Rationale, design and methods of CTCA-PRORECAD (Computed Tomography Coronary Angiography Prognostic Registry for Coronary Artery Disease): a multicentre and multivendor registry.

PURPOSE: This study was done to assess the prognostic value of computed tomography coronary angiography (CTCA) in a large multicentre population of patients with suspected coronary artery disease (CAD) and, in particular, its incremental value compared with traditional methods for risk stratification. MATERIALS AND METHODS: This is a retrospective observational study that began in January 2003 conducted on patients with suspected CAD assessed with CTCA on the basis of symptoms (chest pain, dyspnoea) and/or abnormal or equivocal stress test and/or a high cardiovascular risk profile. The participating centres will provide data obtained with CTCA performed with 16-slice or higher equipment. Exclusion criteria are renal insufficiency, allergy to iodinated contrast material, pregnancy and previous myocardial infarction or revascularisation (percutaneous coronary intervention and/or coronary artery bypass graft). All patients are stratified by means of clinical assessment and/or data retrieved from a clinical database. Risk factors considered are hypertension, dyslipidaemia, diabetes mellitus, smoking, family history and obesity. Symptoms are classified as absent, typical chest pain, atypical chest pain and dyspnoea. Primary endpoints are death, major adverse cardiovascular events (cardiac death, unstable angina requiring hospitalisation, acute myocardial infarction) and shifting of cardiovascular risk category on the basis of coronary plaque burden. The secondary endpoint is coronary revascularisation. Telephone interviews and/or clinical databases are used for the follow-up. The study will be conducted on a population >1,000 patients. CONCLUSIONS: The information collected from the Prognostic Registry for Coronary Artery Disease (PRORECAD) will provide insight into the prognostic value of CTCA in addition to demographic and clinical features. The results will allow for better use and interpretation of CTCA for prognostic purposes.

MDCT findings of aortic branch artery pseudoaneurysms associated with type B intramural haematoma.

PURPOSE: The purpose of this study was to evaluate prevalence, morphological characteristics and evolution of aortic branch artery pseudoaneurysms associated with type B aortic intramural haematoma (IMH) using multidetector computed tomography (MDCT). MATERIALS AND METHODS: We enrolled 14 patients (nine men; mean age 64.6±9.6; range 42-75 years) with a diagnosis in the acute phase of type B IMH without evidence of intimal tear. All patients underwent clinical and MDCT follow-up. RESULTS: Twenty-two pseudoaneurysms in six patients (6/14, 43%) were observed at MDCT. In the majority of patients (5/6, 83%) the pseudoaneurysms were multiple and involved the branches of the descending thoracic aorta (14/22, 64%), mainly the intercostal arteries (11/22, 50%). At a mean follow-up of 10.6±8.7 months, 21 pseudoaneurysms showed resolution, reduction or dimensional stability (95%), whereas only one increased in size (5%). CONCLUSIONS: Aortic branch artery pseudoaneurysms associated with IMH may be considered a benign disease, as the majority of cases resolved or did not change in size, with haematoma resorption. However, because a dynamic change in pseudoaneurysms in the acute and subacute phases was frequently observed, close clinical and imaging follow-up is mandatory.

Classification of noncalcified coronary atherosclerotic plaque components on CT coronary angiography: impact of vascular attenuation and density thresholds.

PURPOSE: The authors assessed the effect of vascular attenuation and density thresholds on the classification of noncalcified plaque by computed tomography coronary angiography (CTCA). MATERIALS AND METHODS: Thirty patients (men 25; age 59 ± 8 years) with stable angina underwent arterial and delayed CTCA. At sites of atherosclerotic plaque, attenuation values (HU) were measured within the coronary lumen, noncalcified and calcified plaque material and the surrounding epicardial fat. Based on the measured CT attenuation values, coronary plaques were classified as lipid rich (attenuation value below the threshold) or fibrous (attenuation value above the threshold) using 30-HU, 50-HU and 70-HU density thresholds. RESULTS: One hundred and sixty-seven plaques (117 mixed and 50 noncalcified) were detected and assessed. The attenuation values of mixed plaques were higher than those of exclusively noncalcified plaques in both the arterial (148.3 ± 73.1 HU vs. 106.2 ± 57.9 HU) and delayed (111.4 ± 50.5 HU vs. 64.4 ± 43.4 HU) phases (p<0.01). Using a 50-HU threshold, 12 (7.2%) plaques would be classified as lipid rich on arterial scan compared with 28 (17%) on the delayed-phase scan. Reclassification of these 16 (9.6%) plaques from fibrous to lipid rich involved 4/30 (13%) patients. CONCLUSIONS: Classification of coronary plaques as lipid rich or fibrous based on absolute CT attenuation values is significantly affected by vascular attenuation and density thresholds used for the definition.

Computed tomography coronary angiography in the selection of outlier patients: a feasibility report.

PURPOSE: This study evaluated criteria, presence and distribution of outlier patients by means of computed tomography coronary angiography (CTCA) in a large institutional database. MATERIAL AND METHODS: From a population of 2,881 consecutive patients (1,842 men, mean age 62 ± 13 years) in sinus rhythm who underwent CTCA, we extracted data on patients with suspected coronary artery disease (CAD). We selected patient outliers in the fifth and sixth decades of life with the following criteria: ≥ 3 risk factors and absence of CAD, zero to one risk factors and ≥ 5 diseased coronary segments. Diabetes was excluded from risk factors because of the different impact on CAD. RESULTS: The patient population consisted of 2,432 individuals with suspected CAD (1,495 men, age 62 ± 13 years). The prevalence of obstructive CAD (≥ 50% lumen reduction at CTCA) was 36% (863/2,432). Patients with normal coronary arteries accounted for 34% of the total (837/2,432; 431 men, age 55 ± 14 years). Of these, 210 were in the fifth and 231 in the 6th decade (men 196, women 245); those with ≥ 3 risk factors accounted for 4.2% of the total (102/2,432; men 42, women 60). Patients with ≥ 5 diseased coronary segments accounted for 28% of the total (686/2,432; 510 men, age 68 ± 10 years). Of these, 115 were in the fifth and 270 in the sixth decade (men 309, women 76); those with zero to one risk factors accounted for 3.0% (73/2,432; men 66, women 7). CONCLUSIONS: CTCA is a reliable noninvasive diagnostic modality that can be used to identify outlier patients. This will enable dedicated trials aimed at characterising biomarkers and genomics of protective and nonprotective factors against CAD and its complications.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data on the comparison between male and female population.

PURPOSE: This study was undertaken to evaluate the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (≥50% lumen reduction) compared with conventional coronary angiography (CAG) in a male and female population. MATERIAL AND METHODS: A total of 1,372 patients (882 men, 490 women; mean age 59.3 ± 11.9 years) in sinus rhythm imaged with CTCA (64-slice technology) and CAG were enrolled. Diagnostic accuracy and likelihood ratios (LR+ and LR-) of CTCA were assessed against CAG for the male and female populations. RESULTS: The prevalence of obstructive disease was 53% (men 58%; women 43%). CAG demonstrated the absence of significant coronary artery disease (CAD) in 47% (men 42%; women 56%), single-vessel disease in 25% (men 36%; women 22%) and multivessel disease in 29% (men 32%; women 23%) of patients. In the per-patient analysis, sensitivity, specificity and positive (PPV) and negative (NPV) predictive values of CTCA were 99% (men 98%; women 100%), 92% (men 92%; women 92%), 94% (men 95%; women 90%) and 99% (men 98%; women 100%), respectively. The per-patient likelihood ratios (LR) in the total population (LR+=12.4 and LR-=0.011), the male (LR+=12.9 and LR-=0.016) and female (LR =11.9 and LR-=0) populations were very good. We observed no significant differences in diagnostic accuracy between male and female populations. CONCLUSIONS: CTCA is a reliable diagnostic modality with high sensitivity and NPV in the female population.

Diagnostic accuracy of second-generation dual-source computed tomography coronary angiography with iterative reconstructions: a real-world experience.

PURPOSE: The authors evaluated the diagnostic accuracy of second-generation dual-source (DSCT) computed tomography coronary angiography (CTCA) with iterative reconstructions for detecting obstructive coronary artery disease (CAD). MATERIALS AND METHODS: Between June 2010 and February 2011, we enrolled 160 patients (85 men; mean age 61.2±11.6 years) with suspected CAD. All patients underwent CTCA and conventional coronary angiography (CCA). For the CTCA scan (Definition Flash, Siemens), we use prospective tube current modulation and 70-100 ml of iodinated contrast material (Iomeprol 400 mgI/ ml, Bracco). Data sets were reconstructed with iterative reconstruction algorithm (IRIS, Siemens). CTCA and CCA reports were used to evaluate accuracy using the threshold for significant stenosis at ≥50% and ≥70%, respectively. RESULTS: No patient was excluded from the analysis. Heart rate was 64.3±11.9 bpm and radiation dose was 7.2±2.1 mSv. Disease prevalence was 30% (48/160). Sensitivity, specificity and positive and negative predictive values of CTCA in detecting significant stenosis were 90.1%, 93.3%, 53.2% and 99.1% (per segment), 97.5%, 91.2%, 61.4% and 99.6% (per vessel) and 100%, 83%, 71.6% and 100% (per patient), respectively. Positive and negative likelihood ratios at the per-patient level were 5.89 and 0.0, respectively. CONCLUSIONS: CTCA with second-generation DSCT in the real clinical world shows a diagnostic performance comparable with previously reported validation studies. The excellent negative predictive value and likelihood ratio make CTCA a first-line noninvasive method for diagnosing obstructive CAD.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data on the impact of calcium score.

PURPOSE: This study evaluated the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (≥50% lumen reduction) at different coronary calcium score (CACS) values with conventional coronary angiography (CAG) as the reference standard. MATERIAL AND METHODS: A total of 1,500 patients (928 men, mean age 58.2±12.5 years) in sinus rhythm who underwent CTCA (64-slice technology) and CAG were enrolled. Diagnostic accuracy and likelihood ratios (LR) of CTCA were evaluated against CAG for the total population and in different CACS classes (0; 1-10; 11-100; 101-400; 401-1,000; >1,000). RESULTS: The prevalence of obstructive disease was 51% (23.5% single vessel; 27.5% multivessel; progressive increase from 17.9% to 94% through the CACS classes). In the per-patient analysis, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CTCA were 99%, 92%, 94% and 99%, respectively. Per-patient analysis showed a worse PPV of CTCA (76-77%) in classes with low CACS (1-10/11-100). Per-patient LR were higher in classes with extreme CACS values (0 = LR+ 18.3 and LR- = 0.0; c1,000 = LR+ 17.0 and LR- = 0.0) with values always >7 for LR+ and <0.033 for LR- for all CACS classes. CONCLUSIONS: CTCA is a reliable diagnostic modality, with high sensitivity and NPV regardless of CACS.

Prognostic value of computed tomography coronary angiography in patients with chest pain of suspected cardiac origin.

PURPOSE: The authors sought to determine the prognostic value of computed tomography coronary angiography (CTCA) in patients with acute chest pain (ACP). MATERIALS AND METHODS: A total of 145 consecutive patients (75 men; 64±12 years) with ACP were referred from the Emergency Department for CTCA, which was performed with a standard protocol using a 64-slice scanner. Patients were stratified according to the Morise clinical score (low, intermediate, high) and to the CTCA findings [absence of coronary artery disease (CAD), nonobstructive CAD, obstructive CAD]. Patients were followed up for the occurrence of major events: cardiac death, nonfatal myocardial infarction, unstable angina and revascularisation. RESULTS: One hundred and twenty-seven (87.6%) patients were without a history of CAD, and 18 (12.4%) patients had a history of CAD. Obstructive CAD (>50% luminal narrowing) was detected in 35 (24%) patients; nonobstructive CAD (≤ 50% luminal narrowing) in 62 (43%) and absence of CAD in 48 (33%) patients. During a mean follow-up of 20 ± 3 months, 20 events occurred (four hard events). Sixteen events (three hard events) occurred in patients without a history of CAD, and four events (one hard event) occurred in patients with a history of CAD. In patients with absence of CAD as detected by CTCA, the rate of events was 0%. At multivariate analysis, hypercholesterolaemia and obstructive CAD were significant predictors of events (p<0.05). CONCLUSIONS: An excellent prognosis was observed in patients with ACP and normal CTCA. CTCA shows the potential for optimal stratification of patients with ACP.

Prognostic value of CT coronary angiography: focus on obstructive vs. nonobstructive disease and on the presence of left main disease.

PURPOSE: The authors investigated the prognostic value of computed tomography coronary angiography (CTCA) for major adverse cardiac events (MACE) in patients with suspected or known coronary artery disease (CAD), with particular focus on left main (LM) disease and obstructive vs. nonobstructive disease. MATERIALS AND METHODS: A total of 727 consecutive patients (485 men, age 62 ± 11 years) with suspected (514; 70.1%) or known (213; 29.9%) CAD underwent CTCA. Patients were followed up for the occurrence of MACE (i.e. cardiac death, nonfatal myocardial infarction, unstable angina, percutaneous/surgical revascularisation). RESULTS: A total of 117 MACE [five cardiac deaths, 11 acute myocardial infarctions (AMI), five unstable angina, 86 percutaneous coronary interventions, ten coronary artery bypass grafts] occurred during a mean follow-up of 20 months. Severity and extension of CAD was associated with a progressively worse prognosis. The event rate was 0% among patients with normal coronary arteries at CTCA. The presence of LM disease was not associated with a worse prognosis either in patients with no history of CAD or in those with a history of CAD. At multivariate analysis, presence of obstructive CAD and diabetes were the only independent predictors of MACE. CONCLUSIONS: Evaluation of atherosclerotic burden by CTCA provides an independent prognostic value for prediction of MACE. Patients with normal CTCA findings have an excellent prognosis at follow-up.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data in NSTEMI acute coronary syndrome and influence of gender and risk factors.

PURPOSE: This study sought to evaluate the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (≥50% lumen reduction) compared with conventional coronary angiography (CAG) in non-ST-elevation myocardial infarction-acute coronary syndrome (NSTEMI-ACS) and in subgroups selected by gender and number of risk factors (RF). MATERIALS AND METHODS: We selected from a population of 1,500 patients in a multicentre registry with NSTEMI-ACS who had undergone CTCA and CAG, (n=237; 187 men, mean age 63±10 years). Diagnostic accuracy and likelihood ratios (LR) of CTCA were assessed against CAG in the total population and subgroups (men, women: 0 RF = absence of RF, 1-2 RF = presence of one or two RF, >2 RF = presence of more than two RF). RESULTS: The prevalence of obstructive disease was 53%. In the per-patient analysis, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CTCA were 100% (men 100%; women 100%; 0 RF 100%; 1-2 RF 100%; >2 RF 100%), 95% (men 98%; women 50%; 0 RF NA% (NA, not assessable); 1-2 RF 96%; >2 RF 96%), 95% (men 98%; women 91%; 0 RF 91%; 1-2 RF 96%; >2 RF 96%), 100% (men 100%; women 100%; 0 RF NV%; 1-2 RF 100%; >2 RF 100%), respectively. The per-segment analysis showed a reduction in PPV (ranging between 56% and 67%). The per-patient LR+ ranged between 18 and 27, whereas LR-were always 0. We observed no significant differences in diagnostic accuracy between subgroups. CONCLUSIONS: CTCA is a reliable diagnostic modality with high sensitivity and NPV in NSTEMI-ACS patients who are not candidates for early revascularisation, regardless of gender and number of risk factors.

Computed tomography coronary angiography in asymptomatic patients.

PURPOSE: This study assessed the accuracy of computed tomography coronary angiography (CT-CA) for detecting significant coronary artery disease (CAD; ≥50% lumen reduction) in intermediate/high-risk asymptomatic patients. MATERIALS AND METHODS: A total of 183 consecutive asymptomatic individuals (92 men; mean age 54±11 years) with more than one major risk factor (obesity, hypertension, diabetes, hypercholesterolaemia, family history, smoking) and an inconclusive or nonfeasible noninvasive stress test result (stress electrocardiography, stress echocardiography, nuclear stress scintigraphy) underwent CT-CA in an outpatient setting. All patients underwent conventional coronary angiography (CAG) within 4 weeks. Data from CT-CA were compared with CAG regarding the presence of significant CAD (≥50% lumen reduction). RESULTS: Mean calcium score was 177±432, mean heart rate during the CT-CA scan was 58±8 bpm and the prevalence (per-patient) of obstructive CAD was 19%. CT-CA showed single-vessel CAD in 9% of patients, two-vessel CAD in 9% and three-vessel CAD in 0%. Per-patient sensitivity, specificity, positive predictive value and negative predictive value of CT-CA were 100% (90-100), 98% (96-99), 97% (85-99), 100% (97-100), respectively. Positive and negative likelihood ratios were 151 and 0, respectively. CONCLUSIONS: CT-CA is an excellent noninvasive imaging modality for excluding significant CAD in intermediate/ high-risk asymptomatic patients with inconclusive or nonfeasible noninvasive stress test.

Coronary plaque burden in patients with stable and unstable coronary artery disease using multislice CT coronary angiography.

PURPOSE: We evaluated the multislice computed tomography (MSCT) coronary plaque burden in patients with stable and unstable angina pectoris. MATERIALS AND METHODS: Twenty-one patients with stable and 20 with unstable angina pectoris scheduled for conventional coronary angiography (CCA) underwent MSCT-CA using a 64-slice scanner offering a fast rotation time (330 ms) and higher X-ray tube output (900 mAs). To determine the MSCT coronary plaque burden, we assessed the extent (number of diseased segments), size (small or large), type (calcific, noncalcific, mixed) of plaque, its anatomic distribution and angiographic appearance in all available ≥2-mm segments. In a subset of 15 (seven stable, eight unstable) patients, the detection and classification of coronary plaques by MSCT was verified by intracoronary ultrasound (ICUS). RESULTS: Sensitivity and specificity of MSCT compared with ICUS to detect significant plaques (defined as ≥1-mm plaque thickness on ICUS) was 83% and 87%. Overall, 473 segments were examined, resulting in 11.6±1.5 segments per patient. Plaques were present in 62% of segments and classified as large in 47% of diseased segments. Thirty-two percent were noncalcific, 25% calcific and 43% mixed. Plaques were most frequently located in the proximal and mid segments. Plaque was found in 33% of segments classified as normal on CCA. Unstable patients had significantly more noncalcific plaques when compared with stable patients (45% vs. 21%, p<0.05). CONCLUSIONS: MSCT-CA provides important information regarding the coronary plaque burden in patients with stable and unstable angina.

Prognostic value of Morise clinical score, calcium score and computed tomography coronary angiography in patients with suspected or known coronary artery disease.

PURPOSE: Our aim was to determine the prognostic value of computed tomography coronary angiography (CTCA), coronary artery calcium scoring (CACS) and Morise clinical score in patients with known or suspected coronary artery disease (CAD). MATERIALS AND METHODS: A total of 722 patients (480 men; 62.7±10.9 years) who were referred for further cardiac evaluation underwent CACS and contrast-enhanced CTCA to evaluate the presence and severity of CAD. Of these, 511 (71%) patients were without previous history of CAD. Patients were stratified according to the Morise clinical score (low, intermediate, high), to CACS (0-10, 11-100, 101-400, 401-1,000, >1,000) and to CTCA (absence of CAD, nonsignificant CAD, obstructive CAD). Patients were followed up for the occurrence of major events: cardiac death, nonfatal myocardial infarction, unstable angina and revascularisation. RESULTS: Significant CAD (>50% luminal narrowing) was detected in 260 (36%) patients; nonsignificant CAD (<50% luminal narrowing) in 250 (35%) and absence of CAD in 212 (29%). During a mean follow-up of 20±4 months, 116 events (21 hard) occurred. In patients with normal coronary arteries on CTCA, the major event rate was 0% vs. 1.7% in patients with nonsignificant CAD and 7.3% in patients with significant CAD (p<0.0001). Three hard events (14%) occurred in patients with CACS≤100 and two (9.5%) in patients with intermediate Morise score; one revascularisation was observed in a patient with low Morise score. At multivariate analysis, diabetes, obstructive CAD and CACS >1,000 were significant predictors of events (p<0.05). CONCLUSIONS: An excellent prognosis was noted in patients with a normal CTCA (0% event rate). CACS ≤100 and low-intermediate Morise score did not exclude the possibility of events at follow-up.

Low dose CT of the heart: a quantum leap into a new era of cardiovascular imaging.

In 10 years, computed tomography coronary angiography (CTCA) has shifted from an investigational tool to clinical reality. Even though CT technologies are very advanced and widely available, a large body of evidence supporting the clinical role of CTCA is missing. The reason is that the speed of technological development has outpaced the ability of the scientific community to demonstrate the clinical utility of the technique. In addition, with each new CT generation, there is a further broadening of actual and potential applications. In this review we examine the state of the art on CTCA. In particular, we focus on issues concerning technological development, radiation dose, implementation, training and organisation.

Dose reduction in spiral CT coronary angiography with dual source equipment. Part II. Dose surplus due to slope-up and slope-down of prospective tube current modulation in a phantom model.

PURPOSE: This study was undertaken to estimate surplus radiation dose in retrospectively electrocardiography (ECG)-gated dual-source computed tomography coronary angiography (DSCT-CA) due to the slope-up and slope-down of the tube current using prospectively ECG-triggered tube modulation. MATERIALS AND METHODS: We used an anthropomorphic phantom with an ECG-gated retrospective protocol and a DSCT scanner (Definition, Siemens). We used four tube current modulation algorithms: narrow pulsing window, with tube current reduction to 20% (A) and 4% (B) of peak current; and wide pulsing window, with tube current reduction to 20% (C) and 4% (D). Each algorithm was applied at five heart rates (HR=45, 60, 75, 90 and 120 bpm) with adaptive pitch values (0.2-0.5). Data sets were reconstructed in 5% increments from 0-95% of the R-R interval. Noise was measured at each R-R step in order to identify low noise (100% dose), medium noise (slope-up/down) and high noise (4/20% dose). Width of the transition window (slope-up/slope-down from 4/20% to 100% dose) was calculated. The surplus dose due to slope-up/slope-down was calculated. RESULTS: Surplus dose was 19% (A), 34% (B), 14% (C) and 21% (D). The transition window lasted 10%+10% (slope-up + down) for HR <75 bpm and all HR in C (except for 120 bpm; 25%+15%), 15%+15% for HR >90 bpm (A). For C and D, instead, the slope-up increased with progressively higher HR (10%-25% of the R-R interval, except for 90 bpm, 10%), whereas the slope-down remained constant at 5% (except for 120 bpm; 10%). CONCLUSIONS: The adaptive ECG-pulsing windows produced an increment of the surplus dose with increasing HR. The transition window was a constant source of surplus radiation dose in the range of 14%-34%.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data and review of multicentre trials.

PURPOSE: This study was undertaken to evaluate the diagnostic accuracy of computed tomography coronary angiography (CT-CA) for the detection of significant coronary artery stenosis (> or =50% lumen reduction) compared with conventional coronary angiography (CCA) in a registry and to review major multicentre trials. MATERIALS AND METHODS: A total of 1,372 patients (882 men, 490 women; mean age 59.3+/-11.9 years) in sinus rhythm were studied with CT-CA (64-slice technology) and CCA. The diagnostic accuracy of CT-CA was evaluated against quantitative CCA as a reference standard for coronary artery stenosis. Positive and negative likelihood ratios and inter- and intraobserver agreement were calculated. RESULTS: The prevalence of disease was 53%. CCA demonstrated the absence of significant coronary artery disease in 46.6% (639/1372), single-vessel disease in 24.7% (337/1372) and multivessel disease in 28.9% (396/1372) of patients. In per-patient analysis sensitivity, specificity and positive and negative predictive value of CT-CA were 99% [confidence interval (CI) 97-99], 92% (CI 89-94), 94% (CI 91-95) and 99% (CI 97-99), respectively. Per-patient and per-segment likelihood ratios (LR+=12.4 and LR-=0.011; LR+=18.3 and LR-=0.064, respectively), were good. Inter- and intraobserver variability was 0.78 and 0.85, respectively. CONCLUSIONS: CT-CA is a reliable diagnostic modality both in terms of sensitivity and negative predictive value. Differences in trial results are also due to the different parameters used for patient inclusion.

Impact of contrast material volume on quantitative assessment of reperfused acute myocardial infarction using delayed-enhancement 64-slice CT: experience in a porcine model.

PURPOSE: Our purpose in this study was to compare the impact of contrast material volume in delayed-enhancement computer tomography (CT) imaging for assessing acute reperfused myocardial infarction. MATERIALS AND METHODS: In five domestic pigs (20-30 kg), the circumflex coronary artery (CX) was balloon-occluded for 2 h followed by reperfusion. After 5 days, CT imaging was performed after intravenous administration of iodinated contrast material (Iomeprol 400 mgI/ml; Bracco, Italy). A 64-slice multidetector CT (MDCT) (Sensation 64, Siemens) scanner was used for imaging, with standard angiography characteristics. Three scans were performed: first, coronary angiography at first pass with 1.25 gI/kg of contrast material (ART); and remaining delayed-enhancement (DE(1)-DE(2)) 15 min after administration of 1.25 (DE(1)) and 15 min after additional administration of 2.50 gI/kg (=total 3.75 gI/kg - DE(2)). Mean heart rate decreased to 51+/-9 bpm after intravenous administration of Zatebradine (10 mg/kg). Data sets were reconstructed during the end-diastolic phase of the cardiac cycle. Areas of infarction-enhanced (DE), no-reflow (no-reflow) and remote myocardial [remote left ventricle (LV)] were manually contoured. CT attenuation values (Hounsfield units) were measured using five regions of interest: DE, no-reflow, remote LV, left ventricular cavity (lumen LV) and in air. Differences, correlations, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. RESULTS: We found significant differences between the attenuation of DE, no-reflow and remote LV (p<0.001). DE and no-reflow size were assessed accurately with DEMDCT. In particular, SNR and CNR showed higher values in DE(2) (approximately 6.0 and 3.5, respectively; r(2)=0.90) vs. DE(1) (approximately 4.0 and 2.2, respectively; r(2)=0.85). CONCLUSIONS: The increase of contrast material volume determines a significant improvement in myocardial infarction image quality with DE-MDCT.

Left ventricular ejection fraction: real-world comparison between cardiac computed tomography and echocardiography in a large population.

PURPOSE: This study compared cardiac computed tomography (CT) and two-dimensional transthoracic echocardiography (ECC) for assessing left ventricular ejection fraction (LVEF) using real-world data from a large patient population. MATERIALS AND METHODS: We studied 450 patients (284 males; mean age 64±12 years; range 12-88) who underwent CT and ECC due to suspected coronary artery disease. For CT, we used multiphase short-axis reconstructions and evaluated them with a dedicated software tool that uses Simpson's rule to compute LV volumes. For ECC, computation was based on the biplane Simpson's method. Results in terms of EF were compared with the paired Student's t test, Pearson's correlation coefficient (r), and Bland-Altman analysis. RESULTS: EF was 52%±15% for CT and 55%±13% for ECC. Statistically significant differences, albeit with good correlation, were observed between the measurements (r=0.71; p<0.05). ECC showed a slight tendency to overestimate EF. When the population was divided into subgroups according to EF, this was underestimated by ECC in the subgroup with EF >50% and overestimated in those with EF 35%-50% and <35%, with consistently significant differences between ECC and CT (p<0.05) and progressively lower levels of agreement. CONCLUSIONS: In the real-world assessment of EF, ECC provides significantly different data from CT, with a bias that increases proportionally to LV systolic dysfunction.

Impact of tube current in the quantitative assessment of acute reperfused myocardial infarction with 64-slice delayed-enhancement CT: a porcine model.

PURPOSE: This study evaluated the impact of tube current (mAs) in delayed-enhancement computed tomography (CT) imaging for assessing acute reperfused myocardial infarction in a porcine model. MATERIALS AND METHODS: In five domestic pigs (mean weight 24 kg), the circumflex coronary artery was balloon-occluded for 2 h and then reperfused. After 5 days, CT imaging was performed following administration of iodinated contrast material. A 64-slice CT system was used to perform first-pass coronary angiography with a tube current of 15 mAs/kg [Arterial Phase (ART)] followed by two delayed-enhancement (DE) scans 15 min after contrast material administration, with a tube current of 15 mAs/kg and 37.5 mAs/kg, respectively (DE(1) and DE(2)). The mean heart rate decreased to 51±9 beats/min after administration of zatebradine (10 mg/kg IV). The data set was reconstructed during the end-diastolic phase of the cardiac cycle. Areas with DE, no reflow and remote myocardium [remote left ventricular (LV)] were calculated. CT values expressed in Hounsfield units (HU) were measured using five regions of interest (ROI): DE, no reflow, remote LV, LV cavity (LV lumen) and in air, respectively. Differences, correlations, image quality [signal-to-noise ratio (SNR)] and contrast resolution [contrast-to-noise ratio (CNR)] were calculated. RESULTS: Significant differences were found between attenuation of areas of DE, no reflow and remote LV (p<0.001) within the different scans. There was a fair correlation between DE and no-reflow attenuation (r=0.6; p<0.001). In DE(1) vs. DE(2), areas of DE and no reflow were not significantly different (p>0.05). The SNR and CNR were not significantly different in DE(1) vs. DE(2) (p>0.05). CONCLUSIONS: Tube current does not significantly affect infarction area, image quality or contrast resolution of DE imaging with CT.