Contrast-enhanced Coronary Computed Tomography Angiography Research Articles

Meta-Analysis and Systematic Review of the Long-Term Predictive Value of Assessment of Coronary Atherosclerosis by Contrast-Enhanced Coronary Computed Tomography Angiography

We conducted a systematic review and meta-analysis to determine the predictive value of findings of coronary computed tomography angiography for incident cardiovascular events. Initial studies indicate a prognostic value of the technique; however, the level of evidence as well as exact independent risk estimates remain unclear. We searched PubMed, EMBASE, and the Cochrane Library through January 2010 for studies that followed up ≥ 100 subjects for ≥ 1 year and reported at ≥ 1 hazard ratio (HR) of interest. Risk estimates for the presence of significant coronary stenosis (primary endpoint; ≥ 50% diameter stenosis), left main coronary artery stenosis, each coronary stenosis, 3-vessel disease, any plaque, per coronary segment containing plaque, and noncalcified plaque were derived in random effect regression analysis, and causes of heterogeneity were determined in meta-regression analysis. We identified 11 eligible articles including 7,335 participants (age 59.1 ± 2.6 years, 62.8% male) with suspected coronary artery disease. The presence of ≥ 1 significant coronary stenosis (9 studies, 3,670 participants, and 252 outcome events [6.8%] with 62% revascularizations) was associated with an annualized event rate of 11.9% (6.4% in studies excluding revascularization). The corresponding HR was 10.74 (98% confidence interval [CI]: 6.37 to 18.11) and 6.15 (95% CI: 3.22 to 11.74) in studies excluding revascularization. Adjustment for coronary calcification did not attenuate the prognostic significance (p = 0.79). The estimated HRs for left main stenosis, presence of plaque, and each coronary segment containing plaque were 6.64 (95% CI: 2.6 to 17.3), 4.51 (95% CI: 2.2 to 9.3), and 1.23 (95% CI: 1.17 to 1.29), respectively. Presence and extent of coronary artery disease on coronary computed tomography angiography are strong, independent predictors of cardiovascular events despite heterogeneity in endpoints, categorization of computed tomography findings, and study population.

The role of multi-slice computed tomography in stable angina management: a current perspective

Contrast-enhanced CT coronary angiography (CTCA) has evolved as a reliable alternative imaging modality technique and may be the preferred initial diagnostic test in patients with stable angina with intermediate pre-test probability of CAD. However, because CTCA is moderately predictive for indicating the functional significance of a lesion, the combination of anatomic and functional imaging will become increasingly important. The technology will continue to improve with better spatial and temporal resolution at low radiation exposure, and CTCA may eventually replace invasive coronary angiography. The establishment of the precise role of CTCA in the diagnosis and management of patients with stable angina requires high-quality randomised study designs with clinical outcomes as a primary outcome.

Vitamin D deficiency is associated with significant coronary stenoses in asymptomatic African American chronic cocaine users

BackgroundChronic cocaine use may lead to premature atherosclerosis, however, the prevalence of and risk factors for coronary artery disease in asymptomatic cocaine users have not been reported. MethodsBetween August 2007 and June 2010, 385 African American chronic cocaine users aged 25 to 54years were consecutively enrolled in a study to investigate the prevalence of CT angiographically-defined significant (≥50%) coronary stenosis and related risk factors. Sociodemographic, drug-use behavior, medical history and medication data were obtained by interview and confirmed by medical chart review. Clinical examinations were performed as well as extensive laboratory tests including those for fasting lipid profiles, HIV, high sensitivity C-reactive protein, and vitamin D. Contrast-enhanced coronary CT angiography was performed. ResultsSignificant coronary stenosis was detected in 52 of 385 participants (13.5%). The prevalences were 12% and 30% in those with low risk and with middle–high risk Framingham score, respectively. In those with low risk scores, the prevalences of significant stenosis were 10% and 18% in those without and with vitamin D deficiency, defined as serum 25-(OH) vitamin D<10ng/mL (p=0.08). Multiple logistic regression analysis revealed that vitamin D deficiency (adjusted OR=2.18, 95% CI: 1.07–4.43) is independently associated with the presence of significant coronary stenosis after controlling for traditional risk factors. ConclusionsThe study indicates that the prevalence of significant coronary stenoses is high in asymptomatic young and middle-aged African American chronic cocaine users. These findings emphasize the importance of aggressive reduction of risk factors, including vitamin D deficiency in this population.

Contrast Enhanced Cardiac CT May Be Used to Accurately Measure the Coronary Calcium Score

Introduction: Coronary artery calcium score (CACS) measurement is a well validated and commonly used prognostic tool that currently requires a second noncontrast scan in additional to contrast enhanced CT coronary angiography. We present the final results of a prospectively registered validation study of a new technique tomeasure the coronary calcium score froma single contrast-enhanced cardiac CT. Methods: Paired contrast enhanced and calcium score scans from 120 sequential patients were prospectively analysed. All scans were performed using a wide-volume 320-detector row CT scanner. Eleven contrast scans were excluded due to pre-specified exclusion criteria of complete coronary occlusion or excessive image noise. The volume of intramural coronary calcium above 320 regional myocardial dysfunction. Cardiac MRI (CMR) accurately evaluates LV morphology and can assess myocardial injury using late gadolinium enhancement (LGE). Although studies during the acute phase of ABS havedocumentedLGE, data is lacking regarding longterm sequelae. Methods: We retrospectively reviewed a cohort of ABS patients who had undergone convalescent CMR (>10 days since admission). Results: Thirty-two patients (mean age 64± 10 yrs) underwent convalescent CMR, and 94% were female. The average peak troponin I = 5.14± 6.39, and mean time to CMR=122± 206 days. LV volumetric analysis was normal with ejection fraction 63± 6%, EDV=127± 27mL andESV 48± 14mL. LGE was noted in four cases (12.5%), and all had a pattern which was non-coronary in distribution. In three cases the LGE was limited to the apical segments of which two notably involved all four apical segments with diffuse transmyocardial enhancement not typical of either ischaemic injury or myocarditis (figure). The apical location correlates to the acute wall motion abnormality – although convalescent wall motion was normal in all. One case had basal septal LGE, also with normal wall motion. Patients with LGE were similar to those without with respect to age, sex, peak troponin and LV volumes.

Assessment of Agatston Coronary Artery Calcium Score Using Contrast-Enhanced CT Coronary Angiography

The purpose of this article is to evaluate to what extent Agatston scores may be derived from CT coronary angiography (CTA) examinations, compared with traditional unenhanced CT calcium scores. Fifty patients with a CT calcium score-Agatston score of zero and 50 patients with a CT calcium score-Agatston score of 1 or greater whose CT calcium scores had been calculated and who had undergone CTA using volumetric 320-MDCT were included. Agatston scores were obtained at 3.0-mm slices for CT calcium score and CTA. Method agreement, interobserver agreement, and diagnostic performance of CTA for detecting coronary calcium were evaluated. Of 50 patients with a positive CT calcium score-Agatston score, coronary artery calcium was detected with CTA in 43 patients by observer 1 (mean CTA score, 102 ± 202; mean CT calcium score, 254 ± 501) and in 46 patients by observer 2 (mean CTA score, 94 ± 147; mean CT calcium score, 272 ± 531). Of the 50 patients with a CT calcium score-Agatston score of zero, 49 (98%, observer 1) and 50 (100%, observer 2) had a zero score with CTA as well. An intraclass correlation of 0.78 and 0.62 was found between CT calcium score and CTA (p < 0.01), whereas higher Agatston scores were underestimated with CTA. For observer 1, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for detection of coronary calcium with CTA were 86%, 98%, 98%, 88%, and 92%, respectively, and the corresponding values for observer 2 were 92%, 100%, 100%, 93%, and 96%, respectively. Interobserver agreement was 0.996 for CT calcium score and 0.93 for CTA. Coronary artery calcium can be detected on CTA images with high accuracy. The Agatston calcium score derived from CTA images shows good correlation with unenhanced CT calcium score and is highly reproducible. However, higher Agatston scores are systematically underestimated when derived from CTA images.

The BioImage Study: Novel approaches to risk assessment in the primary prevention of atherosclerotic cardiovascular disease—study design and objectives

The identification of asymptomatic individuals at risk for near-term atherothrombotic events to ensure optimal preventive treatment remains a challenging goal. In the BioImage Study, novel approaches are tested in a typical health-plan population. Based on certain demographic and risk characteristics on file with Humana Inc, a total of 7,687 men 55 to 80 years of age and women 60 to 80 years of age without evidence of atherothrombotic disease but presumed to be at risk for near-term atherothrombotic events were enrolled between January 2008 and June 2009. Those who met the prespecified eligibility criteria were randomized to a telephonic health survey only (survey only: n = 865), standard risk assessment (Framingham only: n = 718), or comprehensive risk assessment in a dedicated mobile facility equipped with advanced imaging tools (n = 6,104). Baseline examination included assessment of cardiovascular risk factors and screening for subclinical (asymptomatic) atherosclerosis with quantification of coronary artery calcification by computed tomography (CT), measurement of intima-media thickness, presence of carotid atherosclerotic plaques and abdominal aortic aneurysm by ultrasound, and ankle brachial index. Participants with one or more abnormal screening test results underwent advanced imaging with contrast-enhanced magnetic resonance imaging for carotid and aortic plaques, contrast-enhanced coronary CT angiography for luminal stenosis and noncalcified plaques, and 18F-fluorodeoxyglucose-positron emission tomography/CT for carotid and aortic plaque inflammation. Plasma, PAXgene RNA, and DNA samples were obtained, frozen, and stored for future biomarker discovery studies. All individuals will be followed until 600 major atherothrombotic events have occurred in those undergoing imaging. The BioImage Study will help identify those patients with subclinical atherosclerosis who are at risk for near-term atherothrombotic events and enable a more personalized management of care.

Imaging of coronary atherosclerosis by computed tomography

Modern computed tomography (CT) systems afford sufficient spatial and temporal resolution for imaging of the heart and coronary arteries. The detection of coronary artery calcium (CAC) is relatively straightforward and it is applied to detect and quantify subclinical coronary atherosclerosis even in asymptomatic individuals. A large body of evidence has accumulated that uniformly attests to a high predictive value of CAC for future cardiac events. More complex data acquisition protocols, which require higher spatial and temporal resolution, specific patient preparation, and the intravenous injection of contrast agent, allow to perform coronary CT angiography (CTA). With CTA, the presence of luminal stenoses and, given sufficient image quality, calcified as well as non-calcified atherosclerotic plaque can be visualized. Initial studies have shown that certain plaque characteristics, such as positive remodelling or very low CT attenuation, are associated with plaque vulnerability. So far, the available clinical data are not sufficient to draw specific conclusions as to the risk-benefit ratio of contrast-enhanced coronary CTA for risk prediction, especially for asymptomatic individuals. Hence, CTA is currently not recommended for risk stratification purposes. However, the technology of coronary CTA continues to evolve at a rapid pace and clinical applications for plaque imaging and characterization may become possible in the future.

Variation in atherosclerotic plaque composition according to increasing coronary artery calcium scores on computed tomography angiography

Increasing coronary artery calcium scores (CACS) are independently associated with cardiac events. Recent advents in coronary computed tomography angiography (CCTA) have allowed us to better characterize individual plaque. Currently, it is unknown if higher CACS are likely to be associated with more calcified or mixed and heterogeneous plaque burden on CCTA. The study population consisted of 1,043 South Korean asymptomatic subjects (49 ± 10 years, 62% men) who underwent CCTA (64-slice MDCT). Plaques were classified on contrast-enhanced CCTA as non-calcified, mixed, and calcified on a per-segment basis according to the modified American Heart Association classification. The majority of the study participants had no coronary calcification (n = 866, 83%), whereas CACS> 0 was observed in 177 participants (17%). Only 40 (5%) participants in absence of CACS had exclusively non-calcified plaque, whereas 10 (1.2%) had significant coronary artery disease. With increasing CACS, study participants were more likely to have exclusively mixed or combination atherosclerotic plaques (P = 0.001). Among individuals with CACS 1-10, the prevalence of at least two coronary segments with mixed plaques was 4%, increasing up to 18 and 41% with CACS of 11-100 and >100. The respective prevalence of ≥2 coronary segments (calcified plaques) with increasing CACS were 6%, 16 and 26% (P = 0.01) and of non-calcified plaques were 6%, 6 and 11% (P = 0.71). In multivariable adjusted analyses, those with CACS >100 were 7.17 times (95% CI: 1.36-37.68) more likely to have ≥2 coronary segments with calcified plaque comparing with CACS 1-10. On the other hand the respective risk was higher for presence of ≥2 segments with mixed plaques (odds ratio: 15.81, 95% CI: 3.14-79.58). Absence of CAC is associated with a negligible presence of any atherosclerotic disease as detected by CCTA in asymptomatic population. A higher CACS is more likely to be associated with heterogeneous coronary plaque (combination of calcified, non-calcified, and mixed plaques), and appears to be more strongly associated with a higher burden of mixed plaque.

Characterization of culprit lesions in acute coronary syndromes using coronary dual-source CT angiography

Objective We analyzed typical morphological features of coronary atherosclerotic plaques in acute coronary syndromes (ACS) using contrast-enhanced coronary Dual-Source CT angiography (CTA) in comparison to stable coronary lesions. Patients and methods Fifty-five patients with ACS and 55 controls with stable angina pectoris (SAP) with similar atherosclerotic risk profile were studied. CT angiography was performed using a Dual-Source CT scanner (330 ms rotation, 2 × 64 × 0.6 mm collimation, 60–80 mL contrast agent i.v. at 6 mL/s) before invasive catheterization. We analyzed plaque volume (mm 3), mean and minimal CT density (HU), remodeling index, plaque type (calcified/non-calcified/mixed) and presence of “spotty” calcifications as well as presence of contrast rims. Results In patients with ACS and SAP, 28 and 10 lesions showed both calcified and non-calcified components, but in a greater proportion of non-calcified material, 6 and 23 lesions showed a greater proportion of calcified material and 21 and 8 lesions were completely non-calcified, respectively. None of the culprit plaques in ACS and 14 of the lesions in SAP were completely calcified. A “spotty” pattern of calcification within the plaque and a central filling defect surrounded by a rim of contrast were present in 11 and 14 of 55 ACS cases, but never in SAP lesions. For culprit lesions in ACS and for lesions in patients with SAP, mean plaque volumes were 192.8 ± 114.9 mm 3 and 103.8 ± 51.8 mm 3 ( p = 0.001), mean and minimal CT densities were 85.6 ± 45.1 HU and 47.2 ± 33.7 HU versus 143.8 ± 104.1 HU and 95.9 ± 84.0 HU ( p < 0.01) and mean remodeling indices were 1.6 ± 0.4 and 0.97 ± 0.17 ( p < 0.001), respectively. Conclusion Plaques of culprit lesions in ACS show specific morphologic characteristics in non-invasive coronary CT angiography. As compared to stable lesions, culprit lesions in ACS display greater proportion of non-calcified material and presence of “spotty” calcifications/contrast rims as well as larger plaque volumes, lower CT attenuation and higher remodeling indices.

Usefulness of Age and Gender in the Early Triage of Patients With Acute Chest Pain Having Cardiac Computed Tomographic Angiography

To identify the age- and gender-specific subpopulations of patients with acute chest pain in whom coronary computed tomographic angiography (CTA) will yield the greatest diagnostic benefit. Subjects with acute chest pain and an inconclusive initial evaluation (nondiagnostic electrocardiograhic findings, negative cardiac biomarkers) underwent contrast-enhanced 64-slice coronary CTA as a part of an observational cohort study. Independent investigators determined the presence of significant coronary stenosis (>50% luminal narrowing) and the occurrence of acute coronary syndrome (ACS) during the index hospitalization. We determined the diagnostic accuracy and effect on pretest probability of ACS using Bayes' theorem by age and gender. Of 368 patients (age 52.7 +/- 12 years, 61% men), 8% had ACS. The presence of significant coronary stenosis on CTA and the occurrence of ACS increased with age for both men and women (p <0.001). Cardiac CTA was highly sensitive and specific in women <65 years of age (sensitivity 100% and specificity >87%) and men <55 years of age (sensitivity 100% for men <45 years and 80% for men 45 to 54 years old; specificity >88.2%). Moreover, in these patients, coronary CTA led to restratification from low to high risk (for positive findings on CTA) or from low to very low risk (for negative findings on CTA). In contrast, a negative result on CTA did not result in restratification to a low-risk category in women >65 years and men >55 years old. In conclusion, the present analysis provides initial evidence that men <55 years and women <65 years might benefit more from cardiac CTA than older patients. Thus, age and gender might serve as simple criteria to appropriately select patients who would derive the greatest diagnostic benefit from coronary CTA in the setting of acute chest pain.

Abstract 2004: Usefulness of Coronary CT Angiography in the Early Triage of Patients with Acute Chest Pain

Background: Early triage of patients with acute chest pain in the emergency department (ED) may be improved by rapid noninvasive assessment of coronary artery disease (CAD) by coronary computed tomography angiography (CTA). We sought to determine the usefulness of coronary CTA for the early triage of patients with acute chest pain but an inconclusive initial ED evaluation. Methods: Single center, double-blinded observational cohort study in the ED of a large tertiary academic hospital enrolling 368 consecutive patients with acute chest pain and inconclusive initial ED evaluation (normal initial troponin and an initial ECG without evidence of myocardial ischemia) who were awaiting hospital admission between May 2005 and May 2007. All patients underwent 64-slice contrast-enhanced coronary CTA prior to hospital admission with caregivers and patients blinded to the results of the examination. Diagnostic accuracy and discriminatory power of coronary CTA findings (coronary plaque and stenosis [&gt;50% luminal narrowing]) for acute coronary syndrome (ACS) during index hospitalization and major adverse cardiac events (MACE) during 6- month follow-up. Results: Among 368 patients (mean age 53±12 years, 61% male) 31 (8%) developed ACS but no MACE occurred during follow-up. Fifty percent (n=183) of the study population had neither plaque nor stenosis, a finding which had 100% negative predictive value (95% confidence interval [CI]: 98 to 100%) for ACS. In adjusted analysis, the extent of coronary plaque and presence of stenosis were associated with an increased risk for ACS (OR: 1.28, 95% CI: 1.14 to 1.43 and OR: 11.69, 95% CI: 4.4 to 31.0; respectively). Coronary CT findings (no CAD, plaque but no stenosis, and stenosis) discriminated patients at low, intermediate, or high risk of ACS (OR: 8.65, 95% CI: 3.69 to 20.26; AUC: 0.91). Conclusion : Half of the patients with acute chest pain and low to intermediate likelihood of ACS have no CAD and may be safely discharged directly from the ED. Coronary CT has excellent discriminatory power in defining patient risk for ACS.

Volumetric measurement of pericardial adipose tissue from contrast-enhanced coronary computed tomography angiography: A reproducibility study

Pericardial adipose tissue may exert unique metabolic and cardiovascular risks in patients. The use of cardiac multidetector computed tomography (MDCT) imaging may enable the accurate localization and quantification of pericardial and intrathoracic adipose tissue. The reproducibility of electrocardiogram-gated high-resolution cardiac MDCT-based volumetric quantification of pericardial and intrathoracic adipose tissue has not been reported. We included 100 consecutive patients (age 54.5 +/- 12.0 yr, 60% men) who underwent a standard contrast-enhanced coronary CT for the evaluation of coronary artery plaque and stenosis (64-slice MDCT, temporal resolution: 210 ms, spatial resolution: 0.6 mm, 850 mAs, 120, kvp) after a presentation of acute chest pain. Two independent observers measured intrathoracic (IAT) and pericardial adipose tissue (PAT) by using a semiautomatic segmentation algorithm based on three-dimensional analysis. Inter-reader reproducibility was excellent (relative difference: 7.35 +/- 7.22% for PAT and 6.23 +/- 4.91% for IAT, intraclass correlation 0.98 each). Similar results were obtained for intra-observer reproducibility (relative difference: 5.18 +/- 5.19% for PAT and 4.34 +/- 4.12% for IAT, intraclass correlation 0.99 each). This study demonstrates that MDCT-based 3D semiautomatic segmentation for volumetric quantification of PAT and IAT is highly reproducible. Further research is warranted to assess whether volumetric measurements may substantially improve the predictive value of obesity measures for insulin resistance, type 2 diabetes mellitus, and cardiovascular diseases.

Nichtinvasive Untersuchung der Herzkranzgefäße mittels Mehrzeilen-Spiral-CT

Multi-detector computed tomography (MDCT) techniques have been improved rapidly during the last decade. Beside a high spatial and temporal resolution, newest scanner generations provide a fast volume coverage which allows imaging of the heart and the visualization of the coronary arteries in less than 10 seconds. However, despite numerous studies concerning the detection of coronary artery calcifications, the clinical role of CT for the evaluation of the coronary arteries has to be defined. Current statements of the American College of Cardiology and the American Heart Association discuss the possible clinical use of MDCT for the evaluation of coronary artery disease. Besides the detection of coronary artery calcifications as a sub-clinical marker for the presence of coronary artery atherosclerosis with a strong predictive value for future cardiovascular events, contrast-enhanced CT coronary angiography has demonstrated its ability to reliably exclude significant coronary artery stenoses in patients with a low to intermediate pre-test likelihood. This article will provide a brief summary of clinical data and possible indications of MDCT for the evaluation of the coronary arteries.

Catheter contrast-enhanced coronary CT-angiography using an aortic root injection- preliminary technical development in four patients

The feasibility of performing coronary computed tomographic angiography (CTA) with an intra-aortic injection of iodinated contrast was tested in four patients immediately following diagnostic cardiac catheterization and placement of a 6-french pigtail catheter into the aortic root. A diluted contrast mixture [75 cc Omnipaque 350 mixed with 125 cc normal saline (4-slice scanner) vs. 40 cc Omnipaque 350 mixed with 60 cc normal saline (16-slice scanner)] was injected at a rate of 6 to 7.7 cc/sec at the onset of breath-hold and helical (4 slice, n=3, and 16-slice, n=1) retrospective ECG-triggered acquisition. The proximal and distal coronary vasculature including small tributaries were depicted with high signal-to-noise (S/N) and free from underlying blood pool enhancement. The right coronary artery was sub optimally enhanced in two patients. No significant disease was found on CTA or XRA in two patients; however, severe multivessel disease was demonstrated on both modalities in two patients. Catheter contrast-enhanced coronary CTA is feasible utilizing low injection rates and low iodinated contrast volumes, however, catheter modifications are required for consistent and homogeneous opacification of the aortic root.

Current Results and New Developments of Coronary Angiography With Use of Contrast-Enhanced Computed Tomography of the Heart

Electron beam computed tomography (EBCT) is the reference standard for x-ray-based tomographic imaging of the heart because of its high temporal resolution, but it is available in only a few centers. Quantification of coronary calcium is the most widely recognized use of EBCT for cardiac imaging. This technique requires no contrast media and provides an accurate assessment of overall plaque burden in the coronary tree; however, it does not directly identify or localize coronary stenoses. Multislice spiral (helical) CT (MSCT) is a new technology that provides images of the beating heart in diagnostic quality under many circumstances and may facilitate the broader application of cardiac and coronary CT. Currently, for imaging of the heart, much more experience exists with EBCT than with MSCT. Contrast-enhanced CT coronary angiography (CTCA) can be done with EBCT or MSCT to obtain images of the major branches of the coronary tree and to define luminal narrowing. Studies at experienced centers performed with small numbers of patients show that sensitivity, specificity, and negative predictive value are good with CTCA in the assessment of obstructive coronary artery disease, but CTCA remains an investigational technique for these applications. Computed tomographic coronary angiography can be clinically useful for assessing coronary artery bypass graft patency and congenital coronary abnormalities.