Coronary plaque burden detected by multislice computed tomography after acute myocardial infarction with near-normal coronary arteries by angiography

Effect of heart rate on the diagnostic accuracy of 256-slice computed tomography angiography in the detection of coronary artery stenosis: ROC curve analysis

The aim of the present study was to investigate the effect of heart rate (HR) on the diagnostic accuracy of 256-slice computed tomography angiography (CTA) in the detection of coronary artery stenosis. Coronary imaging was performed using a Philips 256-slice spiral CT, and receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic value of 256-slice CTA in coronary artery stenosis. The HR of the research subjects in the study was within a certain range (39-107 bpm). One hundred patients suspected of coronary heart disease underwent 256-slice CTA examination. The cases were divided into three groups: Low HR (HR <75 bpm), moderate HR (75≤ HR <90 bpm) and high HR (HR ≥90 bpm). For the three groups, two observers independently assessed the image quality for all coronary segments on a four-point ordinal scale. An image quality of grades 1-3 was considered diagnostic, while grade 4 was non-diagnostic. A total of 97.76% of the images were diagnostic in the low-HR group, 96.86% in the moderate-HR group and 95.80% in the high-HR group. According to the ROC curve analysis, the specificity of CTA in diagnosing coronary artery stenosis was 98.40, 96.00 and 97.60% in the low-, moderate- and high-HR groups, respectively. In conclusion, 256-slice coronary CTA can be used to clearly show the main segments of the coronary artery and to effectively diagnose coronary artery stenosis. Within the range of HRs investigated, HR was found to have no significant effect on the diagnostic accuracy of 256-slice coronary CTA for coronary artery stenosis.

Takotsubo cardiomyopathy: how much do we know of this syndrome in children and young adults?

Since Takotsubo cardiomyopathy was first described by Sato in 1990, multiple cases have been reported, but only few in children, among whom this type of cardiomyopathy is to some extent underappreciated. A series of children with this syndrome were therefore reviewed, drawing comparison with cases reported by others. The review addresses the current challenges in diagnosis, presentation, triggers, clinical course, management, and possible pathogenic mechanisms of the entity.

Coronary plaque burden, as determined by cardiac computed tomography, in patients with myocardial infarction and angiographically normal coronary arteries compared to healthy volunteers: a prospective multicenter observational study

Objectives

Patients presenting with acute myocardial infarction and angiographically normal coronary arteries (MINCA) represent a diagnostic and a therapeutic challenge. Cardiac computed tomography (CT) allows detection of coronary artery disease (CAD) even in the absence of significant stenosis. We aimed to investigate whether patients suffering from MINCA had a greater coronary plaque burden, as determined by cardiac CT, than a matched group of healthy volunteers.

Methods

Consecutive patients, aged 45 to 70, with MINCA were enrolled in the Stockholm metropolitan area. Patients with myocarditis were excluded using cardiovascular magnetic resonance imaging. Remaining patients underwent cardiac CT, as did a reference group of healthy volunteers matched by age and gender, with no known cardiovascular disease. Plaque burden was evaluated semi-quantitatively on a per patient and a per segment level.

Results

Despite a higher prevalence of smoking and hypertension, patients with MINCA did not have more CAD than healthy volunteers. Among 57 MINCA patients and 58 volunteers no signs of CAD were found in 24 (42%) and 25 (43%) respectively. On a per segment level, MINCA patients had less segments with stenosis ≥20% (2% vs. 5%, p<0.01), as well as a smaller proportion of large (2% vs. 4%, p<0.05) and mixed type plaques (1% vs. 4%, p<0.01). The median coronary calcium score did not differ between MINCA patients and healthy volunteers (6 vs. 8, ns).

Conclusions

MINCA patients with no or minimal angiographic stenosis do not have more coronary atherosclerosis than healthy volunteers, and a large proportion of these patients do not have any signs of CAD, as determined by cardiac CT. The MINCA patient group is probably heterogeneous, with a variety of different underlying mechanisms. Non-obstructive CAD is most likely not the most prevalent cause of myocardial infarction in this patient group.

Comparison of outcomes in patients with ST-segment elevation myocardial infarction discharged on versus not on statin therapy (from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction Trial)

Statin therapy is indicated after ST-segment elevation myocardial infarction (STEMI) to reduce recurrent ischemic events, but approximately 6% of patients with STEMI do not receive a statin prescription at discharge. This substudy aimed to define the clinical outcomes and patient characteristics associated with statin nonprescription after STEMI. We compared clinical, angiographic, and procedural characteristics and in-hospital, 30-day, 1-year, 2-year, and 3-year outcomes in 3,512 patients discharged after STEMI with and without (6%) statin prescriptions in the harmonizing outcomes with revascularization and stents in acute myocardial infarction trial (www.clinicaltrials.gov, NCT00433966). Statin nonprescription was associated with female sex, nonwhite race, previous bypass surgery, heart failure, renal impairment, anemia, thrombocytopenia, care in the United States, lower prescription rates of antiplatelets and neurohormonal antagonists, less percutaneous coronary intervention and stents, and, in 26% of cases, angiographically normal or nonobstructed coronary arteries. At every time point of follow-up after discharge, patients with no discharge statin prescription had significantly higher rates of net adverse clinical events, major adverse cardiac events, major bleeding unrelated to bypass surgery, and death. After multivariable adjustment, absence of a discharge statin prescription independently predicted 3-year major adverse cardiac event (hazard ratio 1.54, 95% confidence interval 1.15 to 2.07, p=0.0037) and death (hazard ratio 2.30, 95% confidence interval 1.41 to 3.77, p=0.0009). In conclusion, within the framework of this randomized trial of patients presenting with STEMI, approximately 6% of patients were discharged without statin therapy. Absence of a discharge statin prescription after STEMI was an independent predictor of ischemic events including death.

Long-term prognosis of patients presenting with ST-segment elevation myocardial infarction with no significant coronary artery disease (from the HORIZONS-AMI trial)

The clinical features and prognosis of patients with ST-segment elevation myocardial infarction (STEMI) and no significant coronary artery disease (CAD) have not been well studied. We examined the outcomes of patients with STEMI in the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial according to the presence or absence of significant CAD. "No-CAD" was defined by the absence of any lesion with a diameter stenosis of ≥30% on quantitative coronary angiography of the baseline coronary angiogram. Of 3,602 patients, 127 (3.5%) had no-CAD. Of these, 86 (67.7%) had angiographically normal coronary arteries, and 41 (32.3%) had mild disease (diameter stenosis <30%). Eight patients had previously been treated with coronary artery bypass grafting. Compared to patients with CAD, patients with no-CAD were younger, had a lower body mass index, were more frequently black, had a lower prevalence of smoking and previous angina, and had a greater left ventricular ejection fraction. Cardiac enzymes were elevated in fewer patients with no-CAD than in those with CAD (63.2% vs 98.7%, p <0.001). At 3 years of follow-up, the patients with no-CAD versus CAD had lower rates of major adverse cardiovascular events (7.7% vs 22.2%, p = 0.002), net adverse clinical events (major adverse cardiovascular events or major bleeding not related to coronary artery bypass grafting, 12.5% vs 26.9%, p = 0.005), and postprocedure coronary revascularization (0% vs 19.5%, p <0.001). The differences in the rates of death or reinfarction, stroke, and major bleeding were not statistically significant. In conclusion, 3.5% of patients with STEMI had no significant CAD. The 3-year prognosis for these patients was favorable compared to that of patients with STEMI and with obstructive CAD.

The impact of aging and atherosclerotic risk factors on transthoracic coronary flow reserve in subjects with normal coronary angiography

Age may affect coronary flow reserve (CFR) especially in subjects with atherosclerotic risk factors (ARFs). The aim of this prospective, multicenter, observational study was to determine the effects of aging on CFR in patients with normal epicardial coronary arteries and ARFs. Three-hundred-thirty-five subjects (mean age = 61 years) with at least one ARF but normal coronary angiography underwent high-dose dipyridamole stress-echo with Doppler evaluation of left anterior descending artery. CFR was calculated as the ratio between hyperemic and resting coronary diastolic peak velocities. Patients were divided in age quartiles. CFR was progressively reduced with aging (1st quartile: 3.01 ± 0.69, 4th quartile: 2.39 ± 0.49, p < 0.001). This was mainly due to a gradual increase of resting velocities (1st quartile = 26.3 ± 6.1 cm/s, 4th quartile = 30.2 ± 6.4 cm/s, p < 0.001) while the reduction of hyperemic velocities remained unaffected (1st quartile = 77.7 ± 18.9 cm/s, 4th quartile = 70.9 ± 18.4 cm/s, NS). When age quartiles and ARFs were entered into a regression model, third and fourth age quartile (p < 0.0005 and p < 0.0001 respectively), left ventricular mass index (p < 0.0001), diastolic blood pressure (p < 0.001), total cholesterol (p < 0.002), fasting blood glucose (p < 0.01) and male gender (p < 0.05) were independent determinants of CFR in the whole population. Aging reduces coronary flow reserve in patients with angiographically normal coronary arteries due to a gradual increase of resting coronary flow velocity. CFR is also affected by atherosclerotic risk factors and left ventricular hypertrophy.

Takotsubo cardiomyopathy--the current state of knowledge

Takotsubo cardiomyopathy is defined as acute chest pain during stressful incidents which is associated with ST-segment abnormalities and/or increased serum troponin levels. There is also regressive systolic dysfunction which is usually localized in the apical and medial left ventricles but there are no significant coronary artery lesions. The ventricular asynergy is also described in the right ventricle but is less common. Almost all the patients are women. The onset of this disease is typically triggered by an acute emotional or stress event or by an accumulation of trivial and repetitive stresses. The etiology of this syndrome remains unclear. Myocardial ischemia and reperfusion due to microvascular spasm, aborted myocardial infarction and related no-reflow phenomenon have been proposed as inducers of Takotsubo cardiomyopathy. The temporal relationship between the stressful event and the triggering of the clinical syndrome as well as the report of elevated catecholamine plasma levels during the acute phase suggest a possible involvement of the sympathetic nervous system. A smaller left ventricular size and hormonal disturbances in women may also play a role.

Cardiac multi-detector CT: its unique contribution to cardiology practice

Medical practice is moving fast towards non-invasive and non-surgical disease management. While significant progress has been made with coronary artery disease prevention, MDCT stands as an ideal non-invasive tool for its progression. It accurately assesses both arterial lumen and wall disease. Although the main concern of current cardiology practice is the coronary stenotic disease, arterial wall calcification itself may significantly contribute to patients' symptoms. Thus, in addition to the beneficial use of MDCT in patients with mild to moderate risk for coronary disease, the unique information it provides on wall disease may assist the management of symptomatic patients with no flow-limiting lesions.

Applications of multislice coronary computed tomographic angiography to percutaneous coronary intervention: how did we ever do without it?

By providing data previously available only by intravascular ultrasound, 64-slice multidetector computed tomographic angiography (CTA) will impact percutaneous coronary intervention (PCI) in multiple areas: (1) pre-PCI patient selection; (2) identification of significant lesions; (3) in-stent restenosis; (4) procedure planning: stent sizing, choice of intervention, and equipment, chronic total occlusions, 3D-CTA in the catheterization laboratory; (5) plaque evaluation and identification of high-risk lesions; (6) postcatheterization decisions, and (7) structural heart disease. The likely outcome is transformation of the catheterization laboratory into a streamlined interventional suite, utilizing on-line CTA data in an interactive format.

Imaging techniques for the vulnerable coronary plaque

The goal of this article is to illustrate the main invasive and noninvasive diagnostic modalities to image the vulnerable coronary plaque, which is responsible for acute coronary syndrome. The main epidemiologic and histological issues are briefly discussed in order to provide an adequate background. Comprehensive coronary atherosclerosis imaging should involve visualization of the entire coronary artery tree and plaque characterization, including three-dimensional morphology, relationship with the lumen, composition, vascular remodelling and presence of inflammation. No single technique provides such a comprehensive description, and no available modality extensively identifies the vulnerable plaque. In particular, we describe multislice computed tomography, which at present seems to be the most promising noninvasive tool for an exhaustive image-based quantification of coronary atherosclerosis.

Atherosclerotic Plaque Characterization by Multidetector Row Computed Tomography Angiography

Multidetector row computed tomography angiography (MDCTA) is seen as a potential alternative to current imaging methods for the assessment of vessel anatomy and atherosclerotic plaque composition/morphology in a great variety of arterial beds. Recent advances represented by the increase in gantry speed to <500 ms per rotation and in the number of detector rows from 4 to 64, in addition to the decrease in slice thickness to submillimetric levels, brought significant improvement in diagnostic accuracy by coronary MDCTA. In general, it has a good correlation with both intravascular ultrasound (IVUS) and histopathology for discrimination between soft, intermediate, and calcified plaques. Plaque area and volume tend to be underestimated by 12-detector row MDCTA and overestimated by 16-detector row MDCTA, but the number of patients studied so far is relatively small. However, it seems that 64-detector row MDCTA can measure plaque area and volume with greater accuracy. Plaque remodeling is overestimated in small vessels by 12-detector row MDCTA, whereas 16- and 64-detector row MDCTA show a good correlation with IVUS. Although still under development, the potential of MDCTA to characterize atherosclerotic plaque composition as well as to precisely determine plaque area, volume, and remodeling in the future is quite promising.

Computed Tomographic Angiography of the Coronary Arteries: Techniques and Applications

Computed tomographic coronary angiography (CT-CA) is a direct but minimally invasive method of visualizing coronary arteries. Multidetector-row computed tomography (MDCT) is currently the CT modality most commonly used for coronary artery imaging. MDCT has been successfully used to detect stenoses in coronary arteries and coronary artery bypass grafts and to assess congenital coronary anomalies. Patients should not undergo CT-CA with MDCT if they have an irregular heart rhythm, a heart rate greater than 70 beats/min, and contraindications to pharmacologic agents for heart rate control, or if they have severe coronary artery disease or are likely to require revascularization.

[Multislice computed tomography to detect coronary stenosis among asymptomatic patients with cardiovascular risk factors and equivocal prior stress test: preliminary study]

Multislice computed tomography (MSCT) is a non-invasive and validated technique to detect coronary stenoses. Some questions remain about its accuracy to detect coronary stenoses (CS), especially for asymptomatic patients (P) when a prior stress test isn't conclusive.

METHODS

MSCT was performed among 45 asymptomatic men (mean age: 58,3 +/- 16), with a high ten year risk of fatal cardiovascular disease (SCORE 2003 data for low-risk regions of Europe), without any previous coronary history and with previous non conclusive exercise testing. When significant (> 50%) CS was suspected at MSCT, an angiocoronarography (AC) was done.

RESULTS

Eighteen MSCT were normal, unsignificant CS (< 50%) were detected on 14 MSCT and significant coronary stenoses (SCS) for 13 P. Among this 13 P, 19 SCS were identified: 2 SCS of left main coronary artery (CA), 9 of the left descending CA, 6 of the right CA and 2 of the left circumflex CA. 13 CS were confirmed at AC. Finally, because of critical angiographic lesions +/- ischemia at nuclear tomoscintigraphy (NT), 9 P had coronary revascularization (7 catheter based, 2 surgical bypass), 4 P had medical treatment.

DISCUSSION

Benefits of this preliminary study are obvious: 9 coronary revascularization/45 P. However, the place of MSCT for the screening of CS is uncertain, but may be usefull as a complement for the screening of coronary arterial disease.

Noninvasive detection of coronary artery disease -- challenges for prevention of disease and clinical events

Atherosclerosis is a chronic inflammatory disease that affects essentially all arterial beds including the aorta, coronaries, carotids, and peripheral arteries. It is the main cause of death in the western hemisphere, due to cardiovascular syndromes such as myocardial infarction, heart failure, and cerebrovascular accidents. Very substantial economic and human resources have been used on treatments of its complications, including imaging studies, coronary bypass surgery, catheter interventions, pacemakers, and medical treatments. Treating complications, however, are remedial actions. A better alternative is to prevent the development of atherosclerosis, or at least to identify patients who are at risk of acute events and intervene before they occur. The aims of this review are to discuss the predictive value of traditional and emerging risk factors, as well as the role of noninvasive diagnostic methods for coronary atherosclerosis, including exercise stress test, echo stress test, duplex ultrasound, computed tomography, and magnetic resonance. A combination of serum biomarkers and noninvasive approaches is of practical utility for identifying early disease. It is to be expected that future developments will soon perfect our ability to identify the vulnerable patient and allow a more individualized approach.

Comparison of lumens of intermediate coronary stenosis using 16-slice computed tomography versus intravascular ultrasound

We aimed to quantify ambiguous coronary stenosis using the minimal lumen area with 16-slice computed tomography compared with intravascular ultrasound. The sensitivity, specificity, and accuracy for significant lesion classification was 68%, 86%, and 78%, respectively. The correlation between intravascular ultrasound and CT minimal lumen area was r = 0.73 (p <0.001), and the 95% confidence interval for CT measurement was -72% to +56%.

Technology Insight: possible applications of multislice computed tomography in clinical cardiology

With the introduction of four-slice scanners in 1999, multislice CT (MSCT) technology became available for investigative examination of the heart. Since then, MSCT technology has undergone rapid technical progress; temporal and spatial resolutions have been especially improved. The improved diagnostic image quality has led to more possible uses of MSCT being defined. At present, issues such as visualization of coronary artery bypass grafts, detection of stenoses of native coronary arteries, description of coronary anomalies, and calcium scoring, can be investigated reasonably well. Other features, such as plaque imaging and visualization of intracoronary stents, need further evaluation. A large number of factors, however, such as heart rate, atrial fibrillation, breathing artefacts and severe calcification, still influence image quality and reduce validity. In this article we provide a summary of current fields of application of cardiac MSCT. The word 'indication' is consciously avoided because official guidelines for the use of MSCT in heart examination have not yet been issued. Hopefully, prospective multicenter trials will be performed soon, providing more data with which to establish guidelines for both cardiologist and radiologist.

Multislice spiral computed tomographic angiography of coronary arteries in patients with suspected coronary artery disease: an effective filter before catheter angiography?

BACKGROUND

Despite impressive image quality, it is unclear if noninvasive coronary angiography with multislice spiral computed tomography (CT) is powerful enough to act as a filter before invasive angiography (INV-A) in symptomatic patients.

METHODS AND RESULTS

We therefore studied 133 consecutive symptomatic patients with suspected coronary artery disease (CAD) and an indication for INV-A (chest pain and signs of ischemia in conventional stress tests). Patients with known CAD, acute coronary syndrome, or a calcium volume score >1000 were excluded. In all patients, both INV-A and multislice CT angiography (MSCT-A) (Philips MX 8000 multislice spiral CT, scan time 250 milliseconds, slice thickness 1.3 mm, 120 mL of contrast agent, 4 mL/s, retrospective gating) were directly compared by 2 independent investigators using the American Heart Association 15-segment model. Altogether, we studied 1596 segments, 74% had diagnostic image quality. Multislice CT angiography correctly identified 68 significant stenoses of the 75 stenoses seen with INV-A (sensitivity 91%). In 945 of 1185 diagnostic segments, stenosis could correctly be ruled out with MSCT-A. There were 3 times more stenoses seen with MSCT-A compared with INV-A (positive predictive value 29%) mainly because of misclassification of nonobstructive plaques as stenosis. The per-patient analysis allowed to exclude significant CAD in 42 (32%) of 133 patients. In only 6 of 53 patients, MSCT-A failed to detect significant stenosis, 4 of those were in small segments not requiring intervention. Calcium scoring alone was less suited as a filter before angiography: 25 patients (18% of study group) had a calcium score = 0, and 8 of these patients turned out to have significant stenoses.

CONCLUSION

Multislice CT angiography, but not calcium scoring alone, offers promise to reduce the number of INV-A in symptomatic patients with suspected CAD by up to one third with minimal risk for the patient.

Visualising noncalcified coronary plaques by CT

Due to a rapid improvement of the new generation submillimetre multislice CT-technology noninvasive tomographic imaging of the coronary vessel wall has become reality. First clinical studies have shown the ability in particular of 16-slice CT to determine plaque burden, plaque composition and compensatory vessel-wall remodelling. These novel findings already constitute an important step forward to assess coronary atherosclerosis noninvasively in a detailed manner which opens promising new opportunities for a better understanding and riskstratification of coronary atherosclerosis. Current limitations, mainly the insufficient accuracy to detect small lesions in distal coronary segments, might be overcome by improved spatial and temporal resolution of the new generation scanners operating with 64 and more detectors.

Characteristics and outcomes of patients with acute myocardial infarction and angiographically normal coronary arteries

This study on patients undergoing coronary angiography for acute myocardial infarction demonstrated that 2.8% of patients had angiographically normal coronary arteries and that these patients have a better prognosis than patients with angiographically verified coronary artery disease. The trend toward a higher prevalence of malignancy in this unique patient group raises the possibility of malignancy-induced hypercoagulability or inflammation as an underlying etiologic factor.

Non-invasive evaluation of atherosclerosis with contrast enhanced 16 slice spiral computed tomography: results of ex vivo investigations

OBJECTIVE

To evaluate the diagnostic accuracy of 16 slice computed tomography (CT) in determining plaque morphology and composition in an experimental setting. The results were compared with histopathological analysis as the reference standard.

METHODS

Nine human popliteal arteries derived from amputations because of atherosclerotic disease were investigated with multislice spiral CT (MSCT). Atherosclerotic lesions were morphologically classified (completely or partially occlusive, concentric, eccentric), and tissue densities were determined within these plaques. In addition, vessel dimensions were quantitatively measured.

RESULTS

The results were compared with histological analysis. The concordance index kappa for morphological classification was 0.88. Plaque density (n = 51 lesions) was significantly different (p < 0.0001) between lipid rich, fibrotic, and calcified lesions (Stary stage III: n = 2, 58 (8) Hounsfield units (HU); Stary V: n = 11, 50 (21) HU; Stary VI: n = 14, 96 (42) HU; Stary VII: n = 6, 858 (263) HU; Stary VIII: n = 18, 126 (99) HU). The concordance index kappa for the classification of plaques based on density was 0.51. Vessel dimensions had a good correlation (r = 0.98).

CONCLUSIONS

16 slice CT was found to be a reliable non-invasive imaging technique for assessing atherosclerotic plaque morphology and composition. Although calcified lesions can be differentiated from non-calcified lesions, the diagnostic accuracy in further subclassifying non-calcified plaques as lipid rich and fibrotic is low, even under experimental conditions.

Comparison of measurement of cross-sectional coronary atherosclerotic plaque and vessel areas by 16-slice multidetector computed tomography versus intravascular ultrasound

In 26 patients, 16-slice multidetector computed tomography (MDCT) with 0.75-mm collimation and intravascular ultrasound (IVUS) of 1 coronary artery were performed. At 100 sites within the coronary arteries, the measurement of cross-sectional luminal area and, if detectable, the cross-sectional area of atherosclerotic plaque was performed independently with IVUS and MDCT. The mean luminal area (r = 0.92), measured at 100 sites, and plaque area (r = 0.55), measured at 65 sites, were significantly correlated (p <0.001) between MDCT and IVUS. The mean luminal area and mean plaque area were slightly but significantly overestimated with MDCT. MDCT permits the noninvasive measurement of coronary cross-sectional luminal and plaque areas with moderate accuracy.

Maladie coronaire : les questions cliniques et les réponses potentielles en scanner multicoupe et en IRM

If the role of multislice CT and MRI is not clearly defined in ischemic heart disease, these new cardiac imaging techniques are very promising due to recent technological advances. The detection of coronary artery plaque and stenosis, as well as coronary bypass graft and stenting patency, the evaluation of left ventricular remodeling after infarction, are available in routine with a 16-slices multislice CT. MRI is the technique of choice to appreciate the impact of a coronary artery lesion on myocardium: detection of ischemia by first-pass perfusion imaging at rest and under pharmacological stress, detection and extension of infarcted myocardium and assessment of myocardial viability. The potential indications will be discussed for each technique in the light of the main clinical questions asked by the cardiologist in daily practice.

[Non-invasive coronary angiography by multidetector spiral computed tomography and magnetic resonance imaging]

Coronary angiography is the reference standard to confirm the presence and severity of coronary stenoses. Given the invasiveness of this procedure, a noninvasive mean allowing to visualize coronary anatomy would be of obvious clinical interest. Multidetector spiral computed tomography and magnetic resonance imaging are new and promising techniques for noninvasive detection of significant coronary stenoses. The purpose of this article is to review the present knowledge on these noninvasive techniques.

Characterization of vulnerable nonstenotic plaque with 16-slice computed tomography compared with intravascular ultrasound

We compared 16-slice computed tomography with intravascular ultrasound in the detection of unstable component characteristics of nonstenotic plaque responsible for acute coronary syndrome. Computed tomography accurately assessed plaque eccentricity, calcification, and remodeling, and intraplaque hypodensity correlated with intravascular ultrasound echolucent area.