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Optimized energy of spectral coronary CT angiography for coronary plaque detection and quantification.
Symons, R, Choi, Y, Cork, TE, Ahlman, MA, Mallek, M, Bluemke, DA, Sandfort, V
Journal of cardiovascular computed tomography. 2018;(2):108-114
Abstract
BACKGROUND To optimize spectral coronary computed tomography angiography (CTA) for quantification of coronary artery plaque components. MATERIALS AND METHODS Fifty-one subjects were prospectively enrolled (88.2% male) (NCT02740699). Dual energy coronary CTA was performed at 90/Sn150 kVp using a 3rd generation dual-source CT scanner (SOMATOM Force, Siemens Healthcare). Dual energy images were reconstructed with a) linear mixed blending of 90 and Sn150 kVp data, b) virtual monoenergetic algorithm from 40 to 150 keV (at 10- keV intervals), and c) noise-optimized virtual monoenergetic algorithm from 40 to 150 keV. Image noise, iodine signal-to-noise-ratio (SNR), and contrast-to-noise ratio (CNR) for calcified and non-calcified plaque were measured. Qualitative readings of image quality were performed. Semi-automated software (QAngioCT, Medis) was used to quantify coronary plaque. Linear mixed-models that account for within-subject correlation of plaques were used to compare the results. RESULTS 100-150 keV noise-optimized virtual monoenergetic images had lower image noise than linear mixed images (all P < 0.05). The highest iodine SNR was achieved in 40 keV noise-optimized virtual monoenergetic images (33.3 ± 0.6 vs 23.3 ± 0.7 for linear mixed images, P < 0.001). 40-70 keV noise-optimized virtual monoenergetic images and 70 keV virtual monoenergetic images had superior coronary plaque CNR versus linear mixed images (all P < 0.01) with a maximum improvement of 20.1% and 22.7% for calcified plaque and non-calcified plaque (38.8 ± 2.2 vs 32.3 ± 2.3 and 17.3 ± 1.3 vs 14.1 ± 1.4, respectively). Using 90/Sn150 kVp linear mixed images as a reference, the plaque quantity was similar for 70 keV noise-optimized virtual monoenergetic images whereas low keV images (e.g. 40 keV) yielded significantly higher coronary plaque volumes (all P < 0.001). CONCLUSION Spectral coronary CTA with low energy (40-70 keV) post-processing can improve the CNR of coronary plaque components. However, low energies (such as 40 keV) resulted in different absolute volumes of coronary plaque compared to "conventional" mixed 90/Sn150 kVp images.
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[Impact of rotational coronary angiography in the amount of iodinated contrast and the exposure to ionising radiations in patients undergoing invasive coronary procedures: A systematic review and meta-analysis].
Fernández-Rodríguez, D, Anmad Shihadeh, L, Martos-Maine, JL, Couto-Comba, P, Quijada-Fumero, A, Pimienta, R, Grillo-Pérez, JJ, Rodríguez-Esteban, M, Pérez-Hernández, H, Hernández-Afonso, J, et al
Archivos de cardiologia de Mexico. 2018;(4):277-286
Abstract
BACKGROUND Invasive coronary procedures involve the administration of iodinated contrast and the exposure to ionising radiations, increasing morbidity and mortality. The rotational coronary angiography (RCA) allows acquiring multiple projections with a unique injection of iodinated contrast. To date, there are no meta-analyses specifically comparing RCA and conventional coronary angiography (CCA) in patients undergoing invasive coronary procedures, whether diagnostic or diagnostic and therapeutic. The aim of this meta-analysis is to assess the impact of RCA on the amount of iodinated contrast and the exposure to ionising radiations during invasive coronary procedures. METHODS A search in PubMed and Ovid databases was conducted to identify studies, including diagnostic and diagnostic and therapeutic studies, comparing RCA and CCA. The manuscripts were evaluated on quality and biases, and were included if they analysed any of the following endpoints: volume of contrast and exposure to ionising radiations measured as dose-area product, and Kerma-air or fluoroscopy time. RESULTS Sixteen studies, with a total of 2,327 patients, were included in the final analysis (1,146 patients underwent RCA and 1,181 patients underwent CCA), with significant differences being detected in volume of contrast (standard difference in means [95% confidence interval] -1.887 [-2.472 to -1.302]; P<.001), dose-area product (-0.726 [-1.034 to -0.418]; P<.001), Kerma-air (-0.842 [-1.104 to -0.581]; P<.001), and fluoroscopy time (0.263 [-0.496 to -0.030]; P=.027). CONCLUSIONS RCA reduces the volume of contrast and the exposure to radiation, evaluated as dose-area product, Kerma-air, and fluoroscopy time, in patients undergoing invasive coronary procedures.
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Coronary calcium score improves the estimation for pretest probability of obstructive coronary artery disease and avoids unnecessary testing in individuals at low extreme of traditional risk factor burden: validation and comparison of CONFIRM score and genders extended model.
Wang, M, Liu, Y, Zhou, X, Zhou, J, Zhang, H, Zhang, Y
BMC cardiovascular disorders. 2018;(1):176
Abstract
BACKGROUND Reliability of models for estimating pretest probability (PTP) of obstructive coronary artery disease (CAD) has not been investigated in individuals at low extreme of traditional risk factor (RF) burden. Thus, we sought to validate and compare CONFIRM score and Genders extended model (GEM) among these individuals. METHODS We identified symptomatic individuals with 0 or 1 RF who underwent coronary calcium scan and coronary computed tomographic angiography (CCTA). Follow-up clinical data were also recorded. PTP of obstructive CAD for every individual was estimated according to CONFIRM score and GEM, respectively. Area under the receiver operating characteristic curve (AUC), integrated discrimination improvement (IDI), net reclassification improvement (NRI) and Hosmer-Lemeshow (H-L) test were used to assess the performance of models. RESULTS There were 1201 individuals with 0 RF and 2415 with 1 RF. The AUC for GEM was significantly larger than that for CONFIRM score, no matter in individuals with 0 (0.843 v.s. 0.762, p < 0.0001) or 1 (0.823 v.s. 0.752, p < 0.0001) RF. Compared to CONFIRM score, GEM demonstrated positive IDI (5% in individuals with 0 RF and 8% in individuals with 1 RF), positive NRI (41.50% in individuals with 0 RF and 40.19% in individuals with 1 RF), better prediction of clinical events and less discrepancy between observed and predicted probabilities, resulting in a significant decrease of unnecessary testing, especially in negative individuals. CONCLUSION In individuals at low extreme of traditional RF burden of CAD, the addition of coronary calcium score provided a more accurate estimation for PTP and application of GEM instead of CONFIRM score could avoid unnecessary testing.
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Prognostic Value of Risk Factors, Calcium Score, Coronary CTA, Myocardial Perfusion Imaging, and Invasive Coronary Angiography in Kidney Transplantation Candidates.
Winther, S, Svensson, M, Jørgensen, HS, Rasmussen, LD, Holm, NR, Gormsen, LC, Bouchelouche, K, Bøtker, HE, Ivarsen, P, Bøttcher, M
JACC. Cardiovascular imaging. 2018;(6):842-854
Abstract
OBJECTIVES This study sought to perform a prospective head-to-head comparison of the predictive value of clinical risk factors and a variety of cardiac imaging modalities including coronary artery calcium score (CACS), coronary computed tomography angiography (CTA), single-photon emission computed tomography (SPECT), and invasive coronary angiography (ICA) on major adverse cardiac events (MACE) and all-cause mortality in kidney transplantation candidates. BACKGROUND Current guidelines recommend screening for coronary artery disease in kidney transplantation candidates. Furthermore, noninvasive stress imaging is recommended in current guidelines, despite its low diagnostic accuracy and uncertain prognostic value. METHODS The study prospectively evaluated 154 patients referred for kidney transplantation. All patients underwent CACS, coronary CTA, SPECT, and ICA testing. The clinical endpoints were extracted from patients' interviews, patients' records, and registries. RESULTS The mean follow-up time was 3.7 years. In total, 27 (17.5%) patients experienced MACE, and 31 (20.1%) patients died during follow-up. In a time-to-event analysis, both risk factors and CACS significantly predicted death, but only CACS predicted MACE. Combining risk factors with CACS identified a very-low-risk cohort with a MACE event rate of 2.1%, and a 1.0% mortality rate per year. Of the diagnostic modalities, coronary CTA and ICA significantly predicted MACE, but only coronary CTA predicted death. In contrast, SPECT predicted neither MACE nor death. CONCLUSIONS Compared with traditional risk factors and other cardiac imaging modalities, CACS and coronary CTA seem superior for risk stratification in kidney transplant candidates. Applying a combination of risk factors and CACS and subsequently coronary CTA seems to be the most appropriate strategy. (Angiographic CT of Renal Transplantation Candidate Study [ACToR]; NCT01344434).
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Differences in the association of total versus local coronary artery calcium with acute coronary syndrome and culprit lesions in patients with acute chest pain: The coronary calcium paradox.
Puchner, SB, Mayrhofer, T, Park, J, Lu, MT, Liu, T, Maurovich-Horvat, P, Ghemigian, K, Bittner, DO, Fleg, JL, Udelson, JE, et al
Atherosclerosis. 2018;:251-257
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BACKGROUND AND AIMS Total coronary artery calcium (CAC) burden is associated with an increased cardiovascular risk, while local CAC may represent stable plaques. We determined differences in relationship of total CAC with acute coronary syndrome (ACS) and local CAC with culprit lesions in patients with suspected ACS. METHODS We performed computed tomography (CT) for CAC and CT angiography to assess the presence of significant stenosis and high-risk plaque (positive remodeling, low CT attenuation, napkin-ring sign, spotty calcium) in 37 patients with ACS and 223 controls. Total and segmental Agatston scores were measured. Culprit lesions were assessed in subjects with ACS. RESULTS Patients (n = 260) with vs. without ACS had higher total CAC score (median 229, 25th-75th percentile 75-517 vs. 27, 25th-75th percentile 0-99, p<0.001), higher prevalence of significant stenosis (78% vs. 7%, p<0.001) and high-risk plaque (95% vs. 59%, p<0.001). In those with ACS, culprit (n = 41) vs. non-culprit (n = 200) lesions, had similar segmental CAC score (median 22, 25th-75th percentile 4-71 vs. 14, 25th-75th percentile 0-51; p=0.37), but higher prevalence of significant stenosis (81% vs. 11%, p<0.001) and high-risk plaque (76% vs. 51%, p=0.005). Significant stenosis (odds ratio 40.2, 95%CI 15.6-103.9, p<0.001) and high-risk plaque (odds ratio 3.4, 95%CI 1.3-9.1, p=0.02), but not segmental CAC score (odds ratio 1.0, 95%CI 1.0-1.0, p=0.47), were associated with culprit lesions of ACS. CONCLUSIONS Total CAC burden was associated with ACS but segmental CAC was not associated with culprit lesions. Our findings suggest that total but not local CAC is a marker of ACS risk and support the hypothesis that extensive local CAC is a marker of plaque stability.
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Comparative assessment of image quality for coronary CT angiography with iobitridol and two contrast agents with higher iodine concentrations: iopromide and iomeprol. A multicentre randomized double-blind trial.
Achenbach, S, Paul, JF, Laurent, F, Becker, HC, Rengo, M, Caudron, J, Leschka, S, Vignaux, O, Knobloch, G, Benea, G, et al
European radiology. 2017;(2):821-830
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OBJECTIVES To demonstrate non-inferiority of iobitridol 350 for coronary CT angiography (CTA) compared to higher iodine content contrast media regarding rate of patients evaluable for the presence of coronary artery stenoses. METHODS In this multicentre trial, 452 patients were randomized to receive iobitridol 350, iopromide 370 or iomeprol 400 and underwent coronary CTA using CT systems with 64-detector rows or more. Two core lab readers assessed 18 coronary segments per patient regarding image quality (score 0 = non diagnostic to 4 = excellent quality), vascular attenuation, signal and contrast to noise ratio (SNR, CNR). Patients were considered evaluable if no segment had a score of 0. RESULTS Per-patient, the rate of fully evaluable CT scans was 92.1, 95.4 and 94.6 % for iobitridol, iopromide and iomeprol, respectively. Non-inferiority of iobitridol over the best comparator was demonstrated with a 95 % CI of the difference of [-8.8 to 2.1], with a pre-specified non-inferiority margin of -10 %. Although average attenuation increased with higher iodine concentrations, average SNR and CNR did not differ between groups. CONCLUSIONS With current CT technology, iobitridol 350 mg iodine/ml is not inferior to contrast media with higher iodine concentrations in terms of image quality for coronary stenosis assessment. KEY POINTS • Iodine concentration is an important parameter for image quality in coronary CTA. • Contrast enhancement must be balanced against the amount of iodine injected. • Iobitridol 350 is non-inferior compared to CM with higher iodine concentrations. • Higher attenuation with higher iodine concentrations, but no SNR or CNR differences.
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Prevalence and severity of coronary artery calcification based on the epidemiologic pattern: A propensity matched comparison of asymptomatic Korean and Chinese adults.
Han, D, Gao, Y, Ó Hartaigh, B, Gransar, H, Lee, JH, Rizvi, A, Choi, SY, Chun, EJ, Sung, J, Han, HW, et al
International journal of cardiology. 2017;:353-358
Abstract
BACKGROUND Lifestyle, environmental, and genetic factors substantially influence cardiovascular disease (CVD) risk. We aimed to explore epidemiologic trends in coronary artery calcium scores (CACS), as a marker of CVD, along with possible differences by geographic area and study period in separate East Asian populations. METHODS We generated 3 matched groups (n=702) using a propensity scoring approach derived from a Korean (N=48,901) and Chinese cohort (N=927) as follows: (1) A recent Chinese group and (2) recent Korean group, both of whom underwent CACS scanning from 2012-2014; and (3) a past Korean group who underwent CACS scanning 8-10years before the index group (2002-2006). We used logistic regression to generate odds ratios (OR) with 95% confidence intervals (95% CI) to estimate the likelihood of having CACS between the groups, based on CACS stratified by severity: >0 (any), >100 (moderate), and >400 (severe). RESULTS The prevalence of any, moderate, or severe CACS did not differ significantly between the recent Chinese and Korean groups. Notably, the odds of the presence of moderate CACS in the recent Chinese group (OR: 3.05, 95% CI: 1.49-6.71, P-value<0.001) and the presence of any CACS in the recent Korean group (OR: 1.58, 95% CI: 1.17-2.15, P-value<0.001) were significantly higher than in the past Korean group. CONCLUSIONS In this study involving separate East Asian populations, there were no geographic differences in the prevalence of CACS. However, changes in other unmeasured factors over time are likely the culprits for the elevated prevalence of CACS in asymptomatic East Asians.
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Validation and comparison of four models to calculate pretest probability of obstructive coronary artery disease in a Chinese population: A coronary computed tomographic angiography study.
Zhou, J, Liu, Y, Huang, L, Tan, Y, Li, X, Zhang, H, Ma, Y, Zhang, Y
Journal of cardiovascular computed tomography. 2017;(4):317-323
Abstract
OBJECTIVE We sought to compare the performance of the updated Diamond-Forrester method (UDFM), Duke clinical score (DCS), Genders clinical model (GCM) and Genders extended model (GEM) in a Chinese population referred to coronary computed tomography angiography (coronary CTA). BACKGROUND The reliability of existing models to calculate the pretest proability (PTP) of obstructive coronary artery disease (CAD) have not been fully investigated, especially in a Chinese population. METHODS We identified 5743 consecutive patients with suspected stable CAD who underwent coronary calcium scoring (CCS) and coronary CCTA. Obstructive CAD was defined as with the presence of ≥50% diameter stenosis in coronary CTA or unassessable segments due to severe calcification. Area under the receiver operating characteristic curve (AUC), integrated discrimination improvement (IDI), net reclassification improvement (NRI) and Hosmer-Lemeshow goodness-of-fit statistic (H-L χ2) were assessed to validate and compare these models. RESULTS Overall, 1872 (32%) patients had obstructive CAD and 2467 (43%) had a CCS of 0. GEM demonstrated improved discrimination over the other models through the largest AUC (0.816 for GEM, 0.774 for GCM, 0.772 for DCS and 0.765 for UDFM). UDFM (-0.3255, p < 0.0001), DCS (-0.3149, p < 0.0001) and GCM (-0.2264, p < 0.0001) showed negative IDI compared to GEM. The NRI was significantly higher for GEM than the other models (0.7152, p < 0.0001, 0.5595, p < 0.0001 and 0.3195, p < 0.0001, respectively). All of the four models overestimated the prevalence of obstructive CAD, with unsatisfactory (p < 0.01 for all) calibration for UDFM (H-L χ2 = 137.82), DCS (H-L χ2 = 156.70), GCM (H-L χ2 = 51.17) and GEM (H-L χ2 = 29.67), respectively. CONCLUSION Although GEM was superior for calculating PTP in a Chinese population referred for coronary CTA, developing new models allowing for more accurate and operational estimation are warranted.
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Incremental prognostic value of computed tomography in stroke: rationale and design of the IMPACTS study.
Lee, JW, Hur, J, Choi, SI, Chun, EJ, Kang, JW, Jin, GY, Kim, EY, Yong, HS, Kang, EJ, Han, K, et al
The international journal of cardiovascular imaging. 2016;:83-9
Abstract
This study was designed to determine the prognostic value of coronary computed tomography angiography (CCTA) in ischemic stroke patients and to identify any incremental risk stratification benefits of CCTA findings compared with coronary artery calcium scoring (CACS) and traditional Framingham risk scores (FRS) in ischemic stroke patients without chest pain. IMPACTS is a prospective, multicenter, observational cohort study in which at least seven centers in Korea will participate. All participants will be enrolled in this study after providing informed consent. Nine hundred total ischemic stroke patients without chest pain will be enrolled and will undergo CACS and CCTA. All participants will be followed-up for a minimum of 24 months to determine the endpoints. The primary endpoint will be occurrence of major adverse cardiovascular events (MACEs), defined as all-cause mortality, cardiovascular death, myocardial infarction, or cardiovascular events requiring hospitalization and revascularization either by percutaneous coronary intervention or by coronary artery bypass graft after 90 days of index testing during the follow-up period. Patient enrollment should be completed within 2.5 years. We plan to analyze and identify the CCTA predictors of MACEs. In addition, we will compare several models used to assess independent relationships between the variables and MACEs using a shared frailty model and therefore determine the incremental prognostic value of CCTA findings compared with either the CACS or FRS. The results of IMPACTS will provide valuable information for risk stratification with CCTA in ischemic stroke patients without chest pain.
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Coronary CT angiography derived fractional flow reserve: Methodology and evaluation of a point of care algorithm.
Coenen, A, Lubbers, MM, Kurata, A, Kono, A, Dedic, A, Chelu, RG, Dijkshoorn, ML, van Geuns, RJ, Schoebinger, M, Itu, L, et al
Journal of cardiovascular computed tomography. 2016;(2):105-13
Abstract
BACKGROUND Recently several publications described the diagnostic value of coronary CT angiography (coronary CTA) derived fractional flow reserve (CTA-FFR). For a recently introduced on-site CTA-FFR application, detailed methodology and factors potentially affecting performance have not yet been described. OBJECTIVE To provide a methodological background for an on-site CTA-FFR application and evaluate the effect of patient and acquisition characteristics. METHODS The on-site CTA-FFR application utilized a reduced-order hybrid model applying pressure drop models within stenotic regions. In 116 patients and 203 vessels the diagnostic performance of CTA-FFR was investigated using invasive FFR measurements as a reference. The effect of several potentially relevant factors on CTA-FFR was investigated. RESULTS 90 vessels (44%) had a hemodynamically relevant stenosis according to invasive FFR (threshold ≤0.80). The overall vessel-based sensitivity, specificity and accuracy of CTA-FFR were 88% (CI 95%:79-94%), 65% (55-73%) and 75% (69-81%). The specificity was significantly lower in the presence of misalignment artifacts (25%, CI: 6-57%). A non-significant reduction in specificity from 74% (60-85%) to 48% (26-70%) was found for higher coronary artery calcium scores. Left ventricular mass, diabetes mellitus and large vessel size increased the discrepancy between invasive FFR and CTA-FFR values. CONCLUSIONS On-site calculation of CTA-FFR can identify hemodynamically significant CAD with an overall per-vessel accuracy of 75% in comparison to invasive FFR. The diagnostic performance of CTA-FFR is negatively affected by misalignment artifacts. CTA-FFR is potentially affected by left ventricular mass, diabetes mellitus and vessel size.