Contrast-enhanced Coronary Computed Tomography Angiography Research Articles

Coronary calcium scoring from contrast coronary CT angiography using a semiautomated standardized method

BackgroundWhen coronary calcium scoring is performed in patients with suspected coronary artery disease, a separate noncontrast scan is acquired before contrast-enhanced coronary CT angiography (CTA). ObjectiveOur aim was to develop and validate an automated method for calculating the coronary calcium score (CCS) from coronary CTA. MethodsWe analyzed coronary CTA and noncontrast CT data sets of 84 patients (Agatston score >0). The CCS on noncontrast CT was measured using commercial methods. Coronary calcium volume was measured on coronary CTA using an automated standardized method with scan-specific calcium thresholds. Data sets were split into derivation (n = 40) and validation groups (n = 44). To calculate the CCS on coronary CTA, a conversion factor between calcium scores measured in noncontrast CT and the calcium volume measured on coronary CTA was derived by linear regression. ResultsIn the validation group, the median calculated CCS derived from CTA was 277 and 244 on noncontrast images (P = .12). This CCS showed an excellent correlation with the CCS from noncontrast images (Pearson, r = 0.95). In the validation group, 39 of 44 patients (88.6%) were classified into the same standard category (1–10, 11–100, 101–400, or >400) with an excellent agreement (weighted κ of 0.87). ConclusionCCSs can be accurately measured from contrast-enhanced coronary CTA by using an automated, standardized method, obviating the need for a noncontrast scan.

Intravenous ivabradine for control of heart rate during coronary CT angiography: A randomized, double-blind, placebo-controlled trial

BackgroundLow heart rates (HRs) are preferable for coronary CT angiography (CTA). We evaluated the use of an intravenous bolus of ivabradine, a selective sinus node inhibitor, to lower HR before coronary CTA in a prospective, randomized, double-blind, placebo-controlled multicenter trial. MethodsA total of 370 patients scheduled for CTA, with sinus rhythm ≥70 beats/min but ineligible for intravenous beta-blockers, were randomized to an intravenous bolus of 10 mg (HR, 70–79 beats/min) or 15 mg (HR ≥80 beats/min) ivabradine or placebo. Primary end point was the proportion of patients achieving HR ≤65 beats/min at the initiation of coronary CTA (Ta). ResultsBaseline HR was 79 ± 8.5 beats/min. At Ta, HR ≤65 beats/min was achieved in 55% of the ivabradine group vs 23% for placebo (P < .0001) and in 68% vs 16% 1-hour after bolus administration (P < .0001). Contrast-enhanced coronary CTA was performed in 87% of the ivabradine group vs 65% for placebo (P < .0001). Mean HR at Ta was 67 ± 10 beats/min for ivabradine vs 75 ± 10 beats/min for placebo (P < .0001). Procedural convenience was scored better with ivabradine (“good” or “very good” in 79% vs 63% for placebo; P = .0005). The effective radiation dose of contrast-enhanced CTA was 13 ± 7 mSv for ivabradine vs 16 ± 7 mSv for placebo (P < .05). Ivabradine was well tolerated. ConclusionsAn intravenous bolus of ivabradine achieves rapid, safe, and sustained HR lowering during coronary CTA, increasing procedural convenience and reducing radiation exposure vs placebo.

Additive Prognostic Value of Coronary Artery Calcium Score Over Coronary Computed Tomographic Angiography Stenosis Assessment in Symptomatic Patients Without Known Coronary Artery Disease

The objective of this study was to examine the additive prognostic performance of coronary artery calcium score (CACS) over coronary computed tomography angiography (CCTA) stenosis assessment in symptomatic patients suspected for coronary artery disease (CAD) undergoing CCTA. A total of 805 symptomatic patients without known history of CAD who underwent coronary evaluation by multidetector cardiac CT were analyzed. Mean age of the cohort was 58 ± 13 years. A total of 44% (354 of 805) of the patients had a 0 CACS, 27% (215 of 805) had CACS 1 to 100, 14% (111 of 805) had CACS 101 to 400, and 15% (125 of 805) had CACS >400. CCTA showed normal coronary arteries in 43% (349 of 805) of patients, ≤50% stenosis in 42% (333 of 805), and >50% stenosis in 15% (123 of 805). Patients were followed for 2.3 ± 0.9 years. Major adverse cardiac event (MACE) was defined as cardiac death, nonfatal myocardial infarction, and late coronary revascularization. Overall incidence of MACE was 1.4% per year. Both CACS and CCTA stenosis were independently associated with increased MACE (p <0.05 for both). Addition of CACS into the model with clinical risk factors and CCTA stenosis significantly improved predictive performance for MACE from the model with clinical risk factors and CCTA stenosis only (global chi-square score 108 vs 70; p = 0.019). In conclusion; in symptomatic patients without known CAD, both CACS and CCTA stenosis were independently associated with increased cardiac events, and performing non-contrast-enhanced CACS evaluation in addition to contrast-enhanced CCTA improved predictive ability for future cardiac events compared to CCTA stenosis assessment alone.

When Do We Really Need Coronary Calcium Scoring Prior to Contrast-Enhanced Coronary Computed Tomography Angiography? Analysis by Age, Gender and Coronary Risk Factors

AimsTo investigate the value of coronary calcium scoring (CCS) as a filter scan prior to coronary computed tomography angiography (CCTA).Methods and ResultsBetween February 2008 and April 2011, 732 consecutive patients underwent clinically indicated CCTA. During this ‘control phase’, CCS was performed in all patients. In patients with CCS≥800, CCTA was not performed. During a subsequent ‘CCTA phase’ (May 2011–May 2012) another 200 consecutive patients underwent CCTA, and CCS was performed only in patients with increased probability for severe calcification according to age, gender and atherogenic risk factors. In patients where CCS was not performed, calcium scoring was performed in contrast-enhanced CCTA images. Significant associations were noted between CCS and age (r = 0.30, p<0.001) and coronary risk factors (χ2 = 37.9; HR = 2.2; 95%CI = 1.7–2.9, p<0.001). Based on these associations, a ≤3% pre-test probability for CCS≥800 was observed for males <61 yrs. and females <79 yrs. According to these criteria, CCS was not performed in 106 of 200 (53%) patients during the ‘CCTA phase’, including 47 (42%) males and 59 (67%) females. This resulted in absolute radiation saving of ∼1 mSv in 75% of patients younger than 60 yrs. Of 106 patients where CCS was not performed, estimated calcium scoring was indeed <800 in 101 (95%) cases. Non-diagnostic image quality due to calcification was similar between the ‘control phase’ and the ‘CCTA’ group (0.25% versus 0.40%, p = NS).ConclusionThe value of CCS as a filter for identification of a high calcium score is limited in younger patients with intermediate risk profile. Omitting CCS in such patients can contribute to further dose reduction with cardiac CT studies.

Attenuation Correction Maps for SPECT Myocardial Perfusion Imaging from Contrast-Enhanced Coronary CT Angiography: Gemstone Spectral Imaging with Single-Source Dual Energy and Material Decomposition

The aim of this study was to explore the feasibility of attenuation correction (AC) of myocardial perfusion imaging (MPI) with a virtual unenhanced cardiac CT scan synthesized from contrast-enhanced single-source dual-energy coronary CT angiography. Segmental myocardial percentage uptake values obtained with AC were analyzed by use of correlation analysis and Bland-Altman limits of agreement (20-segment model), and clinical agreement was evaluated in 30 patients. The 2 methods showed an excellent correlation for segmental myocardial percentage uptake at stress (r = 0.93; P < 0.001; low dose) and at rest (r = 0.90; P < 0.001; high dose) with narrow Bland-Altman limits of agreement (-6.8% to 7.8% and -7.8% to 7.4%, respectively). The levels of clinical agreement of SPECT MPI corrected with standard versus virtual unenhanced CT AC were 99% per coronary territory and 97% per patient. Our results suggest that AC of SPECT MPI with a virtual unenhanced CT scan synthesized from contrast-enhanced coronary CT angiography is feasible and reliable.

Automatic Assessment of Coronary Artery Calcium Score from Contrast-Enhanced 256-Row Coronary Computed Tomography Angiography

The coronary artery calcium score (CS), an independent predictor of cardiovascular events, can be obtained from a stand-alone nonenhanced computed tomography (CT) scan (CSCT) or as an additional nonenhanced procedure before contrast-enhanced coronary CT angiography (CCTA). We evaluated the accuracy of a novel fully automatic tool for computing CS from the CCTA examination. One hundred thirty-six consecutive symptomatic patients (aged 59 ± 11 years, 40% female) without known coronary artery disease who underwent both 256-row CSCT and CCTA were studied. Original scan reconstruction (slice thickness) was maintained (3 mm for CSCT and 0.67 mm for CCTA). CS was computed from CCTA by an automatic tool (COR Analyzer, rcadia Medical Imaging, Haifa, Israel) and compared with CS results obtained by standard assessment of nonenhanced CSCT (HeartBeat CS, Philips, Cleveland, Ohio). We also compared both methods for classification into 5 commonly used CS categories (0, 1 to 10, 11 to 100, 101 to 400, >400 Agatston units). All scans were of diagnostic quality. CS obtained by the COR Analyzer from CCTA classified 111 of 136 (82%) of patients into identical categories as CS by CSCT and 24 of remaining 25 into an adjacent category. Overall, CS values from CCTA showed high correlation with CS values from CSCT (Spearman rank correlation= 0.95, p <0.0001). In conclusion, CS values automatically computed from 256-row CCTA correlated highly with standard CS values obtained from nonenhanced CSCT. CS obtained directly from CCTA may obviate the need for an additional scan and attendant radiation.

Does coronary CT angiography improve risk stratification over coronary calcium scoring in symptomatic patients with suspected coronary artery disease? Results from the prospective multicenter international CONFIRM registry

The prognostic value of coronary artery calcium (CAC) scoring is well established and has been suggested for use to exclude significant coronary artery disease (CAD) for symptomatic individuals with CAD. Contrast-enhanced coronary computed tomographic angiography (CCTA) is an alternative modality that enables direct visualization of coronary stenosis severity, extent, and distribution. Whether CCTA findings of CAD add an incremental prognostic value over CAC in symptomatic individuals has not been extensively studied. We prospectively identified symptomatic patients with suspected but without known CAD who underwent both CAC and CCTA. Symptoms were defined by the presence of chest pain or dyspnoea, and pre-test likelihood of obstructive CAD was assessed by the method of Diamond and Forrester (D-F). CAC was measured by the method of Agatston. CCTAs were graded for obstructive CAD (>70% stenosis); and CAD plaque burden, distribution, and location. Plaque burden was determined by a segment stenosis score (SSS), which reflects the number of coronary segments with plaque, weighted for stenosis severity. Plaque distribution was established by a segment-involvement score (SIS), which reflects the number of segments with plaque irrespective of stenosis severity. Finally, a modified Duke prognostic index-accounting for stenosis severity, plaque distribution, and plaque location-was calculated. Nested Cox proportional hazard models for a composite endpoint of all-cause mortality and non-fatal myocardial infarction (D/MI) were employed to assess the incremental prognostic value of CCTA over CAC. A total of 8627 symptomatic patients (50% men, age 56 ± 12 years) followed for 25 months (interquartile range 17-40 months) comprised the study cohort. By CAC, 4860 (56%) and 713 (8.3%) patients had no evident calcium or a score of >400, respectively. By CCTA, 4294 (49.8%) and 749 (8.7%) had normal coronary arteries or obstructive CAD, respectively. At follow-up, 150 patients experienced D/MI. CAC improved discrimination beyond D-F and clinical variables (area under the receiver-operator characteristic curve 0.781 vs. 0.788, P = 0.004). When added sequentially to D-F, clinical variables, and CAC, all CCTA measures of CAD improved discrimination of patients at risk for D/MI: obstructive CAD (0.82, P < 0.001), SSS (0.81, P < 0.001), SIS (0.81, P = 0.003), and Duke CAD prognostic index (0.82, P < 0.0001). In symptomatic patients with suspected CAD, CCTA adds incremental discriminatory power over CAC for discrimination of individuals at risk of death or MI.

Predictive Value of Zero Calcium Score and Low-End Percentiles for the Presence of Significant Coronary Artery Stenosis in Stable Patients with Suspected Coronary Artery Disease

To prospectively investigate the predictive value of a zero calcium score (CS) value as well as age- and sex-adjusted low-end CS percentiles for the presence of significant coronary artery stenosis in stable patients with suspected coronary artery disease (CAD). In total, 87 consecutive stable patients with suspected CAD were prospectively enrolled in this study (33 women; 66 ± 10 years). All patients underwent non-enhanced CT for calcium scoring (CSCT) and contrast-enhanced coronary CT angiography (cCTA). Invasive coronary angiography (ICA) served as the reference standard in all patients. Diagnostic performance for the presence of significant stenosis (≥ 50% diameter) was calculated separately for CS in comparison to cCTA and ICA. ICA identified significant stenosis in 56/87 patients (64%). The mean CS was 571 ± 599. On a per patient based analysis, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for patients with a zero CS were 98.5%, 18.2%, 78.0% and 80.0%, respectively, compared to cCTA and 100%, 16.1%, 68.3% and 100%, respectively, compared to ICA. Low-end age- and sex-adjusted percentiles derived from asymptomatic Caucasian populations showed results comparable to a CS of zero. The prevalence of significant coronary artery stenosis is low in stable patients with suspected CAD and a CS of zero but also in patients below certain low-end age- and sex-adjusted percentile ranks. Thus, CS should be used as a gatekeeper prior to further diagnostic procedures in these patients. A CS value below certain age- and sex-adjusted percentile ranks seems to be of identical diagnostic value to a CS of zero in stable patients.

ACCURACY AND CLINICAL OUTCOMES OF COMPUTED TOMOGRAPHY CORONARY ANGIOGRAPHY IN THE PRESENCE OF A HIGH CORONARY CALCIUM SCORE

A high coronary calcium burden may adversely affect the image quality of contrast-enhanced CT coronary angiography (CTCA), however the impact on diagnostic accuracy and overall utility of CTCA in this setting is controversial. We sought to assess the clinical outcome, coronary intervention rate and

A Voxel-Map Quantitative Analysis Approach for Atherosclerotic Noncalcified Plaques of the Coronary Artery Tree

Noncalcified plaques (NCPs) are associated with the presence of lipid-core plaques that are prone to rupture. Thus, it is important to detect and monitor the development of NCPs. Contrast-enhanced coronary Computed Tomography Angiography (CTA) is a potential imaging technique to identify atherosclerotic plaques in the whole coronary tree, but it fails to provide information about vessel walls. In order to overcome the limitations of coronary CTA and provide more meaningful quantitative information for percutaneous coronary intervention (PCI), we proposed a Voxel-Map based on mathematical morphology to quantitatively analyze the noncalcified plaques on a three-dimensional coronary artery wall model (3D-CAWM). This approach is a combination of Voxel-Map analysis techniques, plaque locating, and anatomical location related labeling, which show more detailed and comprehensive coronary tree wall visualization.

What is the role of calcium scoring in the age of coronary computed tomographic angiography?

Non-contrast-enhanced CT for coronary artery calcification (CAC) as a marker of coronary atherosclerosis has been studied extensively in the primary prevention setting. With rapidly evolving multidetector CT technology, contrast-enhanced coronary CT angiography (CCTA) has emerged as the non-invasive method of choice for detailed imaging of the coronary tree. In this review, we systematically evaluate the role of CAC testing in the age of CCTA in both asymptomatic and symptomatic patients, across varying levels of risk. Although the role of CAC testing is well established in asymptomatic subjects, its use in evaluating those with stable symptoms that represent possible obstructive coronary artery disease is controversial. Nevertheless, available data suggest that in low-to-intermediate risk symptomatic patients, CAC scanning may serve as an appropriate gatekeeper to further testing with either CCTA (if no or only mild CAC present) versus functional imaging or invasive coronary angiography (when moderate or severe CAC present). Given the strong short-term prognostic value of CAC = 0, studies are needed to further evaluate the role of CAC scanning in low-risk patients with acute chest pain presenting to the emergency room.

CT coronary angiography: impact of adapted statistical iterative reconstruction (ASIR) on coronary stenosis and plaque composition analysis

To assess the impact of adaptive statistical iterative reconstruction (ASIR) on coronary plaque volume and composition analysis as well as on stenosis quantification in high definition coronary computed tomography angiography (CCTA). We included 50 plaques in 29 consecutive patients who were referred for the assessment of known or suspected coronary artery disease (CAD) with contrast-enhanced CCTA on a 64-slice high definition CT scanner (Discovery HD 750, GE Healthcare). CCTA scans were reconstructed with standard filtered back projection (FBP) with no ASIR (0 %) or with increasing contributions of ASIR, i.e. 20, 40, 60, 80 and 100 % (no FBP). Plaque analysis (volume, components and stenosis degree) was performed using a previously validated automated software. Mean values for minimal diameter and minimal area as well as degree of stenosis did not change significantly using different ASIR reconstructions. There was virtually no impact of reconstruction algorithms on mean plaque volume or plaque composition (e.g. soft, intermediate and calcified component). However, with increasing ASIR contribution, the percentage of plaque volume component between 401 and 500 HU decreased significantly (p < 0.05). Modern image reconstruction algorithms such as ASIR, which has been developed for noise reduction in latest high resolution CCTA scans, can be used reliably without interfering with the plaque analysis and stenosis severity assessment.

Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose &lt;0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction

We evaluated the potential of prospectively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv. Contrast-enhanced coronary dual source CT angiography (2 × 128 × 0.6 mm, 80 kV, 50 mAs) in prospectively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals (body weight <100 kg, heart rate ≤60/min). Images were reconstructed with raw data-based filtered back projection (FBP) and iterative reconstruction (IR). Image quality was assessed on a 4-point scale (1 = no artefacts, 4 = unevaluable). Mean effective dose was 0.06 ± 0.01 mSv. Image noise was significantly reduced in IR (128.9 ± 46.6 vs. 158.2 ± 44.7 HU). The mean image quality score was lower for IR (1.9 ± 1.1 vs. 2.2 ± 1.0, P < 0.0001). Of 292 coronary segments, 55 in FBP and 40 in IR (P = 0.12) were graded "unevaluable". In patients with a body weight ≤75 kg, both in FBP and in IR, the rates of fully evaluable segments were significantly higher in comparison to patients >75 kg. Coronary CT angiography with an estimated effective dose <0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data-based iterative reconstruction.

ASYMPTOMATIC INDIVIDUALS WITH NON-CALCIFIED PLAQUE ALONE BY CORONARY CT ANGIOGRAPHY: ASSOCIATION TO CORONARY ARTERY DISEASE RISK FACTORS AND PROGNOSTIC IMPLICATIONS FOR PATIENTS IN THE PROSPECTIVE MULTICENTER INTERNATIONAL CONFIRM REGISTRY

In asymptomatic individuals, non-contrast coronary calcium CT allows robust prediction of MACE. Contrast-enhanced coronary CT angiography (CCTA) permits detection of purely non-calcified plaques (NCP), but the relationship of NCP to risk factors and incident MACE has not been examined. Within the

DOES NONCALCIFIED PLAQUE IMPROVE THE DIAGNOSTIC AND PROGNOSTIC UTILITY OF CORONARY CT ANGIOGRAPHY? A STUDY OF PROPENSITY-MATCHED INDIVIDUALS WITH SIMILAR CORONARY CALCIUM SCORES FROM THE PROSPECTIVE MULTICENTER INTERNATIONAL CONFIRM REGISTRY

Calcified plaque (CP) on non-contrast coronary calcium scoring (CCS) robustly predicts future major adverse cardiac events (MACE). Noncalcified plaques (NCP) are detectable by contrast-enhanced coronary CT angiography (CCTA), but whether NCP improves diagnostic and prognostic utility beyond CCS

Cardiovascular risk assessment based on the quantification of coronary calcium in contrast-enhanced coronary computed tomography angiography

The extent of coronary artery calcification (CAC) has been shown to be a strong and independent predictor for cardiovascular events. Usually, CAC scoring is performed in non-contrast-enhanced computed tomography (CT) examinations. The ability and accuracy of cardiovascular risk classification according to the degree of CAC determined in contrast-enhanced coronary CT angiography (CCTA) has not been investigated so far. The aim of this analysis was to develop and validate a method for CAC risk classification in CCTA. In a test series of 100 patients who underwent both non-enhanced CAC scoring and CCTA, we developed a method to assess the extent of coronary calcification and the associated cardiovascular risk category in CCTA. The accuracy of the developed approach of CAC assessment in CCTA was determined in 500 consecutive patients in comparison to CAC scoring in the non-enhanced scan. CAC scoring results in the non-enhanced scan and CCTA scan showed a high correlation (r = 0.954; P < 0.001). CAC quantification in CCTA correctly identified 98% of patients without CAC as shown in the non-enhanced scan (184 of 188 patients). When compared with non-enhanced CAC scoring, CAC scoring in CCTA grouped more than 95% of high-risk patients correctly into the same risk category according to the 75th age- and gender-specific percentiles or the absolute calcium scores. Assessing cardiovascular risk associated with CAC is feasible and accurate in contrast-enhanced CCTA. This new technique may allow for reducing the radiation exposure of coronary CT studies while maintaining an accurate cardiovascular risk assessment, because the addition of non-enhanced scans to CCTA becomes unnecessary for comprehensive coronary CT studies.

Predictors of worsening renal function after computed tomography coronary angiography: Assessed by cystatin C

An increase in cystatin C (CyC) of ≥10% for 24 hours may predict contrast-induced nephropathy and worse outcomes in patients with renal dysfunction undergoing invasive coronary angiography. We investigated the changes in CyC in patients with preserved renal function referred for contrast-enhanced coronary computed tomography angiography (CTA). We studied 151 patients undergoing CTA with 70 mL of iopamidol. Serum creatinine and CyC, a sensitive measure of renal dysfunction, shown to be associated with adverse outcomes, were measured 1 day and 1 week after CTA, respectively. The percentage change in CyC (%CyC) was determined and evaluated in comparison to fluid intake. The patients were dichotomized into 2 groups: 47 patients had ≥10% increase in CyC 1 day after CTA (group A) and 104 did not (group B). The percentage of diabetic patients, hemoglobin A1c (HbA1c), and the CyC levels at 1 week were significantly greater, and the oral fluid volume was significantly lower in group A than in group B. The %CyC inversely correlated with oral fluid volume (r = -0.80, P < 0.0001) and positively with HbA1c (r = 0.38, P < 0.001). Multiple regression analysis showed that oral fluid intake (β = -0.796, P < 0.0001) and HbA1c (β = 0.128, P=0.007) are independent predictors for %CyC of ≥10%. Frequency of CyC elevation was strongly related to hydration after the study and also weakly related to HbA1c. Sufficient oral fluid intake (oral fluid volume/kg ≥ 20 mL/kg) is crucial, particularly for poorly controlled diabetic patients referred for CTA even though they show preserved renal function.

Indicators associated with coronary atherosclerosis in metabolic syndrome

BackgroundMetabolic factors associated with coronary atherosclerosis (CA) in metabolic syndrome (MetS) remain unclear. MethodsA total of 550 consecutive subjects without documented coronary artery disease who received contrast-enhanced coronary computed tomography angiography were analyzed. CA was defined as coronary artery calcification (CAC) scores >0 or, zero CAC score combining noncalcified plaques within the proximal third segment of major coronary arteries. Metabolic factors and novel atherosclerotic biomarkers including high-sensitive C-reactive protein (hs-CRP) and adiponectin were measured. MetS was recognized according to the ethnicity-specific National Cholesterol Educational Program Adult Treatment Panel III, 2001. ResultsAfter adjusted with novel atherosclerotic biomarkers, MetS was significantly associated with CA Odds ratio [OR], 2.88; 95% confidence interval [CI], 1.88 to 4.42; p<0.001). Subgroup analysis revealed that fasting blood glucose ≥110mg/dl/diabetes mellitus in non-MetS subjects (OR, 1.40; 95%CI, 1.08 to 1.82; p<0.05) and total cholesterol (TC)/high density lipoprotein-cholesterol (HDL-C) ≥4.2 in MetS subjects (OR, 4.44; 95%CI, 1.93 to 10.20; p<0.001) were independently associated with CA. Both indicators were significantly associated with increased serum hs-CRP and reduced adiponectin levels in all subjects. ConclusionsMetS is independently associated with CA after adjustment of atherosclerotic biomarkers. TC/HDL-C ≥4.2 in MetS and fasting blood glucose ≥110mg/dl/diabetes mellitus in non-MetS subjects are independent indicators of CA, suggesting the potential difference in pathophysiology of CA.

Subtraction Coronary CT Angiography for the Evaluation of Severely Calcified Lesions Using a 320-Detector Row Scanner

One of the major challenges in coronary computed tomography (CT) is the presence of severe calcification, which may interfere with the assessment of lesions and may reduce diagnostic accuracy. However, such calcifications may potentially be eliminated by subtracting precontrast CT image data from contrast-enhanced coronary CT angiography data. Such examinations require perfect alignment and can be performed in two ways: 1) the “single breath-hold method,” in which both precontrast and postcontrast CT data are acquired during a breath-hold, and 2) the “two breath-hold method,” in which the calcium scoring data are used as the precontrast CT data. Misregistration artifacts must be corrected manually based on visual assessment, which results in long image processing times. Although a number of challenges remain to be overcome, subtraction coronary CT angiography might improve the diagnostic accuracy of coronary CT angiography in patients with severe calcification in the future.

Coronary CT Angiography in Takayasu Arteritis

The aim of this study was to use coronary computed tomographic (CT) angiography to characterize coronary artery involvement in patients with known Takayasu arteritis who present with anginal chest pain or shortness of breath. Takayasu arteritis is a primary vasculitis of the large vessels, which mainly affects the aorta and its branches but can also involve the coronary arteries. Coronary CT angiography allows visualization of the coronary vessels and can be used to detect both stenotic and nonstenotic coronary artery lesions. Eighteen consecutive patients with Takayasu arteritis and angina (typical or atypical) and/or dyspnea underwent contrast-enhanced 64-slice coronary CT angiography. The arterial injury was classified according to the Numano classification. Three patients had prior known coronary artery disease. Coronary arteries were evaluated concerning the presence of obstructive and nonobstructive lesions, and differences between the clinical presentations of patients with and without coronary artery involvement on CT angiography were analyzed. Coronary artery involvement was found in 8 patients (44.4%), 3 of them with clinical activity. A total of 19 coronary lesions were present (13 in ostial locations, 5 in proximal coronary artery segments, and 1 in a mid segment). Eight lesions exceeded 50% diameter reduction (2 in ostial locations and 6 in proximal coronary artery segments). Median disease duration was significantly different between patients with coronary artery involvement (176 months; range 13 to 282 months) compared with those without (21 months; range 1 to 142 months) (p = 0.013). Coronary CT angiography allows the assessment of coronary artery involvement in patients with Takayasu arteritis. These data confirm prior observations that most coronary lesions are in ostial or proximal coronary artery locations. Disease duration in patients with coronary artery involvement is longer than in patients without.