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Nyman U, Leander P, Liss P, Sterner G, Brismar T. Absolute and relative GFR and contrast medium dose/GFR ratio: cornerstones when predicting the risk of acute kidney injury. Eur Radiol 2024; 34:612-621. [PMID: 37540321 PMCID: PMC10791854 DOI: 10.1007/s00330-023-09962-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 08/05/2023]
Abstract
Glomerular filtration rate (GFR) is considered the best overall index of kidney function in health and disease and its use is recommended to evaluate the risk of iodine contrast medium-induced acute kidney injury (CI-AKI) either as a single parameter or as a ratio between the total contrast medium dose (gram iodine) and GFR. GFR may be expressed in absolute terms (mL/min) or adjusted/indexed to body surface area, relative GFR (mL/min/1.73 m2). Absolute and relative GFR have been used interchangeably to evaluate the risk of CI-AKI, which may be confusing and a potential source of errors. Relative GFR should be used to assess the GFR category of renal function as a sign of the degree of kidney damage and sensitivity for CI-AKI. Absolute GFR represents the excretion capacity of the individual and may be used to calculate the gram-iodine/absolute GFR ratio, an index of systemic drug exposure (amount of contrast medium in the body) that relates to toxicity. It has been found to be an independent predictor of AKI following percutaneous coronary angiography and interventions but has not yet been fully validated for computed tomography (CT). Prospective studies are warranted to evaluate the optimal gram-iodine/absolute GFR ratio to predict AKI at various stages of renal function at CT. Only GFR estimation (eGFR) equations based on standardized creatinine and/or cystatin C assays should be used. eGFRcystatin C/eGFRcreatinine ratio < 0.6 indicating selective glomerular hypofiltration syndrome may have a stronger predictive power for postcontrast AKI than creatinine-based eGFR. CLINICAL RELEVANCE STATEMENT: Once the degree of kidney damage is established by estimating relative GFR (mL/min/1.73 m2), contrast dose in relation to renal excretion capacity [gram-iodine/absolute GFR (mL/min)] may be the best index to evaluate the risk of contrast-induced kidney injury. KEY POINTS: • Relative glomerular filtration rate (GFR; mL/min/1.73 m2) should be used to assess the GFR category as a sign of the degree of kidney damage and sensitivity to contrast medium-induced acute kidney injury (CI-AKI). • Absolute GFR (mL/min) is the individual's actual excretion capacity and the contrast-dose/absolute GFR ratio is a measure of systemic exposure (amount of contrast medium in the body), relates to toxicity and should be expressed in gram-iodine/absolute GFR (mL/min). • Prospective studies are warranted to evaluate the optimal contrast medium dose/GFR ratio predicting the risk of CI-AKI at CT and intra-arterial examinations.
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Affiliation(s)
- Ulf Nyman
- Department of Translational Medicine, Division of Medical Radiology, University of Lund, Malmö, Sweden.
| | - Peter Leander
- Department of Translational Medicine, Division of Medical Radiology, University of Lund, Malmö, Sweden
| | - Per Liss
- Department of Surgical Sciences, Section of Radiology, Uppsala University, Uppsala, Sweden
| | - Gunnar Sterner
- Department of Nephrology, Skåne University Hospital, Malmö, Sweden
| | - Torkel Brismar
- Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institute/Karolinska University Hospital, Stockholm, Sweden
- Department of Radiology, Karolinska University Hospital in Huddinge, Stockholm, Sweden
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Nyman U, Brismar T, Carlqvist J, Hellström M, Lindblom M, Lidén M, Liss P, Sterner G, Wikner F, Leander P. Revised Swedish guidelines on intravenous iodine contrast medium-induced acute kidney injury 2022: A summary. Acta Radiol 2023; 64:1859-1864. [PMID: 36749001 DOI: 10.1177/02841851231151511] [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: 02/08/2023]
Abstract
The Swedish Society of Uroradiology has revised their computed tomography (CT) guidelines regarding iodine contrast media-induced acute kidney injury (CI-AKI). They are more cautious compared to the European Society of Urogenital Radiology and the American College of Radiology since the actual risk of CI-AKI remains uncertain in patients with moderate to severe kidney damage due to a lack of prospective controlled studies and mainly based on retrospective propensity score-matched studies with low-grade evidence. Another source of uncertainty is the imprecision of glomerular filtration rate (GFR) estimating equations. However, randomized hydration studies indictae an upper limit risk of CI-AKI of about 5% for outpatients with a GFR in the range of 30-44 or 45-59 mL/min/1.73m2 combined with multiple risk factors. Apart from GFR limits, the guideline also includes limits for systemic contrast medium exposure expressed in gram-iodine/GFR ratio.
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Affiliation(s)
- Ulf Nyman
- Department of Translational Medicine, Division of Medical Radiology, University of Lund, Malmö, Sweden
| | - Torkel Brismar
- Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institute/Karolinska University Hospital, Stockholm, Sweden.,Department of Radiology, Karolinska University Hospital in Huddinge, Stockholm, Sweden
| | - Jeanette Carlqvist
- Department of Radiology, Institute of Clinical Sciences, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mikael Hellström
- Department of Radiology, Institute of Clinical Sciences, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Maria Lindblom
- Department of Radiology, Linköping University Hospital, Linköping, Sweden
| | - Mats Lidén
- Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Per Liss
- Department of Surgical Sciences, Section of Radiology, Uppsala University, Uppsala, Sweden
| | - Gunnar Sterner
- Department of Nephrology, Skåne University Hospital, Malmö, Sweden
| | | | - Peter Leander
- Department of Translational Medicine, Division of Medical Radiology, University of Lund, Malmö, Sweden
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Saleh M, Mujtaba B, Jensen C, Aslam R, Elsayes A, Kuchana V, Bhosale P. Feasibility of half the recommended dose of IV contrast in DECT: image quality evaluation and diagnostic acceptability in cancer patients. Clin Imaging 2022; 88:59-65. [DOI: 10.1016/j.clinimag.2022.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/21/2022] [Accepted: 04/27/2022] [Indexed: 11/30/2022]
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Ichikawa S, Motosugi U, Shimizu T, Kromrey ML, Aikawa Y, Tamada D, Onishi H. Diagnostic performance and image quality of low-tube voltage and low-contrast medium dose protocol with hybrid iterative reconstruction for hepatic dynamic CT. Br J Radiol 2021; 94:20210601. [PMID: 34586900 DOI: 10.1259/bjr.20210601] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE To evaluate the diagnostic performance and image quality of the low-tube voltage and low-contrast medium dose protocol for hepatic dynamic CT. METHODS This retrospective study was conducted between January and May 2018. All patients underwent hepatic dynamic CT using one of the two protocols: tube voltage, 80 kVp and contrast dose, 370 mgI/kg with hybrid iterative reconstruction or tube voltage, 120 kVp and contrast dose, 600 mgI/kg with filtered back projection. Two radiologists independently scored lesion conspicuity and image quality. Another radiologist measured the CT numbers of abdominal organs, muscles, and hepatocellular carcinoma (HCC) in each phase. Lesion detectability, HCC diagnostic ability, and image quality of the arterial phase were compared between the two protocols using the non-inferiority test. CT numbers and HCC-to-liver contrast were compared between the protocols using the Mann-Whitney U test. RESULTS 424 patients (70.5 ± 10.1 years) were evaluated. The 80-kVp protocol showed non-inferiority in lesion detectability and diagnostic ability for HCC (sensitivity, 85.7-89.3%; specificity, 96.3-98.6%) compared with the 120-kVp protocol (sensitivity, 91.0-93.3%; specificity, 93.6-97.3%) (p < 0.001-0.038). The ratio of fair image quality in the 80-kVp protocol also showed non-inferiority compared with that in the 120-kVp protocol in assessments by both readers (p < 0.001). HCC-to-liver contrast showed no significant differences for all phases (p = 0.309-0.705) between the two protocols. CONCLUSION The 80-kVp protocol with hybrid iterative reconstruction for hepatic dynamic CT can decrease iodine doses while maintaining diagnostic performance and image quality compared with the 120-kVp protocol. ADVANCES IN KNOWLEDGE The 80- and 120-kVp protocols showed equivalent hepatic lesion detectability, diagnostic ability for HCC, image quality, and HCC-to-liver contrast.The 80-kVp protocol showed a 38.3% reduction in iodine dose compared with the 120-kVp protocol.
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Affiliation(s)
- Shintaro Ichikawa
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Utaroh Motosugi
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.,Department of Diagnostic Radiology, Kofu Kyoritsu Hospital, 1-9-1 Takara, Kofu, Yamanashi, Japan
| | - Tatsuya Shimizu
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Marie Luise Kromrey
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.,Department of Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Domstraße 11, Greifswald, Germany
| | - Yoshihito Aikawa
- Division of Radiology, University of Yamanashi Hospital, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Daiki Tamada
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Hiroshi Onishi
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
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Geissler F, Heiß R, Kopp M, Wiesmüller M, Saake M, Wuest W, Wimmer A, Prell V, Uder M, May MS. Personalized computed tomography - Automated estimation of height and weight of a simulated digital twin using a 3D camera and artificial intelligence. ROFO-FORTSCHR RONTG 2020; 193:437-445. [PMID: 33142337 DOI: 10.1055/a-1253-8558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE The aim of this study was to develop an algorithm for automated estimation of patient height and weight during computed tomography (CT) and to evaluate its accuracy in everyday clinical practice. MATERIALS AND METHODS Depth images of 200 patients were recorded with a 3D camera mounted above the patient table of a CT scanner. Reference values were obtained using a calibrated scale and a measuring tape to train a machine learning algorithm that fits a patient avatar into the recorded patient surface data. The resulting algorithm was prospectively used on 101 patients in clinical practice and the results were compared to the reference values and to estimates by the patient himself, the radiographer and the radiologist. The body mass index was calculated from the collected values for each patient using the WHO formula. A tolerance level of 5 kg was defined in order to evaluate the impact on weight-dependent contrast agent dosage in abdominal CT. RESULTS Differences between values for height, weight and BMI were non-significant over all assessments (p > 0.83). The most accurate values for weight were obtained from the patient information (R² = 0.99) followed by the automated estimation via 3D camera (R² = 0.89). Estimates by medical staff were considerably less precise (radiologist: R² = 0.78, radiographer: R² = 0.77). A body-weight dependent dosage of contrast agent using the automated estimations matched the dosage using the reference measurements in 65 % of the cases. The dosage based on the medical staff estimates would have matched in 49 % of the cases. CONCLUSION Automated estimation of height and weight using a digital twin model from 3D camera acquisitions provide a high precision for protocol design in computer tomography. KEY POINTS · Machine learning can calculate patient-avatars from 3D camera acquisitions.. · Height and weight of the digital twins are comparable to real measurements of the patients.. · Estimations by medical staff are less precise.. · The values can be used for calculation of contrast agent dosage.. CITATION FORMAT · Geissler F, Heiß R, Kopp M et al. Personalized computed tomography - Automated estimation of height and weight of a simulated digital twin using a 3D camera and artificial intelligence. Fortschr Röntgenstr 2021; 193: 437 - 445.
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Affiliation(s)
- Frederik Geissler
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Department of Radiology, University Hospital Erlangen, Erlangen, Germany
| | - Rafael Heiß
- Department of Radiology, University Hospital Erlangen, Erlangen, Germany
| | - Markus Kopp
- Department of Radiology, University Hospital Erlangen, Erlangen, Germany
| | - Marco Wiesmüller
- Department of Radiology, University Hospital Erlangen, Erlangen, Germany
| | - Marc Saake
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Department of Radiology, University Hospital Erlangen, Erlangen, Germany
| | - Wolfgang Wuest
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Department of Radiology, University Hospital Erlangen, Erlangen, Germany.,Imaging Science Institute, Erlangen, Germany
| | | | | | - Michael Uder
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Department of Radiology, University Hospital Erlangen, Erlangen, Germany.,Imaging Science Institute, Erlangen, Germany
| | - Matthias Stefan May
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Department of Radiology, University Hospital Erlangen, Erlangen, Germany.,Imaging Science Institute, Erlangen, Germany
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Miyoshi K, Onoda H, Tanabe M, Nakao S, Higashi M, Iida E, Okada M, Furukawa M, Ito K. Image quality in dual-source multiphasic dynamic computed tomography of the abdomen: evaluating the effects of a low tube voltage (70 kVp) in combination with contrast dose reduction. Abdom Radiol (NY) 2020; 45:3755-3762. [PMID: 32382819 DOI: 10.1007/s00261-020-02565-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To compare the image quality of multiphasic (arterial, portal, and equilibrium phases) dynamic computed tomography (CT) of the abdomen obtained by a low tube voltage (70kVp) in combination with a half-dose iodine load using low-concentration contrast agent in high tube output dual-source CT with a standard tube voltage (120kVp) and full-dose iodine load using the same group of adult patients. METHODS Fifty-five patients who underwent both low-tube-voltage (70kVp) abdominal CT with a half-dose iodine load and standard-tube-voltage (120kVp) CT with a full-dose iodine load were analyzed. The mean CT values and signal-to-noise ratio (SNR) of the liver, aorta and portal veins were quantitatively assessed. In addition, the contrast enhancement of the abdominal organs and overall image quality were qualitatively evaluated. RESULTS The mean CT values and SNR of the liver parenchyma were significantly higher in 70-kVp protocol than in 120-kVp protocol in all 3 phases (p = 0.018 ~ < 0.001). Regarding the qualitative analysis, the overall image quality in the 70-kVp protocol was significantly better than in the 120-kVp protocol in all 3 phases (p < 0.001). In addition, the contrast enhancement scores of the liver parenchyma and hepatic vein in the equilibrium phase were also significantly higher in the 70-kVp protocol than in the 120-kVp protocol (p < 0.001). CONCLUSION A low tube voltage (70kVp) in combination with a half-dose iodine load using a low-concentration contrast agent and an iterative reconstruction algorithm in high tube output dual-source CT may improve the contrast enhancement and image quality in multiphasic dynamic CT of the abdomen in patients under 71 kg of body weight.
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Affiliation(s)
- Keisuke Miyoshi
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Hideko Onoda
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Mashiro Tanabe
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Sei Nakao
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Mayumi Higashi
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Etsushi Iida
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Munemasa Okada
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Matakazu Furukawa
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Katsuyoshi Ito
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan.
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Funama Y, Takahashi H, Goto T, Aoki Y, Yoshida R, Kumagai Y, Awai K. Improving Low-contrast Detectability and Noise Texture Pattern for Computed Tomography Using Iterative Reconstruction Accelerated with Machine Learning Method: A Phantom Study. Acad Radiol 2020; 27:929-936. [PMID: 31918961 DOI: 10.1016/j.acra.2019.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/01/2019] [Accepted: 09/11/2019] [Indexed: 11/15/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate the performance of iterative reconstruction (IR) and filtered back projection (FBP) images in terms of low-contrast detectability at different radiation doses, IR levels, and slice thickness using the mathematical model observer with a focus on low-contrast detectability. MATERIALS AND METHODS The CCT189 MITA CT IQ Low-Contrast Phantom was used and helical scans were performed using a 64-detector CT scanner. Tube voltage was set at 120 kVp and tube current was adjusted from 45 to 600 mA. Images were reconstructed at slice thicknesses of 0.625 and 5.0 mm with FBP and five types of iterative progressive reconstruction with visual modeling (IPV) algorithms. The noise power spectrum (NPS) and normalized NPS were calculated. To evaluate low-contrast detectability, the model observer with the channelized Hotelling observer model was applied using low-contrast modules in the phantom. RESULTS The NPS and normalized NPS for IPV images had similar curves as that for FBP images. At a slice thickness of 0.625 mm and equivalent radiation dose level, the mean improvement of low-contrast detectability for IPV images was 1.19-2.15-fold greater than FBP images with corresponding noise reduction levels. At equivalent noise levels of 5.0-8.0 HU, low-contrast detectability of the IPVstd2 to IPVstr2 images as almost the same or better than that of the FBP images. However, the detectability of the IPVstr4 image was lower than that of the FBP image (p = 0.02). CONCLUSION Low-contrast detectability of the IPV images was improved with a similar normalized NPS as with FBP images. Furthermore, a radiation reduction of >50% was achieved for the IPV images, while maintaining similar low-contrast detectability.
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Affiliation(s)
- Yoshinori Funama
- Department of Medical Radiation Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto 862-0976, Japan.
| | | | - Taiga Goto
- Hitachi Ltd. Healthcare Business Unit, Kashiwa, Chiba, Japan
| | - Yuko Aoki
- Hitachi Ltd. Healthcare Business Unit, Kashiwa, Chiba, Japan
| | - Ryo Yoshida
- Hitachi Ltd. Healthcare Business Unit, Kashiwa, Chiba, Japan
| | - Yukio Kumagai
- Hitachi Ltd. Healthcare Business Unit, Kashiwa, Chiba, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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Holmquist F, Söderberg M, Nyman U, Fält T, Siemund R, Geijer M. 80-kV p hepatic CT to reduce contrast medium dose in azotemic patients: a feasibility study. Acta Radiol 2020; 61:441-449. [PMID: 31378079 DOI: 10.1177/0284185119866807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Low peak kilovoltage (kVp) computed tomography (CT) may be used to reduce contrast medium doses in patients at risk of contrast medium-induced acute kidney injury if image noise can be controlled by increasing X-ray tube loading (mAs). Purpose To evaluate objective and subjective image quality in 80-kVp CT with reduced contrast medium dose and compensated mAs for unchanged image noise in patients with estimated glomerular filtration rate <45 mL/min compared with the standard 120-kVp protocol. Material and Methods 80-kVp CT with 300 mg I/kg in 40 patients (body mass index 18–32 kg/m2, glomerular filtration rate <45 mL/min) and 120-kVp CT with 500 mg I/kg in 40 patients (body mass index = 17–30 kg/m2, glomerular filtration rate ≥45 mL/min) was compared on mean hepatic attenuation, image noise, contrast medium enhancement, signal-to-noise ratio, contrast-to-noise ratio, effective radiation dose, and subjective image quality. Results There were no significant differences regarding median hepatic post-contrast attenuation, image noise, contrast medium enhancement, signal-to-noise ratio, contrast-to-noise ratio, or effective dose between the 80-kVp and 120-kVp cohorts: 114/110 HU; 14/14 HU; 57/53 HU; 8.0/7.4; 3.8/3.5; and 5.3/5.9 mSv, respectively. However, subjective image visual grading showed statistically significantly inferior scores for 80 kVp for six of eight items. After exclusion of seven inferior examinations not caused by the chosen kVp technique, only three items showed inferior scores for 80 kVp. Only 5% of gradings regarding overall image quality were <3 of 5 points. Conclusion Despite lower subjective image quality, objective data indicate that 80-kVp CT with reduced contrast medium doses and compensated mAs may have the potential to provide satisfactory diagnostic quality in patients with body mass index <30 kg/m2, which could benefit patients at risk of contrast medium-induced acute kidney injury.
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Affiliation(s)
- Fredrik Holmquist
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Marcus Söderberg
- Department of Translational Medicine, Medical Radiation Physics, Skåne University Hospital, Lund University, Malmö, Sweden.,Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Malmö, Sweden
| | - Ulf Nyman
- Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Tobias Fält
- Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Roger Siemund
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Mats Geijer
- Institute of Clinical Sciences, Department of Radiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
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Holmquist F, Söderberg M, Nyman U, Fält T, Siemund R, Geijer M. Can iterative reconstruction algorithms replace tube loading compensation in low kVp hepatic CT? Subjective versus objective image quality. Acta Radiol Open 2020; 9:2058460120910575. [PMID: 32206344 PMCID: PMC7076580 DOI: 10.1177/2058460120910575] [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: 11/14/2019] [Accepted: 02/10/2020] [Indexed: 11/16/2022] Open
Abstract
Background Hepatic computed tomography (CT) with decreased peak kilovoltage (kVp) may be used to reduce contrast medium doses in patients at risk of contrast-induced acute kidney injury (CI-AKI); however, it increases image noise. To preserve image quality, noise has been controlled by X-ray tube loading (mAs) compensation (TLC), i.e. increased mAs. Another option to control image noise would be to use iterative reconstructions (IR) algorithms without TLC (No-TLC). It is unclear whether this may preserve image quality or only reduce image noise. Purpose To evaluate image quality of 80 kVp hepatic CT with TLC and filtered back projection (FBP) compared with 80 kVp with No-TLC and IR algorithms (SAFIRE 3 and 5) in patients with eGFR <45 mL/min. Material and Methods Forty patients (BMI 18–32 kg/m2) were examined with both protocols following injection of 300 mg I/kg. Hepatic attenuation, image noise, enhancement, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality were evaluated for each patient. Results Comparing TLC/FBP with No-TLC/IR-S5, there were no significant differences regarding hepatic attenuation, image noise, enhancement, SNR and CNR: 114 vs. 115 HU, 14 vs. 14 HU, 55 vs. 57 HU, 8.0 vs. 8.4, and 3.8 vs. 4.0 in median, respectively. No-TLC/IR-S3 resulted in higher image noise and lower SNR and CNR than TLC/FBP. Subjective image quality scoring with visual grading showed statistically significantly inferior scores for IR-S5 images. Conclusion CT of 80 kVp to reduce contrast medium dose in patients at risk of CI-AKI combined with IR algorithms with unchanged tube loading to control image noise does not provide sufficient diagnostic quality.
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Affiliation(s)
- Fredrik Holmquist
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Marcus Söderberg
- Medical Radiation Physics, Department of Translational Medicine, Skåne University Hospital, Lund University, Malmö, Sweden.,Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Malmö, Sweden
| | - Ulf Nyman
- Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Tobias Fält
- Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Roger Siemund
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Mats Geijer
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden.,Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Region Västra Götaland, Sahlgrenska University Hospital, Department of Radiology, Gothenburg, Sweden
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