Abstract: Coronary computed tomography angiography (CTA) has been increasingly used to detect coronary artery disease. The diagnostic performance of coronary CTA is well established with a high sensitivity and negative predictive value. Nevertheless, the diagnostic value of coronary CTA is offset by a high false positive rate, partly due to the technique lacking physio logical lesion assessment when performed in the conventional way. This has raised concerns regarding unnecessary invasive coronary angiography referrals and inappropriate revasculariza tion procedures. Recent advances in computational fluid dynamics and imagebased modeling have enabled the calculation of coronary artery blood flow and pressure under various modeled physiologic conditions from coronary CTA without the need for hyperemiainducing medica tions, modification of acquisition protocol or further radiation. Coronary flow and pressure can be derived both at rest and during simulated maximum hyperemia allowing for the calculation of fractional flow reserve from coronary CTA (FFR CTA ) across stenotic lesions in a fashion similar to invasive FFR. This novel noninvasive technology offers concurrent anatomical and functional assessment of major epicardial coronary arteries. The diagnostic performance of FFR CTA has been tested in three major trials where it resulted in accurate identification of ischemiarelated lesions. Similar to an invasive FFRguided management strategy, the use of FFR CTA has been shown to improve patients’ outcomes and reduce health care costs. FFR CTA is emerging as an attractive alternative to invasive FFR. There are, however, several challenges that need to be overcome before FFR CTA can be incorporated into routine clinical practice.
Background: Estimation of functional relevance of a coronary stenosis by fractional flow reserve (FFR) from coronary computed tomography angiography (CCTA) has recently provided encouraging results. Due to its limited availability, the corrected contrast opacification (CCO) decrease and the transluminal attenuation gradient (TAG) were suggested as less complex alternatives. The aim of the present study was to assess the accuracy of CCO decrease and TAG to predict ischemia as assessed by single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Results: This retrospective study included 72 patients who underwent hybrid CCTA/SPECT MPI with at least one coronary artery stenosis. Of 127 vessels with a coronary stenosis in CCTA, 38 (30%) were causing ischemia in its subtending myocardium. The area under the curve (AUC) for CCO decrease to predict ischemia was 0.707 with sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of 74, 64, 85, 47, and 67%, respectively. For TAG, the AUC was 0.469.
criterion in diagnosing CAD has been increasingly reported in the literature with improved diagnostic accuracy when compared to conventional CCTA (16-21). A cut-off value of 80° is recommended by these studies to decide the significance of coronary stenosis. This is also confirmed in this study with wider angulations (>80°) associated with hemodynamic changes when compared to narrower angulations. This is in accordance with previous reports based on realistic and patient-specific coronary models showing the direct correlation between coronary angulation and corresponding hemodynamic changes (25,26,37-40). In their recent study, Park et al analyzed hemodynamic features in relation to different types of coronary plaques based on CCTA-generated CFD models in 80 patients with plaques distributed at the left coronary artery (40). Their results showed that WSS offers additional information than coronary lumen stenosis in determining plaque features, in particular, differentiating high-risk plaques from stable ones. Findings of this study are consistent with their results showing that WSS changes in coronary arteries in wide angulation are associated with significant coronary stenosis, indicating hemodynamic significance. This study focuses on analysis of calcified coronary plaques because this is a challenging area for CCTA due to high false positive rates resulting from blooming artifacts. Thus, results add valuable information to the existing literature.
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classification of congenital variations of the coronary artery and assigned to the group of major coronary anomalies . Angelini and Dodge-Khatami's classification, and Angelini and Dodge- Khatami's modified classifications are currently used for coronary anatomy anomalies, both extracting coronary artery fistulas [21, 22]. The Sakakibara et al. classification, basing on angiography, divides fistulas basing on dilatation of supplying vessel . The mentioned and accessible classifications do not divide the fistulas basing on their clinical or functional relevance. Taking the advantage of CT, which enables the morphological assessment of a fistula and potential additional findings, a novel system of classifying the fistulas was proposed by the authors, with 5 types: linear, spiral, aneurysmal, grid-like and mixed. The presented morphological classification may be used by radiologists to assess all coronary artery fistulas, regardless of the supplying vessel, fistula diameters and the drainage site, being a useful tool for qualification to intravascular or surgical corrections.
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We searched Pubmed, ScienceDirect, Cochrane Library, Web of Science, and CNKI for articles from 2011 to 2018. Search items were “chronic total occlu- sion”, “percutaneous coronary intervention”, “scoring systems”, “predictablity”. We selected six clinically used scoring systems. The first and globally accepted scoring system (J-CTO score) was developed in 2011 by Morino et al.  Inde- pendent predictors included blunt stump, calcification, bending, occlusion length > 20 mm, and previously failed attempt. After several years J-CTO score, CT-RECTOR (Computed tomography registry of chronic total occlusion revas- cularization) score was developed by Opolski et al. in 2015 . It used non-invasive investigation of coronary computed tomography angiography to predict difficult in CTO re-vascularization. A total of 240 consecutive CTO lesions from 4 centres in Germany were analysed. They also predicted the probability of suc- cessful guidewire crossing ≤ 30 min. All CCTA were performed 4 weeks prior to percutaneous coronary intervention. Six independent predictors were included i.e. presence of multiple occlusion, blunt stump at entry or exit site, severe calci- fication, bending ≥ 45˚, previously failed PCI at CTO, and duration of CTO ≥ 12 months or unknown. Clinical and Lesion (CL) related score was presented by Alessandrino et al. to predict PCI success in CTO . It was developed based on both clinical and angiographic parameters of 1671 consecutive patients with CTO lesion. Successful procedure was defined as the achievement of < 30% re- sidual diameter stenosis as assessed by CAG and associated with TIMI grade 3. Independent predictive variables were severely calcified lesion, previous CABG, lesion length ≥ 20 mm, previous MI, blunt stump, and non-LAD CTO location, and were scored according to their odd ratio. Only severe calcification was as- signed as independent predictor.
The use of procedures with a high load of radiation has changed the practice of medicine, with unprecedented clinical and diagnostic benefits. Medical sources of radiation were about one-fifth that of natural radiation in 1987, close to half in 1993 and over 100% that of natural radiation in 2006 , . The contribution of CT in general, and Cardiac CT in particular, to cumulative radiation dose is high and still rising. In 2006, CT ac- counted for 24% of overall (natural and medical) radiation exposure, with nuclear medicine and interventional fluoroscopy accounting for 12% and 7% respectively . The use of Cardiac CT is growing exponentially, and CT has been listed as a special focus of interest by the US President’s Cancer Panel as an environmental cause of cancer amenable to reduction . The process of radiological audit is essential to avoiding unnecessary med- ical radiation exposure in patients. In 2010 the International Atomic Energy Agency launched the “3A’s cam- paign”: audit, appropriateness, awareness for radiological justification and optimization, an effective tool for cancer prevention . Optimization is especially important for Cardiac CT, whose doses may vary widely from less than 1 mSv to more than 50 mSv depending on the technology used, type of scan (with or without aorta), administration of contrast (with repeated scans and without contrast), patient habits and attention paid to opti- mization , . This aspect is particularly important for cardiology patients, who already received high cumu- lative doses in the pre-cardiac CT era both as adult  and pediatric patients . For these reasons, recently the Food and Drug Administration , American Heart Association , American College of Cardiology  and American College of Radiology  strongly recommended that each user facility, to a feasible extent, develop its own locally-based diagnostic reference levels, for use and audit until more broadly recognized levels are available. Moreover, in 2010 ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR published the “appro- priate use criteria for cardiac computed tomography” , in 2011 the American Association of Physicists in Medicine, Task Group 204, provided an user-friendly method to estimate patient size specific dose (SSDE)  and Society of Cardiovascular Computed Tomography published the guidelines on radiation dose and dose-op- timization strategies in cardiovascular CT . All these tools foster justification and optimization balance. Aim of the present study is to audit the scanner radiation output and estimate of patient-size specific doses of cardiac CT over a 6-year period in a tertiary care cardio-radiology referral center.
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Methods: We conducted a single-center retrospective study. A total of 601 outpatients (338 males; 263 females; mean age, 69.8±10.0 years) who underwent coronary computed tomog- raphy angiography between April 2006 and March 2012 were analyzed. The associations between coronary artery stenosis (75%) as determined by coronary computed tomography angiography and clinical and laboratory parameters were evaluated by multivariate logistic regression. Valida- tion of maximum-IMT as measured by ultrasonography as a surrogate marker of coronary artery stenosis was analyzed by receiver operating characteristic (ROC) curve analysis.
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CHD: coronary heart disease; CCTA: coronary computed tomography angiography; RCA: right coronary artery; LAD: left anterior descending; LCX: left circumflex artery; 0D/3D: zero-dimensional/three-dimensional; WSS: wall shear stress; OSI: oscillatory shear index; CFD: computational fluid dynamic; CABG: coronary artery bypass grafting; SVG: saphenous vein graft; LV: left ventricle; LPM: lumped parameter model.
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We approached our patient according to a diagnostic algo- rithm based on the current AHA/ACC guidelines. Our patient had been asymptomatic since the MI event and had had no high-risk features for adverse outcomes in rou- tine non-invasive tests. Medical history, clinical features and non-invasive tests did not provide specific diagnosis and prognosis, which allowed us only to continue the cur- rent medical therapy. According to the scheme provided by the current guidelines, we should have considered fur- ther imaging studies. However, in our patient, routine non-invasive imaging studies, such as nuclear stress test- ing or stress echocardiography would not have provided any new information for a better risk- and prognosis strat- ification. We considered the low age and the low cardio- vascular risk profile of the patient at the time of acute MI, the absence of symptoms after the event and the absence of inducible ischaemia during the treadmill exercise test and decided that a non-invasive delineation of the pres- Coronary computed tomography angiography shows absence of flow limiting stenosis in both left (1a) and right (1b) coronary circulation
Severe coronary calcification causes artifacts in CTCA as a result of partial volume effect and beam hardening and therefore the plaque size and stenosis can be evalu- ated larger than they are. Also it may hinder to evaluate lumen integrity reliably in case of high calcium density. As a result of these, CTCA can assess severity of stenosis more than it is, especially in calcified vessels . In general, the severity of lesions in CTCA were also found one more degree severe than in CCA in our study. For example, although there was a statistical concordance (p: 0.003) between CTCA and CCA for determining lesions, we could not find any statistical adjustment in none of three coronary arteries according to lesion’s severity (p: 0.271 for LAD, p: 0.08 for Cx, p: 0.271 for RCA). An- other reason may be that classification of lesions had been generally made visually by clinicians.
All computed tomography examinations were performed using a 64-row multidetector computed tomography sys- tem (Brilliance Computed Tomography scanner, Philips Healthcare). Coronary calcium quantification was perfor- med in all subjects with the acquisition parameters of 2.5 mm section thickness, 120 kV, and 55 mAs. Then the images of MDCT-CA were acquired following the infu- sion of non-ionic iodine contrast agent by a power inject- tor at a rate of with 4 mL/s rate via an 18 gauge periph- eral line inserted into an antecubital vein. The scan pa- rameters of angiographic series were: 120 kV; 500 - 900 mAs; gantry rotation time, 0.40 s; detector collimation, 64 × 0.625 mm; slice thickness, 0.9 mm. All the data were transferred to a workstation (Extended Brilliance Workspace, Philips Healthcare). Axial, coronal and sag- ittal reformatted images, volume rendering and maxi- mum intensity projection images were created using Car- diac Viewer and Cardiac CTA programs at the worksta- tion. Plaque segmentation analysis of coronary vessels was also performed. Reconstruction was performed rou- tinely using a window centered at 75% of the R-R inter- val in all patients.
Purpose: Acute coronary lesions commonly trigger out-of-hospital cardiac arrest (OHCA). However, the prevalence of coronary artery disease (CAD) in Asian pa- tients with OHCA and whether electrocardiogram (ECG) and other findings might predict acute myocardial infarction (AMI) have not been fully elucidated. Materi- als and Methods: Of 284 consecutive resuscitated OHCA patients seen between January 2006 and July 2013, we enrolled 135 patients who had undergone coronary evaluation. ECGs, echocardiography, and biomarkers were compared between pa- tients with or without CAD. Results: We included 135 consecutive patients aged 54 years (interquartile range 45‒65) with sustained return of spontaneous circula- tion after OHCA between 2006 and 2012. Sixty six (45%) patients had CAD. The initial rhythm was shockable and non-shockable in 110 (81%) and 25 (19%) pa- tients, respectively. ST-segment elevation predicted CAD with 42% sensitivity, 87% specificity, and 65% accuracy. ST elevation and/or regional wall motion ab- normality (RWMA) showed 68% sensitivity, 52% specificity, and 70% accuracy in the prediction of CAD. Finally, a combination of ST elevation and/or RWMA and/ or troponin T elevation predicted CAD with 94% sensitivity, 17% specificity, and 55% accuracy. Conclusion: In patients with OHCA without obvious non-cardiac causes, selection for coronary angiogram based on the combined criterion could de- tect 94% of CADs. However, compared with ECG only criteria, the combined cri- terion failed to improve diagnostic accuracy with a lower specificity.
Methods: Women of 45 - 55 years, who experienced a reproductive disorder (PCOS, POI, HPD), are invited to participate in this multicenter, prospective, cohort study. Women will be recruited after regular cardiovascular screening, including assessment of classical cardiovascular risk factors. CT of the coronary arteries (both coronary artery calcium scoring (CACS), and contrast-enhanced coronary CT angiography (CCTA)) and carotid siphon calcium scoring (CSC) is planned in 300 women with HPD and 300 women with PCOS or POI. In addition, arterial stiffness (non-invasive pulse wave velocity (PWV)) measurement and cell-based biomarkers (inflammatory circulating cells) will be obtained. Discussion: Initial inclusion is focused on women of 45 - 55 years. However, the age range (40 - 45 years and/or ≥ 55 years) and group composition may be adjusted based on the findings of the interim analysis. Participants can potentially benefit from information obtained in this study concerning their current cardiovascular health and expected future risk of cardiovascular events. The results of this study will provide insights in the development of CVD in women with a history of reproductive disorders. Ultimately, this study may lead to improved cardiovascular prediction models and will provide an opportunity for timely adjustment of preventive strategies. Limitations of this study include the possibility of overdiagnosis and the average radiation dose of 3.5 mSv during coronary and carotid siphon CT, although the increased lifetime malignancy risk is negligible.
Cardiac CT can be applied for visualization of the coro- nary artery lumen after intravenous injection of a contrast agent. The administration of beta blockers before the cardiac CT scan and the use of sublingual nitroglycerin can achieve coronary vasodilation and maximize image quality. Studies using 64 slice CT scanning with invasive coronary angiography report sensitivities and specifici- ties of 94% - 99% and 86% - 97%, respectively, and im- portantly, a negative predictive value of 98% - 100% [10-12]. Patency and occlusion of bypass grafts can be established with very high accuracy in cardiac CT [13, 14]. But, the limitations are the detection of stenoses at
(Siemens, Germany) for vessel or plaque analysis. The software is based on maximum intensity projections and multiplanar reconstructions. Images were displayed along and orthogonally to the center line of the coronary arteries. For additional orientation, thin-slab maximum intensity projections and three-dimensional volume renderings were also applied. Degree of coronary diameter stenosis (D%) was defined as referential diameter-luminal diameter/ referential diameter. In turn, referential diameter was defined as the diameter located in the proximal normal vessel. Luminal cross-sectional area (L-CSA) and external elastic membrane cross-sectional area (EEM-CSA) were calculated (Figure 1). A cross-section of the targeted lesion was acquired definiti- vely and further L-CSA and EEM-CSA were also calculated by plaque analysis after manual definition of the border of the vessel lumen and EEM. The Hounsfield (Hu) value was acquired automatically by plaque analysis software.
and tortuous coronary arteries, and we further evaluate the chamber size and cardiac function using echocardiog- raphy. However, the complete anatomy of a CAF is best visualized by CAA and CCTA. These imaging modalities are especially useful in evaluating the features of a CAF, along with important findings such as the origin and drainage sites of the fistula, the serpiginous course of the coronary arteries and their relationship with structures as- sociated with other congenital anomalies, and the pres- ence and severity of atherosclerosis [2, 7, 8].
Case presentation: A 70-year-old Caucasian man came to our hospital with slight limitation of physical activity (New York Heart Association class II). He was asymptomatic for angina, syncope, and palpitations. Cardiac magnetic resonance imaging was performed after echocardiography because a hypertrophic cardiomyopathy was suspected; a plausible coronary artery anomaly was demonstrated as collateral evidence. Subsequently, coronary computed tomographic angiography showed the anomalous origin of left coronary artery from the pulmonary artery; the coronary vessels appeared markedly dilated and tortuous. Dilated intercoronary vessels along the epicardial surface of the heart and dilated bronchial arteries, corresponding to collateral pathways, were observed. Left ventricular hypertrophy, delayed subendocardial enhancement, and mitral insufficiency were better evaluated on
A retrospective review was performed using data from 1034 self-referred subjects who had undergone both 64-slice MDCT coronary angiography and hepatic ultrasonography as part of a general routine health evaluation at CHA Bundang Medical Center between March 2007 and December 2010. Participants were excluded if they had a history of myocardial infarction or stroke (n=1), coronary artery bypass surgery (n=1), malignan- cy (n=1), positive hepatitis B surface antigen or anti-hepatitis C antibody (n=30), habitual consumption of >20 g/day of al- cohol (n=208), or insufficient medical records (n=21). Ulti- mately, 772 subjects were enrolled in this study. The Institu- tional Review Board of CHA Bundang Medical Center approved the study protocol.
also shown that the diagnostic performance of TAG was only modest compared to cFFR (AUC: 0.67 vs 0.91) in a study of 32 patients. A possible explanation for these findings is that TAG assesses coronary blood flow under resting conditions and not during hyperemic conditions that is simulated for the computation of FFR CT and is induced with adenosine during invasive FFR. Another possibility may be that FFR CT is not affected by the various detector CCTAs with broad Z-axis coverage that influences the degree of TAG. In this regard, the cutoff value of TAG is not uniform and relies on the CCTA detectors. 42 In contrast, the threshold for FFR-derived CT
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Studies that evaluated the effectiveness of IMR for CCTA have indicated that IMR improved image quality and reduced image noise compared to other reconstruction methods when using a conventional 120-kVp protocol [10,22,23]. Yuki et al.  compared IMR, IR, and FBP at 100 kVp in non-obese patients who underwent cardiac CT and reported that IMR resulted in better image quality with less noise and fewer artifacts. Oda et al.  also showed that an IMR algorithm could provide improved qualitative and quantitative image quality compared to IR and FBP in low-dose CCTA when using a 100-kVp protocol and prospective ECG-gated scan- ning. Stehli at el.  have also reported accurate noninvasive diagnosis of coronary artery dis- ease with the use of a model-based IR-reconstructed CCTA. In our previous study, we reported the feasibility of using CCTA with 80 kVp, 200 mAs, prospective ECG gating, and an IMR algorithm to produce images of markedly higher quality (3.6 ± 0.6), compared with the use of IR and FBP (3.1 ± 0.7 for IR; 2.3 ± 0.6 for FBP, p < 0.01) . However, to our knowledge, no study has compared the effectiveness of a reduced tube voltage (80 kVp) combined with IMR to the widely used 100 kVp CCTA protocol combined with IR.
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