Anatomical variants and coronary anomalies detected by dual-source coronary computed tomography angiography in North-eastern Thailand

Purpose: Congenital coronary anomalies are uncommon, with an incidence ranging from 0.17% in autopsy cases to 1.2% in angiographically evaluated cases. The recent development of dual-source coronary computed tomography angiography (coronary CTA) allows accurate and noninvasive depiction of coronary artery anomalies. Material and methods: A retrospective study included a total of 924 patients who underwent coronary CTA because of known or suspected coronary artery disease. In each study, coronary artery anomalies (CAs) were investigated. Results: A total of 924 patients (mean age 51.2 ±12.8 years), who underwent dual-source coronary CTA, were studied. The overall prevalence of CAs in our study was 3.7%, with the following distribution: four single coronary artery, 14 anomalous origin from opposite sinus of Valsalva, three absent left main, four high take-off coronary artery, three anomalous left coronary artery from pulmonary artery, and eight coronary artery fistulas. Conclusions: The present study supports the use of coronary CTA as a reliable noninvasive tool for defining anomalous coronary arteries in an appropriate clinical setting and provides detailed three-dimensional anatomic information that may be difficult to obtain with invasive coronary angiography

CT Coronary Angiography with 100kV tube voltage and a low noise reconstruction filter in non-obese patients: evaluation of radiation dose and diagnostic quality of 2D and 3D image reconstructions using open source software (OsiriX)

INTRODUCTION AND PURPOSE. Computed tomography coronary angiography (CTCA) has seen a dramatic evolution in the last decade owing to the availability of multislice CT scanners with 64 detector rows and beyond. However, this evolution has been paralleled by an increase in radiation dose to patients, that can reach extremely high levels (>20mSv) when retrospective ECG-gating techniques are used. On CT angiography, reduction of tube voltage allows to cut radiation dose with improved contrast resolution due to the lower energy of the X-ray beam and increased photoelectric effect. Our purpose is twofold: 1) to evaluate the radiation dose of CTCA studies carried out using a tube voltage of 100kV and a low noise reconstruction filter, compared with a conventional tube voltage of 120kV and a standard reconstruction kernel; 2) to assess the impact of the 100kV acquisition technique on the diagnostic quality of 2D and 3D image reconstructions performed with open source software (OsiriX). MATERIALS AND METHODS. Fifty-one non-obese patients underwent CTCA on a 64-row CT scanner. Out of them, 28 were imaged using a tube voltage of 100kV and a low noise reconstruction filter, while in the remaining 23 patients a tube voltage of 120kV and a standard reconstruction kernel were selected. All CTCA datasets were exported via PACS to a Macintosh™ computer (iMac™) running OsiriX 4.0 (64-bit version), and Maximum Intensity Projection (MIP), Curved Planar Reformation (CPR), and Volume Rendering (VR) views of each coronary artery were generated using a dedicated plug-in (CMIV CTA; Linköping University, Sweden). Diagnostic quality of MIP, CPR, and VR reconstructions was assessed visually by two radiologists with experience in cardiac CT using a three-point score (1=poor, 2=good, 3=excellent). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), intravascular CT density, and effective dose for each group were also calculated. RESULTS. Image quality of VR views was significantly better with the 100kV than with the 120kV protocol (2.77±0.43 vs 2.21±0.85, p=0.0332), while that of MIP and CPR reconstructions was comparable (2.59±0.50 vs 2.32±0.75, p=0.3271, and 2.68±0.48 vs 2.32±0.67, p=0.1118, respectively). SNR and CNR were comparable between the two protocols (16.42±4.64 vs 14.78±2.57, p=0.2502, and 13.43±3.77 vs 12.08±2.10, p=0.2486, respectively), but in the 100kV group aortic root density was higher (655.9±127.2 HU vs 517.2±69.7 HU, p=0.0016) and correlated with VR image quality (rs=0.5409, p=0.0025). Effective dose was significantly lower with the 100kV than with the 120kV protocol (7.43±2.69 mSv vs 18.83±3.60 mSv, p<0.0001). CONCLUSIONS. Compared with a standard tube voltage of 120kV, usage of 100kV and a low noise filter leads to a significant reduction of radiation dose with equivalent and higher diagnostic quality of 2D and 3D reconstructions, respectively in non-obese patients

State of the art: iterative CT reconstruction techniques

Owing to recent advances in computing power, iterative reconstruction (IR) algorithms have become a clinically viable option in computed tomographic (CT) imaging. Substantial evidence is accumulating about the advantages of IR algorithms over established analytical methods, such as filtered back projection. IR improves image quality through cyclic image processing. Although all available solutions share the common mechanism of artifact reduction and/or potential for radiation dose savings, chiefly due to image noise suppression, the magnitude of these effects depends on the specific IR algorithm. In the first section of this contribution, the technical bases of IR are briefly reviewed and the currently available algorithms released by the major CT manufacturers are described. In the second part, the current status of their clinical implementation is surveyed. Regardless of the applied IR algorithm, the available evidence attests to the substantial potential of IR algorithms for overcoming traditional limitations in CT imaging

Biologics May Prevent Cardiovascular Events in Rheumatoid Arthritis by Inhibiting Coronary Plaque Formation and Stabilizing High-Risk Lesions.

ObjectiveTo evaluate whether biologic disease-modifying antirheumatic drugs (DMARDs) decrease cardiovascular disease (CVD) risk in rheumatoid arthritis (RA) and whether biologic DMARDs might have a beneficial effect on coronary plaque formation or progression.MethodsIn this single-center observational cohort study, 150 patients underwent computed tomographic angiography for evaluation of coronary atherosclerosis (total, noncalcified, mixed/calcified, and low-attenuation plaque); 101 had repeat assessments within a mean ± SD of 6.9 ± 0.3 years to evaluate plaque progression. All CVD events were prospectively recorded, including cardiac death, myocardial infarction, unstable angina, revascularization, stroke, claudication, and hospitalization for heart failure. The Framingham-D'Agostino score was used to assess cardiovascular risk. The segment stenosis score was used to measure plaque burden. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated.ResultsAfter adjustment for the segment stenosis score, the Framingham-D'Agostino score, and time-varying Disease Activity Score in 28 joints using the C-reactive protein level using marginal structural models, current biologic DMARD use was associated with lower long-term CVD risk (OR 0.15 [95% CI 0.04-0.60]). Noncalcified and low-attenuation plaque presence moderated the effect of biologic DMARDs on CVD risk; specifically, biologic DMARD use was associated with lower CVD risk in patients with noncalcified or low-attenuation plaque at baseline (OR 0.21 [95% CI 0.04-0.99] and OR 0.08 [95% CI 0.01-0.70], respectively), but not in those without noncalcified or low-attenuation plaque. Per-segment plaque progression analyses showed that biologic DMARD exposure was associated with transition of noncalcified to mixed/calcified plaque (OR 4.00 [95% CI 1.05-15.32]). Biologic DMARD exposure predicted a lower likelihood of new plaque forming in segments without plaque among patients without mixed/calcified plaque in other coronary segments (OR 0.40 [95% CI 0.17-0.93]), but not among those with calcification. Biologic DMARD treatment also predicted low-attenuation plaque loss (P = 0.042).ConclusionOur findings indicate that in RA, biologic DMARD use is associated with reduced CVD risk, protective calcification of noncalcified lesions, and lower likelihood of new plaque formation in patients with early atherosclerosis

Evaluation of Negative Predictive Value (NPV) of 16-Row CT angiography in comparison with conventional angiography

Negative predictive value (NPV) is one of the important indicatives for evaluating a medical procedure. Herein, we have evaluated the NPV of 16-multidetector-row CT angiography (CTA) in comparison with conventional invasive angiography (CIA) in the diagnosis of significant stenosis. In this regard, 8 patients suspected to stenosis were investigated. They patients were undertaken CIA procedure after CTA. The obtained results show, the NPV of 50 for patient-base analysis. The findings of this study reveal that CT angiography with 16-slice scanner might be considered as an acceptable technique for rapid triage of patients. Low values of NPV reveal a moderate performance of CTA. However, due to low number of patients, the obtained results cannot be used for final decision. Hence, more is required to improve and achieve reliable results

MULTISLICE THOMOGRAPHY EVALUATION IN CORONARY ARTERY DISEASE

Conventional Coronary Angiography (CCA) is the diagnostic standard for identification and evaluation of coronary stenosis and coronary artery bypass graft (CABG) patency. Limits of this technique (invasivity, undeniable costs, risk of mortality and morbidity) and the large, worldwide, procedure number, whose only one third followed by interventional procedures, because of high percentage of uninjured coronary arteries, suggest the usefulness of a new non-invasive way to visualize the coronaric tree in patients with actual indication to CCA and Percutaneous Coronary Interventions (PCI).Multi-slice computed tomography (MSCT) is a rapidly developing technique and allows reliable evaluation of the coronary arteries and CABG in a non-invasive manner. Despite limitations due to calcium, movement, metallic parts and high radiation dose, MSCT – CA showed a good diagnostic capability in detecting significant coronary artery stenosis in patient with suspected or known significant coronary artery disease

Evaluation of specificity of CT angiography compared to conventional angiography for 16-Row Scanner

Herein, authors have evaluated the specificity of CT angiography (CTA) in comparison with conventional invasive angiography (CIA) in the diagnosis of coronary stenosis. For this purpose, 8 patients suspected to stenosis was used. They were undertaken CIA procedure after CTA using 16-multidetector-row machine. Result reveals that for patient-base analysis, the specificity of CTA was 25. The values of specificity reveal a unacceptable performance of CTA. However, due to low number of patients, the obtained results cannot be used for final decision

Cardiac computed tomography: indications, applications, limitations, and training requirements: Report of a Writing Group deployed by the Working Group Nuclear Cardiology and Cardiac CT of the European Society of Cardiology and the European Council of Nuclear Cardiology

As a consequence of improved technology, there is growing clinical interest in the use of multi-detector row computed tomography (MDCT) for non-invasive coronary angiography. Indeed, the accuracy of MDCT to detect or exclude coronary artery stenoses has been high in many published studies. This report of a Writing Group deployed by the Working Group Nuclear Cardiology and Cardiac CT (WG 5) of the European Society of Cardiology and the European Council of Nuclear Cardiology summarizes the present state of cardiac CT technology, as well as the currently available data concerning its accuracy and applicability in certain clinical situations. Besides coronary CT angiography, the use of CT for the assessment of cardiac morphology and function, evaluation of perfusion and viability, and analysis of heart valves is discussed. In addition, recommendations for clinical applications of cardiac CT imaging are given and limitations of the technique are describe

Sixty-four-slice multidetector computed tomography: the future of ED cardiac care

Multidetector computed tomography (MDCT) imaging, a technological advance over traditional CT, is a promising possible alternative to cardiac catheterization for evaluating patients with chest pain in the emergency department (ED). In comparison with traditional CT, MDCT offers increased spatial and temporal resolution that allows reliable visualization of the coronary arteries. In addition, a triple scan, which includes evaluation for pulmonary embolism and thoracic aortic dissection, can be incorporated into a single study. This test will enable emergency physicians to rapidly evaluate patients for life-threatening illnesses and may allow safer and earlier discharges of many patients with chest pain in comparison with a traditional rule-out protocol. In this article, we will highlight the technological advances of MDCT imaging, review the literature on coronary angiography via MDCT, and discuss the future of this technology as it relates to the ED

Low radiation dose in computed tomography: the role of iodine

Recent approaches to reducing radiation exposure during CT examinations typically utilize automated dose modulation strategies on the basis of lower tube voltage combined with iterative reconstruction and other dose-saving techniques. Less clearly appreciated is the potentially substantial role that iodinated contrast media (CM) can play in low-radiation-dose CT examinations. Herein we discuss the role of iodinated CM in low-radiation-dose examinations and describe approaches for the optimization of CM administration protocols to further reduce radiation dose and/or CM dose while maintaining image quality for accurate diagnosis. Similar to the higher iodine attenuation obtained at low-tube-voltage settings, high-iodine-signal protocols may permit radiation dose reduction by permitting a lowering of mAs while maintaining the signal-to-noise ratio. This is particularly feasible in first pass examinations where high iodine signal can be achieved by injecting iodine more rapidly. The combination of low kV and IR can also be used to reduce the iodine dose. Here, in optimum contrast injection protocols, the volume of CM administered rather than the iodine concentration should be reduced, since with high-iodine-concentration CM further reductions of iodine dose are achievable for modern first pass examinations. Moreover, higher concentrations of CM more readily allow reductions of both flow rate and volume, thereby improving the tolerability of contrast administration