CT Calcium Research Articles

Coronary CT angiography outperforms calcium imaging in the triage of acute coronary syndrome

BackgroundIn this prospective study we determine the diagnostic value of coronary CT angiography (CTA) and calcium imaging in low to intermediate risk acute chest pain patients. MethodsOne hundred and eleven consecutive patients (57±11years, 71 males) presenting to the emergency department with chest pain suggestive of acute coronary syndrome (ACS), but without indication for immediate catheter angiography, underwent both coronary CTA and calcium imaging without disclosure of the findings to the treating physicians. ResultsACS was diagnosed in 19 patients (17%). Coronary calcium was present in 71 patients (64%). Coronary CTA identified 74 (67%) patients with coronary plaque and 36 (32%) patients with obstructive (≥50%) plaque. The sensitivity and specificity of the calcium scan were: 89% and 41%. The sensitivity and specificity of coronary CTA were: 100% and 40% based on the presence of any plaque and 89% and 79% based on the presence of >50% stenosis.C-statistics of the GRACE risk score (0.77 [95% CI 0.66–0.89]) improved after addition of coronary CTA (0.93 [0.88–0.98], p<0.01), though not after addition of calcium scores (0.81 [0.71–0.91], p=0.52).Follow-up at 3months revealed four late revascularizations (no deaths or myocardial infarctions), all of whom had obstructive CAD with calcium on CT at presentation. ConclusionsCoronary CTA outperforms calcium imaging in the triage of patients suspected of developing ACS. Absence of plaque on coronary CTA allows safe discharge. Coronary CTA has incremental value to clinical risk scores and has the potential to reduce unnecessary hospital admissions.

Almanac 2011: Stable coronary artery disease. An editorial overview of selected research that has driven recent advances in clinical cardiology

### Diagnostic strategies The widespread application of specialist clinics for early evaluation of patients with chest pain has focused attention on the effectiveness of diagnostic testing. In a study of nearly 400 000 patients with suspected coronary artery disease, the diagnostic yield of cardiac catheterisation was only 37.6%, leading to calls for better strategies for risk stratification.1 As pointed out in correspondence, the low yield was probably due to verification bias, itself a consequence of basing referral decisions in low- risk populations on non-invasive tests such as exercise ECG.2 Similar considerations prompted the NICE guideline group to recommend a more selective approach to non-invasive testing based on a careful clinical assessment of disease probability in patients presenting with stable chest pain.3 For those, with unequivocal histories at the extremes of diagnostic probability ( 90%) no diagnostic tests were considered necessary, while for patients with a high probability of disease (60–90%) invasive angiography without prior ischaemia testing was recommended. The NICE call for CT calcium scoring in patients with a low (10–30%) probability of disease generated greatest concern, particularly after a report that 19% of patients without coronary calcification—who would have been ruled out for angina in the NICE algorithm—had obstructive (>50% stenosis) disease.4 However, the population referred for angiography in this study had a high pre-test probability of disease and in lower-risk populations CT calcium scoring retains a high diagnostic sensitivity.5 NICE recommendations were driven largely by cost-effectiveness analysis but whether they will improve the diagnostic yield of cardiac catheterisation remains to be seen. ### Circulating biomarkers in stable angina The clinical role of circulating biomarkers for diagnosis of obstructive coronary artery disease in patients with suspected angina has yet to be defined. In one study, blood samples for the N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) and various inflammatory markers were …

Digital tomosynthesis for aortic arch calcification evaluation: performance comparison with chest radiography with CT as the reference standard

Recently developed digital tomosynthesis has shown improved detection of pulmonary lesions with a radiation dose comparable to conventional CR but with a much lower radiation dose than CT. To compare the diagnostic performance of digital tomosynthesis (DT) with that of chest radiography (CR) for the detection of aortic arch calcification (AAC). The study included 100 patients who underwent multidetector computed tomography (MDCT), DT, and CR (DT and CR were obtained within one week of CT examination). We evaluated and compared the diagnostic performances of DT and CR for the detection of AAC with MDCT as the reference standard. The extent (four grades 0-3) of AAC on DT and CR was also compared with CT calcium score. Inter-observer agreement was analyzed by using kappa statistics. On DT, overall accuracy for AAC was superior to that of CR (94% and 71%, respectively, P < 0.01). Inter-observer agreement was good with DT and CR (kappa values = 0.74 and 0.62, respectively) for the presence of AAC, and good with DT and moderate with CR (kappa value = 0.64 and 0.53, respectively) for AAC grading. The overall correlation coefficient on AAC grading between DT and CT (calcium score) was superior to that between CR and CT (0.90 and 0.60, respectively). DT is superior to CR for detection and extent evaluation of AAC.

Factors Which Predict Individuals Whose Coronary Arteries are “Old Before Their Time”: The Value of Computed Tomographic (Ct) Calcium Score Testing

Factors Which Predict Individuals Whose Coronary Arteries are “Old Before Their Time”: The Value of Computed Tomographic (Ct) Calcium Score Testing

High Prevalence of Early and Pre-Existing Cognitive Impairment in a Low-Risk Population of Patients with Atrial Fibrillation

FactorsWhich Predict IndividualsWhose CoronaryArteries are “Old Before Their Time”: The Value of Computed Tomographic (Ct) Calcium Score Testing C. Ellis 1,∗, M. Legget 1, C. Edwards1, J. Ormiston1, N. Van Pelt 1, R. Gabriel 1, B. Lowe1, J. Christiansen2, H. Winch1, M. Osborne3, G. Gamble4 1 Auckland Heart Group, New Zealand 2 Waitemata Cardiology, New Zealand 3 Mercy Radiology, Mercy Hospital, Auckland, New Zealand 4 Dept of Medicine, University of Auckland, New Zealand

Abstract P225: Impact of a Comprehensive Cardiovascular Risk Reduction Program on Treatment and Outcomes of Participants at High Risk for Cardiac Events

With increased emphasis on prevention in recent healthcare reform initiatives, more information is needed to validate the effectiveness of programs designed to diagnose and treat individuals at high risk for cardiac events and increased mortality. The purpose of this study was to evaluate early and late outcomes of a community-based cardiovascular risk reduction program (CRRP). Methods: Individuals at high risk for cardiovascular events were referred from community primary care physicians for advanced diagnostic testing and medication management at a hospital-based CRRP. Between March 1, 2005 and August 1, 2007, 182 participants were enrolled and had advanced lipid testing, chemistry panels, stress testing, CT calcium scoring, vascular elasticity studies, and comprehensive assessment of cardiovascular risk factors, family history, diet, activity level and psychological status. Participants had on average 4 visits. Mortality and need for hospitalization were assessed at a mean follow-up time of 45±14 months. Results: On CRRP entry, 84% had elevated lipids, 70% had hypertension, 31% had diabetes, 32% had metabolic syndrome, 10% were current smokers, 17% had an abnormal stress test, 36% had depression, 44% had sleep disturbances, and over 50% were not exercising. Over 30% had conditions that had not been recognized or were left undertreated. By last visit, over 95% of participants were on appropriate medications and had received life-style interventions. Late mortality occurred in 9 (5%) participants and 15 (8%) had at least one hospitalization for cardiac reasons. Those who died were older (67 vs. 56; p=0.007), had significantly higher CT calcium scores (998 vs. 114; p&lt;0.0001) and elevated homocysteine levels (14 vs. 9; p&lt;0.0001). Multivariate analyses showed that homocysteine level was the only independent predictor of mortality. No one with metabolic syndrome died (p=0.038). The only factor related to hospitalization was higher NCEP Framingham Age/Sex-adjusted risk score (18 vs. 12; p=0.037). Conclusions: A comprehensive community-based risk reduction program can provide enhanced evaluation and treatment for individuals who are at high risk for cardiovascular events. Appropriate medications and risk modification may impact late events.

Controversies in nuclear cardiology: CT calcium scoring should be routinely performed in patients undergoing myocardial perfusion imaging who have a normal test result (and should be routinely performed before myocardial perfusion imaging)—pro

Controversies in nuclear cardiology: CT calcium scoring should be routinely performed in patients undergoing myocardial perfusion imaging who have a normal test result (and should be routinely performed before myocardial perfusion imaging)—pro

SHA 004. Diagnostic valve of nitrate enhanced Tc-99m sestamibi gated myocardial spect in myocardial viability: Prospective analysis

ically indicated CCT. Methods: All patients were scanned using retrospective gating on a 64-slice CCT, for clinically indicated reasons, where coronary CT angiogram and calcium score measurements were performed. The amount of radiation was calculated from different parameters in millisievert (mSv). Results: 1287 patients were scanned with mean age of 52 ± 13.2 y, 65% males, and 35% females. Chest pain was the indication in 80% of cases. There mean radiation dose was 15 ± 10.4 (mSv). Patients with body mass index (BMI) P 35 received more radiation compared to those with BMI < 30 was, 15.3 ± 9.3 vs. 14.6 ± 7.4 (mSv), p< 0.002. Patients who had coronary bypass surgery (CABG) received significantly higher dose of radiation, 22.2 ± 9.3 vs. 14.4 ± 10.4 (mSv), P < 0.0001. Conclusion: Overweight patients and patients who underwent CABG are exposed to significantly higher radiation dose during CCT. Measures have to be applied to minimize the radiation dose during CCT.

63 Implications of a likelihood based approach to diagnostic testing in coronary artery disease: impact of the new nice guidelines

Background The NICE clinical guideline for chest pain of recent onset (NCG 95) published in March 2010 recommends diagnosing angina based on clinical assessment and likelihood of coronary artery disease (CAD). If the estimated likelihood of CAD is 61%–90%, coronary angiography should be offered. If 30%–60%, functional imaging should be offered, and if 10%–29%, CT calcium scoring should be offered. We determined the number and types of different investigations to diagnose coronary artery disease in patients referred with suspected cardiac pain before the publication of NCG 95 and compared this with the predicted investigations after the application of the guidelines. Methods Data was collected prospectively in a bespoke database for patients referred to the Rapid Access Chest Pain Clinic, Newcastle upon Tyne, UK. Patients with chest pain of suspected cardiac origin were referred from primary care between February 2002 and March 2010. Patients with previous MI, PCI or CABG were excluded. The analysis comprised 5598 men and women with no past history of coronary disease. Likelihood of CAD was calculated by the Pryor equation using the variables age, sex, type of chest pain (typical or atypical), ECG Q waves, smoking, hyperlipidaemia, diabetes and ST/T changes on ECG. The main outcome measures were actual and predicted future frequency of exercise tests, CT coronary angiograms, functional imaging tests and invasive coronary angiograms by pretest likelihood of coronary artery disease. Results The proportion of the study population before and after the guidelines undergoing exercise testing was 50.1% vs 0.0%; for calcium score/CT coronary angiography 0.0% vs 14.7%; for functional imaging 25.6% vs 13.4%; and for invasive coronary angiography 15.3% vs 25.8%. The proportion not requiring further testing was unchanged (30.0% vs 31.0%). Conclusions Application of NICE CG95 will change the investigation of patients with chest pain substantially. A significant reallocation of resources will be required. Exercise testing will be replaced by anatomic or functional imaging. CT coronary angiography will play an important role and replace functional imaging in some patients. Invasive angiography will take on a more important role in the diagnosis of coronary artery disease. It will, however, empower us to reassure almost a third of referrals that they do not have angina on clinical assessment alone.

56 Clinical and financial repercussions of the march 2010 national institute for health and clinical excellence (NICE) guideline "chest pain of recent onset" on the rapid access chest pain clinic (RACPC)

<h3>Background</h3> The RACPC is a well-established “one-stop” service, with goal to identify patients with stable chest pain due to coronary artery disease (CAD) and quickly reassure those with non-cardiac pain. In March 2010, NICE published a new guideline, which advocates assessing likelihood of CAD based on age, gender, history and risk factors (RF). If estimated likelihood is &gt;60%, invasive coronary angiography (ICA) is recommended as the first-line diagnostic investigation. If estimated likelihood is 30%–60%, functional imaging is recommended. If estimated likelihood is &lt;30%, CT calcium scoring CT coronary angiography (CTCA) is recommended. Significantly, the guideline discourages the use of ETT to diagnose or exclude stable angina in patients without known CAD. <h3>Methods</h3> 167 consecutive patients referred to RACPC between October 2009 and March 2010 were retrospectively assessed for likelihood of CAD according to the new NICE guideline. Choice of investigations and eventual outcome (confirmed CAD vs no evidence of CAD) were compared between subgroups defined by estimated likelihood of CAD. An economic analysis of cost of investigation per patient was undertaken using current Payment by Results national tariffs. <h3>Results</h3> Our patient population had a high prevalence of RF with 38.1% having a total of three or more RF. Consequently 23.2% of patients had an estimated likelihood of CAD of &lt;30%. 27.4% had an estimated likelihood of 30%–60%. 49.4% had an estimated likelihood of &gt;60%. 7.2% of patients were lost to follow-up. 14.4% of patients were ultimately confirmed to have CAD on ICA, which correlated with pre-test estimated likelihood. 6% of patients with likelihood &lt;30%, 8.7% of those with likelihood 30%–60% and 23.2% of those with likelihood &gt;60% were confirmed to have CAD. Average cost of investigation per patient was £528. A negative ETT resulted in average cost per patient of £347. An inconclusive ETT resulted in higher cost (£728) as did inability to exercise (£435) due to the need for further investigations. A positive ETT resulted in average cost of £1174 due to the high cost of ICA. Were the NICE guideline strictly applied to our patient population, average cost per patient would have been substantially higher at £838 (£362 per patient if likelihood &lt;30%, £566 if likelihood 30%–60% and £1218 if likelihood &gt;60%). Overall this corresponds to a 60% increase in cost. <h3>Conclusion</h3> The 2010 NICE guideline appears to significantly overestimate the true risk in our patient population. Were the guideline strictly applied, almost half of our patients would proceed to ICA as a first-line investigation, but many of them would be found to have unobstructed coronary arteries. As ICA is an expensive investigation, this would inevitably result in a significant increase in average cost per patient. Relatively few patients would be eligible for CTCA, which is an excellent non-invasive “rule-out” test for CAD and relatively inexpensive compared with other investigations.

CT coronary plaque burden in asymptomatic patients with familial hypercholesterolaemia

ObjectiveTo determine the calcium score and coronary plaque burden in asymptomatic statin-treated patients with heterozygous familial hypercholesterolaemia (FH) compared with a control group of patients with low probability of coronary...

Radiation Exposure to Patients in a Multicenter Coronary Angiography Trial (CORE 64)

The objective of this study was to assess the exposure of patients to radiation for the cardiac CT acquisition protocol of the multicenter Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE 64) trial. An algorithm for patient dose assessment with Monte Carlo dosimetry was developed for the Aquilion 64-MDCT scanner. During the CORE 64 study, different acquisition protocols were used depending on patient size and sex; therefore, six patient models were constructed representing three men and three women in the categories of small, normal size, and obese. Organ dose and effective dose resulting from the cardiac CT protocol were assessed for these six patient models. The average effective dose for coronary CT angiography (CTA) calculated according to Report 103 of the International Commission on Radiological Protection (ICRP) is 19 mSv (range, 16-26 mSv). The average effective dose for the whole cardiac CT protocol including CT scanograms, bolus tracking, and calcium scoring is slightly higher-22 mSv (range, 18-30 mSv). An average conversion factor for the calculation of effective dose from dose-length product of 0.030 mSv/mGy · cm was derived for coronary CTA. The current methods of assessing patient dose are not well suited for cardiac CT acquisitions, and published effective dose values tend to underestimate effective dose. The effective dose of cardiac CT is approximately 25% higher when assessed according to the preferred ICRP Report 103 compared with ICRP Report 60. Underestimation of effective dose by 43% or 53% occurs in coronary CTA according to ICRP Report 103 when a conversion factor (E / DLP, where E is effective dose and DLP is dose-length product) for general chest CT of 0.017 or 0.014 mSv/mGy · cm, respectively, is used instead of 0.030 mSv/mGy · cm.

Nichtinvasive Diagnostik der chronisch stabilen koronaren Herzkrankheit: evidenzbasierte und nicht evidenzbasierte diagnostische Algorithmen

In Germany, every second left heart catheterization has no immediate interventional or surgical consequence. One main reason for this limited quality of indication of many left heart catheterizations is presumably the inaccuracy of preinvasive testing that is mainly based on clinical evaluation and exercise ECG in Germany. However, exercise electrocardiography has several limitations. The central issues are the inability to exercise in many, especially elderly patients, and the missing interpretability of the stress ECG in cases with already pathological rest ECG. In 2006, the "Nationale Versorgungsleitlinie Chronische KHK (NVL KHK)" was published in Germany, adopting for the first time the evidence-based algorithms of the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for non-invasive stress testing and complementary stress imaging. Stress imaging methods considered comparable and interchangeable are the following: stress echocardiography combined with physical or pharmacological stress testing, myocardial perfusion imaging with physical or pharmacological stress testing, dobutamine stress magnetic resonance imaging (DSMR), or myocardial perfusion magnetic resonance imaging (MRI). Basically, no stress imaging method is definitely superior to the others, each method has its own advantages and disadvantages that should be considered and adjusted to the individual patient. Of pivotal importance of all stress imaging methods is the high negative predictive value of 99% of a normal study predicting a very low (< 1%) cumulative likelihood of cardiac death or myocardial infarction for at least the next 12 months. Hence, in most clinical circumstances, coronary angiography is not necessary during the 12 months subsequent to a normal stress imaging study. In contrast to these established and evidence-based recommendations of the "Nationale Versorgungsleitlinie Chronische KHK" mainly focusing on ischemia stress imaging, many diagnostic centers have developed their own non-evidence based algorithms. In these non-evidence based algorithms the morphology-oriented non-invasive CT coronary angiography has taken over the diagnostic part of evidence-based ischemia stress imaging. However, beyond the scientifically established prognostic value of calcium scoring, there is so far no scientific evidence showing that morphology-oriented CT coronary angiography protocols are superior to functional stress imaging. A new innovative approach of staged non-invasive diagnostics for patients with intermediate likelihood (10-90%) of coronary artery disease are the 2010 recommendations of the National Institute for Health and Clinical Excellence (NICE) guiding the National Health Service (NHS) in the United Kingdom. Following this guidance, in patients with an estimated likelihood of CAD of 10-29% CT calcium scoring should be offered as first-line method, in patients with an estimated likelihood of CAD of 30-60% non-invasive functional imaging should be offered primarily, and in patients with an estimated likelihood of CAD of 61-90%, as in patients with an estimated likelihood of CAD of more than 90%, invasive coronary angiography should be preferred.

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.

Size and nature of emboli produced during carotid artery angioplasty and stenting: In vivo study

Aim Microembolization continues to be a major risk for patients undergoing carotid artery stenting (CAS) of high-grade atherosclerotic carotid stenoses. Further insight into the characteristics and significance of these embolized particles was deemed necessary. We aimed to assess the size and composition of debris captured by filters during CAS and to determine if this could be predicted using standard imaging techniques. Methods 20 patients (10 symptomatic, 15 men, mean age 64.6 years) undergoing CAS for high-grade ICA stenosis were recruited. All underwent pre-operative CT angiography and calcium scoring. All underwent CAS using the same protocol. A filter-type embolic protection device (EPD) was used and retrieved post-operatively and captured particles underwent analysis using a Scanning Electron Microscope (SEM) for counting, sizing, and composition. Results Clinical. Debris was found on 100% of filters when analysed with SEM. There were non-significant trends for CAS in asymptomatic patients to produce a greater number of smaller, calcified particles while in symptomatic patients we observed larger, lipid-rich particles. When stratified according to pre-operative calcium scores, ‘calcium-rich’ plaques produced significantly greater numbers of emboli captured on the EPD ( p = 0.02). Conclusions Filter-type EPDs collect debris of significant quantity and size during the CAS procedure as performed in our institution. The collected material was likely dislocated from the atherosclerotic plaque. CT calcium scoring allows us to predict the nature of material captured by the EPD. These data may allow the clinician to individualise care during CAS and thus reduce peri-operative risk.

Coronary calcium test phantom containing true CaHA microspheres for evaluation of advanced CT calcium scoring methods

Test phantoms with simulated micro-calcifications of true calcium hydroxyapatite (CaHA) density were not available to validate advanced calcium scoring methods or plaque density measurements. We evaluated a coronary calcium scoring (CCS) test phantom containing very small CaHA microspheres and validated a new scoring method for measurements of plaque densities. The semianthropomorphic CCS phantom was constructed with CaHA microspheres (volumes, 0.05-3.1 mm(3)) with the approximate density of biologic calcifications. QRM and CCS phantoms were scored with a new calibrated and automated calcium scoring method (N-vivo; Image Analysis). The densities of the microspheres and 609 individual patient plaques were measured. The range of measured densities of the CaHA microspheres was approximately equivalent to that measured in the patient coronary calcifications. The smallest microspheres scored with the calibrated/automated and the Agatston methods had volumes of 0.075 mm(3) and 0.27 mm(3), respectively. The standard deviations of the mass scores of the microspheres ranged from 0.02 to 0.17 mg with regression slope of 0.962 and R(2) = 0.997. The relationship of measured density to measured mass of the patient plaques was similar to that of the microspheres, suggesting that vascular calcifications are CaHA density. The CaHA microspheres of the CCS test phantom were found to be representative in density and size of coronary calcifications. The measurements show that CT calcium scoring underestimates plaque density and greatly overestimates volume. The heterogeneity of calcium concentration densities measured in the patient plaques was due largely to CT scanner measurement errors.

Incremental Prognostic Value of Coronary CT Angiography in Patients With Suspected Coronary Artery Disease

Multidetector CT coronary angiography (MDCTCA) is capable of detecting coronary artery disease (CAD) with a high diagnostic accuracy. In particular, this technique is credited with having a negative predictive value close to 100%. However, data about the prognostic value of MDCTCA are currently lacking. We sought to determine the prognostic value of MDCTCA in patients with suspected but undocumented CAD and, in particular, the incremental prognostic value as compared with clinical risk and calcium scoring. A total of 441 patients (age, 59.7+/-11.6 years) with suspected CAD underwent MDCTCA to evaluate the presence and severity of the disease. Patients were followed up as to the occurrence of hard cardiac events (cardiac death, nonfatal myocardial infarction, and unstable angina requiring hospitalization). Coronary lesions were detected in 297 (67.3%) patients. During a mean follow-up of 31.9+/-14.8 months, 44 hard cardiac events occurred in 40 patients. CT calcium scoring showed a statistically significant incremental prognostic value as compared to a baseline clinical risk model (P=0.018), whereas MDCTCA provided an additional incremental prognostic value as compared with a baseline clinical risk model plus calcium scoring if considering both nonobstructive versus obstructive CAD (P=0.016) or, better, plaque composition (calcified versus noncalcified and/or mixed plaques, P=0.0001). During follow-up, an excellent prognosis was noted in patients with normal coronary arteries, with an annualized incidence rate of 0.88% if compared with those with mild CAD (3.89%) and with patients with significant coronary disease (8.09%). The presence of noncalcified or mixed plaques, regardless of lesion severity, was found to be the strongest predictor of events (P<0.0001) as a potential marker of plaque vulnerability. MDCTCA provides independent and incremental prognostic information as compared to baseline clinical risk factors and calcium scoring in patients with suspected CAD.

The impact of coronary calcium score and cardiac risk factors on coronary endothelial function

Methods Following navigator coronary MRA scout images, the LAD lumen was imaged in short axis before and during the cold pressor test (CPT) in normal controls and subjects with one or more atherosclerotic risk factors using either supine breath-hold double inversion T2 weighted spin echo imaging (38 subjects, 1.5 T Siemens Sonata) or prone breath-hold SSFP retrospectively gated cine imaging with a 4 element phased array carotid coil (39 subjects, 1.5 T Siemens Avanto). The % change in LAD lumen area with CPT was calculated. CT calcium scores were available or obtained by protocol in each subject and those undergoing prone imaging also had coronary CT angiography to exclude coronary stenoses. Linear associations between continuous variables were measured by Pearson and Spearman (non-parametric) correlation coefficients. ROC analysis was also performed. A p-value < 0.05 was deemed statistically significant.

Coronary Computed Tomography Angiography for Screening of an Asymptomatic Population: Too Much or Too Soon?

Coronary Computed Tomography Angiography for Screening of an Asymptomatic Population: Too Much or Too Soon?

Correlation of regional distribution and morphological pattern of calcification at CT coronary artery calcium scoring with non-calcified plaque formation and stenosis

To investigate whether regional calcification patterns at CT coronary artery calcium scoring (CCS) correlate with stenosis and non-calcified plaque formation. We studied 106 patients with quantitative catheter angiography (QCA), CCS, and coronary CT angiography (cCTA). CCS was determined globally and for each artery separately. The morphological pattern of each calcification was classified as calcified nodule, shell-like, or diffuse. cCTA studies were evaluated for non-calcified plaque. The global and regional CCS and the calcification pattern were correlated with stenosis >or=50% and non-calcified plaque. A total of 48/106 patients had stenosis >or=50% on QCA. There was weak correlation (r = 0.36) of the global CCS with stenosis. Correlation was stronger per vessel (r = 0.55-r = 0.67). Shell-like and diffuse calcifications were significantly (p = 0.0001) more frequently associated with >or=50% stenosis and non-calcified plaque (p = 0.04) than calcified nodules. As shown before, the global CCS does not correlate well with stenosis. However, regional calcium distribution and specific patterns of calcification are correlated with stenosis and non-calcified plaque. Thus, the specificity of CT calcium scoring for identifying individuals with obstructive disease could be improved by vessel-based rather than global quantification of calcium and by differentiating specific morphological patterns of calcification.