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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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Digumarthy SR, Singh R, Rastogi S, Otrakji A, Homayounieh F, Zhang EW, McDermott S, Kalra MK. Low contrast volume dual-energy CT of the chest: Quantitative and qualitative assessment. Clin Imaging 2020; 69:305-310. [PMID: 33045474 DOI: 10.1016/j.clinimag.2020.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/18/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE To evaluate the image quality of chest CT performed on dual-energy scanners using low contrast volume for routine chest (DECT-R) and pulmonary angiography (DECTPA) protocols. MATERIALS AND METHODS This retrospective study included dual-energy CT scans of chest performed with low contrast volume in 84 adults (34M:50F; Age 69 ± 16 years: Weight 71 ± 16kg). There were 42 patients with DECT-R and 42 patients with DECT-PA protocols. Images were reviewed by two thoracic radiologists. Qualitative assessment was done on a four-point scale, for subjective assessment of contrast enhancement and artifacts (1 = Excellent, 2 = optimal, 3 = suboptimal, and 4 = Limited) in the pulmonary arteries and thoracic aorta, on virtual monoenergetic and material decomposition iodine (MDI) images. Quantitative assessment was performed by measuring the CT (Hounsfield) units in aorta and pulmonary arteries. The estimated glomerular filtration rate (eGFR) was calculated before and after CT scans. Two tailed student's t-test was performed to assess the significance of findings, and strength of correlation between readers was determined by Cohen's kappa test. RESULTS DECT-PA and DECT-R demonstrated excellent/adequate contrast density within the pulmonary arteries (up to segmental branch), and aorta. There was no suboptimal or limited examination. There was strong interobserver agreement for arterial enhancement in pulmonary arteries (kappa = 0.62-0.89) and for thoracic aorta (kappa = 0.62-0.94). Pulmonary emboli were seen in 3/42(7%) in DECT-R and in 5/42(12%) in DECT-PA. There was no significant change in eGFR before and after IV contrast injection (p = 0.46-0.52). CONCLUSION DECT-R and DECT-PA performed with low contrast volume provide diagnostic quality opacification of the pulmonary vessels and aorta vessels.
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Affiliation(s)
- Subba R Digumarthy
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America.
| | - Ramandeep Singh
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - Shivam Rastogi
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - Alexi Otrakji
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - Fatemeh Homayounieh
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - Eric W Zhang
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - Shaunagh McDermott
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - Mannudeep K Kalra
- Division of Thoracic Imaging and Intervention, Massachusetts General Hospital, Boston, MA, United States of America; Harvard Medical School, Boston, MA, United States of America
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Alobeidi H, Alshamari M, Widell J, Eriksson T, Lidén M. Minimizing contrast media dose in CT pulmonary angiography with high-pitch technique. Br J Radiol 2020; 93:20190995. [PMID: 32436788 PMCID: PMC7336071 DOI: 10.1259/bjr.20190995] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/30/2020] [Accepted: 04/23/2020] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVES To perform CT pulmonary angiography (CTPA) using a minimal amount of iodinated contrast media. METHODS 47 patients (25 females) with mean age 69 years (range 41-82 years) referred for contrast-enhanced chest CT were prospectively included in this Phase IV clinical drug trial. All participants underwent a study specific CTPA in addition to the chest CT. The participants received 80 mg I/kg body weight Iohexol contrast media using a preparatory saline bolus, a dual flow contrast/saline bolus and a saline flush, and a scanner protocol with 80 kVp dual source high-pitch mode. Three readers independently assessed the image quality on the 3-point scale non-diagnostic, adequate or good-excellent image quality. Additionally, the pulmonary arterial contrast opacification was measured. RESULTS On average, the patients received 16.8 ml Iohexol 350 mg I/mL (range 12-20 ml). Mean patient weight was 71 kg (range 50-85 kg). Identically for all readers, pulmonary embolism (PE) was detected in 1/47 participants. The median number of examinations visually scored concerning pulmonary embolism as good-excellent was 47/47 (range 44-47); adequate 0/47 (0-3) and non-diagnostic 0/47 (range 0-0). The proportion adequate or better examinations was for all readers 47/47, 100% [95% confidence interval 92-100%]. The mean attenuation ± standard deviation in the pulmonary trunk was 325 ± 72 Hounsfield unit (range 165-531 Hounsfield unit). CONCLUSIONS Diagnostic CTPA with 17 ml contrast media is possible in non-obese patients using low kVp, high pitch and carefully designed contrast media administration. ADVANCES IN KNOWLEDGE By combining several procedures in a CTPA protocol, the contrast media dose can be minimized.
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Affiliation(s)
- Hanan Alobeidi
- Department of Radiology, Örebro university Hospital, Region Örebro län, S-70185 Örebro, Sweden
| | - Muhammed Alshamari
- Department of Radiology, Faculty of Medicine and Health, Örebro University, S-70182 Örebro, Sweden
| | - Jonas Widell
- Department of Radiology, Örebro university Hospital, Region Örebro län, S-70185 Örebro, Sweden
| | - Tomas Eriksson
- Department of Radiology, Örebro university Hospital, Region Örebro län, S-70185 Örebro, Sweden
| | - Mats Lidén
- Department of Radiology, Faculty of Medicine and Health, Örebro University, S-70182 Örebro, Sweden
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Reducing Radiation Dose and Contrast Medium Volume With Application of Dual-Energy CT in Children and Young Adults. AJR Am J Roentgenol 2020; 214:1199-1205. [DOI: 10.2214/ajr.19.22231] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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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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Holmquist F, Nyman U, Siemund R, Geijer M, Söderberg M. Impact of iterative reconstructions on image noise and low-contrast object detection in low kVp simulated abdominal CT: a phantom study. Acta Radiol 2016; 57:1079-88. [PMID: 26663036 DOI: 10.1177/0284185115617347] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/17/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Low kilovoltage (kVp) computed tomography (CT) may be used to reduce contrast medium dose in patients at risk of contrast nephropathy, at the cost of increased image noise. PURPOSE To evaluate: (i) the impact of iterative reconstructions (Siemens SAFIRE) on low-contrast object detection to compensate for increased noise instead of increased tube loading when decreasing tube potential; and (ii) the change in iodine attenuation in simulated abdominal CT. MATERIAL AND METHODS A phantom was scanned at 70, 80, 100, and 120 kVp at fixed effective tube loading (170 mAsEFF) and fixed radiation dose (CTDIVOL 10 mGy). Images were reconstructed with filtered back-projection (FBP) and SAFIRE strengths S1-S5. Iodine attenuation, objective image noise, contrast-to-noise ratio (CNR), noise power spectrum (NPS), spatial resolution, and subjective detectability of low-contrast objects were evaluated. RESULTS Compared with 120 kVp iodine attenuation increased by a factor 1.6 and 2.0, and image noise increased by a factor 1.9 and 2.5 at 80 and 70 kVp, respectively. Compared with FBP, SAFIRE showed objective reduction in image noise and increased CNR without loss of spatial resolution or any significant NPS alteration, with general tendency to improve subjective detectability of low-contrast objects. At 170 mAsEFF the number of discernible 1.0% contrast objects at 70 kVp/S5 and 80 kVp/S5 was similar to that at 120 kVp/FBP. CONCLUSION With the SAFIRE algorithm image noise, CNR and detectability of low-contrast objects may be kept unchanged without increased tube loading when using low kVp settings to reduce contrast medium dose in azotemic patients.
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Affiliation(s)
- Fredrik Holmquist
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Ulf Nyman
- Department of Translational Medicine, Division of Medical Radiology, Lund University, Skåne University Hospital, 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
| | - Marcus Söderberg
- Department of Translational Medicine, Medical Radiation Physics, Lund University, Skåne University Hospital, Malmö, Sweden
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Nyman U, Aspelin P, Jakobsen J, Björk J. Controversies in Contrast Material-induced Acute Kidney Injury: Propensity Score Matching of Patients with Different Dose/Absolute Glomerular Filtration Rate Ratios. Radiology 2016; 277:633-7. [PMID: 26599923 DOI: 10.1148/radiol.2015151341] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ulf Nyman
- From the Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden (U.N.); Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Karolinska University Hospital, Stockholm 14186, Sweden (P.A.); Department of Radiology and Nuclear Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway (J.J.); Research and Development Centre Skåne, Skåne University Hospital, Lund, Sweden (J.B.); and Department of Occupational and Environmental Medicine, Lund University, Lund, Sweden (J.B.)
| | - Peter Aspelin
- From the Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden (U.N.); Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Karolinska University Hospital, Stockholm 14186, Sweden (P.A.); Department of Radiology and Nuclear Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway (J.J.); Research and Development Centre Skåne, Skåne University Hospital, Lund, Sweden (J.B.); and Department of Occupational and Environmental Medicine, Lund University, Lund, Sweden (J.B.)
| | - Jarl Jakobsen
- From the Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden (U.N.); Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Karolinska University Hospital, Stockholm 14186, Sweden (P.A.); Department of Radiology and Nuclear Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway (J.J.); Research and Development Centre Skåne, Skåne University Hospital, Lund, Sweden (J.B.); and Department of Occupational and Environmental Medicine, Lund University, Lund, Sweden (J.B.)
| | - Jonas Björk
- From the Department of Translational Medicine, Division of Medical Radiology, Skåne University Hospital, Lund University, Malmö, Sweden (U.N.); Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Karolinska University Hospital, Stockholm 14186, Sweden (P.A.); Department of Radiology and Nuclear Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway (J.J.); Research and Development Centre Skåne, Skåne University Hospital, Lund, Sweden (J.B.); and Department of Occupational and Environmental Medicine, Lund University, Lund, Sweden (J.B.)
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Hendriks BMF, Kok M, Mihl C, Bekkers SCAM, Wildberger JE, Das M. Individually tailored contrast enhancement in CT pulmonary angiography. Br J Radiol 2016; 89:20150850. [PMID: 26689096 DOI: 10.1259/bjr.20150850] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The purpose was to evaluate individually shaped contrast media (CM) delivery in CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE). METHODS 100 consecutive emergency patients with clinical suspicion of PE were evaluated. High-pitch CTPA was performed on a second-generation dual-source CT using the following parameters: 100 kV, 200-250 mAsref, rotation time 0.28 s, 128 × 0.6 mm col. and image reconstruction 1.0/0.8 mm (B30f). Group 1 (n = 50) then received a fixed CM bolus (300 = mgI ml(-1), volume = 90 ml and flow rate = 6 ml s(-1)); Group 2 (n = 50) received a body weight-adapted CM bolus determined by dedicated contrast injection software. For analysis, groups were further subdivided into low-weight (40-75 kg) and high-weight (76-117 kg) groups. Technical image quality was graded using a four-point Likert scale (1 = non-diagnostic; 2 = diagnostic; 3 = good and 4 = excellent image quality) at the level of the pulmonary trunk and pulmonary arteries. Objective image quality analysis was performed by measuring contrast enhancement in Hounsfield units (HU) at the same levels. Attenuation levels > 180 HU were considered diagnostic. RESULTS All examinations were graded as diagnostic at each level. The individual minimum pulmonary attenuation was 184 and 270 HU for Group 1 and 2, respectively. Mean attenuation was as follows: Group 1: 475 ± 105 HU (40-75 kg) and 402 ± 115 HU (76-117 kg), p < 0.03. Group 2: 424 ± 76 HU (40-75 kg) and 418 ± 100 HU (76-117 kg), p = 0.8. For Group 2, CM volumes were: 55 ± 5 ml (40-75 kg) and 66 ± 5 ml (76-117 kg), leading to 16-51% CM reduction. CONCLUSION Even under emergency conditions, individualized CM protocols can provide diagnostic and robust image quality in CTPA for PE with a substantial reduction of CM volume for lower weight patients, compared with a fixed CM protocol. ADVANCES IN KNOWLEDGE CM volume can substantially be reduced by using individualized CM protocols in CT angiography for PE without compromising the diagnostic image quality.
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Affiliation(s)
- Babs M F Hendriks
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Madeleine Kok
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Casper Mihl
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Sebastiaan C A M Bekkers
- 2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands.,3 Departments of Cardiology, Maastricht University Medical Center, Maastricht, Netherlands
| | - Joachim E Wildberger
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Marco Das
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
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70 kVp computed tomography pulmonary angiography: potential for reduction of iodine load and radiation dose. J Thorac Imaging 2015; 30:69-76. [PMID: 25423130 DOI: 10.1097/rti.0000000000000124] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of the study was to evaluate 70 kVp dual-source computed tomography pulmonary angiography (CTPA) with reduced iodine load in comparison with single-source 70 and 100 kVp CTPA with standard iodine load regarding image quality and radiation dose. MATERIALS AND METHODS Three groups with 40 consecutive patients each underwent either standard single-source 100 kVp (120 mAs; group A), single-source 70 kVp (208 mAs; group B), or dual-source 70 kVp CTPA (416 mAs; group C). A volume of 70 mL of contrast material with 400 mg I/mL (groups A, B) or 300 mg I/mL (group C) was administered. Chest diameter, dose-length product, intravascular signal attenuation, image noise, signal to noise ratio (SNR), and contrast to noise ratio (CNR) were compared. Two observers rated subjective image quality regarding intravascular enhancement and image noise using 5-point scales. RESULTS Chest diameter and age were similar (P ≥ 0.28) for all groups. Compared with group A, the average dose-length product was 59% lower in group B (67.3 ± 11.8 vs. 164.7 ± 50.6 mGy cm, P<0.001) and similar between groups A and C (167.7 ± 41.2 mGy cm, P = 0.39). Average SNR and CNR were significantly higher for group C (21.5 ± 4.7 and 19.0 ± 4.5, respectively) compared with groups A (18.3 ± 3.5 and 15.8 ± 3.4, respectively) and B (17.3 ± 5.8 and 15.6 ± 5.5, respectively; all Ps ≤ 0.001). Subjective image quality ratings regarding enhancement and noise were highest for group C (1.73 ± 0.62 and 2.03 ± 0.66, respectively). CONCLUSIONS Compared with standard 100 kVp CTPA, single-source 70 kVp CTPA allows for significant radiation dose savings with comparable SNR and CNR, whereas dual-source 70 kVp CTPA results in a superior objective image quality albeit a reduction of iodine concentration.
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Diagnostic accuracy of computed tomography pulmonary angiography with reduced radiation and contrast material dose: a prospective randomized clinical trial. Invest Radiol 2014; 49:201-8. [PMID: 24473367 DOI: 10.1097/rli.0000000000000016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE The objective of the study was to test the diagnostic performance of low-dose computed tomography pulmonary angiography (CTPA) at peak tube voltage of 80 kVp with both reduced radiation and reduced contrast material (CM) dose. MATERIALS AND METHODS In this single-center, single-blinded prospective randomized trial, 501 patients with body weights of less than 100 kg with suspected acute pulmonary embolism (PE) were assigned to normal-dose CTPA (100-kVp tube energy and 100-mL CM, 255 patients) and low-dose CTPA (80-kVp tube energy and 75-mL CM, 246 patients). Primary end points were evidence of PE in CTPA and accuracy of CTPA on a composite reference standard. Results were compared by calculating the odds ratio with the 95% confidence interval. RESULTS The reference diagnosis was equivocal in 20 of the 501 patients. Diagnosis of CTPA was correct in 240 patients and incorrect in 5 in the normal-dose group. Computed tomography pulmonary angiography was correct in 230 patients and incorrect in 6 in the low-dose group (odds ratio, 1.25; 95% confidence interval, 0.38-4.16; P = 0.77). Sensitivity was 96.9% and 100% and specificity was 98.1% and 97.1% in the normal-dose and low-dose groups, respectively. No PE or PE-related death occurred during the 90-day follow-up. The size-specific dose estimates were 30% lower at 80 kVp (4.8 ± 1.0 mGy) compared with that at 100 kVp (6.8 ± 1.2 mGy; P < 0.001). CONCLUSIONS The accuracy of low-dose CTPA at 80 kVp with a 30% reduced radiation dose and a 25% lower CM volume is not significantly different from that of normal-dose CTPA at 100 kVp in detecting acute PE in patients weighing less than 100 kg.
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Renne J, Falck CV, Ringe KI, Raatschen HJ, Wacker F, Shin HO. CT angiography for pulmonary embolism detection: the effect of breathing on pulmonary artery enhancement using a 64-row detector system. Acta Radiol 2014; 55:932-7. [PMID: 24103917 DOI: 10.1177/0284185113507712] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Computed tomography pulmonary angiography (CTPA) is used most often in routine clinical practice for the assessment of a suspected pulmonary embolism. The diagnostic accuracy relies on sufficient contrast enhancement. PURPOSE To evaluate whether image acquisition during shallow breathing can improve the image quality in patients with insufficient contrast enhancement during breath-hold examinations. MATERIAL AND METHODS A total of 2786 CT pulmonary angiographies, acquired on a 64-row CT during deep-inspiration breath-hold, were reviewed. Twenty-four examinations were considered non-diagnostic due to poor contrast enhancement in the pulmonary arteries (PA), although they showed preserved vascular enhancement of the superior vena cava (SVC) and the ascending aorta (AO). Eleven flawed CTPA examinations, including severe breathing artifacts and incorrect triggering were excluded. In 13 of the remaining patients, the examination was repeated during shallow breathing. Vascular contrast enhancement was compared between both scans by measuring the relative enhancement within the SVC, the main PA, and the AO. Image quality was scored by two, clinically experienced radiologists. The values are given as median and [25th;75th] quartile. RESULTS There was a significant difference in the CT values for the PA between the repeated scans (P = 0.0002, Wilcoxon test), and with the CTPA in deep-inspiration showing a median enhancement of 97 HU (59-173), compared with 303 HU (239-385) in the CTPA acquired during free breathing. The differences for both the AO (P = 0.54) and the SVC (P = 0.78) were not significant. Scoring for the attenuation quality rose significantly (P = 0.0002) and no severe motion artifacts were detected on either scans. CONCLUSION If there is insufficient pulmonary artery enhancement during CTPA, attenuation of the pulmonary arteries can be improved by acquisition during shallow breathing and is without significant loss of the overall diagnostic image quality.
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Affiliation(s)
- Julius Renne
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Christian von Falck
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Kristina Imeen Ringe
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Hans-Jürgen Raatschen
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Frank Wacker
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Hoen-Oh Shin
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
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Szucs-Farkas Z, Megyeri B, Christe A, Vock P, Heverhagen JT, Schindera ST. Prospective randomised comparison of diagnostic confidence and image quality with normal-dose and low-dose CT pulmonary angiography at various body weights. Eur Radiol 2014; 24:1868-77. [DOI: 10.1007/s00330-014-3208-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/14/2014] [Accepted: 04/28/2014] [Indexed: 01/23/2023]
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Low-contrast agent dose dual-energy CT monochromatic imaging in pulmonary angiography versus routine CT. J Comput Assist Tomogr 2013; 37:618-25. [PMID: 23863541 DOI: 10.1097/rct.0b013e31828f5020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study aimed to retrospectively evaluate the feasibility and reliability of low-contrast agent dose dual-energy computed tomography (DECT) monochromatic imaging in pulmonary angiography. METHODS Computed tomography pulmonary angiography was performed in 86 patients, 41 in 120-kVp computed tomography (CT) and 45 in DECT with low-contrast agent dose. The images in DECT were reconstructed at optimal kiloelectron-voltage (keV), demonstrating the best contrast-to-noise ratio between pulmonary artery and soft tissue, and at 70 keV. Image quality was compared by quantitative and subjective indexes. The radiation doses were recorded. RESULTS Compared with 120-kVp CT, optimal keV showed superior quantitative indexes with inferior subjective image quality, whereas 70 keV demonstrated no statistical difference in quantitative indexes with superior subjective image quality. All suspicious pulmonary embolisms in DECT were diagnosed confidently by combination of 2 kinds of monochromatic imaging. The radiation dose in DECT is almost twice as 120-kVp CT. CONCLUSIONS Low-contrast agent dose DECT monochromatic imaging in pulmonary angiography accommodates superior intravascular enhancement and contrast in pulmonary arteries, and improves diagnostic confidence with compatible radiation dose.
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Cao LX, Zhang H, Liu B, Yang WJ, Zhang YY, Pan ZL, Yan FH, Chen KM. Evaluation of high-pitch flash scan for pulmonary venous CTA on a 128-slice dual source CT: compared with prospective ECG-triggered sequence scan. Int J Cardiovasc Imaging 2013; 29:1557-64. [PMID: 23645131 DOI: 10.1007/s10554-013-0227-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 04/19/2013] [Indexed: 11/30/2022]
Abstract
To compare the image quality (IQ) and radiation dose of high-pitch scan and prospective ECG-triggered sequence scan on a 128-slice DSCT system for patients with atrial fibrillation (AF). Pulmonary venous (PV) CTA was performed with two protocols, including high-pitch scan and prospective ECG-triggered sequence scan. For each protocol, 20 sex, age and body-mass-index (mean 24.2 kg/m(2)) matched patients were identified. Two experienced radiologists, who were blinded to the scan protocols, independently graded the CT images of the two groups by a 5-point scale for subjective IQ assessment. Measured CT attenuation (Hounsfield units ± standard deviation), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) at various anatomic locations were also recorded for objective IQ evaluation. Radiation exposure parameters [dose length product (DLP) and effective radiation dose (ERD)] were compared. Twenty-three patients (57.5 %) showed an ECG pattern of AF in total. Subjective IQ was rated excellent in 100 % for the high-pitch scan group, while minor step artifacts were observed in two patients (10 %) with arrhythmia for the prospective ECG-triggered sequence group. There was no significant difference on IQ, neither by subjective, nor by objective measures (SNR, CNR) between the two groups. The ERD of high-pitch flash scan and prospective ECG-triggered sequence scan were 0.9 (± 0.25) and 2.9 (± 0.69) mSv, respectively. Significantly lower radiation was achieved by using high-pitch flash scan (P < 0.05). High-pitch flash scan can provide similar subjective and objective IQ compared with prospective ECG-triggered sequence scan for PV CTA, while radiation exposure was significantly reduced.
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Affiliation(s)
- Li Xiu Cao
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University of Medicine, Shanghai, China
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Delesalle MA, Pontana F, Duhamel A, Faivre JB, Flohr T, Tacelli N, Remy J, Remy-Jardin M. Spectral Optimization of Chest CT Angiography with Reduced Iodine Load: Experience in 80 Patients Evaluated with Dual-Source, Dual-Energy CT. Radiology 2013; 267:256-66. [PMID: 23319663 DOI: 10.1148/radiol.12120195] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Marie-Aurélie Delesalle
- Department of Thoracic Imaging, Hôpital Calmette (EA 2694 Université Lille Nord de France, Boulevard Jules Leclercq, 59037 Lille, France
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80-kV pulmonary CT angiography with 40 mL of iodinated contrast material in lean patients: comparison of vascular enhancement with iodixanol (320 mg I/mL)and iomeprol (400 mg I/mL). AJR Am J Roentgenol 2013; 199:1220-5. [PMID: 23169711 DOI: 10.2214/ajr.11.8122] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE The purpose of this article is to compare the vascular enhancement obtained with a low-kilovoltage pulmonary CT angiography (CTA) protocol in lean patients, using 40 mL of a moderate-concentration isoosmolar (iodixanol, 320 mg I/mL) and a high-concentration low-osmolar (iomeprol, 400 mg I/mL) iodinated contrast medium injected at the same iodine delivery rate. SUBJECTS AND METHODS Forty-two lean patients (31 men and 11 women; body mass index, ≤ 23 kg/m(2)) with suspected pulmonary embolism and non-small cell lung carcinoma underwent pulmonary CTA with a 64-MDCT scanner using a tube voltage of 80 kV. Twenty-three patients (54.8%) received 40 mL of iodixanol (320 mg I/mL) injected at a rate of 5 mL/s, and the remaining 19 patients (45.2%) were administered an equal volume of iomeprol (400 mg I/mL) at a flow rate of 4 mL/s. Intraarterial density was measured in the common pulmonary artery trunk, the main right and left pulmonary arteries, lobar arteries, and at the segmental level, for a total of 15 regions of interest per patient. Intravascular enhancement homogeneity from central to subsegmental level was also assessed visually using a semiquantitative score (1 = poor, 2 = good, and 3 = excellent). RESULTS The overall vascular density of pulmonary arteries down to the segmental level was significantly higher with iodixanol (320 mg I/mL) than with iomeprol (400 mg I/mL) (p = 0.036). Enhancement homogeneity was good with both contrast agents, with no statistically significant difference between them (p = 0.8966). CONCLUSION In 80-kV pulmonary CTA of lean patients, higher intravascular enhancement can be achieved with 40 mL of iodixanol (320 mg I/mL) than with the same volume of iomeprol (400 mg I/mL), with good vessel conspicuity down to the subsegmental level.
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Nyman U, Björkdahl P, Olsson ML, Gunnarsson M, Goldman B. Low-dose radiation with 80-kVp computed tomography to diagnose pulmonary embolism: a feasibility study. Acta Radiol 2012; 53:1004-13. [PMID: 22940858 DOI: 10.1258/ar.2012.120327] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Mounting collective radiation doses from computed tomography (CT) implies an increased risk of radiation-induced cancer in exposed populations, especially in the young. PURPOSE To evaluate radiation dose and image quality at 80-kVp CT to diagnose acute pulmonary embolism (PE) compared with a previous study at 100 and 120 kVp with all other scanning parameters unchanged. MATERIAL AND METHODS A custom-made chest phantom with a 12 mg I/mL-syringe was scanned at 80/100/120 kVp to evaluate relative changes in computed tomographic dose index (CTDI(vol)), attenuation, image noise, and contrast-to-noise ratio (CNR). Fifty patients underwent 80 kVp 16-row detector CT at 100 "Quality reference" mAs. A total of 350 mg I/kg were injected to compensate for increased CNR at 80 kVp, while 300 mg I/kg had been used at 100/120 kVp. CTDI(vol), dose-length product (DLP), and estimated effective dose were evaluated including Monte Carlo simulations. Pulmonary artery attenuation and noise were measured and CNR calculated. Two radiologists evaluated subjective image quality using a four-grade scale. RESULTS Switching from 120 to 80 kVp in the phantom study decreased radiation dose by 67% while attenuation and noise increased 1.6 and 2.0 times, respectively, and CNR decreased by 16%. Switching from 120 to 80 kVp in the patient studies decreased estimated effective dose from 4.0 to 1.2 mSv (70% decrease) in median while pulmonary artery attenuation and noise roughly doubled from 332 to 653 HU and from 22 to 49 HU, respectively, resulting in similar CNR (13 vs. 12). At 80 kVp all examinations were regarded as adequate (8%) or excellent (92%). CONCLUSION Switching from 120 to 80 kVp CT without increased mAs but slightly increased iodine dose may be of special benefit to diagnose PE in younger individuals with preserved renal function where the primary aim is to minimize radiation dose and reaching levels below that of scintigraphy.
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Affiliation(s)
- Ulf Nyman
- Department of Radiology, University of Lund, Lasarettet Trelleborg, Trelleborg
| | | | - Marie-Louise Olsson
- Medical Radiation Physics, Department of Clinical Sciences, University of Lund, Skåne University Hospital, Malmö
| | - Mikael Gunnarsson
- Medical Radiation Physics, Department of Clinical Sciences, University of Lund, Skåne University Hospital, Malmö
| | - Bitte Goldman
- Department of Internal Medicine, Lasarettet Trelleborg, Trelleborg, Sweden
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Bragadottir G, Redfors B, Ricksten SE. Mannitol increases renal blood flow and maintains filtration fraction and oxygenation in postoperative acute kidney injury: a prospective interventional study. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2012; 16:R159. [PMID: 22901953 PMCID: PMC3580749 DOI: 10.1186/cc11480] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/16/2012] [Indexed: 12/31/2022]
Abstract
Introduction Acute kidney injury (AKI), which is a major complication after cardiovascular surgery, is associated with significant morbidity and mortality. Diuretic agents are frequently used to improve urine output and to facilitate fluid management in these patients. Mannitol, an osmotic diuretic, is used in the perioperative setting in the belief that it exerts reno-protective properties. In a recent study on uncomplicated postcardiac-surgery patients with normal renal function, mannitol increased glomerular filtration rate (GFR), possibly by a deswelling effect on tubular cells. Furthermore, experimental studies have previously shown that renal ischemia causes an endothelial cell injury and dysfunction followed by endothelial cell edema. We studied the effects of mannitol on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO2), and extraction (RO2Ex) in early, ischemic AKI after cardiac surgery. Methods Eleven patients with AKI were studied during propofol sedation and mechanical ventilation 2 to 6 days after complicated cardiac surgery. All patients had severe heart failure treated with one (100%) or two (73%) inotropic agents and intraaortic balloon pump (36%). Systemic hemodynamics were measured with a pulmonary artery catheter. RBF and renal filtration fraction (FF) were measured by the renal vein thermo-dilution technique and by renal extraction of chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), respectively. GFR was calculated as the product of FF and renal plasma flow RBF × (1-hematocrit). RVO2 and RO2Ex were calculated from arterial and renal vein blood samples according to standard formulae. After control measurements, a bolus dose of mannitol, 225 mg/kg, was given, followed by an infusion at a rate of 75 mg/kg/h for two 30-minute periods. Results Mannitol did not affect cardiac index or cardiac filling pressures. Mannitol increased urine flow by 61% (P < 0.001). This was accompanied by a 12% increase in RBF (P < 0.05) and a 13% decrease in renal vascular resistance (P < 0.05). Mannitol increased the RBF/cardiac output (CO) relation (P = 0.040). Mannitol caused no significant changes in RO2Ext or renal FF. Conclusions Mannitol treatment of postoperative AKI induces a renal vasodilation and redistributes systemic blood flow to the kidneys. Mannitol does not affect filtration fraction or renal oxygenation, suggestive of balanced increases in perfusion/filtration and oxygen demand/supply.
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Grewal J, Al Hussein M, Feldstein J, Kiess M, Ellis J, Human D, Leipsic J. Evaluation of Silent Thrombus after the Fontan Operation. CONGENIT HEART DIS 2012; 8:40-7. [DOI: 10.1111/j.1747-0803.2012.00699.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/09/2012] [Indexed: 01/05/2023]
Affiliation(s)
- Jasmine Grewal
- Division of Cardiology, St. Paul's Hospital; University of British Columbia; Vancouver; BC; Canada
| | - Mosaad Al Hussein
- Division of Cardiology, St. Paul's Hospital; University of British Columbia; Vancouver; BC; Canada
| | - Jaimee Feldstein
- Division of Cardiology, St. Paul's Hospital; University of British Columbia; Vancouver; BC; Canada
| | - Marla Kiess
- Division of Cardiology, St. Paul's Hospital; University of British Columbia; Vancouver; BC; Canada
| | - Jennifer Ellis
- Department of Radiology, St. Paul's Hospital; University of British Columbia; Vancouver; BC; Canada
| | - Derek Human
- Division of Cardiology, St. Paul's Hospital; University of British Columbia; Vancouver; BC; Canada
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Are intravenous injections of contrast media really less nephrotoxic than intra-arterial injections? Eur Radiol 2012; 22:1366-71. [DOI: 10.1007/s00330-011-2371-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 12/08/2011] [Accepted: 12/17/2011] [Indexed: 12/28/2022]
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Yuan R, Shuman WP, Earls JP, Hague CJ, Mumtaz HA, Scott-Moncrieff A, Ellis JD, Mayo JR, Leipsic JA. Reduced iodine load at CT pulmonary angiography with dual-energy monochromatic imaging: comparison with standard CT pulmonary angiography--a prospective randomized trial. Radiology 2011; 262:290-7. [PMID: 22084206 DOI: 10.1148/radiol.11110648] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To compare quantitative and subjective image quality and radiation dose between standard computed tomographic (CT) pulmonary angiography (CTPA) and CTPA with a dual-energy technique with reduced iodine load. MATERIALS AND METHODS This prospective study was approved by the institutional review board and each participant provided informed consent. Ninety-four patients (59% male; mean age ± standard deviation, 62 years ± 15) were randomized to one of two protocols: standard CTPA (100-120 kVp) with standard contrast medium injection (n = 46) and dual-energy CTPA (image reconstruction at 50 keV) with the same injection volume as in the standard protocol but composed of contrast medium and saline in a 1:1 fashion, resulting in 50% reduction in iodine load (n = 48). Signal intensity and noise in three central and two segmental pulmonary arteries were measured; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A five-point scale was used to subjectively evaluate vascular enhancement and image noise. The proportion of diagnostic (score, ≥ 3) studies and the interreader agreement regarding the dichotomized diagnostic versus nondiagnostic scale were compared between the two groups. RESULTS Compared with standard CTPA, dual-energy CTPA demonstrated higher signal intensity in all pulmonary arteries (all P < .01), inferior noise only in segmental arteries (P < .05), higher SNR and CNR (both P < .05), and compatible effective dose (P > .05). The five-point score was higher in the standard CTPA protocol (P < .05). The interreader agreement regarding the dichotomized diagnostic versus nondiagnostic scale was similar (P > .05) between the two groups. CONCLUSION Dual-energy CTPA with image reconstruction at 50 keV allows a significant reduction in iodine load while improving intravascular signal intensity, maintaining SNR and with comparable radiation dose.
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Affiliation(s)
- Ren Yuan
- Department of Radiology, St Paul's Hospital, University of British Columbia, 1081 Burrard St, Vancouver, BC, Canada
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Diagnostic Accuracy of Pulmonary CT Angiography at Low Tube Voltage: Intraindividual Comparison of a Normal-Dose Protocol at 120 kVp and a Low-Dose Protocol at 80 kVp Using Reduced Amount of Contrast Medium in a Simulation Study. AJR Am J Roentgenol 2011; 197:W852-9. [DOI: 10.2214/ajr.11.6750] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Comparison of image quality and radiation dose of different pulmonary CTA protocols on a 128-slice CT: high-pitch dual source CT, dual energy CT and conventional spiral CT. Eur Radiol 2011; 22:279-86. [DOI: 10.1007/s00330-011-2251-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Revised: 07/23/2011] [Accepted: 08/10/2011] [Indexed: 10/17/2022]
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Redfors B, Bragadottir G, Sellgren J, Swärd K, Ricksten SE. Effects of norepinephrine on renal perfusion, filtration and oxygenation in vasodilatory shock and acute kidney injury. Intensive Care Med 2010; 37:60-7. [PMID: 20949349 DOI: 10.1007/s00134-010-2057-4] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 09/21/2010] [Indexed: 01/17/2023]
Affiliation(s)
- Bengt Redfors
- Department of Cardiothoracic Anaesthesia and Intensive Care, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden
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Computed tomography for the detection of free-floating thrombi in the right heart in acute pulmonary embolism. Eur Radiol 2010; 21:240-5. [DOI: 10.1007/s00330-010-1942-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 06/27/2010] [Accepted: 07/14/2010] [Indexed: 10/19/2022]
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Iodine contrast iso-attenuating with diagnostic gadolinium doses in CTA and angiography results in ultra-low iodine doses. A way to avoid both CIN and NSF in azotemic patients? Eur Radiol 2010; 21:326-36. [DOI: 10.1007/s00330-010-1924-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 07/15/2010] [Accepted: 07/16/2010] [Indexed: 11/30/2022]
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Nyman U. Routine Use of a V/Q SPECT/Low-Dose CT Hybrid System to Diagnose Pulmonary Embolism Seems Premature. J Nucl Med 2010; 51:1329-30; author reply 1330. [DOI: 10.2967/jnumed.110.077313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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