnosis in middle-aged subjects with suspected biliary pain.A total of 183 subjects, who visited the ED for suspected biliary pain from January 2011 to December 2012, were included. Retrospectively, pre-contrast phase and multiphase CT findings were reviewed and the detection rate of findings suggesting disease requiring significant treatment by noncontrast CT (NCCT) was compared with cases detected by multiphase CT.Approximately 70% of total subjects had a significant condition, including 1 case of gallbladder cancer and 126 (68.8%) cases requiring intervention (122 biliary stone-related diseases, 3 liver abscesses, and 1 liver hemangioma). The rate of overlooking malignancy without contrast enhancement was calculated to be 0% to 1.5%. Biliary stones and liver space-occupying lesions were found equally on NCCT and multiphase CT. Calculated probable rates of overlooking acute cholecystitis and biliary obstruction were maximally 6.8% and 4.2% respectively. Incidental significant finding unrelated with pain consisted of 1 case of adrenal incidentaloma, which was also observed in NCCT.NCCT might be sufficient to detect life-threatening or significant disease requiring early treatment in young adults with biliary pain.
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Affiliation(s)
- In Kyeom Hwang
- From the Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam-si (IKH, YSL, JK, J-HH); Department of Internal Medicine, Wonkwang University College of Medicine, Wonkwang University Sanbon Hospital, Gunpo (IKH) and Department of Radiology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea (YJL, JHP)
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Kaza RK, Platt JF, Goodsitt MM, Al-Hawary MM, Maturen KE, Wasnik AP, Pandya A. Emerging techniques for dose optimization in abdominal CT. Radiographics 2015; 34:4-17. [PMID: 24428277 DOI: 10.1148/rg.341135038] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recent advances in computed tomographic (CT) scanning technique such as automated tube current modulation (ATCM), optimized x-ray tube voltage, and better use of iterative image reconstruction have allowed maintenance of good CT image quality with reduced radiation dose. ATCM varies the tube current during scanning to account for differences in patient attenuation, ensuring a more homogeneous image quality, although selection of the appropriate image quality parameter is essential for achieving optimal dose reduction. Reducing the x-ray tube voltage is best suited for evaluating iodinated structures, since the effective energy of the x-ray beam will be closer to the k-edge of iodine, resulting in a higher attenuation for the iodine. The optimal kilovoltage for a CT study should be chosen on the basis of imaging task and patient habitus. The aim of iterative image reconstruction is to identify factors that contribute to noise on CT images with use of statistical models of noise (statistical iterative reconstruction) and selective removal of noise to improve image quality. The degree of noise suppression achieved with statistical iterative reconstruction can be customized to minimize the effect of altered image quality on CT images. Unlike with statistical iterative reconstruction, model-based iterative reconstruction algorithms model both the statistical noise and the physical acquisition process, allowing CT to be performed with further reduction in radiation dose without an increase in image noise or loss of spatial resolution. Understanding these recently developed scanning techniques is essential for optimization of imaging protocols designed to achieve the desired image quality with a reduced dose.
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Affiliation(s)
- Ravi K Kaza
- From the Department of Radiology, University of Michigan Hospitals, 1500 E Medical Center Dr, UH B1 D 502 E, Ann Arbor, MI 48109
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Abstract
Several radiation-related professional societies have concluded that carcinogenic risks associated with doses below 50-100 mSv are either too small to be detected, or are nonexistent. This is especially important in the context of doses from medical imaging. Radiation exposure to the public from medical imaging procedures is rising around the world, primarily due to increased utilization of computed tomography. Professional societies and advisory bodies consistently recommend against multiplying small doses by large populations to predict excess radiation-induced cancers, in large part because of the potential for sensational claims of health impacts which do not adequately take the associated uncertainties into account. Nonetheless, numerous articles have predicted thousands of future cancers as a result of CT scanning, and this has generated considerable concern among patients and parents. In addition, some authors claim that we now have direct epidemiological evidence of carcinogenic risks from medical imaging. This paper critically examines such claims, and concludes that the evidence cited does not provide direct evidence of low-dose carcinogenicity. These claims themselves have adverse public health impacts by frightening the public away from medically justified exams. It is time for the medical and scientific communities to be more assertive in responding to sensational claims of health risks.
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Affiliation(s)
- Brant A. Ulsh
- Principal Health Physicist, M.H. Chew & Associates, Livermore, CA
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