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Objective: To prospectively examine coronary artery plaques as predictors of myocardial ischaemia using cardiac magnetic resonance (CMR).Methods: Fifty-two patients (46 men; age 64 ± 10) with suspected coronary artery disease (CAD) referred for catheter coronary angiography (CA) underwent CMR and computed tomography coronary angiography (CTCA). All coronary segments were evaluated for morphological stenosis based on CA. Any plaque according to its composition was assessed based on CTCA.Results: Numbers of total and calcified coronary artery plaques represented the best predictors of myocardial ischaemia (AUC = 0.87; [95%CI: 0.77-0.97] and AUC = 0.87; [95%CI: 0.77-0.96], respectively, p = 0.56) with the total plaque number significantly higher in patients with corresponding ischaemia than those without (p < 0.01, p < 0.05 adjusted for pre-test probability and stenosis). Compared with the AUC of coronary stenosis assessment by CA (AUC = 0.90; [95%CI: 0.80-1.00]), AUCs were equivalent using either the total number or the number of calcified plaques alone (p = 0.73 and p = 0.69). Multivariate logistic regression analyses demonstrated the total plaque number as an independent predictor of ischaemia (odds +20%; [95%CI: 1.096-1.368]), improving a model including clinical probability estimates of CAD (c-statistics, 0.66 to 0.89).Conclusion: Coronary artery plaque number according to CTCA is a significant, independent predictor of myocardial ischaemia with similar accuracy to stenosis assessment. [ABSTRACT FROM AUTHOR]

Purpose: To differentiate proxy renal cystic lesions containing protein, blood, iodine contrast or saline solutions using dual-energy CT (DECT) equipped with a new tin filter technology (TFT).Materials and Methods: 70 proxies (saline, protein, blood and contrast agent) were placed in unenhanced and contrast-enhanced kidney phantoms. DECT was performed at 80/140 kV with and without tin filtering. Two readers measured the CT attenuation values in all proxies twice. An 80/140 kV ratio was calculated.Results: All intra- and interobserver agreements were excellent (r = 0.93-0.97; p < 0.001). All CT attenuation values were significantly higher in the enhanced than in the unenhanced setting (p < 0.05; average increase, 12.5 ± 3.6 HU), while the ratios remained similar (each, p > 0.05). The CT attenuation of protein, blood and contrast agent solution differed significantly with tin filtering (p < 0.01-0.05). Significant differences were found between the ratios of protein and blood compared to contrast medium solution (each, p < 0.05) and between the ratios of protein and blood in both phantoms with tin filtering (each, p < 0.05).Conclusion: DECT allows discrimination between a proxy renal lesion containing contrast agent and lesions containing protein and blood through their different attenuation at 80 kV and 140 kV. Further discrimination between protein and blood containing proxies is possible when using a tin filter. [ABSTRACT FROM AUTHOR]

Purpose: To compare image quality and radiation dose of high-pitch computed tomography angiography(CTA) of the aortic valve-aortic root complex with and without prospective ECG-gating compared to a retrospectively ECG-gated standard-pitch acquisition.Materials and Methods: 120 patients (mean age 68±13 years) were examined using a 128-slice dual-source CT system using prospectively ECG-gated high-pitch (group A; n=40), non-ECG-gated high-pitch (group B; n=40) or retrospectively ECG-gated standard-pitch (C; n=40) acquisition techniques. Image quality of the aortic root, valve and ascending aorta including the coronary ostia was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated.Results: Interobserver agreement was good(κ=0.64-0.78). Image quality was diagnostic in 38/40 patients (group A), 37/40(B) and 38/40(C) with no significant difference in number of patients with diagnostic image quality among all groups (p=0.56). Significantly more patients showed excellent image quality in group A compared to groups B and C (each, p<0.01). Average image noise was significantly different between all groups (p<0.05). Mean radiation dose estimates in groups A and B (each; 2.4±0.3 mSv) were significantly lower compared to group C (17.5±4.4 mSv; p<0.01).Conclusion: High-pitch dual-source CTA provides diagnostic image quality of the aortic valve-aortic root complex even without ECG-gating at 86% less radiation dose when compared to a standard-pitch ECG-gated acquisition. [ABSTRACT FROM AUTHOR]

Objective: To assess the effect of systolic data acquisition for electrocardiography (ECG)-triggered high-pitch computed tomography (CT) on motion artefacts of coronary arteries in patients with high heart rates (HRs).Methods: Eighty consecutive patients (15 women, age 67 ± 14 years) with HR ≥ 70 bpm underwent CT angiography of the thoracic aorta (CTA) on 128-slice dual-source CT in ECG-triggered high-pitch acquisition mode (pitch = 3.2) set at 60% (group A, n = 40) or 30% (group B, n = 40) of the RR interval. Two blinded readers graded coronary artery image quality on a three-point scale. Radiation doses were calculated.Results: Inter-observer agreement in grading image quality of the 1,154 coronary segments was good (κ = 0.62). HRs were similar in groups A and B (85 ± 13 bpm vs 85 ± 14 bpm, p not significant). Significantly fewer coronary segments with non-diagnostic image quality occurred (i.e. score 3) in group B than in group A [2.8% (16/579) vs 8.3% (48/575), p < 0.001]. Seventeen patients (42.5%) of group A and 12 patients (30.0%) of group B had at least one non-diagnostic segment. Effective radiation doses were 2.3 ± 0.3 mSv for chest CTA.Conclusion: A systolic acquisition window for high-pitch dual-source CTA in patients with high HRs (≥ 70 bpm) significantly improves coronary artery image quality at a low radiation dose. [ABSTRACT FROM AUTHOR]

Objective: To assess the effect of reader experience on variability, evaluation time and accuracy in the detection of coronary artery plaques with computed tomography coronary angiography (CTCA).Methods: Three independent, blinded readers with three different experience levels twice labelled 50 retrospectively electrocardiography (ECG)-gated contrast-enhanced dual-source CTCA data sets (15 female, age 67.3 +/- 10.4 years, range 46-86 years) indicating the presence or absence of coronary plaques. The evaluation times for the readings were recorded. Intra- and interobserver variability expressed as kappa statistics and sensitivity, specificity, and negative and positive predictive values were calculated for plaque detection, with a consensus reading of the three readers taken as the standard of reference. A bootstrap method was applied in the statistical analysis to account for clustering.Results: Significant correlations were found between reader experience and, respectively, evaluation times (r = -0.59, p < 0.05) and intraobserver variability (r = 0.73, p < 0.05). The evaluation time significantly differed among the readers (p < 0.05). The observer variability for plaque detection, compared with the consensus, varied between kappa = 0.582 and kappa = 0.802. Variability of plaque detection was significantly smaller (p < 0.05) and more accurate (p < 0.05) for the most experienced reader.Conclusion: Reader experience significantly correlated with observer variability, evaluation time and accuracy of coronary plaque detection at CTCA. [ABSTRACT FROM AUTHOR]

Objectives: The objective was to prospectively investigate the diagnostic accuracy of high-pitch (HP) dual-source computed tomography coronary angiography (CTCA) compared with catheter coronary angiography (CCA) for the diagnosis of significant coronary stenoses.Methods: Thirty-five patients (seven women; mean age 62 ± 8 years) underwent both CTCA and CCA. CTCA was performed with a second-generation dual-source CT system permitting data acquisition at an HP of 3.4. Patients with heart rates >60 bpm were excluded from study enrolment. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a four-point scale (1: excellent to 4: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). CCA served as the standard of reference. Radiation dose values were calculated using the dose-length product.Results: Diagnostic image quality was found in 99% of all segments (455/459). Non-diagnostic image quality occurred in a single patient with a sudden increase in heart rate immediately before and during CTCA. Taking segments with non-evaluative image quality as positive for disease, the sensitivity, specificity and positive and negative predictive values were 94, 96, 80 and 99% per segment and 100, 91, 88 and 100% per patient. The effective radiation dose was on average 0.9 ± 0.1 mSv.Conclusion: In patients with heart rates ≤60 bpm, CTCA using the HP mode of the dual-source CT system is associated with high diagnostic accuracy for the assessment of coronary artery stenoses at sub-milli-Sievert doses. [ABSTRACT FROM AUTHOR]

Patients intended for circulatory support by cardiac assist devices (CAD) usually suffer from end-stage acute or chronic heart failure. Since the introduction of CAD in 1963 by DeBakey and coworkers, the systems have gone through a substantial evolution and have been increasingly used in the intervening decades. The spectrum of CAD includes a variety of systems serving to assist the systolic function of the left ventricle, the right ventricle, or both. Conventional radiography and multislice spiral computed tomography (CT) are the most commonly used radiological techniques for imaging patients with a CAD. CT is very useful for evaluating CAD systems by using both two- and three-dimensional reconstructions of the volumetric data sets. The two techniques together allow for the comprehensive assessment of patients with devices by imaging the in- and outflow cannulae, the anastomoses, the position of the pump, as well as associated complications. A close collaboration with cardiac surgeons with expertise in the field of circulatory support is deemed necessary for adequate image interpretation. This article describes the technical diversity of the currently available CAD systems. The imaging characteristics on conventional radiography and multislice spiral CT as well as the typical complications of their use are demonstrated. [ABSTRACT FROM AUTHOR]

Detailed knowledge of aortic root geometry is a prerequisite to anticipate complications of transcatheter aortic valve (TAV) implantation. We determined coronary ostial locations and aortic root dimensions in patients with aortic stenosis (AS) and compared these values with normal subjects using computed tomography (CT). One hundred consecutive patients with severe tricuspid AS and 100 consecutive patients without valvular pathology (referred to as the controls) undergoing cardiac dual-source CT were included. Distances from the aortic annulus (AA) to the left coronary ostium (LCO), right coronary ostium (RCO), the height of the left coronary sinus (HLS), right coronary sinus (HRS), and aortic root dimensions [diameters of AA, sinus of Valsalva (SV), and sino-tubular junction (STJ)] were measured. LCO and RCO were 14.9 +/- 3.2 mm (8.2-25.9) and 16.8 +/- 3.6 mm (12.0-25.7) in the controls, 15.5 +/- 2.9 mm (8.8-24.3) and 17.3 +/- 3.6 mm (7.3-26.0) in patients with AS. Controls and patients with AS had similar values for LCO (P = 0.18), RCO (P = 0.33) and HLS (P = 0.88), whereas HRS (P < 0.05) was significantly larger in patients with AS. AA (r = 0.55,P < 0.001), SV (r = 0.54,P < 0.001), and STJ (r = 0.52,P < 0.001) significantly correlated with the body surface area in the controls; whereas no correlation was found in patients with AS. Patients with AS had significantly larger AA (P < 0.01) and STJ (P < 0.01) diameters when compared with the controls. In patients with severe tricuspid AS, coronary ostial locations were similar to the controls, but a transverse remodelling of the aortic root was recognized. Owing to the large distribution of ostial locations and the dilatation of the aortic root, CT is recommended before TAV implantation in each patient. [ABSTRACT FROM AUTHOR]

Triage decisions in patients suffering from acute chest pain remain a challenge. The patient's history, initial cardiac enzyme levels, or initial electrocardiograms (ECG) often do not allow selecting the patients in whom further tests are needed. Numerous vascular and non-vascular chest problems, such as pulmonary embolism (PE), aortic dissection, or acute coronary syndrome, as well as pulmonary, pleural, or osseous lesions, must be taken into account. Nowadays, contrast-enhanced multi-detector-row computed tomography (CT) has replaced previous invasive diagnostic procedures and currently represents the imaging modality of choice when the clinical suspicion of PE or acute aortic syndrome is raised. At the same time, CT is capable of detecting a multitude of non-vascular causes of acute chest pain, such as pneumonia, pericarditis, or fractures. Recent technical advances in CT technology have also shown great advantages for non-invasive imaging of the coronary arteries. In patients with acute chest pain, the optimization of triage decisions and cost-effectiveness using cardiac CT in the emergency department have been repetitively demonstrated. Triple rule-out CT denominates an ECG-gated protocol that allows for the depiction of the pulmonary arteries, thoracic aorta, and coronary arteries within a single examination. This can be accomplished through the use of a dedicated contrast media administration regimen resulting in a simultaneous attenuation of the three vessel territories. This review is intended to demonstrate CT parameters and contrast media administration protocols for performing a triple rule-out CT and discusses radiation dose issues pertinent to the protocol. Typical life-threatening and non-life-threatening diseases causing acute chest pain are illustrated. [ABSTRACT FROM AUTHOR]

To overcome the limitations of the classical volume scoring method for quantifying coronary calcifications, including accuracy, variability between examinations, and dependency on plaque density and acquisition parameters, a mesh-based volume measurement method has been developed. It was evaluated and compared with the classical volume scoring method for accuracy, i.e., the normalized volume (measured volume/ground-truthed volume), and for variability between examinations (standard deviation of accuracy). A cardiac computed-tomography (CT) phantom containing various cylindrical calcifications was scanned using different tube voltages and reconstruction kernels, at various positions and orientations on the CT table and using different slice thicknesses. Mean accuracy for all plaques was significantly higher (p < 0.0001) for the proposed method (1.220 +/- 0.507) than for the classical volume score (1.896 +/- 1.095). In contrast to the classical volume score, plaque density (p = 0.84), reconstruction kernel (p = 0.19), and tube voltage (p = 0.27) had no impact on the accuracy of the developed method. In conclusion, the method presented herein is more accurate than classical calcium scoring and is less dependent on tube voltage, reconstruction kernel, and plaque density. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the prognostic value of 64-slice CT angiography (CTA) in patients with known or suspected coronary artery disease (CAD). Sixty-four-slice coronary CTA was performed in 220 patients [mean age 63 +/- 11 years, 77 (35%) female] with known or suspected CAD. CTA images were analyzed with regard to the presence and number of coronary lesions. Patients were followed-up for the occurrence of the following clinical endpoints: death, nonfatal myocardial infarction, unstable angina, and coronary revascularization. During a mean follow-up of 14 +/- 4 months, 59 patients (27%) reached at least one of the predefined clinical endpoints. Patients with abnormal coronary arteries on CTA (i.e., presence of coronary plaques) had a 1st-year event rate of 34%, whereas in patients with normal coronary arteries no events occurred (event rate, 0%, p < 0.001). Similarly, obstructive lesions (> or =50% luminal narrowing) on CTA were associated with a high first-year event rate (59%) compared to patients without stenoses (3%, p < 0.001). The presence of obstructive lesions was a significant independent predictor of an adverse cardiac outcome. Sixty-four-slice CTA predicts cardiac events in patients with known or suspected CAD. Conversely, patients with normal coronary arteries on CTA have an excellent mid-term prognosis. [ABSTRACT FROM AUTHOR]

Purpose: To prospectively evaluate the accuracy of ultralow radiation dose CT of the chest with tin filtration at 100 kV for pulmonary nodule detection., Materials and Methods: 202 consecutive patients undergoing clinically indicated chest CT (standard dose, 1.8 ± 0.7 mSv) were prospectively included and additionally scanned with an ultralow dose protocol (0.13 ± 0.01 mSv). Standard dose CT was read in consensus by two board-certified radiologists to determine the presence of lung nodules and served as standard of reference (SOR). Two radiologists assessed the presence of lung nodules and their locations on ultralow dose CT. Sensitivity and specificity of the ultralow dose protocol was compared against the SOR, including subgroup analyses of different nodule sizes and types. A mixed effects logistic regression was used to test for independent predictors for sensitivity of pulmonary nodule detection., Results: 425 nodules (mean diameter 3.7 ± 2.9 mm) were found on SOR. Overall sensitivity for nodule detection by ultralow dose CT was 91%. In multivariate analysis, nodule type, size and patients BMI were independent predictors for sensitivity (p < 0.001)., Conclusions: Ultralow dose chest CT at 100 kV with spectral shaping enables a high sensitivity for the detection of pulmonary nodules at exposure levels comparable to plain film chest X-ray., Keypoints: • 91% of all lung nodules were detected with ultralow dose CT • Sensitivity for subsolid nodule detection is lower in ultralow dose CT (77.5%) • The mean effective radiation dose in 202 patients was 0.13 mSv • Ultralow dose CT seems to be feasible for lung cancer screening.

Purpose: To evaluate the potential of advanced modeled iterative reconstruction (ADMIRE) for optimizing radiation dose of high-pitch coronary CT angiography (CCTA)., Methods: High-pitch 192-slice dual-source CCTA was performed in 25 patients (group 1) according to standard settings (ref. 100 kVp, ref. 270 mAs/rot). Images were reconstructed with filtered back projection (FBP) and ADMIRE (strength levels 1-5). In another 25 patients (group 2), high-pitch CCTA protocol parameters were adapted according to results from group 1 (ref. 160 mAs/rot), and images were reconstructed with ADMIRE level 4. In ten patients of group 1, vessel sharpness using full width at half maximum (FWHM) analysis was determined. Image quality was assessed by two independent, blinded readers., Results: Interobserver agreements for attenuation and noise were excellent (r = 0.88/0.85, p < 0.01). In group 1, ADMIRE level 4 images were most often selected (84%, 21/25) as preferred data set; at this level noise reduction was 40% compared to FBP. Vessel borders showed increasing sharpness (FWHM) at increasing ADMIRE levels (p < 0.05). Image quality in group 2 was similar to that of group 1 at ADMIRE levels 2-3. Radiation dose in group 2 (0.3 ± 0.1 mSv) was significantly lower than in group 1 (0.5 ± 0.3 mSv; p < 0.05)., Conclusions: In a selected population, ADMIRE can be used for optimizing high-pitch CCTA to an effective dose of 0.3 mSv., Key Points: • Advanced modeled IR (ADMIRE) reduces image noise up to 50% as compared to FBP. • Coronary artery vessel borders show an increasing sharpness at higher ADMIRE levels. • High-pitch CCTA with ADMIRE is possible at a radiation dose of 0.3 mSv.

Objectives: To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA)., Methods: First, a cardiac motion phantom simulating heart rates (HRs) from 60-90 bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250 ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50 years) undergoing clinically indicated CCTA were included., Results: In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1 mm or less. Distortion increased above 1 mm at HR of 80-90 bpm. Patients had a mean HR of 66 bpm (47-78 bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73 bpm. Average effective radiation dose in patients was 0.6 ± 0.3 mSv., Conclusions: Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75 bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6 mSv., Key Points: • CCTA is feasible with the turbo high-pitch mode. • Turbo high-pitch CCTA provides diagnostic image quality up to 73 bpm. • The radiation dose of high-pitch CCTA is 0.6 mSv on average.

The aim of this study was to determine the feasibility and image quality of dual-source computed tomography angiography (DSCTA) in patients with acute chest pain for the assessment of the lung, thoracic aorta, and for pulmonary and coronary arteries. Sixty consecutive patients (32 female, 28 male, mean age 58.1+/-16.3 years) with acute chest pain underwent contrast-enhanced electrocardiography-gated DSCTA without prior beta-blocker administration. Vessel attenuation of different thoracic vascular territories was measured, and image quality was semi-quantitatively analyzed by two independent readers. Image quality of the thoracic aorta was diagnostic in all 60 patients, image quality of pulmonary arteries was diagnostic in 59, and image quality of coronary arteries was diagnostic in 58 patients. Pairwise intraindividual comparisons of attenuation values were small and ranged between 1+/-6 HU comparing right and left coronary artery and 56+/-9 HU comparing the pulmonary trunk and left ventricle. Mean attenuation was 291+/-65 HU in the ascending aorta, 334+/-93 HU in the pulmonary trunk, and 285+/-66 HU and 268+/-67 HU in the right and left coronary artery, respectively. DSCTA is feasible and provides diagnostic image quality of the thoracic aorta, pulmonary and coronary arteries in patients with acute chest pain.

Temporal windows providing the best image quality of different segments and types of coronary artery bypass grafts (CABGs) with 64-slice computed tomography (CT) were evaluated in an experimental set-up. Sixty-four-slice CT with a rotation time of 330 ms was performed in 25 patients (four female; mean age 59.9 years). A total of 84 CABGs (62 individual and 22 sequential grafts) were evaluated, including 28 internal mammary artery (33.3%), one radial artery with sequential grafting (2.4%), and 54 saphenous vein grafts (64.3%). Ten data sets were reconstructed in 10% increments of the RR-interval. Each graft was separated into segments (proximal and distal anastomosis, and body), and CABG types were grouped according to target arteries. Two readers independently assessed image quality of each CABG segment in each temporal window. Diagnostic image quality was found with good inter-observer agreement (kappa=0.62) in 98.5% (202/205) of all graft segments. Image quality was significantly better for saphenous vein grafts versus arterial grafts (P<0.001) and for distal anastomosis to the right coronary compared with other target coronary arteries (P<0.05). Overall, best image quality was found at 60%. Image quality of proximal segments did not significantly vary with the temporal window, whereas for all other segments image quality was significantly better at 60% compared with other temporal windows (P<0.05). Sixty-four-slice CT provides best image quality of various segments and types of CABG at 60% of the RR-interval.

We aimed at assessing stent geometry and in-stent contrast attenuation with 64-slice CT in patients with various coronary stents. Twenty-nine patients (mean age 60 +/- 11 years; 24 men) with 50 stents underwent CT within 2 weeks after stent placement. Mean in-stent luminal diameter and reference vessel diameter proximal and distal to the stent were assessed with CT, and compared to quantitative coronary angiography (QCA). Stent length was also compared to the manufacturer's values. Images were reconstructed using a medium-smooth (B30f) and sharp (B46f) kernel. All 50 stents could be visualized with CT. Mean in-stent luminal diameter was systematically underestimated with CT compared to QCA (1.60 +/- 0.39 mm versus 2.49 +/- 0.45 mm; P < 0.0001), resulting in a modest correlation of QCA versus CT (r = 0.49; P < 0.0001). Stent length as given by the manufacturer was 18.2 +/- 6.2 mm, correlating well with CT (18.5 +/- 5.7 mm; r = 0.95; P < 0.0001) and QCA (17.4 +/- 5.6 mm; r = 0.87; P < 0.0001). Proximal and distal reference vessel diameters were similar with CT and QCA (P = 0.06 and P = 0.03). B46f kernel images showed higher image noise (P < 0.05) and lower in-stent CT attenuation values (P < 0.001) than images reconstructed with the B30f kernel. 64-slice CT allows measurement of coronary artery in-stent density, and significantly underestimates the true in-stent diameter compared to QCA.

The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1+/-11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14+/-9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter > or =1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3+/-3.9 kg/m2 (range 22.4-36.3 kg/m2), mean heart rate during CT was 70.3+/-14.2 bpm (range 47-102 bpm), and mean Agatston score was 821+/-904 (range 0-3,110). Image quality was diagnostic (scores 1-3) in 98.6% (414/420) of segments (mean image quality score 1.68+/-0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control.

The purpose of this study was to evaluate the influence of ejection fraction (EF), stroke volume (SV), heart rate, and cardiac output (CO) on coronary artery opacification with 64-slice computed tomography (CT). Sixty patients underwent, retrospectively, electrocardiography-gated 64-slice CT coronary angiography. Left ventricular EF, SV, and CO were calculated with semi-automated software. Attenuation values were measured and contrast-to-noise ratios (CNRs) were calculated in the proximal right coronary artery (RCA) and left main artery (LMA). Mean EF during scanning was 61.5+/-12.4%, SV was 63.2+/-15.6 ml, heart rate was 62.5+/-11.8 beats per minute (bpm), and CO was 3.88+/-1.06 l/min. There was no significant correlation between the EF and heart rate and the attenuation and CNR in either coronary artery. A significant negative correlation was found in both arteries between SV and attenuation (RCA r=-0.26, P<0.05; LMA r=-0.34, P<0.01) and between SV and CNR (RCA r=-0.26, P<0.05; LMA r=-0.26, P<0.05). Similarly, a significant negative correlation was found between the CO and attenuation (RCA r=-0.42, P<0.05; LMA r=-0.56, P<0.001) and between the CO and CNR (RCA r=-0.39, P<0.05; LMA r=-0.44, P<0.001). The actual hemodynamic status of the patient influences the coronary artery opacification with 64-slice CT, in that vessel opacification decreases as SV and CO increase.