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1.
A Review of the Applications of Dual-Energy CT in Acute Neuroimaging.
Gibney, B, Redmond, CE, Byrne, D, Mathur, S, Murray, N
Canadian Association of Radiologists journal = Journal l'Association canadienne des radiologistes. 2020;(3):253-265
Abstract
Dual-energy computed tomography (CT) is a promising tool with increasing availability and multiple emerging and established clinical applications in neuroradiology. With its ability to allow characterization of materials based on their differential attenuation when imaged at two different energy levels, dual-energy CT can help identify the composition of brain, neck, and spinal components. Virtual monoenergetic imaging allows a range of simulated single energy-level reconstructions to be created with postprocessing. Low-energy reconstructions can aid identification of edema, ischemia, and subtle lesions due to increased soft tissue contrast as well as increasing contrast-to-noise ratios on angiographic imaging. Higher energy reconstructions can reduce image artifact from dental amalgam, aneurysm clips and coils, spinal hardware, dense contrast, and dense bones. Differentiating iodine from hemorrhage may help guide management of patients after thrombectomy and aid diagnosis of enhancing tumors within parenchymal hemorrhages. Iodine quantification may predict hematoma expansion in aneurysmal bleeds and outcomes in traumatic brain injury. Calcium and bone subtraction can be used to distinguish hemorrhage from brain parenchymal mineralization as well as improving visualization of extra-axial lesions and vessels adjacent to dense plaque or skull. This article reviews the basics of dual-energy CT and highlights many of its clinical applications in the evaluation of acute neurological presentations.
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2.
Computed tomography for myocardial characterization in ischemic heart disease: a state-of-the-art review.
Assen, MV, Vonder, M, Pelgrim, GJ, Von Knebel Doeberitz, PL, Vliegenthart, R
European radiology experimental. 2020;(1):36
Abstract
This review provides an overview of the currently available computed tomography (CT) techniques for myocardial tissue characterization in ischemic heart disease, including CT perfusion and late iodine enhancement. CT myocardial perfusion imaging can be performed with static and dynamic protocols for the detection of ischemia and infarction using either single- or dual-energy CT modes. Late iodine enhancement may be used for the analysis of myocardial infarction. The accuracy of these CT techniques is highly dependent on the imaging protocol, including acquisition timing and contrast administration. Additionally, the options for qualitative and quantitative analysis and the accuracy of each technique are discussed.
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3.
Benefit of dual-layer spectral CT in emergency imaging of different organ systems.
Demirler Simsir, B, Danse, E, Coche, E
Clinical radiology. 2020;(12):886-902
Abstract
Computed tomography (CT) has been the first choice of imaging technique in the emergency department and has a crucial role in many acute conditions. Since its implementation, spectral CT has gained widespread application with the potential to improve diagnostic performance and impact patient care. In spectral CT, images are acquired at two different energy levels allowing this technique to differentiate tissues by exploiting their energy-dependent attenuation properties. Dual-layer spectral CT provides additional information with its material decomposition applications that include virtual non-contrast imaging, iodine density, and effective atomic number (Zeff) maps along with virtual monoenergetic images without the need for preselection of a protocol. This review aims to demonstrate its added value in the emergency department in different organ systems enabling better evaluation of inflammatory and ischaemic conditions, assessment of organ perfusion, tissue/lesion characterisation and mass detection, iodine quantification, and the use of lower volumes of contrast medium. With improved diagnostic performance, spectral CT could also aid in rapid decision-making to determine the treatment method in many acute conditions without increased radiation dose to the patient.
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4.
Assessing skeletal muscle radiodensity by computed tomography: An integrative review of the applied methodologies.
Poltronieri, TS, de Paula, NS, Chaves, GV
Clinical physiology and functional imaging. 2020;(4):207-223
Abstract
Low-radiodensity skeletal muscle has been related to the degree of muscle fat infiltration and seems to be associated with worse outcomes. The aim of this study was to summarize the methodologies used to appraise skeletal muscle radiodensity by computed tomography, to describe the terms used in the literature to define muscle radiodensity and to give recommendations for its measurement standardization. An integrative bibliographic review in four databases included studies published until August 2019 in Portuguese, English or Spanish and performed in humans, adults and/or the elderly, of both sex, which investigated skeletal muscle radiodensity through computed tomography (CT) of the region between the third and fifth lumbar vertebrae and evaluated at least two muscular groups. One hundred and seventeen studies were selected. We observed a trend towards selecting all abdominal region muscle. A significant methodological variation in terms of contrast use, selection of skeletal muscle areas, radiodensity ranges delimitation and their cut-off points, as well as the terminologies used, was also found. The methodological differences detected are probably due to the lack of more precise information about the correlation between skeletal muscle radiodensity by CT and its molecular composition, among others. Therefore, until the gaps are addressed in future studies, authors should avoid arbitrary approaches when reporting skeletal muscle radiodensity, especially when it comes to prognosis inference. Studies using both CT and direct methods of muscle composition evaluation are encouraged, to enable the definition and validation of the best approach to classify fat-infiltrated muscle tissue, which will favour the nomenclature uniformization.
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5.
Aortic valve stenosis-multimodality assessment with PET/CT and PET/MRI.
Tzolos, E, Andrews, JP, Dweck, MR
The British journal of radiology. 2020;(1113):20190688
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Abstract
Aortic valve disease is the most common form of heart valve disease in developed countries and a growing healthcare burden with an ageing population. Transthoracic and transoesophageal echocardiography remains central to the diagnosis and surveillance of patients with aortic stenosis, providing gold standard assessments of valve haemodynamics and myocardial performance. However, other multimodality imaging techniques are being explored for the assessment of aortic stenosis, including combined PET/CT and PET/MR. Both approaches provide unique information with respect to disease activity in the valve alongside more conventional anatomic assessments of the valve and myocardium in this condition. This review investigates the emerging use of PET/CT and PET/MR to assess patients with aortic stenosis, examining how the complementary data provided by each modality may be used for research applications and potentially in future clinical practice.
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6.
Current and Future Applications of Thoracic Dual-Energy CT in Children: Pearls and Pitfalls of Technique and Interpretation.
Rapp, JB, Biko, DM, Barrera, CA, Kaplan, SL, Otero, HJ
Seminars in ultrasound, CT, and MR. 2020;(5):433-441
Abstract
Dual-energy computer tomography (DECT) technology has experienced rapid growth in recent years, now allowing for the collection of 2 CT data sets and opening the potential for functional data acquisition. Data from a single postcontrast phase are deconstructed and Iodine can be subtracted to create a virtual noncontrast image, or selectively represented as a contrast map that allows for the qualification and quantification of lung perfusion. Virtual monoenergetic images can also be used to reduce beam-hardening artifact from concentrated contrast or metal implants. In children, DECT is of particular interest because it has been shown to be dose neutral in most applications, dose-reducing in multiphase studies, and to increase the contrast to noise ratio in suboptimal studies. We review the basics of acquisition, postprocessing, and thoracic applications of DECT with a focus on pulmonary blood volumes as a surrogate for perfusion imaging. The discussed applications include pulmonary embolism, hypoplastic lung, pulmonary hypertension in bronchopulmonary dysplasia, and pediatric lung masses.
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7.
Utility of Iodine Density Perfusion Maps From Dual-Energy Spectral Detector CT in Evaluating Cardiothoracic Conditions: A Primer for the Radiologist.
Kikano, EG, Rajdev, M, Salem, KZ, Laukamp, K, Felice, CD, Gilkeson, RC, Gupta, A
AJR. American journal of roentgenology. 2020;(4):775-785
Abstract
OBJECTIVE. The purpose of this article is to outline the utility of iodine density maps for evaluating cardiothoracic disease and abnormalities. Multiple studies have shown that the variety of images generated from dual-energy spectral detector CT (SDCT) improve identification of cardiothoracic conditions. CONCLUSION. Understanding the technique of SDCT and being familiar with the features of different cardiothoracic conditions on iodine density map images help the radiologist make a better diagnosis.
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8.
Extra-abdominal dual-energy CT applications: a comprehensive overview.
Cicero, G, Ascenti, G, Albrecht, MH, Blandino, A, Cavallaro, M, D'Angelo, T, Carerj, ML, Vogl, TJ, Mazziotti, S
La Radiologia medica. 2020;(4):384-397
Abstract
Unlike conventional computed tomography, dual-energy computed tomography is a relatively novel technique that exploits ionizing radiations at different energy levels. The separate radiation sets can be achieved through different technologies, such as dual source, dual layers or rapid switching voltage. Body tissue molecules vary for their specific atomic numbers and electron density, and the interaction with different sets of radiations results in different attenuations, allowing to their final distinction. In particular, iodine recognition and quantification have led to important information about intravenous contrast medium delivery within the body. Over the years, useful post-processing algorithms have also been validated for improving tissue characterization. For instance, contrast resolution improvement and metal artifact reduction can be obtained through virtual monoenergetic images, dose reduction by virtual non-contrast reconstructions and iodine distribution highlighting through iodine overlay maps. Beyond the evaluation of the abdominal organs, dual-energy computed tomography has also been successfully employed in other anatomical districts. Although lung perfusion is one of the most investigated, this evaluation has been extended to narrowly fields of application, such as musculoskeletal, head and neck, vascular and cardiac. The potential pool of information provided by dual-energy technology is already wide and not completely explored, yet. Therefore, its performance continues to raise increasing interest from both radiologists and clinicians.
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9.
Progresses in the imaging of calcium pyrophosphate crystal disease.
Andrés, M, Sivera, F, Pascual, E
Current opinion in rheumatology. 2020;(2):140-145
Abstract
PURPOSE OF REVIEW Calcium pyrophosphate crystal disease (CPPD) may be considered a neglected disorder, common in clinics and wards, but not receiving enough attention since the time it was recognized as a disease entity. This review aims to highlight the advances occurred in recent years in terms of imaging of CPPD, and their potential aid in diagnosing CPPD. RECENT FINDINGS The main advances in CPPD imaging have occurred with ultrasound and computed tomography. Ultrasound has been shown as more sensitive than conventional radiography in detecting chondrocalcinosis. OMERACT definitions of ultrasound signs of CPPD have been provided; validations process is still ongoing. Computed tomography has been used to assess CPPD at the spine. Some studies suggest that dual-energy scans could accurately detect chondrocalcinosis and discriminate from other calcified structures. SUMMARY Ultrasound and computed tomography may have a role in CPPD detection, though the specifics are still unclear. It remains necessary to have studies comparing them with synovial fluid analysis for crystals in a clinical scenario.
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10.
Accelerating the future of cardiac CT: Social media as sine qua non?
Choi, AD, Feuchtner, GM, Weir-McCall, J, Shaw, LJ, Min, JK, Villines, TC
Journal of cardiovascular computed tomography. 2020;(5):382-385
Abstract
The vision for the Journal of Cardiovascular Computed Tomography's social media efforts is to amplify the impact of the Journal while driving engagement, increasing journal visibility and disseminating content to new audiences globally. Serving as "the front door" to the Journal, this digital evolution represents an important step forward for a field in which advancements in hardware, image processing and clinical evidence have evolved rapidly. However, is social media the panem et circenses of cardiovascular computed tomography (CT), that of superficial appeasement, or of sine qua non; an essential ingredient to the acceleration of the Journal and of the field of cardiovascular CT? This paper aims to present the initial impact of social media within a dedicated cardiovascular CT journal.