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Lee WC, Poon JK, Siah JJH, Chong MC, Lai C. Feasibility of low contrast volume and low injection flow rate in CT pulmonary angiography. J Med Imaging Radiat Sci 2024:101349. [PMID: 38897899 DOI: 10.1016/j.jmir.2023.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/12/2023] [Accepted: 11/22/2023] [Indexed: 06/21/2024]
Abstract
BACKGROUND Computed Tomography Pulmonary Angiography (CTPA) is currently the gold standard for diagnosing Pulmonary Embolism (PE), with a high flowrate (>4.5ml/s) for contrast media (CM) administration recommended for sufficient pulmonary artery opacification. However, this may not be achievable for patients with challenging IV access. AIM To determine if a low volume CM, low flowrate (LVLF) CTPA protocol produces images of similar image quality compared to a standard protocol in two aspects, in terms of peak arterial enhancement through the quantitative measurement of Hounsfield unit (HU) and based on subjective overall image quality. METHODS Retrospective collection of 151 patients who underwent CTPA via 320 slice multi-detector CT due to clinical suspicion of PE. 80 patients underwent the standard protocol, with a fixed flowrate of 4.5ml/s and 50ml of CM, while 71 patients underwent the LVLF protocol with up to a 37% and 30% reduction in flowrate and CM administered, respectively. Two independent radiographers measured the attenuation of multiple pulmonary arteries in HU, with ≥200HU being considered diagnostic. Overall image quality was also reviewed using a 5-point close-ended questionnaire by two independent radiologists. RESULTS There was no significant difference in terms of attenuation measured in HU for the seven regions of interest (main pulmonary trunk, right and left pulmonary arteries, right and left lobar arteries, and right and left subsegmental arteries (RSA and LSA)) between the LVLF and standard CTPA protocol. Similarly, there were no significant differences in the overall image quality score obtained from standard and LVLF protocols reported by both radiologists. CONCLUSION The LVLF protocol can achieve similar enhancement and subjective image quality as the standard CTPA protocol, potentially allowing for further optimisation in the CM dosage.
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Affiliation(s)
- Wan Chin Lee
- Radiography, Changi General Hospital, Singapore.
| | - Jun Kai Poon
- Health and Social Science Cluster, Singapore Institute of Technology, Singapore, Singapore
| | | | | | - Christopher Lai
- Health and Social Science Cluster, Singapore Institute of Technology, Singapore, Singapore
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Fleitmann M, Uzunova H, Pallenberg R, Stroth AM, Gerlach J, Fürschke A, Barkhausen J, Bischof A, Handels H. Artificial Intelligence-Based Prediction of Contrast Medium Doses for Computed Tomography Angiography Using Optimized Clinical Parameter Sets. Methods Inf Med 2024. [PMID: 38262476 DOI: 10.1055/s-0044-1778694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
OBJECTIVES In this paper, an artificial intelligence-based algorithm for predicting the optimal contrast medium dose for computed tomography (CT) angiography of the aorta is presented and evaluated in a clinical study. The prediction of the contrast dose reduction is modelled as a classification problem using the image contrast as the main feature. METHODS This classification is performed by random decision forests (RDF) and k-nearest-neighbor methods (KNN). For the selection of optimal parameter subsets all possible combinations of the 22 clinical parameters (age, blood pressure, etc.) are considered using the classification accuracy and precision of the KNN classifier and RDF as quality criteria. Subsequently, the results of the evaluation were optimized by means of feature transformation using regression neural networks (RNN). These were used for a direct classification based on regressed Hounsfield units as well as preprocessing for a subsequent KNN classification. RESULTS For feature selection, an RDF model achieved the highest accuracy of 84.42% and a KNN model achieved the best precision of 86.21%. The most important parameters include age, height, and hemoglobin. The feature transformation using an RNN considerably exceeded these values with an accuracy of 90.00% and a precision of 97.62% using all 22 parameters as input. However, also the feasibility of the parameter sets in routine clinical practice has to be considered, because some of the 22 parameters are not measured in routine clinical practice and additional measurement time of 15 to 20 minutes per patient is needed. Using the standard feature set available in clinical routine the best accuracy of 86.67% and precision of 93.18% was achieved by the RNN. CONCLUSION We developed a reliable hybrid system that helps radiologists determine the optimal contrast dose for CT angiography based on patient-specific parameters.
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Affiliation(s)
- Marja Fleitmann
- Artificial Intelligence in Medical Imaging, German Research Center for Artificial Intelligence, Kaiserslautern, Germany
| | - Hristina Uzunova
- Artificial Intelligence in Medical Imaging, German Research Center for Artificial Intelligence, Kaiserslautern, Germany
| | - René Pallenberg
- Institute for Signal Processing, University of Lübeck, Schleswig-Holstein, Germany
| | - Andreas M Stroth
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein (UKSH) Lübeck, Lübeck, Germany
| | - Jan Gerlach
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein (UKSH) Lübeck, Lübeck, Germany
| | - Alexander Fürschke
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein (UKSH) Lübeck, Lübeck, Germany
| | - Jörg Barkhausen
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein (UKSH) Lübeck, Lübeck, Germany
| | - Arpad Bischof
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein (UKSH) Lübeck, Lübeck, Germany
- IMAGE Information Systems Europe, Rostock, Germany
| | - Heinz Handels
- Artificial Intelligence in Medical Imaging, German Research Center for Artificial Intelligence, Kaiserslautern, Germany
- Institute of Medical Informatics, University of Lübeck, Schleswig-Holstein, Germany
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Kaproth-Joslin K, Hobbs S, Rajiah P, Chaturvedi A, Chaturvedi A. Optimizing low contrast volume thoracic CT angiography: From the basics to the advanced. J Clin Imaging Sci 2022; 12:41. [PMID: 36128360 PMCID: PMC9479554 DOI: 10.25259/jcis_51_2022] [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: 05/13/2022] [Accepted: 06/30/2022] [Indexed: 11/04/2022] Open
Abstract
Contrast-enhanced CT angiography (CTA) is a widely used, noninvasive imaging technique for evaluating cardiovascular structures. Contrast-induced nephrotoxicity is a concern in renal disease; however, the true nephrotoxic potential of iodinated contrast media (CM) is unknown. If a renal impaired patient requires CTA, it is important to protect the kidneys from further harm by reducing total iodinated CM volume while still obtaining diagnostic quality imaging. These same reduced volume CM techniques can also be applied to nonrenal impaired patients in times of CM shortage. This educational review discusses several modifications to CTA that can be adapted to both conventional 64-slice and the newer generation CT scanners which enable subsecond acquisition with a reduced CM volume technique. Such modifications include hardware and software adjustments and changes to both the volume and flow rate of administered CM, with the goal to reduce the dose of CM without compromising diagnostic yield.
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Affiliation(s)
| | - Susan Hobbs
- Department of Imaging Sciences, University of Rochester, Rochester, New York, United States,
| | - Prabhakar Rajiah
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, United States,
| | - Apeksha Chaturvedi
- Department of Imaging Sciences, University of Rochester, Rochester, New York, United States,
| | - Abhishek Chaturvedi
- Department of Imaging Sciences, University of Rochester, Rochester, New York, United States,
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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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Nguyen ET, Hague C, Manos D, Memauri B, Souza C, Taylor J, Dennie C. Canadian Society of Thoracic Radiology/Canadian Association of Radiologists Best Practice Guidance for Investigation of Acute Pulmonary Embolism, Part 1: Acquisition and Safety Considerations. Can Assoc Radiol J 2021; 73:203-213. [PMID: 33781098 DOI: 10.1177/08465371211000737] [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] [Indexed: 11/15/2022] Open
Abstract
Acute pulmonary embolism (APE) is a well-recognized cause of circulatory system compromise and even demise which can frequently present a diagnostic challenge for the physician. The diagnostic challenge is primarily due to the frequency of indeterminate presentations as well as several other conditions which can have a similar clinical presentation. This often obliges the physician to establish a firm diagnosis due to the potentially serious outcomes related to this disease. Computed tomography pulmonary angiography (CTPA) has increasingly cemented its role as the primary investigation tool in this clinical context and is widely accepted as the standard of care due to several desired attributes which include great accuracy, accessibility, rapid turn-around time and the ability to suggest an alternate diagnosis when APE is not the culprit. In Part 1 of this guidance document, a series of up-to-date recommendations are provided to the reader pertaining to CTPA protocol optimization (including scan range, radiation and intravenous contrast dose), safety measures including the departure from breast and gonadal shielding, population-specific scenarios (pregnancy and early post-partum) and consideration of alternate diagnostic techniques when clinically deemed appropriate.
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Affiliation(s)
- Elsie T Nguyen
- Department of Radiology, Joint Department of Medical Imaging, Toronto General Hospital, University of Toronto, Ontario, Canada
| | - Cameron Hague
- Department of Radiology, University of British Columbia, Ontario, Canada
| | - Daria Manos
- Department of Diagnostic Radiology, Dalhousie University, Ontario, Canada
| | - Brett Memauri
- Department of Radiology, University of Manitoba, Cardiothoracic Sciences Division, St. Boniface General Hospital, Ontario, Canada
| | - Carolina Souza
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ontario, Canada
| | - Jana Taylor
- Department of Radiology, McGill University Health Centre, Ontario, Canada
| | - Carole Dennie
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ontario, Canada.,Department of Radiology, University of Ottawa, Ottawa Hospital Research Institute, Ontario, Canada
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Liu H, Fu Y, Zhao B, Zhang X, Li G, Liu M, Li H. EFFECTS OF TEST-BOLUS AND LOW-DOSE SCAN ON CT PULMONARY ANGIOGRAPHY IMAGE QUALITY IN PATIENTS WITH DIFFERENT BODY MASS INDEXES. RADIATION PROTECTION DOSIMETRY 2020; 192:387-395. [PMID: 33415327 DOI: 10.1093/rpd/ncaa217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/30/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
This study aimed to investigate different methods of obtaining high-quality Computed Tomography pulmonary angiography (CTPA) images using low-dose scanning in patients with different body mass index (BMI) values. Sixty patients with suspected pulmonary embolism were grouped based on their BMI values (BMI < 25, designated N, and BMI ≥ 25, designated O) and were assigned to receive either test bolus (TB) or bolus tracking (BT) at conventional (C) or low (L) dose. The effective dose (ED) in the N-TB-L group was lower than in the group N-TB-C (0.56 ± 0.05 vs. 3.78 ± 1.16, p < 0.001), with similar image quality (4.90 ± 0.31 vs. 4.70 ± 0.47, p = 0.120). The ED in the O-TB-L group was lower than in the O-TB-C group (0.54 ± 0.03 vs. 5.14 ± 1.34, p < 0.001), but the group O-TB-C's image quality was higher (4.65 ± 0.59 vs. 3.95 ± 0.89, p = 0.006). Groups N-TB-L versus O-TB-L, groups N-TB-L versus N-BT-L and groups O-TB-C versus O-BT-C had similar EDs (all ps > 0.05), but the image quality was different (all ps < 0.05). In conclusion, the results showed that the image quality of low-dose CTPA scanning using TB was similar to that of the conventional-dose CTPA in patients with BMI < 25 but was lower in patients with BMI ≥ 25. TB was better than BT for all patients, regardless of BMI, when receiving the same ED.
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Affiliation(s)
- Huijia Liu
- Radiology Department, Second Hospital of Tianjin Medical University, Pingjiang Road, Hexi District, 300211, Tianjin, China
| | - Yan Fu
- Radiology Department, Second Hospital of Tianjin Medical University, Pingjiang Road, Hexi District, 300211, Tianjin, China
| | - Bo Zhao
- Radiology Department, Second Hospital of Tianjin Medical University, Pingjiang Road, Hexi District, 300211, Tianjin, China
| | - Xuening Zhang
- Radiology Department, Second Hospital of Tianjin Medical University, Pingjiang Road, Hexi District, 300211, Tianjin, China
| | - Guilai Li
- Radiology Department, Second Hospital of Tianjin Medical University, Pingjiang Road, Hexi District, 300211, Tianjin, China
| | - Meizhou Liu
- Radiology Department, Second Hospital of Tianjin Medical University, Pingjiang Road, Hexi District, 300211, Tianjin, China
| | - Hewen Li
- Radiology Department, Second Hospital of Tianjin Medical University, Pingjiang Road, Hexi District, 300211, Tianjin, China
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Aldosari S, Sun Z. A Systematic Review of Double Low-dose CT Pulmonary Angiography in Pulmonary Embolism. Curr Med Imaging 2020; 15:453-460. [PMID: 32008552 DOI: 10.2174/1573405614666180813120619] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 07/20/2018] [Accepted: 07/31/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND The aim of this study is to perform a systematic review of the feasibility and clinical application of double low-dose CT pulmonary angiography (CTPA) in the diagnosis of patients with suspected pulmonary embolism. DISCUSSION A total of 13 studies were found to meet selection criteria reporting both low radiation dose (70 or 80 kVp versus 100 or 120 kVp) and low contrast medium dose CTPA protocols. Lowdose CTPA resulted in radiation dose reduction from 29.6% to 87.5% in 12 studies (range: 0.4 to 23.5 mSv), while in one study, radiation dose was increased in the dual-energy CT group when compared to the standard 120 kVp group. CTPA with use of low contrast medium volume (range: 20 to 75 ml) was compared to standard CTPA (range: 50 to 101 ml) in 12 studies with reduction between 25 and 67%, while in the remaining study, low iodine concentration was used with 23% dose reduction achieved. Quantitative assessment of image quality (in terms of signal-to-noise ratio and contrast-to-noise ratio) showed that low-dose CTPA was associated with higher, lower and no change in image quality in 3, 3 and 6 studies, respectively when compared to the standard CTPA protocol. The subjective assessment indicated similar image quality in 11 studies between low-dose and standard CTPA groups, and improved image quality in 1 study with low-dose CTPA. CONCLUSION This review shows that double low-dose CTPA is feasible in the diagnosis of pulmonary embolism with significant reductions in both radiation and contrast medium doses, without compromising diagnostic image quality.
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Affiliation(s)
- Sultan Aldosari
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
| | - Zhonghua Sun
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
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Improved Visualization and Identification of the Right Adrenal Vein in 70-kVp Contrast-Enhanced Computed Tomography. J Comput Assist Tomogr 2020; 44:153-159. [PMID: 31939897 DOI: 10.1097/rct.0000000000000960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE The aim of this study was to assess the utility of 70-kilovoltage-peak (kVp) contrast-enhanced computed tomography (CECT) for visualization and identification of the right adrenal vein (RAV) in comparison with that of conventional 120-kVp CECT. METHODS This retrospective study included patients who underwent adrenal venous sampling with concurrent biphasic 120-kVp (120-kVp group, n = 43) or 70-kVp (70-kVp group, n = 47) CECT. Signal-to-noise ratios, contrast-to-noise ratios, longitudinal lengths, conspicuity scores, RAV detection rates, and size-specific dose estimates were compared between the 2 groups. RESULTS In comparison with the 120-kVp group, the 70-kVp group had significantly higher signal-to-noise and contrast-to-noise ratios (P < 0.001-P = 0.033), greater longitudinal lengths (P < 0.001-P = 0.002), superior conspicuity scores for the RAV (P < 0.001), higher RAV detection rates (P = 0.015-P = 0.033), and lower size-specific dose estimates (P < 0.001). CONCLUSIONS Seventy-kilovoltage-peak CECT has advantages over conventional 120-kVp CECT and is potentially useful for noninvasive assessment of the precise anatomy of the RAV.
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Suntharalingam S, Stenzel E, Wetter A, Guberina N, Umutlu L, Schlosser T, Nassenstein K. Third generation dual-energy CT with 80/150 Sn kV for head and neck tumor imaging. Acta Radiol 2019; 60:586-592. [PMID: 30089396 DOI: 10.1177/0284185118788896] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Dual-energy CT (DECT) provides additional image datasets which enable improved tumor delineation or reduction of beam hardening artifacts in patients with head and neck squamous cell carcinoma (SCC). PURPOSE To assess radiation dose and image quality of third-generation DECT of the head and neck in comparison to single-energy CT (SECT). MATERIAL AND METHODS Thirty patients with SCC who underwent both SECT (reference tube voltage 120 kVp) and DECT (80/150 Sn kVp) of the head and neck region for staging were retrospectively selected. Attenuation measurements of the sternomastoid muscle, internal jugular vein, submandibular gland and tongue were compared. Image noise was assessed at five anatomic levels. Subjective image quality was evaluated by two radiologists in consensus. RESULTS CTDIvol was 55% lower with DECT (4.2 vs. 9.3 mGy; P = 0.002). Median image noise was equal or lower in DECT at all levels (nasopharynx: 3.9 vs. 5.8, P < 0.0001; floor of mouth: 3.6 vs. 4.5, P = 0.0002; arytenoids: 3.6 vs. 3.1, P = 0.096; lower thyroid: 4.4 vs. 5.7, P = 0.002; arch of aorta: 5.6 vs. 6.5, P = 0.001). Attenuation was significantly lower in DECT ( P < 0.05). Subjective image analysis revealed that DECT is equal or superior to SECT with regard to overall image quality (nasopharynx: 5 vs. 5, P = 1; floor of mouth: 5 vs. 5, P = 0.0041; arytenoids: 5 vs. 5, P = 0.6; lower thyroid: 5 vs. 3, P < 0.0001; arch of aorta: 5 vs. 4, P < 0.0001). CONCLUSION Head and neck imaging with third-generation DECT can reduce radiation dose by half compared to SECT, while maintaining excellent image quality.
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Affiliation(s)
- Saravanabavaan Suntharalingam
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Elena Stenzel
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Axel Wetter
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Nika Guberina
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Thomas Schlosser
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Kai Nassenstein
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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Ultra-Low-Dose Neck CT With Low-Dose Contrast Material for Preoperative Staging of Thyroid Cancer: Image Quality and Diagnostic Performance. AJR Am J Roentgenol 2019; 212:748-754. [PMID: 30900916 DOI: 10.2214/ajr.18.20334] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Although CT has been used as a complementary diagnostic method for the preoperative diagnosis of thyroid cancer, it has the shortcomings of substantial radiation exposure and the use of contrast material (CM). The purpose of this article is to evaluate the image quality and diagnostic performance of 70-kVp thyroid CT with low volumes of CM versus conventional 120-kVp thyroid CT protocol. MATERIALS AND METHODS Eighty patients referred for preoperative thyroid CT were randomly divided into two groups (group A: 40 patients, 70 kVp, 60 mL of CM; group B: 40 patients, 120 kVp, 100 mL of CM). Quantitative and qualitative image quality and radiation doses for the two groups were compared using the Mann-Whitney U and chi-square tests. Degrees of agreement between preoperative CT staging and pathologic results were evaluated and compared using the Wald statistic. RESULTS Calculated signal-to-noise ratios of different anatomic structures, calculated contrast-to-noise ratios, overall image quality, subjective noise, and streak artifacts were not significantly different between the two groups (all p > 0.05), and neither were the accuracies of preoperative CT staging (all p > 0.05). The estimated effective doses were significantly lower in group A (mean [± SD], 0.52 ± 0.14 mSv in group A and 2.28 ± 0.29 mSv in group B; p < 0.001). CONCLUSION Ultra-low-dose 70-kVp CT with a low volume of CM provides sufficient image quality for preoperative staging of thyroid cancer and substantially reduces the radiation dose compared with standard 120-kVp CT.
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Optimizing Pulmonary Embolism Computed Tomography in the Age of Individualized Medicine: A Prospective Clinical Study. Invest Radiol 2019; 53:306-312. [PMID: 29438139 DOI: 10.1097/rli.0000000000000443] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE The aim of the study was to simultaneously optimize contrast media (CM) injection and scan parameters for the individual patient during computed tomography pulmonary angiography (CTPA). METHODS In this study (NCT02611115), 235 consecutive patients suspected of having pulmonary embolism were prospectively enrolled. Automated kV selection software on a third-generation multidetector computed tomography adapted tube voltage to the individual patient, based on scout scans. The contrast injection protocol was adapted to both patient body weight and kV-setting selection via a predefined formula, based on previous research. Injection data were collected from a contrast media and radiation dose monitoring software. Attenuation was measured in Hounsfield units (HU) in the pulmonary trunk (PT); attenuation values 200 HU or greater were considered diagnostic. Subjective image quality was assessed by using a 4-point Likert scale at the level of the PT, lobar, segmental, and subsegmental arteries. Results between groups were reported as mean ± SD. RESULTS Two hundred twenty-two patients (94%) were scanned at a kV setting below 100 kV: n = 108 for 70 kV, n = 82 for 80 kV, and n = 32 for 90 kV. Mean CM bolus volume (in milliliters) and total iodine load (in grams of iodine) for 70 to 90 kV were as follows: 24 ± 3 mL and 7 ± 1 g I, 29 ± 4 mL and 9 ± 2 g I, and 38 ± 4 mL and 11 ± 1 g I, respectively. Mean flow rates (in milliliters per second) and iodine delivery rates (in grams of iodine per second) were 3.0 ± 0.4 mL/s and 0.9 ± 0.1 g I/s (70 kV), 3.6 ± 0.4 mL/s and 1.0 ± 0.1 g I/s (80 kV), and 4.7 ± 0.5 mL/s and 1.3 ± 0.1 g I/s (90 kV). Mean radiation doses were 1.3 ± 0.3 mSv at 70 kV, 1.7 ± 0.4 mSv at 80 kV, and 2.2 ± 0.6 mSv at 90 kV. Mean vascular attenuation in the PT for each kV group was as follows: 397 ± 101 HU for 70 kV, 398 ± 96 HU for 80 kV, and 378 ± 100 HU for 90 kV, P = 0.59. Forty-six patients (21%) showed pulmonary embolism on the CTPA. One scan (90 kV) showed nondiagnostic segmental pulmonary arteries, and 5% of subsegmental arteries were of nondiagnostic image quality. All other segments were considered diagnostic-excellent subjective image quality. CONCLUSIONS Simultaneously optimizing both CM injections and kV settings to the individual patient in CTPA results in diagnostic attenuation with on average 24 to 38 mL of CM volume and a low radiation dose for most patients. This individualized protocol may help overcome attenuation-variation problems between patients and kV settings in CTPA.
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Martin SS, van Assen M, Griffith LP, De Cecco CN, Varga-Szemes A, Bauer MJ, Wichmann JL, Vogl TJ, Schoepf UJ. Dual-Energy CT Pulmonary Angiography: Quantification of Disease Burden and Impact on Management. CURRENT RADIOLOGY REPORTS 2018. [DOI: 10.1007/s40134-018-0297-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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13
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Kalra MK, Becker HC, Enterline DS, Lowry CR, Molvin LZ, Singh R, Rybicki FJ. Contrast Administration in CT: A Patient-Centric Approach. J Am Coll Radiol 2018; 16:295-301. [PMID: 30082238 DOI: 10.1016/j.jacr.2018.06.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/19/2018] [Accepted: 06/22/2018] [Indexed: 12/16/2022]
Abstract
Patient-centric care has garnered the attention of the radiology community. The authors describe a patient-centric approach to iodinated contrast administration designed to optimize the diagnostic yield of contrast-enhanced CT while minimizing patient iodine load and exposure to ionizing radiation, thereby enhancing patient safety while providing reasonable diagnostic efficacy. Patient-centric CT hardware settings and contrast media administration are important considerations for clinical CT quality and safety.
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Affiliation(s)
- Mannudeep K Kalra
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts.
| | - Hans-Christoph Becker
- Department of Radiology, Stanford University, Stanford, California; Department of Radiology, Ludwig-Maximilians-Universität, Munich, Germany
| | | | - Carolyn R Lowry
- Department of Radiology, Duke University, Durham, North Carolina
| | - Lior Z Molvin
- Department of Radiology, Stanford University, Palo Alto, California; Stanford Healthcare, Palo Alto, California
| | - Ramandeep Singh
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts
| | - Frank J Rybicki
- Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada; The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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14
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Dane B, Patel H, O'Donnell T, Girvin F, Brusca-Augello G, Alpert JB, Niu B, Attia M, Babb J, Ko JP. Image Quality on Dual-energy CTPA Virtual Monoenergetic Images: Quantitative and Qualitative Assessment. Acad Radiol 2018; 25:1075-1086. [PMID: 29398436 DOI: 10.1016/j.acra.2017.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/08/2017] [Accepted: 12/17/2017] [Indexed: 01/14/2023]
Abstract
RATIONALE AND OBJECTIVES This study aims to determine the optimal photon energy for image quality of the pulmonary arteries (PAs) on dual-energy computed tomography (CT) pulmonary angiography (CTPA) utilizing low volumes of iodinated contrast. MATERIALS AND METHODS The study received institutional review board exemption and was Health Insurance Portability and Accountability Act compliant. Adults (n = 56) who underwent dual-energy CTPA with 50-60 cc of iodinated contrast on a third-generation dual-source multidetector CT were retrospectively and consecutively identified. Twelve virtual monoenergetic kiloelectron volt (keV) image data sets (40-150 keV, 10-keV increments) were generated with a second-generation noise-reducing algorithm. Standard regions of interest were placed on main, right, left, and right interlobar pulmonary arteries; pectoralis muscle; and extrathoracic air. Attenuation [mean CT number (Hounsfield unit, HU)], noise [standard deviation (HU)], signal to noise (SNR), and contrast to noise ratio were evaluated. Three blinded chest radiologists rated (from 1 to 5, with 5 being the best) randomized monoenergetic and weighted-average images for attenuation and noise. P <.05 was considered significant. RESULTS Region of interest mean CT number increased as keV decreased, with 40 keV having the highest value (P < .001). Mean SNR was highest for 40-60 keV (P <.05) (14.5-14.7) and was higher (P <.05) than all remaining energies (90-150 keV) for all vessel regions combined. Contrast to noise ratio was highest for 40 keV (P <.001) and decreased as keV increased. SNR was highest at 60 and 70 keV, only slightly higher than 40-50 keV (P <.05). Reader scores for 40-50 keV were greater than other energies and weighted-average images (P <.05). CONCLUSIONS Kiloelectron volt images of 40-50 keV from the second-generation algorithm optimize attenuation on dual-energy CTPA and can potentially aid in interpretation and avoiding nondiagnostic examinations.
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Affiliation(s)
- Bari Dane
- Department of Radiology, NYU Langone Health, 660 First Avenue, New York, NY 10016.
| | - Hersh Patel
- Department of Radiology, NYU Langone Health, 660 First Avenue, New York, NY 10016
| | | | - Francis Girvin
- Department of Radiology, NYU Langone Health, 660 First Avenue, New York, NY 10016
| | | | - Jeffrey B Alpert
- Department of Radiology, NYU Langone Health, 660 First Avenue, New York, NY 10016
| | - Bowen Niu
- Department of Radiology, NYU Langone Health, 660 First Avenue, New York, NY 10016
| | | | - James Babb
- Department of Radiology, NYU Langone Health, 660 First Avenue, New York, NY 10016
| | - Jane P Ko
- Department of Radiology, NYU Langone Health, 660 First Avenue, New York, NY 10016
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15
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Iezzi R, Larici AR, Franchi P, Marano R, Magarelli N, Posa A, Merlino B, Manfredi R, Colosimo C. Tailoring protocols for chest CT applications: when and how? Diagn Interv Radiol 2018; 23:420-427. [PMID: 29097345 DOI: 10.5152/dir.2017.16615] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the medical era of early detection of diseases and tailored therapies, an accurate characterization and staging of the disease is pivotal for treatment planning. The widespread use of computed tomography (CT)-often with the use of contrast material (CM)-probably represents the most important advance in diagnostic radiology. The result is a marked increase in radiation exposure of the population for medical purposes, with its intrinsic carcinogenic potential, and CM affecting kidney function. The radiologists should aim to minimize patient's risk by reducing radiation exposure and CM amount, while maintaining the highest image quality. To achieve this goal, it is necessary to perform "patient-centric imaging". The purpose of this review is to provide radiologists with "tips and tricks" to control radiation dose at CT, summarizing technical artifices in order to reduce image noise and increase image contrast. Also chest CT tailored protocols are supplied, with particular attention to three most common thoracic CT protocols: aortic/cardiac CT angiography (CTA), pulmonary CTA, and routine chest CT.
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Affiliation(s)
- Roberto Iezzi
- Institute of Radiology, Department of Radiological Sciences, Università Cattolica del Sacro Cuore, Rome, Italy.
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16
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Eller A, Wuest W, Saake M, Ellmann S, Kaemmerer N, Hammon M, Janka R, Uder M, May MS. Extent of simultaneous radiation dose and iodine reduction at stable image quality in computed tomography of the chest: A systematic approach using automated tube voltage adaption and iterative reconstructions. Medicine (Baltimore) 2018; 97:e0388. [PMID: 29642199 PMCID: PMC5908636 DOI: 10.1097/md.0000000000010388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Aim of this study was to systematically combine tube voltage adaptation and iterative reconstructions for reduction of iodine and radiation dose. METHODS Settings for the study protocol were evaluated in ex-ante trials to provide image quality that is comparable to a reference protocol at 120 kV with tube current modulation. Consecutive patients were randomized to undergo computed tomography (CT) of the chest using the study protocol (n = 62) or reference protocol (n = 50). Objective and subjective image quality was assessed and compared. RESULTS Tube voltage was decreased to 100 kV in 47 patients and to 80 kV in 15 patients in the study group. The iodine dosage (16.1 vs 10.5 g) and the effective radiation dose (3.6 vs 2.5 mSv) were significantly decreased in the study group (both P < .001). Contrast-to-noise ratio was comparable in the pulmonary trunk and increased in the aorta (P < .01). Subjective image quality was comparable without statistically significance. CONCLUSIONS Simultaneous reductions in iodine dosage and radiation dose by one-third are feasible for CT of the chest.
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Affiliation(s)
- Achim Eller
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
| | - Wolfgang Wuest
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
- Imaging Science Institute, Ulmenweg 18, Erlangen, Germany
| | - Marc Saake
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
| | - Stephan Ellmann
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
| | - Nadine Kaemmerer
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
| | - Matthias Hammon
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
| | - Rolf Janka
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
| | - Michael Uder
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
- Imaging Science Institute, Ulmenweg 18, Erlangen, Germany
| | - Matthias Stefan May
- Department of Radiology, University Hospital Erlangen, Maximiliansplatz 3
- Imaging Science Institute, Ulmenweg 18, Erlangen, Germany
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17
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Takahashi Y, Ota H, Omura K, Dendo Y, Otani K, Matsuura T, Kitami M, Seiji K, Tezuka Y, Nezu M, Ono Y, Morimoto R, Satoh F, Takase K. Image quality and radiation dose of low-tube-voltage CT with reduced contrast media for right adrenal vein imaging. Eur J Radiol 2017; 98:150-157. [PMID: 29279155 DOI: 10.1016/j.ejrad.2017.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 11/15/2017] [Accepted: 11/24/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To compare image quality and radiation dose of right adrenal vein (RAV) imaging computed tomography (CT) among conventional, low kV, and low kV with reduced contrast medium protocols. METHODS One-hundred-and-twenty patients undergoing adrenal CT were randomly assigned to one of three protocols: contrast dose of 600mgI/kg at 120-kV tube voltage setting (600-120 group), 600mgI/kg at 80kV (600-80 group), and 360mgI/kg at 80kV (360-80 group). Iterative reconstruction was used for 80-kV groups. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the RAV and size-specific dose estimates (SSDE) were measured. Three radiologists evaluated 4-point visualisation scores of RAV by consensus reading. RESULTS The RAV detectability was 95%, 97.2%, and 97.3% for 600-120, 600-80, and 360-80 groups, respectively (p=1.000). Visualisation scores were not significantly different among the groups (p=0.152). There were no significant differences in CNR or SNR between the 600-120 and 360-80 groups. SSDE of the 360-80 group was significantly lower than that of the 600-120 group (5.86mGy±1.44 vs. 7.27mGy±1.81, p<0.001). CONCLUSIONS 80-kV scans with 360 mgI/kg contrast media showed comparable detectability of RAV to conventional scans, while reducing 19% of SSDE.
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Affiliation(s)
- Yuki Takahashi
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Hideki Ota
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan.
| | - Kensuke Omura
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Yutaka Dendo
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Katharina Otani
- Diagnostic Imaging Business Area, DI Research & Collaboration Department, Siemens Healthcare KK, Gate City Osaki West Tower, 1-11-1, Osaki, Shinagawa-ku, Tokyo, 141-8644, Japan
| | - Tomonori Matsuura
- Department of Diagnostic Radiology, Tohoku Medical and Pharmaceutical University Hospital, 1-12-1 Fukumuro, Miyagino-ku, Sendai 983-8512, Japan
| | - Masahiro Kitami
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Kazumasa Seiji
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Yuta Tezuka
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Masahiro Nezu
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Yoshikiyo Ono
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Ryo Morimoto
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Fumitoshi Satoh
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Kei Takase
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
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18
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CTPA protocol optimisation audit: challenges of dose reduction with maintained image quality. Clin Radiol 2017; 73:320.e1-320.e8. [PMID: 29111239 DOI: 10.1016/j.crad.2017.09.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/29/2017] [Accepted: 09/29/2017] [Indexed: 11/23/2022]
Abstract
AIM To assess computed tomography (CT) pulmonary angiography (CTPA) dose and image quality in a large teaching hospital, and subsequently, to optimise the protocol in order to reduce the dose without affecting image quality. MATERIALS AND METHODS Dose-length product (DLP), patient size, and objective quality parameters (contrast-to-noise ratio and signal-to-noise ratio on standardised levels) were recorded from 31 patients undergoing CTPA, where also a subjective image quality evaluation was carried out independently by three specialist cardiothoracic consultant radiologists. An equivalent objective and subjective quality assessment was carried out on a cohort of the same size in a different tertiary healthcare centre. Moreover, experimental tests using anthropomorphic chest phantoms were performed, using different scan parameters. In light of the above analysis, two of the scanner settings for CTPA were modified, i.e., the SureExposure pre-set was changed to "Standard" noise level, quantified with standard deviation (SD) of 19, and the minimum amperage setting lowered from 80 to 40 mA. A second cohort of patients using this new protocol was audited, following the same methodology. RESULTS The average DLP of patients undergoing CTPA was initially found to be higher than both local and national dose reference levels (DRLs; 559 versus 300 mGy·cm and 400 mGy·cm, respectively). The new protocol led to a reduction in average DLP (359 mGy·cm) while the image quality, assessed by three cardiothoracic consultant radiologists, was preserved. CONCLUSION The CTPA protocol was implemented in the Royal Infirmary of Edinburgh resulting in significant dose reduction, and is now compliant with national and local DRLs. The image quality was maintained.
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19
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Clark TJ, Gunn ML. CT Angiography in the Emergency Department: Maximizing Contrast Enhancement and Image Quality While Minimizing Radiation Dose and Contrast Material Volume: Vascular/Interventional Radiology. Radiographics 2017; 37:1304-1305. [PMID: 28696854 DOI: 10.1148/rg.2017160171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Toshimasa J Clark
- From the Department of Radiology, University of Colorado-Denver, 12401 E 17th Ave, MS L954, Aurora, CO 80045 (T.J.C.); and Department of Radiology, University of Washington, Seattle, Wash (M.L.G.)
| | - Martin L Gunn
- From the Department of Radiology, University of Colorado-Denver, 12401 E 17th Ave, MS L954, Aurora, CO 80045 (T.J.C.); and Department of Radiology, University of Washington, Seattle, Wash (M.L.G.)
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20
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Automated Attenuation Based Tube Potential Selection of the Lower Extremity Runoff. J Comput Assist Tomogr 2017; 41:817-822. [DOI: 10.1097/rct.0000000000000602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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State-of-the-Art Pulmonary CT Angiography for Acute Pulmonary Embolism. AJR Am J Roentgenol 2016; 208:495-504. [PMID: 27897042 DOI: 10.2214/ajr.16.17202] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Pulmonary CT angiography (CTA) is the imaging modality of choice in suspected acute pulmonary embolism (PE). Current pulmonary CTA techniques involve ever lower doses of contrast medium and radiation along with advanced postprocessing applications to enhance image quality, diagnostic accuracy, and provide added value in patient management. The objective of this article is to summarize these current developments and discuss the appropriate use of state-of-the-art pulmonary CTA. CONCLUSION Pulmonary CTA is well established as a fast and reliable means of excluding or diagnosing PE. Continued developments in CT system hardware and postprocessing techniques will allow incremental reductions in radiation and contrast material requirements while improving image quality. Advances in risk stratification and prognostication from pulmonary CTA examinations should further refine its clinical value while minimizing the potential harm from overutilization and overdiagnosis.
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