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Kawai N, Noda Y, Nakamura F, Kaga T, Suzuki R, Miyoshi T, Mori F, Hyodo F, Kato H, Matsuo M. Low-tube-voltage whole-body CT angiography with extremely low iodine dose: a comparison between hybrid-iterative reconstruction and deep-learning image-reconstruction algorithms. Clin Radiol 2024; 79:e791-e798. [PMID: 38403540 DOI: 10.1016/j.crad.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 01/29/2024] [Accepted: 02/07/2024] [Indexed: 02/27/2024]
Abstract
AIM To evaluate arterial enhancement, its depiction, and image quality in low-tube potential whole-body computed tomography (CT) angiography (CTA) with extremely low iodine dose and compare the results with those obtained by hybrid-iterative reconstruction (IR) and deep-learning image-reconstruction (DLIR) methods. MATERIALS AND METHODS This prospective study included 34 consecutive participants (27 men; mean age, 74.2 years) who underwent whole-body CTA at 80 kVp for evaluating aortic diseases between January and July 2020. Contrast material (240 mg iodine/ml) with simultaneous administration of its quarter volume of saline, which corresponded to 192 mg iodine/ml, was administered. CT raw data were reconstructed using adaptive statistical IR-Veo of 40% (hybrid-IR), DLIR with medium- (DLIR-M), and high-strength level (DLIR-H). A radiologist measured CT attenuation of the arteries and background noise, and the signal-to-noise ratio (SNR) was then calculated. Two reviewers qualitatively evaluated the arterial depictions and diagnostic acceptability on axial, multiplanar-reformatted (MPR), and volume-rendered (VR) images. RESULTS Mean contrast material volume and iodine weight administered were 64.1 ml and 15.4 g, respectively. The SNRs of the arteries were significantly higher in the following order of the DLIR-H, DLIR-M, and hybrid-IR (p<0.001). Depictions of six arteries on axial, three arteries on MPR, and four arteries on VR images were significantly superior in the DLIR-M or hybrid-IR than in the DLIR-H (p≤0.009 for each). Diagnostic acceptability was significantly better in the DLIR-M and DLIR-H than in the hybrid-IR (p<0.001-0.005). CONCLUSION DLIR-M showed well-balanced arterial depictions and image quality compared with the hybrid-IR and DLIR-H.
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Affiliation(s)
- N Kawai
- Department of Radiology, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan
| | - Y Noda
- Department of Radiology, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan.
| | - F Nakamura
- Department of Radiology, Gifu Municipal Hospital, 7-1 Kashima, Gifu 500-8513, Japan
| | - T Kaga
- Department of Radiology, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan
| | - R Suzuki
- Department of Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan
| | - T Miyoshi
- Department of Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan
| | - F Mori
- Department of Radiology, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan
| | - F Hyodo
- Department of Pharmacology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan; Center for One Medicine Innovative Translational Research (COMIT), Institute for Advanced Study, Gifu University, Japan
| | - H Kato
- Department of Radiology, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan
| | - M Matsuo
- Department of Radiology, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan
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Du B, Zhang W, Shao X, An J, Ma H, Zhao X, Xu L, An D, Tian Y, Dong Y, Niu H. "Triple-low" radiation dose bronchial artery CT angiography before bronchial artery embolisation: a feasibility study. Clin Radiol 2023; 78:e1017-e1022. [PMID: 37813755 DOI: 10.1016/j.crad.2023.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 09/01/2023] [Accepted: 09/12/2023] [Indexed: 10/11/2023]
Abstract
AIM To explore the feasibility of a "triple-low" dose (low tube voltage, low tube current, and low contrast agent volume) bronchial artery computed tomography (CT) angiography (CTA) to replace routine dose bronchial artery CTA before bronchial artery embolisation (BAE). MATERIALS AND METHODS CTA was obtained from 60 patients with body mass index (BMI) < 30 kg/m2 using a 256 multi-section iCT system, and they were divided into two groups: (1) group A: 100 kVp, 100 mAs, 50 ml contrast medium (CM); (2) group B: 120 kVp, automatic tube current modulation (ACTM), 80 ml CM. CT attenuation of the thoracic aorta, image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated, and subjective image quality scores and traceability scores assessed. The effective radiation dose was calculated. RESULTS The radiation dose was reduced by 79.7% in group A compared to group B (p<0.05). The CT attenuation of the thoracic aorta was increased by approximately 13% in group A compared to group B (p<0.05). Higher image noise, lower SNR, and CNR were obtained in group A compared to group B (all p<0.05). Both subjective image quality scores and traceability scores did not differ between groups A and B (both p>0.05). CONCLUSION It is feasible to use the "triple-low" dose CTA protocol for patients with a body mass index (BMI) < 30 kg/m2. The radiation dose was reduced by 79.7%, and the dose of contrast medium was reduced by 37.5% to ensure the diagnostic value.
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Affiliation(s)
- B Du
- Department of Radiology, Hebei Medical University, No. 361 Zhongshan East Road, Shijiazhuang, 050011, Hebei, China
| | - W Zhang
- Chengde Medical University, Anyuan Road, Chengde, 067000, Hebei, China
| | - X Shao
- Department of Radiology, Hebei Medical University, No. 361 Zhongshan East Road, Shijiazhuang, 050011, Hebei, China
| | - J An
- Department of Interventional Treatment, First Hospital of Qinhuangdao, No. 258 Wenhua Road, Qinhuangdao, 066099, Hebei, China
| | - H Ma
- Chengde Medical University, Anyuan Road, Chengde, 067000, Hebei, China
| | - X Zhao
- Department of Radiology, Hebei Medical University, No. 361 Zhongshan East Road, Shijiazhuang, 050011, Hebei, China
| | - L Xu
- Department of Radiology, Hebei Medical University, No. 361 Zhongshan East Road, Shijiazhuang, 050011, Hebei, China
| | - D An
- Department of Interventional Treatment, First Hospital of Qinhuangdao, No. 258 Wenhua Road, Qinhuangdao, 066099, Hebei, China
| | - Y Tian
- Department of Interventional Treatment, First Hospital of Qinhuangdao, No. 258 Wenhua Road, Qinhuangdao, 066099, Hebei, China
| | - Y Dong
- Department of Interventional Treatment, First Hospital of Qinhuangdao, No. 258 Wenhua Road, Qinhuangdao, 066099, Hebei, China
| | - H Niu
- Department of Interventional Treatment, First Hospital of Qinhuangdao, No. 258 Wenhua Road, Qinhuangdao, 066099, Hebei, China.
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Euler A, Higashigaito K, Mergen V, Sartoretti T, Zanini B, Schmidt B, Flohr TG, Ulzheimer S, Eberhard M, Alkadhi H. High-Pitch Photon-Counting Detector Computed Tomography Angiography of the Aorta: Intraindividual Comparison to Energy-Integrating Detector Computed Tomography at Equal Radiation Dose. Invest Radiol 2022; 57:115-121. [PMID: 34352805 DOI: 10.1097/rli.0000000000000816] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aims of this study were to determine the objective and subjective image quality of high-pitch computed tomography (CT) angiography of the aorta in clinical dual-source photon-counting detector CT (PCD-CT) and to compare the image quality to conventional dual-source energy-integrating detector CT (EID-CT) in the same patients at equal radiation dose. MATERIALS AND METHODS Patients with prior CT angiography of the thoracoabdominal aorta acquired on third-generation dual-source EID-CT in the high-pitch mode and with automatic tube voltage selection (ATVS, reference tube voltage 100 kV) were included. Follow-up imaging was performed on a first-generation, clinical dual-source PCD-CT scanner in the high-pitch and multienergy (QuantumPlus) mode at 120 kV using the same contrast media protocol as with EID-CT. Radiation doses between scans were matched by adapting the tube current of PCD-CT. Polychromatic images for both EID-CT and PCD-CT (called T3D) and virtual monoenergetic images at 40, 45, 50, and 55 keV for PCD-CT were reconstructed. Computed tomography attenuation was measured in the aorta; noise was defined as the standard deviation of attenuation; contrast-to-noise ratio (CNR) was calculated. Subjective image quality (noise, vessel attenuation, vessel sharpness, and overall quality) was rated by 2 blinded, independent radiologists. RESULTS Forty patients were included (mean age, 63 years; 8 women; mean body mass index [BMI], 26 kg/m2). There was no significant difference in BMI, effective diameter, or radiation dose between scans (all P's > 0.05). The ATVS in EID-CT selected 70, 80, 90, 100, 110, and 120 kV in 2, 14, 14, 7, 2, and 1 patients, respectively. Mean CNR was 17 ± 8 for EID-CT and 22 ± 7, 20 ± 6, 18 ± 5, 16 ± 5, and 12 ± 4 for PCD-CT at 40, 45, 50, 55 keV, and T3D, respectively. Contrast-to-noise ratio was significantly higher for 40 and 45 keV of PCD-CT as compared with EID-CT (both P's < 0.05). The linear regression model (adjusted R2, 0.38; P < 0.001) revealed that PCD-CT reconstruction (P < 0.001), BMI group (P = 0.007), and kV of the EID-CT scan (P = 0.01) were significantly associated with CNR difference, with an increase by 34% with PCD-CT for overweight as compared with normal weight patients. Subjective image quality reading revealed slight differences between readers for subjective vessel attenuation and sharpness, whereas subjective noise was rated significantly higher for 40 and 45 keV (P < 0.001) and overall quality similar (P > 0.05) between scans. CONCLUSIONS High-pitch PCD-CT angiography of the aorta with VMI at 40 and 45 keV resulted in significantly increased CNR compared with EID-CT with ATVS at matched radiation dose. The CNR gain of PCD-CT increased in overweight patients. Taking into account the subjective analysis, VMI at 45 to 50 keV is proposed as the best trade-off between objective and subjective image quality.
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Affiliation(s)
- André Euler
- From the Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Kai Higashigaito
- From the Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Victor Mergen
- From the Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | | | - Bettina Zanini
- From the Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | | | | | | | - Matthias Eberhard
- From the Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Hatem Alkadhi
- From the Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
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Determine Cumulative Radiation Dose and Lifetime Cancer Risk in Marfan Syndrome Patients Who Underwent Computed Tomography Angiography of the Aorta in Northeast Thailand: A 5-Year Retrospective Cohort Study. Tomography 2022; 8:120-130. [PMID: 35076626 PMCID: PMC8788545 DOI: 10.3390/tomography8010010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/30/2021] [Accepted: 01/02/2022] [Indexed: 11/17/2022] Open
Abstract
Objective: To evaluate computed tomography angiography (CTA) data focusing on radiation dose parameters in Thais with Marfan syndrome (MFS) and estimate the distribution of cumulative radiation exposure from CTA surveillance and the risk of cancers. Methods: Between 1st January 2015 and 31st December 2020, we retrospectively evaluated the cumulative CTA radiation doses of MFS patients who underwent CTA at Khon Kaen University Hospital, a leading teaching hospital and advanced tertiary care institution in northeastern Thailand. We utilized the Radiation Risk Assessment Tool (RadRAT) established at the National Cancer Institute in Bethesda, Maryland, to evaluate the risk of cancer-related CTA radiation. Results: The study recruited 29 adult MFS patients who had CTA of the aorta during a 5-year study period with 89 CTA studies. The mean cumulative CTDI vol is 21.5 ± 14.68 mGy, mean cumulative DLP is 682.2 ± 466.7 mGy.cm, the mean baseline future risk for all cancer is 26,134 ± 7601 per 100,000, and the excess lifetime risk for all cancer is 2080.3 ± 1330 per 100,000. The excess lifetime risk of radiation-induced cancer associated with the CTA surveillance study is significantly lower than the risk of aortic dissection or rupture and lower than the baseline future cancer risk. Conclusions: We attempted to quantify the radiation-induced cancer risk from CTA surveillance imaging performed for MFS patients in this study, with all patients receiving a low-risk cumulative radiation dose (less than 1 Gy) and all patients having a low excessive lifetime risk of cancer as a result of CTA. The risk–benefit decision must be made at the point of care, and it entails balancing the benefits of surveillance imaging in anticipating rupture and providing practical, safe treatment, therefore avoiding morbidity and mortality.
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Chatzaraki V, Kubik-Huch RA, Thali M, Niemann T. Quantifying image quality in chest computed tomography angiography: Evaluation of different contrast-to-noise ratio measurement methods. Acta Radiol 2021; 63:1353-1362. [PMID: 34647842 DOI: 10.1177/02841851211041813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Contrast-to-noise ratio is used to objectively evaluate image quality in chest computed tomography angiography (CTA). Different authors define and measure contrast-to-noise ratio using different methods. PURPOSE To summarize and evaluate the different contrast-to-noise ratio calculation formulas in the current literature. MATERIAL AND METHODS A systematic review of the recent literature for studies using contrast-to-noise ratio was performed. Contrast-to-noise ratio measurement methods reported by the different authors were recorded and reproduced in three patients who underwent chest CTA in our department for exploring variations among the different measurement methods. RESULTS The search resulted in 109 articles, of which 26 were included. The studies involved 69 different measurements and overall, three different formula patterns. In all three, aorta and pulmonary arteries comprised the objects of interest in the numerator. In the denominator, standard deviation of the attenuation of the object of interest itself or of another background were used to reflect image noise. Some authors averaged the ratio values at different levels to obtain global ratio values. Using the object of interest itself for image noise calculation in the denominator compared to the usage of another background caused the most prominent variances of contrast-to-noise ratio between the two different protocols used for the reproduction of the measurements. CONCLUSION We recommend using the standard deviation of the attenuation of a background indicator as image noise rather than the object of interest itself for more reliable and comparative values. Global contrast-to-noise ratios based on averaging the values of different measurement levels should be avoided.
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Affiliation(s)
- Vasiliki Chatzaraki
- Institute of Radiology, Kantonsspital Baden, Baden, Switzerland
- Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | | | - Michael Thali
- Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Tilo Niemann
- Institute of Radiology, Kantonsspital Baden, Baden, Switzerland
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Moloney F, Twomey M, Fama D, Balta JY, James K, Kavanagh RG, Moore N, Murphy MJ, O'Mahony SM, Maher MM, Cryan JF, O'Connor OJ. Determination of a suitable low-dose abdominopelvic CT protocol using model-based iterative reconstruction through cadaveric study. J Med Imaging Radiat Oncol 2018; 62:625-633. [PMID: 29656596 DOI: 10.1111/1754-9485.12733] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 03/08/2018] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Cadaveric studies provide a means of safely assessing new technologies and optimizing scanning prior to clinical validation. Reducing radiation exposure in a clinical setting can entail incremental dose reductions to avoid missing important clinical findings. The use of cadavers allows assessment of the impact of more substantial dose reductions on image quality. Our aim was to identify a suitable low-dose abdominopelvic CT protocol for subsequent clinical validation. METHODS Five human cadavers were scanned at one conventional dose and three low-dose settings. All scans were reconstructed using three different reconstruction algorithms: filtered back projection (FBP), hybrid iterative reconstruction (60% FBP and 40% adaptive statistical iterative reconstruction (ASIR40)), and model-based iterative reconstruction (MBIR). Two readers rated the image quality both quantitatively and qualitatively. RESULTS Model-based iterative reconstruction images had significantly better objective image noise and higher qualitative scores compared with both FBP and ASIR40 images at all dose levels. The greatest absolute noise reduction, between MBIR and FBP, of 34.3 HU (equating to a 68% reduction) was at the lowest dose level. MBIR reduced image noise and improved image quality even in CT images acquired with a mean radiation dose reduction of 62% compared with conventional dose studies reconstructed with ASIR40, with lower levels of objective image noise, superior diagnostic acceptability and contrast resolution, and comparable subjective image noise and streak artefact scores. CONCLUSION This cadaveric study demonstrates that MBIR reduces image noise and improves image quality in abdominopelvic CT images acquired with dose reductions of up to 62%.
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Affiliation(s)
- Fiachra Moloney
- Department of Radiology, Cork University Hospital, Cork, Ireland.,Department of Anatomy and Neuroscience, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Maria Twomey
- Department of Radiology, Cork University Hospital, Cork, Ireland.,Department of Anatomy and Neuroscience, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Daniel Fama
- Department of Radiology, Cork University Hospital, Cork, Ireland
| | - Joy Y Balta
- Department of Anatomy and Neuroscience, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Karl James
- Department of Radiology, Cork University Hospital, Cork, Ireland.,Department of Anatomy and Neuroscience, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Richard G Kavanagh
- Department of Radiology, Cork University Hospital, Cork, Ireland.,Department of Anatomy and Neuroscience, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Niamh Moore
- Department of Radiology, Cork University Hospital, Cork, Ireland
| | - Mary Jane Murphy
- Department of Radiology, Cork University Hospital, Cork, Ireland
| | - Siobhan M O'Mahony
- Department of Anatomy and Neuroscience, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Michael M Maher
- Department of Radiology, Cork University Hospital, Cork, Ireland.,Alimentary Pharmabiotic Centre Microbiome Ireland, University College Cork, Cork, Ireland
| | - John F Cryan
- Department of Anatomy and Neuroscience, College of Medicine and Health, University College Cork, Cork, Ireland.,Alimentary Pharmabiotic Centre Microbiome Ireland, University College Cork, Cork, Ireland
| | - Owen J O'Connor
- Department of Radiology, Cork University Hospital, Cork, Ireland.,Alimentary Pharmabiotic Centre Microbiome Ireland, University College Cork, Cork, Ireland
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Hou P, Feng X, Liu J, Wang X, Jiang Y, Dong L, Gao J. Low Tube Voltage and Iterative Model Reconstruction in Follow-up CT Angiography After Thoracic Endovascular Aortic Repair: Ultra-low Radiation Exposure and Contrast Medium Dose. Acad Radiol 2018; 25:494-501. [PMID: 29249576 DOI: 10.1016/j.acra.2017.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/31/2017] [Accepted: 11/03/2017] [Indexed: 12/27/2022]
Abstract
RATIONALE AND OBJECTIVES This study aimed to investigate the feasibility of reducing radiation exposure and contrast medium (CM) dose in follow-up computed tomography angiography (CTA) after thoracic endovascular aortic repair (TEVAR) using low tube voltage and knowledge-based iterative model reconstruction (IMR). MATERIALS AND METHODS Thirty-six patients that required follow-up CTA after TEVAR were included in this intra-individual study. The conventional protocol with standard tube voltage of 120 kVp and CM volume of 70 mL was applied in the first follow-up CTA of all the patients (control group A). The ultra-low CM dose protocol with low tube voltage of 80 kVp and weight-adapted CM volume of 0.4 mL/kg was utilized in the second follow-up CTA (study group B). Set A.FBP (group A filtered back-projection) contained images for group A that were reconstructed through FBP method. Three sets (B.FBP, B.HIR, and B.IMR) for group B were reconstructed using three methods, FBP, hybrid iterative reconstruction (HIR), and IMR, respectively. Objective measurements including aortic attenuations, image noise, contrast-to-noise ratios (CNRs), and figure of merit of CNR (FOMCNR), and subjective rating scores of the four image sets were compared. RESULTS Compared to the images in set A.FBP, the images in set B.IMR had better quality in terms of equivalent attenuation values, equivalent subjective scores, lower noise, higher or equivalent CNRs, and higher FOMCNR. The quality of images in sets B.FBP and B.HIR was unacceptable. The radiation exposure and CM dose in group B were 1.94 mGy and 28 ± 5 mL, respectively, representing reductions of 77.6% (P < .001) and 60% (P < .001) as compared to those in group A. CONCLUSIONS In follow-up examinations after TEVAR, CTA with ultra-low radiation exposure and CM dose is feasible using low tube voltage and IMR for nonobese patients.
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Affiliation(s)
- Ping Hou
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No. 1, East Jianshe Road, Zhengzhou, Henan Province 450052, China
| | - Xiangnan Feng
- School of Economics and Management, Southwest Jiaotong University, Chengdu, China
| | - Jie Liu
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No. 1, East Jianshe Road, Zhengzhou, Henan Province 450052, China
| | - Xiaopeng Wang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No. 1, East Jianshe Road, Zhengzhou, Henan Province 450052, China
| | - Yaojun Jiang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No. 1, East Jianshe Road, Zhengzhou, Henan Province 450052, China
| | - Leigang Dong
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No. 1, East Jianshe Road, Zhengzhou, Henan Province 450052, China
| | - Jianbo Gao
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No. 1, East Jianshe Road, Zhengzhou, Henan Province 450052, China.
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Zhao YX, Zuo ZW, Suo HN, Wang JN, Chang J. CT Pulmonary Angiography Using Automatic Tube Current Modulation Combination with Different Noise Index with Iterative Reconstruction Algorithm in Different Body Mass Index: Image Quality and Radiation Dose. Acad Radiol 2016; 23:1513-1520. [PMID: 27717760 DOI: 10.1016/j.acra.2016.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/20/2016] [Accepted: 07/01/2016] [Indexed: 10/20/2022]
Abstract
RATIONALE AND OBJECTIVES This study aimed to determine the appropriate body mass index (BMI)-dependent noise index (NI) setting in computed tomography pulmonary angiography (CTPA) with automatic tube current modulation with adaptive statistical iterative reconstruction (ASiR). MATERIALS AND METHODS A total of 480 patients who had a CTPA were divided into group A (18.5 kg/m2 ≤ BMI < 25 kg/m2), group B (25 kg/m2 ≤ BMI < 30 kg/m2), and group C (BMI ≥ 30 kg/m2), according to their BMI values; each group had 160 patients. The three groups were further randomly divided into four subgroups: A1, A2, A3, A4; B1, B2, B3, B4; and C1, C2, C3, C4, with corresponding NI values of 26, 36, 40, and 46, respectively. All images were restructured with the ASiR algorithm, and the images with the lowest NI (26 Hounsfield units) in each group were used as reference standard. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for the pulmonary artery of each group were calculated. Subjective image quality was evaluated using a five-score method by two independent radiologists. The CT dose index of volume and dose-length product were recorded and were converted to effective dose (ED). SNR and CNR in the group A, B, and C subgroups were compared to repeated measures analysis of variance, and the subjective score, Volumetric CT dose index of volume, dose-length product, and ED were compared to one-way analysis of variance. RESULTS For groups A and B, the SNR, CNR, and subjective scores of the images in their subgroups showed no statistical differences (P >.05). The ED in subgroups A4 and B4 was significantly lower than that in subgroups A1 (by 33.24%) and B1 (by 34.47%) (P <.01). For group C, there was no significant difference in the SNR, CNR, and the subjective image scores between subgroups C3 and C1 (P >.05). The ED in subgroup C3 was significantly lower than the ED in subgroup C1 (by 47.75%) (P <.01) CONCLUSIONS: Patient BMI-dependent NI settings that are higher than the recommended value may be used in CTPA with automatic tube current modulation and ASiR to effectively reduce radiation dose while maintaining diagnostic image quality.
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