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BACKGROUND: Physicians use fixed C-arm fluoroscopy equipment with many interventional radiological and cardiological procedures. The associated effective dose to a patient is generally considered low risk, as the benefit-risk ratio is almost certainly highly favorable. However, X-ray-induced skin injuries may occur due to high absorbed patient skin doses from complex fluoroscopically guided interventions (FGI). Suitable action levels for patient-specific follow-up could improve the clinical practice. There is a need for a refined metric regarding follow-up of X-ray-induced patient injuries and the knowledge gap regarding skin dose-related patient information from fluoroscopy devices must be filled. The most useful metric to indicate a risk of erythema, epilation or greater skin injury that also includes actionable information is the peak skin dose, that is, the largest dose to a region of skin. MATERIALS AND METHODS: The report is based on a comprehensive review of best practices and methods to estimate peak skin dose found in the scientific literature and situates the importance of the Digital Imaging and Communication in Medicine (DICOM) standard detailing pertinent information contained in the Radiation Dose Structured Report (RDSR) and DICOM image headers for FGI devices. Furthermore, the expertise of the task group members and consultants have been used to bridge and discuss different methods and associated available DICOM information for peak skin dose estimation. RESULTS: The report contributes an extensive summary and discussion of the current state of the art in estimating peak skin dose with FGI procedures with regard to methodology and DICOM information. Improvements in skin dose estimation efforts with more refined DICOM information are suggested and discussed. CONCLUSIONS: The endeavor of skin dose estimation is greatly aided by the continuing efforts of the scientific medical physics community, the numerous technology enhancements, the dose-controlling features provided by the FGI device manufacturers, and the emergence and greater availability of the DICOM RDSR. Refined and new dosimetry systems continue to evolve and form the infrastructure for further improvements in accuracy. Dose-related content and information systems capable of handling big data are emerging for patient dose monitoring and quality assurance tools for large-scale multihospital enterprises.
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Radiometria , Pele , Fluoroscopia , Humanos , Doses de Radiação , Radiografia Intervencionista , Radiologia IntervencionistaRESUMO
Contrast-enhanced mammography (CEM) is an imaging technique that uses iodinated contrast medium to improve visualization of breast lesions and assessment of tumor neovascularity. Through modifications in x-ray energy, high- and low-energy images of the breast are combined to highlight areas of contrast medium pooling. The use of contrast material introduces different workflows, artifacts, and risks related to the contrast medium dose. In addition, the need to acquire multiple images in each view introduces different workflows, artifacts, and risks associated with the radiation dose. Although CEM and conventional mammography share many underlying principles, it is important to understand how these two mammographic examinations differ and the mechanisms that facilitate image contrast at CEM. ©RSNA, 2021.
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Neoplasias da Mama , Mamografia , Artefatos , Mama/diagnóstico por imagem , Neoplasias da Mama/diagnóstico por imagem , Meios de Contraste , Feminino , Humanos , Neovascularização Patológica , Intensificação de Imagem RadiográficaRESUMO
OBJECTIVE: Endovascular aneurysm repair (EVAR) can result in high radiation dose to patients and operators. This prospective randomized study aimed to assess whether patient radiation dose sustained during EVAR could be decreased by predominantly using digital fluoroscopy (DF) vs the standard technique using digital subtraction angiography (DSA). METHODS: Between February 2011 and June 2017, patients with EVAR of infrarenal abdominal aortic aneurysms were prospectively enrolled and randomly assigned to a standard treatment DSA cohort or a DF cohort in which two or fewer DSA acquisitions were allowed for confirmatory imaging. Primary end points included dose-area product (DAP) and cumulative air kerma. Secondary end points included technical success and conversion to DSA standard treatment (if DF was inadequate for visualization). RESULTS: For all 43 patients enrolled (26 in the DF cohort, 17 in the DSA cohort), technical success was 100%. Of the 26 DF patients, 5 (19%) required conversion to the DSA cohort. In an intention-to-treat analysis, mean DAP was significantly lower in the DF cohort than in the DSA cohort (132 vs 174 Gy·cm2; P = .04). When patients were separated by number of DSA acquisitions (two or fewer vs three or more), mean DAP decreased 41% (109 vs 185 Gy·cm2; P = .005) and cumulative air kerma decreased 40% (578 vs 964 mGy; P = .004). CONCLUSIONS: In most patients (81%), DF or limited DSA was adequate for visualization during EVAR. In both intention-to-treat DF and limited-DSA cohorts, mean DAP was significantly decreased. If image quality allows, a DF-only or limited-DSA approach to EVAR decreases radiation dose.
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Angiografia Digital , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/cirurgia , Aortografia , Implante de Prótese Vascular , Procedimentos Endovasculares , Doses de Radiação , Radiografia Intervencionista , Idoso , Idoso de 80 Anos ou mais , Angiografia Digital/efeitos adversos , Aortografia/efeitos adversos , Arizona , Prótese Vascular , Implante de Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/instrumentação , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/instrumentação , Feminino , Fluoroscopia , Humanos , Masculino , Segurança do Paciente , Valor Preditivo dos Testes , Estudos Prospectivos , Exposição à Radiação/prevenção & controle , Radiografia Intervencionista/efeitos adversos , Método Simples-Cego , Stents , Resultado do TratamentoRESUMO
Content used by Medical Physicists for fluoroscopy safety training to staff is deliverable via several formats, that is, online content or a live audience slide presentations. Here, we share one example of a kinesthetic (live, hands-on simulation) educational program in use at our facility for some time (~10 years). In this example, the format and content specifically target methods of reducing physician operator exposures from scattered x rays. A kinesthetic format identifies and promotes the adoption of exposure-reducing behaviors. Key kinesthetic elements of this type of training include: physician hands-on measurements of radiation levels at locations specific to their standing positions (e.g., primary arterial access points) in the room using handheld exposure rate meters, measurement of exposure rate reduction to physicians provided by using personal protective equipment, that is, wearable aprons, hanging lead drapes, and pull-down shields. Physician choice of procedure-specific tableside selectable controls affecting exposure rate from optional fluoroscopy, Cine or digital subtraction angiography (DSA), along with comparative measured contribution to physician exposure is demonstrated. The inverse square exposure rate reduction to physicians when stepping back from the table during DSA is a key observation. Kinesthetic simulations in the rooms used by physicians have been found to provide the highest level of understanding giving rise to adoption of practices that are impactful for physicians. Specific training scripts are in place for physician sub-specialization in interventional radiology, cardiology, neurosurgery, vascular surgery, and gastroenterology. This training is used for new physician staff while classroom presentations (whose content mimics in room training) are used with staff who have had previously had in room training.
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Exposição Ocupacional , Médicos , Proteção Radiológica , Fluoroscopia , Humanos , Exposição Ocupacional/análise , Doses de Radiação , Radiografia Intervencionista , Raios XRESUMO
Nuclear stress testing is being increasingly justified in the cardiovascular risk stratification of patients. Radiation is an important consideration, and attempts to minimize exposure should be implemented. Efficiency and cost effectiveness are cornerstones in the delivery of quality patient care and should also be considered when implementing change. Methods: We studied 88 consecutive patients who presented to our stress lab for pharmacologic nuclear stress testing. A single-day rest-and-stress protocol with low-level exercise was used for all patients. After the stress portion of the examination, we measured Geiger counter activity above the bladder area to establish a baseline. Patients were then allowed to void, and repeat measurements were taken. Results: We detected a 16.9% reduction from baseline radiation levels above the bladder area after voiding. Conclusion: Urinary voiding is a simple, cost-effective strategy at reducing radiation exposure in the nuclear stress lab.
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Medicina Nuclear/instrumentação , Exposição à Radiação/prevenção & controle , Micção , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão do Miocárdio/efeitos adversos , Exposição à Radiação/efeitos adversos , Bexiga Urinária/fisiologia , Bexiga Urinária/efeitos da radiaçãoRESUMO
Derived from 2 yr of deliberations and community engagement, Medical Physics 3.0 (MP3.0) is an effort commissioned by the American Association of Physicists in Medicine (AAPM) to devise a framework of strategies by which medical physicists can maintain and improve their integral roles in, and contributions to, health care and its innovation under conditions of rapid change and uncertainty. Toward that goal, MP3.0 advocates a broadened and refreshed model of sustainable excellence by which medical physicists can and should contribute to health care. The overarching conviction of MP3.0 is that every healthcare facility can benefit from medical physics and every patient's care can be improved by a medical physicist. This large and expansive challenge necessitates a range of strategies specific to each area of medical physics: clinical practice, research, product development, and education. The present paper offers a summary of the Phase 1 deliberations of the MP3.0 initiative pertaining to strategic directions of the discipline primarily but not exclusively oriented toward the clinical practice of medical physics in the United States.
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OBJECTIVE: We aimed to compare radiation dose received during contrast-enhanced spectral mammography (CESM) using high- and low-energy projections with radiation dose received during 2D full field digital mammography (FFDM) and 3D tomosynthesis on phantoms and patients with varying breast thickness and density. MATERIALS AND METHODS: A single left craniocaudal projection was chosen to determine the doses for 6214 patients who underwent 2D FFDM, 3662 patients who underwent 3D tomosynthesis, and 173 patients who underwent CESM in this retrospective study. Dose measurements were also collected in phantoms with composition mimicking nondense and dense breast tissue. RESULTS: Average glandular dose (AGD) ± SD was 3.0 ± 1.1 mGy for CESM exposures at a mean breast thickness of 63 mm. At this thickness, the dose was 2.1 mGy from 2D FFDM and 2.5 mGy from 3D tomosynthesis. The nondense phantom had a mean AGD of 1.0 mGy with 2D FFDM, 1.3 mGy with 3D tomosynthesis, and 1.6 mGy with CESM. The dense breast phantom had a mean AGD of 1.3 mGy with 2D FFDM, 1.4 mGy with 3D tomosynthesis, and 2.1 mGy with CESM. At a compressed thickness of 4.5 cm, radiation exposure from CESM was approximately 25% higher in dense breast phantoms than in nondense breast phantoms. The dose in the dense phantom at a compressed thickness of 6 cm was approximately 42% higher than the dose in the nondense phantom at a compressed thickness of 4.5 cm. CONCLUSION: CESM was found to increase AGD at a mean breast thickness of 63 mm by approximately 0.9 mGy and 0.5 mGy compared with 2D FFDM and 3D tomosynthesis, respectively. Of note, CESM provides a standard image (similar to 2D FFDM) that is obtained using the low-energy projection. Overall, the AGD from CESM falls below the dose limit of 3 mGy set by Mammography Quality Standards Act regulations.
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Mama/diagnóstico por imagem , Mama/efeitos da radiação , Imageamento Tridimensional/métodos , Mamografia/métodos , Exposição à Radiação/análise , Intensificação de Imagem Radiográfica/métodos , Adulto , Idoso , Meios de Contraste , Humanos , Masculino , Mamografia/instrumentação , Pessoa de Meia-Idade , Órgãos em Risco/efeitos da radiação , Imagens de Fantasmas , Doses de Radiação , Exposição à Radiação/prevenção & controle , Exposição à Radiação/estatística & dados numéricos , Proteção Radiológica/métodos , Intensificação de Imagem Radiográfica/instrumentação , Radiometria , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodosRESUMO
Technical improvements in the acquisition and display of dual-energy computed tomography (DECT) have made this technique increasingly applicable to clinical practice, particularly in the setting of oncologic imaging. DECT allows for qualitative and quantitative analysis of tissue composition beyond the standard anatomical evaluation possible with single-energy computed tomography. For example, DECT can be used to interrogate iodine and calcium concentrations and to increase iodine signal, which makes many pathologic processes more conspicuous and provides improved understanding of internal structure within mass lesions. A working understanding of common postprocessing DECT displays will allow radiologists to maximize the additional diagnostic information available in DECT examinations. In this article, we describe common strategies for DECT interrogation by organ system, which may improve the conspicuity and understanding of suspected malignancies.
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Neoplasias/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Humanos , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
PURPOSE: Noise reduction in material density images is a necessary preprocessing step for the correct interpretation of dual-energy computed tomography (DECT) images. In this paper we describe a new method based on a local adaptive processing to reduce noise in DECT images METHODS: An adaptive neighborhood Wiener (ANW) filter was implemented and customized to use local characteristics of material density images. The ANW filter employs a three-level wavelet approach, combined with the application of an anisotropic diffusion filter. Material density images and virtual monochromatic images are noise corrected with two resulting noise maps. RESULTS: The algorithm was applied and quantitatively evaluated in a set of 36 images. From that set of images, three are shown here, and nine more are shown in the online supplementary material. Processed images had higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) than the raw material density images. The average improvements in SNR and CNR for the material density images were 56.5 and 54.75%, respectively. CONCLUSION: We developed a new DECT noise reduction algorithm. We demonstrate throughout a series of quantitative analyses that the algorithm improves the quality of material density images and virtual monochromatic images.
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Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Imagens de Fantasmas , Tomografia Computadorizada por Raios X/métodos , Humanos , Imageamento por Ressonância Magnética , Razão Sinal-RuídoRESUMO
Vertigo induced by exposure to the magnetic field of a magnetic resonance imaging (MRI) scanner is a well-known phenomenon within the radiology community but is not widely appreciated by other clinical specialists. Here, we describe a case of an anesthetist experiencing acute vertigo while providing sedation to a patient undergoing a 3 Tesla MRI scan. After discussing previous reports, and the evidence surrounding MRI-induced vertigo, we review potential etiologies that include the effects of both static and time-varying magnetic fields on the vestibular apparatus. We conclude our review by discussing the occupational standards that exist for MRI exposure and methods to minimize the risks of MRI-induced vertigo for clinicians working in the MRI environment.
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AIM: To determine whether fluoroscope time is a good predictor of patient radiation exposure during endoscopic retrograde cholangiopancreatography. METHODS: This is a prospective observational study of consecutive patients undergoing endoscopic retrograde cholangiopancreatography in a tertiary care setting. Data related to radiation exposure were collected. The following measures were obtained: Fluoroscopy time (FT), dose area product (DAP) and dose at reference point (DOSERP). Coefficients of determination were calculated to analyze the correlation between FT, DAP and DOSRP. Agreement between FT and DAP/DOSRP was assessed using Bland Altman plots. RESULTS: Four hundred sixty-three data sets were obtained. Fluoroscopy time average was 7.3 min. Fluoroscopy related radiation accounted for 86% of the total DAP while acquisition films related radiation accounted for 14% of the DAP. For any given FT there are wide ranges of DAP and DOSERP and the variability in both increases as fluoroscopy time increases. The coefficient of determination (R(2)) on the non transformed data for DAP and DOSERP versus FT were respectively 0.416 and 0.554. While fluoroscopy use was the largest contributor to patient radiation exposure during endoscopic retrograde cholangiography (ERCP), there is a wide variability in DAP and DOSERP that is not accounted for by FT. DAP and DOSERP increase in variability as FT increases. This translates into poor accuracy of FT in predicting DAP and DOSERP at higher radiation doses. CONCLUSION: DAP and DOSERP in addition to FT should be adopted as new ERCP quality measures to estimate patient radiation exposure.
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Colangiopancreatografia Retrógrada Endoscópica , Doses de Radiação , Lesões por Radiação/prevenção & controle , Radiografia Intervencionista , Arizona , Colangiopancreatografia Retrógrada Endoscópica/efeitos adversos , Colangiopancreatografia Retrógrada Endoscópica/normas , Fluoroscopia , Humanos , Estudos Prospectivos , Indicadores de Qualidade em Assistência à Saúde , Lesões por Radiação/etiologia , Monitoramento de Radiação , Radiografia Intervencionista/efeitos adversos , Radiografia Intervencionista/normas , Fatores de Risco , Centros de Atenção Terciária , Fatores de TempoRESUMO
Excessive cephalocaudal anatomic (Z-axis) coverage can lead to unnecessary radiation exposure to a patient. In this study, an automated computing model was developed for identifying instances of potentially excessive Z-axis coverage with abdomen-pelvis examinations. Eight patient and imaging attributes including patient gender, age, height, weight, volume CT dose index (CTDIvol), dose length product (DLP), maximum abdomen width, and maximum abdomen thickness were used to build a feedforward neural network model to predict a target Z-axis coverage whether it is an excessive or non-excessive Z-axis coverage scans. 264 CT abdomen-pelvis exams were used to develop the model which is validated using 10-fold cross validation. The result showed that 244 out of 264 exams (92.4%) correctly predicted Z-axis excessive coverage. The promising results indicate that this tool has the potential to be used for CT exams of the chest and colon, urography, and other site-specified CT studies having defined limited length.
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Pelve/diagnóstico por imagem , Doses de Radiação , Radiografia Abdominal , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
PURPOSE: Dual-energy computed tomography (DECT) images can undergo a two-material decomposition process which results in two images containing material density information. Material density images obtained by that process result in images with increased pixel noise. Noise reduction in those images is desirable in order to improve image quality. METHODS: A noise reduction algorithm for material density images was developed and tested. A three-level wavelet approach combined with the application of an anisotropic diffusion filter was used. During each level, the resulting noise maps are further processed, until the original resolution is reached and the final noise maps obtained. Our method works in image space and, therefore, can be applied to any type of material density images obtained from any DECT vendor. A quantitative evaluation of the noise-reduced images using the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and 2D noise power spectrum was done to quantify the improvements. RESULTS: The noise reduction algorithm was applied to a set of images resulting in images with higher SNR and CNR than the raw density images obtained by the decomposition process. The average improvement in terms of SNR gain was about 49 % while CNR gain was about 52 %. The difference between the raw and filtered regions of interest mean values was far from reaching statistical significance (minimum [Formula: see text], average [Formula: see text]). CONCLUSION: We have demonstrated through a series of quantitative analyses that our novel noise reduction algorithm improves the image quality of DECT material density images.
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Processamento de Imagem Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Anisotropia , Meios de Contraste , Humanos , Imageamento por Ressonância Magnética , Razão Sinal-RuídoRESUMO
Computed tomography (CT) is an imaging test that is widely used worldwide to establish medical diagnoses and perform image-guided interventions. More recently, concern has been raised about the risk of carcinogenesis from medical radiation, with a focus on CT. The purpose of this article is to (a) describe the importance of educating radiology personnel, patients, and referring clinicians about the concerns over CT radiation, (b) describe commonly used CT parameters and radiation units, (c) discuss the importance of establishing a dedicated radiology team to manage CT radiation, and (d) describe specific CT techniques to minimize radiation while providing diagnostic examinations.
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Doses de Radiação , Proteção Radiológica/métodos , Radiometria/métodos , Tomografia Computadorizada por Raios X , Algoritmos , Humanos , Equipe de Assistência ao Paciente/organização & administração , Segurança do Paciente , Interpretação de Imagem Radiográfica Assistida por Computador , Radiologia/educação , Terminologia como AssuntoRESUMO
We sought to determine whether dual-energy computed tomography (DECT) measurements correlate with positron emission tomography (PET) standardized uptake values (SUVs) in pancreatic adenocarcinoma, and to determine the optimal DECT imaging variables and modeling strategy to produce the highest correlation with maximum SUV (SUVmax). We reviewed 25 patients with unresectable pancreatic adenocarcinoma seen at Mayo Clinic, Scottsdale, Arizona, who had PET-computed tomography (PET/CT) and enhanced DECT performed the same week between March 25, 2010 and December 9, 2011. For each examination, DECT measurements were taken using one of three methods: (1) average values of three tumor regions of interest (ROIs) (method 1); (2) one ROI in the area of highest subjective DECT enhancement (method 2); and (3) one ROI in the area corresponding to PET SUVmax (method 3). There were 133 DECT variables using method 1, and 89 using the other methods. Univariate and multivariate analysis regression models were used to identify important correlations between DECT variables and PET SUVmax. Both R2 and adjusted R2 were calculated for the multivariate model to compensate for the increased number of predictors. The average SUVmax was 5 (range, 1.8-12.0). Multivariate analysis of DECT imaging variables outperformed univariate analysis (r = 0.91; R2 = 0.82; adjusted R2 = 0.75 vs. r < 0.58; adjusted R2 < 0.34). Method 3 had the highest correlation with PET SUVmax (R2 = 0.82), followed by method 1 (R2 = 0.79) and method 2 R2 = 0.57). DECT thus has clinical potential as a surrogate for, or as a complement to, PET in patients with pancreatic adenocarcinoma.
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Adenocarcinoma/diagnóstico , Imagem Multimodal/métodos , Neoplasias Pancreáticas/diagnóstico , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste , Feminino , Humanos , Imageamento Tridimensional/métodos , Masculino , Pessoa de Meia-Idade , Pâncreas/diagnóstico por imagem , Projetos Piloto , Intensificação de Imagem Radiográfica/métodos , Reprodutibilidade dos Testes , Estudos RetrospectivosRESUMO
Coronary heart disease (CHD) is the most prevalent cause of death worldwide. Atherosclerosis which is the condition of plaque buildup on the inside of the coronary artery wall is the main cause of CHD. Rupture of unstable atherosclerotic coronary plaque is known to be the cause of acute coronary syndrome. Vulnerability of atherosclerotic plaque has been related to a large lipid core covered by a fibrous cap. Non-invasive assessment of plaque characterization is necessary due to prognostic importance of early stage identification. The purpose of this study is to use the additional attenuation data provided by dual energy computed tomography (DECT) for plaque characterization. We propose to train supervised learners on pixel values recorded from DECT monochromatic X-ray and material basis pairs images, for more precise classification of fibrous and lipid plaques. The interaction of the pixel values from different image types is taken into consideration, as single pixel value might not be informative enough to separate fibrous from lipid. Organic phantom plaques scanned in a fabricated beating heart phantom were used as ground truth to train the learners. Our results show that support vector machines, artificial neural networks and random forests provide accurate results both on phantom and patient data.
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Doença da Artéria Coronariana/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Redes Neurais de Computação , Placa Aterosclerótica/diagnóstico por imagem , Máquina de Vetores de Suporte , Tomografia Computadorizada por Raios X/métodos , Árvores de Decisões , Humanos , Imagens de Fantasmas , Reprodutibilidade dos TestesRESUMO
OBJECTIVE: CT dose reduction has become a top priority for many radiology practices as a result of federal and state initiatives and public concern. Implementing this in practice, however, is difficult because of the variability between practices, CT scanners, radiologist preferences, and institutional capacity. CONCLUSION: This article will discuss strategies for successful CT dose reduction instituted in multivendor practices.
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Doses de Radiação , Proteção Radiológica/métodos , Tomografia Computadorizada por Raios X , Carga Corporal (Radioterapia) , Humanos , Equipe de Assistência ao Paciente , Lesões por Radiação/etiologia , Lesões por Radiação/prevenção & controle , Radiologia/normas , Tomografia Computadorizada por Raios X/efeitos adversos , Estados Unidos , Recursos HumanosRESUMO
The purpose of this study is to evaluate a direct measure of calcium burden by using dual-energy computed tomography (DECT) during contrast-enhanced coronary imaging, potentially eliminating the need for an extra noncontrast X-ray acquisition. The ambiguity of separation of calcium from contrast material on contrast-enhanced images was solved by using virtual noncontrast images obtained by DECT. A new threshold CT number was required to detect the calcium carrying potential risk for adverse coronary events on virtual noncontrast images. Two methods were investigated to determine the 130 HU threshold for DECT scoring. An in vitro anthropomorphic phantom with 29 excised patient calcium plaques inserted was used for both a linear and a logistic regression analysis. An IRB approved in vivo prospective study of six patients was also performed to be used for logistic regression analysis. The threshold found by logistic regression model to define the calcium burden on virtual noncontrast images detects the calcium carrying potential risk for adverse coronary events correctly (2.45% error rate). DECT calcium mass and volume scores obtained by using the threshold correlates with both conventional Agatston and volume scores (r = 0.98, p < 0.001). A conventional CT cardiac exam requires two scans, including a noncontrast scan for calcium quantification and a contrast-enhanced scan for coronary angiography. With the ability to quantify calcium on DECT contrast-enhanced images, a DECT cardiac exam could be accomplished with one contrast-enhanced scan for both calcium quantification and coronary angiography.