Collateral non cardiac findings in clinical routine CT coronary angiography: results from a multi-center registry.

PURPOSE: The aim of the study was to evaluate the prevalence of collateral findings detected in computed tomography coronary angiography (CTCA) in a multi-center registry. MATERIALS AND METHODS: We performed a retrospective review of 4303 patients (2719 males, mean age 60.3 ± 10.2 years) undergoing 64-slice CTCA for suspected or known coronary artery disease (CAD) at various academic institutions between 01/2006 and 09/2010. Collateral findings were recorded and scored as: non-significant (no signs of relevant pathology, not necessary to be reported), significant (clear signs of pathology, mandatory to be reported), or major (remarkable pathology, mandatory to be reported and further investigated). RESULTS: We detected 6886 non-cardiac findings (1.6 non cardiac finding per patient). Considering all centers, only 865/4303 (20.1 %) patients were completely without any additional finding. Overall, 2095 (30.4 %) non-significant, 4486 (65.2 %) significant, and 305 (4.4 %) major findings were detected. Among major findings, primary lung cancer was reported in 21 cases. In every center, most prevalent significant findings were mediastinal lymph nodes >1 cm. In 256 patients, collateral findings were clinically more relevant than coexisting CAD and justified the symptoms of patients. CONCLUSIONS: The prevalence of significant and major collateral findings in CTCA is high. Radiologists should carefully evaluate the entire scan volume in each patient.

Stress myocardial perfusion: imaging with multidetector CT.

Computed tomographic (CT) coronary angiography is a well-established, noninvasive imaging modality for detection of coronary stenosis, but it has limited accuracy in demonstrating whether a coronary stenosis is hemodynamically significant. An additional functional test is often required because both anatomic and functional information is needed for guiding patient care. Recent developments in CT technology allow CT evaluation of myocardial perfusion during vasodilator stress, thereby providing information about myocardial ischemia. Investigators in several single-center studies have established the feasibility of performing stress myocardial perfusion CT imaging in small groups of patients and have shown that stress myocardial perfusion CT in combination with CT coronary angiography improved the diagnostic accuracy in comparison with CT coronary angiography alone. However, CT perfusion acquisition protocols must be optimized in terms of acquisition and reconstruction parameters, contrast material protocol injections, and radiation dose. Further research is needed to establish the clinical usefulness of this novel technique. The purpose of this review is to (a) provide an overview of the physiology of coronary circulation and myocardial perfusion; (b) describe the technical prerequisites, challenges, and mathematic modeling related to CT perfusion imaging; (c) note recent advances in CT scanners and CT perfusion protocols; and (d) discuss the interpretation of CT perfusion images. Finally, a review and summary of the current literature are provided, and future directions for research are discussed.

Coronary computed tomography versus exercise testing in patients with stable chest pain: comparative effectiveness and costs.

BACKGROUND: To determine the comparative effectiveness and costs of a CT-strategy and a stress-electrocardiography-based strategy (standard-of-care; SOC-strategy) for diagnosing coronary artery disease (CAD). METHODS: A decision analysis was performed based on a well-documented prospective cohort of 471 outpatients with stable chest pain with follow-up combined with best-available evidence from the literature. Outcomes were correct classification of patients as CAD- (no obstructive CAD), CAD+ (obstructive CAD without revascularization) and indication for Revascularization (using a combination reference standard), diagnostic costs, lifetime health care costs, and quality-adjusted life years (QALY). Parameter uncertainty was analyzed using probabilistic sensitivity analysis. RESULTS: For men (and women), diagnostic cost savings were €245 (€252) for the CT-strategy as compared to the SOC-strategy. The CT-strategy classified 82% (88%) of simulated men (women) in the appropriate disease category, whereas 83% (85%) were correctly classified by the SOC-strategy. The long-term cost-effectiveness analysis showed that the SOC-strategy was dominated by the CT-strategy, which was less expensive (-€229 in men, -€444 in women) and more effective (+0.002 QALY in men, +0.005 in women). The CT-strategy was cost-saving (-€231) but also less effective compared to SOC (-0.003 QALY) in men with a pre-test probability of ≥ 70%. The CT-strategy was cost-effective in 100% of simulations, except for men with a pre-test probability ≥ 70% in which case it was 59%. CONCLUSIONS: The results suggest that a CT-based strategy is less expensive and equally effective compared to SOC in all women and in men with a pre-test probability <70%.

Diagnostic accuracy of 128-slice dual-source CT coronary angiography: a randomized comparison of different acquisition protocols.

OBJECTIVES: To compare the diagnostic performance and radiation exposure of 128-slice dual-source CT coronary angiography (CTCA) protocols to detect coronary stenosis with more than 50 % lumen obstruction. METHODS: We prospectively included 459 symptomatic patients referred for CTCA. Patients were randomized between high-pitch spiral vs. narrow-window sequential CTCA protocols (heart rate below 65 bpm, group A), or between wide-window sequential vs. retrospective spiral protocols (heart rate above 65 bpm, group B). Diagnostic performance of CTCA was compared with quantitative coronary angiography in 267 patients. RESULTS: In group A (231 patients, 146 men, mean heart rate 58 ± 7 bpm), high-pitch spiral CTCA yielded a lower per-segment sensitivity compared to sequential CTCA (89 % vs. 97 %, P = 0.01). Specificity, PPV and NPV were comparable (95 %, 62 %, 99 % vs. 96 %, 73 %, 100 %, P > 0.05) but radiation dose was lower (1.16 ± 0.60 vs. 3.82 ± 1.65 mSv, P < 0.001). In group B (228 patients, 132 men, mean heart rate 75 ± 11 bpm), per-segment sensitivity, specificity, PPV and NPV were comparable (94 %, 95 %, 67 %, 99 % vs. 92 %, 95 %, 66 %, 99 %, P > 0.05). Radiation dose of sequential CTCA was lower compared to retrospective CTCA (6.12 ± 2.58 vs. 8.13 ± 4.52 mSv, P < 0.001). Diagnostic performance was comparable in both groups. CONCLUSION: Sequential CTCA should be used in patients with regular heart rates using 128-slice dual-source CT, providing optimal diagnostic accuracy with as low as reasonably achievable (ALARA) radiation dose.

Quantification of myocardial blood flow by adenosine-stress CT perfusion imaging in pigs during various degrees of stenosis correlates well with coronary artery blood flow and fractional flow reserve.

AIMS: Only few preliminary experimental studies demonstrated the feasibility of adenosine stress CT myocardial perfusion imaging to calculate the absolute myocardial blood flow (MBF), thereby providing information whether a coronary stenosis is flow limiting. Therefore, the aim of our study was to determine whether adenosine stress myocardial perfusion imaging by Dual Source CT (DSCT) enables non-invasive quantification of regional MBF in an animal model with various degrees of coronary flow reduction. METHODS AND RESULTS: In seven pigs, a coronary flow probe and an adjustable hydraulic occluder were placed around the left anterior descending coronary artery to monitor the distal coronary artery blood flow (CBF) while several degrees of coronary flow reduction were induced. CT perfusion (CT-MBF) was acquired during adenosine stress with no CBF reduction, an intermediate (15-39%) and a severe (40-95%) CBF reduction. Reference standards were CBF and fractional flow reserve measurements (FFR). FFR was simultaneously derived from distal coronary artery pressure and aortic pressure measurements. CT-MBF decreased progressively with increasing CBF reduction severity from 2.68 (2.31-2.81)mL/g/min (normal CBF) to 1.96 (1.83-2.33) mL/g/min (intermediate CBF-reduction) and to 1.55 (1.14-2.06)mL/g/min (severe CBF-reduction) (both P < 0.001). We observed very good correlations between CT-MBF and CBF (r = 0.85, P < 0.001) and CT-MBF and FFR (r = 0.85, P < 0.001). CONCLUSION: Adenosine stress DSCT myocardial perfusion imaging allows quantification of regional MBF under various degrees of CBF reduction.

Plaque imaging with CT coronary angiography: Effect of intra-vascular attenuation on plaque type classification.

AIM: To assess the attenuation of non-calcified atherosclerotic coronary artery plaques with computed tomography coronary angiography (CTCA). METHODS: Four hundred consecutive patients underwent CTCA (Group 1: 200 patients, Sensation 64 Cardiac, Siemens; Group 2: 200 patients, VCT GE Healthcare, with either Iomeprol 400 or Iodixanol 320, respectively) for suspected coronary artery disease (CAD). CTCA was performed using standard protocols. Image quality (score 0-3), plaque (within the accessible non-calcified component of each non-calcified/mixed plaque) and coronary lumen attenuation were measured. Data were compared on a per-segment/per-plaque basis. Plaques were classified as fibrous vs lipid rich based on different attenuation thresholds. A P < 0.05 was considered significant. RESULTS: In 468 atherosclerotic plaques in Group 1 and 644 in Group 2, average image quality was 2.96 ± 0.19 in Group 1 and 2.93 ± 0.25 in Group 2 (P ≥ 0.05). Coronary lumen attenuation was 367 ± 85 Hounsfield units (HU) in Group 1 and 327 ± 73 HU in Group 2 (P < 0.05); non-calcified plaque attenuation was 48 ± 23 HU in Group 1 and 39 ± 21 HU in Group 2 (P < 0.05). Overall signal to noise ratio was 15.6 ± 4.7 in Group 1 and 21.2 ± 7.7 in Group 2 (P < 0.01). CONCLUSION: Higher intra-vascular attenuation modifies significantly the attenuation of non-calcified coronary plaques. This results in a more difficult characterization between lipid rich vs fibrous type.

Prediction model to estimate presence of coronary artery disease: retrospective pooled analysis of existing cohorts.

OBJECTIVES: To develop prediction models that better estimate the pretest probability of coronary artery disease in low prevalence populations. DESIGN: Retrospective pooled analysis of individual patient data. SETTING: 18 hospitals in Europe and the United States. PARTICIPANTS: Patients with stable chest pain without evidence for previous coronary artery disease, if they were referred for computed tomography (CT) based coronary angiography or catheter based coronary angiography (indicated as low and high prevalence settings, respectively). MAIN OUTCOME MEASURES: Obstructive coronary artery disease (≥ 50% diameter stenosis in at least one vessel found on catheter based coronary angiography). Multiple imputation accounted for missing predictors and outcomes, exploiting strong correlation between the two angiography procedures. Predictive models included a basic model (age, sex, symptoms, and setting), clinical model (basic model factors and diabetes, hypertension, dyslipidaemia, and smoking), and extended model (clinical model factors and use of the CT based coronary calcium score). We assessed discrimination (c statistic), calibration, and continuous net reclassification improvement by cross validation for the four largest low prevalence datasets separately and the smaller remaining low prevalence datasets combined. RESULTS: We included 5677 patients (3283 men, 2394 women), of whom 1634 had obstructive coronary artery disease found on catheter based coronary angiography. All potential predictors were significantly associated with the presence of disease in univariable and multivariable analyses. The clinical model improved the prediction, compared with the basic model (cross validated c statistic improvement from 0.77 to 0.79, net reclassification improvement 35%); the coronary calcium score in the extended model was a major predictor (0.79 to 0.88, 102%). Calibration for low prevalence datasets was satisfactory. CONCLUSIONS: Updated prediction models including age, sex, symptoms, and cardiovascular risk factors allow for accurate estimation of the pretest probability of coronary artery disease in low prevalence populations. Addition of coronary calcium scores to the prediction models improves the estimates.

Computed tomography coronary angiography accuracy in women and men at low to intermediate risk of coronary artery disease.

OBJECTIVES: To investigate the diagnostic accuracy of CT coronary angiography (CTCA) in women at low to intermediate pre-test probability of coronary artery disease (CAD) compared with men. METHODS: In this retrospective study we included symptomatic patients with low to intermediate risk who underwent both invasive coronary angiography and CTCA. Exclusion criteria were previous revascularisation or myocardial infarction. The pre-test probability of CAD was estimated using the Duke risk score. Thresholds of less than 30 % and 30-90 % were used for determining low and intermediate risk, respectively. The diagnostic accuracy of CTCA in detecting obstructive CAD (≥50 % lumen diameter narrowing) was calculated on patient level. P < 0.05 was considered significant. RESULTS: A total of 570 patients (46 % women [262/570]) were included and stratified as low (women 73 % [80/109]) and intermediate risk (women 39 % [182/461]). Sensitivity, specificity, PPV and NPV were not significantly different in and between women and men at low and intermediate risk. For women vs. men at low risk they were 97 % vs. 100 %, 79 % vs. 90 %, 80 % vs. 80 % and 97 % vs. 100 %, respectively. For intermediate risk they were 99 % vs. 99 %, 72 % vs. 83 %, 88 % vs. 93 % and 98 % vs. 99 %, respectively. CONCLUSION: CTCA has similar diagnostic accuracy in women and men at low and intermediate risk. KEY POINTS : • Coronary artery disease (CAD) is increasingly investigated by computed tomography angiography (CTCA). • CAD detection or exclusion by CTCA is not different between sexes. • CTCA diagnostic accuracy was similar between low and intermediate risk sex-specific-groups. • CTCA rarely misses obstructive CAD in low-intermediate risk women and men. • CAD yield by invasive coronary angiography after positive CTCA is similar between sex-risk-specific groups.

Regression-based cardiac motion prediction from single-phase CTA.

State of the art cardiac computed tomography (CT) enables the acquisition of imaging data of the heart over the entire cardiac cycle at concurrent high spatial and temporal resolution. However, in clinical practice, acquisition is increasingly limited to 3-D images. Estimating the shape of the cardiac structures throughout the entire cardiac cycle from a 3-D image is therefore useful in applications such as the alignment of preoperative computed tomography angiography (CTA) to intra-operative X-ray images for improved guidance in coronary interventions. We hypothesize that the motion of the heart is partially explained by its shape and therefore investigate the use of three regression methods for motion estimation from single-phase shape information. Quantitative evaluation on 150 4-D CTA images showed a small, but statistically significant, increase in the accuracy of the predicted shape sequences when using any of the regression methods, compared to shape-independent motion prediction by application of the mean motion. The best results were achieved using principal component regression resulting in point-to-point errors of 2.3±0.5 mm, compared to values of 2.7±0.6 mm for shape-independent motion estimation. Finally, we showed that this significant difference withstands small variations in important parameter settings of the landmarking procedure.

Natural history of coronary atherosclerosis by multislice computed tomography.

OBJECTIVES: This study sought to analyze the natural history of coronary atherosclerosis by multislice computed tomography (MSCT) and assess the serial changes in coronary plaque burden, lumen dimensions, and arterial remodeling. BACKGROUND: MSCT can comprehensively assess coronary atherosclerosis by combining lumen and plaque size parameters. METHODS: Thirty-two patients with acute coronary syndromes underwent 64-slice computed tomography angiography after percutaneous coronary intervention at baseline and after a median of 39 months. All patients received contemporary medical treatment. All available coronary segments in every subject were analyzed. The progression of atherosclerosis per segment and per patient was assessed by means of change in percent atheroma volume (PAV), change in normalized total atheroma volume (TAVnorm), and percent change in TAV (% change in TAV). Serial coronary remodeling was also assessed. Measures of lumen stenosis included percent diameter stenosis (%DS), minimum lumen diameter (MLD), percent area stenosis (%AS), and minimum lumen area (MLA). For each patient, the mean of all matched segments was calculated at the 2 time points. Clinical events at follow-up were documented. RESULTS: The PAV did not change significantly (-0.15 ± 3.64%, p = 0.72). The mean change in TAVnorm was 47.36 ± 143.24 mm(3) (p = 0.071), and the % change in TAV was 6.7% (p = 0.029). The MLD and MLA increased by 0.15 mm (-0.09 to 0.24, p = 0.039) and 0.52 mm(2) (-0.38 to 1.04, p = 0.034) respectively, which was accompanied by vessel enlargement, with 53% of the patients showing expansive positive remodeling. Patients with clinical events had a larger TAVnorm at baseline (969.72 mm(3) vs. 810.77 mm(3), p = 0.010). CONCLUSIONS: MSCT can assess the progression of coronary atherosclerosis and may be used for noninvasive monitoring of pharmacological interventions in coronary artery disease. ( PROSPECT: An Imaging Study in Patients With Unstable Atherosclerotic Lesions; NCT00180466).

Left and right ventricle assessment with Cardiac CT: validation study vs. Cardiac MR.

OBJECTIVES: To compare Magnetic Resonance (MR) and Computed Tomography (CT) for the assessment of left (LV) and right (RV) ventricular functional parameters. METHODS: Seventy nine patients underwent both Cardiac CT and Cardiac MR. Images were acquired using short axis (SAX) reconstructions for CT and 2D cine b-SSFP (balanced-steady state free precession) SAX sequence for MR, and evaluated using dedicated software. RESULTS: CT and MR images showed good agreement: LV EF (Ejection Fraction) (52 ± 14% for CT vs. 52 ± 14% for MR; r = 0.73; p > 0.05); RV EF (47 ± 12% for CT vs. 47 ± 12% for MR; r = 0.74; p > 0.05); LV EDV (End Diastolic Volume) (74 ± 21 ml/m² for CT vs. 76 ± 25 ml/m² for MR; r = 0.59; p > 0.05); RV EDV (84 ± 25 ml/m² for CT vs. 80 ± 23 ml/m² for MR; r = 0.58; p > 0.05); LV ESV (End Systolic Volume)(37 ± 19 ml/m² for CT vs. 38 ± 23 ml/m² for MR; r = 0.76; p > 0.05); RV ESV (46 ± 21 ml/m² for CT vs. 43 ± 18 ml/m² for MR; r = 0.70; p > 0.05). Intra- and inter-observer variability were good, and the performance of CT was maintained for different EF subgroups. CONCLUSIONS: Cardiac CT provides accurate and reproducible LV and RV volume parameters compared with MR, and can be considered as a reliable alternative for patients who are not suitable to undergo MR. KEY POINTS: • Cardiac-CT is able to provide Left and Right Ventricular function. • Cardiac-CT is accurate as MR for LV and RV volume assessment. • Cardiac-CT can provide accurate evaluation of coronary arteries and LV and RV function.

Major adverse cardiac events and the severity of coronary atherosclerosis assessed by computed tomography coronary angiography in an outpatient population with suspected or known coronary artery disease.

PURPOSE: To investigate the predictive value of 64-slice computed tomography coronary angiography (CTCA) for major adverse cardiac events (MACEs) in patients with suspected or known coronary artery disease (CAD). MATERIALS AND METHODS: Seven hundred and sixty-seven consecutive patients (496 men, age 62±11 y) with suspected or known heart disease referred to an outpatient clinic underwent 64-slice CTCA. The patients were followed for the occurrence of MACE (ie, cardiac death, nonfatal myocardial infarction, unstable angina). RESULTS: Eleven thousand five hundred and sixty-four coronary segments were assessed. Of these, 178 (1.5%) were not assessable because of insufficient image quality. Overall, CTCA revealed the absence of CAD in 219 (28.5%) patients, nonobstructive CAD (coronary plaque ≤50%) in 282 (36.8%) patients, and obstructive CAD in 266 (34.7%) patients. A total of 21 major cardiac events (4 cardiac deaths, 12 myocardial infarctions, and 5 unstable angina) occurred during a mean follow-up of 20 months. One noncardiac death occurred. Seventeen events occurred in the group of patients with obstructive CAD, and 4 events occurred in the group with nonobstructive CAD. The event rate was 0% among patients with normal coronary arteries at CTCA. In multivariate analysis, the presence of obstructive CAD and diabetes were the only independent predictors of MACE. CONCLUSIONS: Coronary plaque evaluation by CTCA provides an independent prognostic value for the prediction of MACE. Patients with normal CTCA findings have an excellent prognosis at follow-up.

Accelerated subclinical coronary atherosclerosis in patients with familial hypercholesterolemia.

OBJECTIVES: We determined the extent, severity, distribution and type of coronary plaques in cardiac asymptomatic patients with familial hypercholesterolemia (FH) using computed tomography (CT). BACKGROUND: FH patients have accelerated progression of coronary artery disease (CAD) with earlier major adverse cardiac events. Non-invasive CT coronary angiography (CTCA) allows assessing the coronary plaque burden in asymptomatic patients with FH. MATERIALS AND METHODS: A total of 140 asymptomatic statin treated FH patients (90 men; mean age 52 ± 8 years) underwent CT calcium scoring (Agatston) and CTCA using a Dual Source CT scanner with a clinical follow-up of 29 ± 8 months. The extent, severity (obstructive or non-obstructive plaque based on >50% or <50% lumen diameter reduction), distribution and type (calcified, non-calcified, or mixed) of coronary plaque were evaluated. RESULTS: The calcium score was 0 in 28 (21%) of the patients. In 16% of the patients there was no CT-evidence of any CAD while 24% had obstructive disease. In total 775 plaques were detected with CT coronary angiography, of which 11% were obstructive. Fifty four percent of all plaques were calcified, 25% non-calcified and 21% mixed. The CAD extent was related to gender, treated HDL-cholesterol and treated LDL-cholesterol levels. There was a low incidence of cardiac events and no cardiac death occurred during follow-up. CONCLUSION: Development of CAD is accelerated in intensively treated male and female FH patients. The extent of CAD is related to gender and cholesterol levels and ranges from absence of plaque in one out of 6 patients to extensive CAD with plaque causing >50% lumen obstruction in almost a quarter of patients with FH.

Image quality and radiation exposure using different low-dose scan protocols in dual-source CT coronary angiography: randomized study.

PURPOSE: To compare image quality, radiation dose, and their relationship with heart rate of computed tomographic (CT) coronary angiographic scan protocols by using a 128-section dual-source CT scanner. MATERIALS AND METHODS: Institutional review board approved the study; all patients gave informed consent. Two hundred seventy-two patients (175 men, 97 women; mean ages, 58 and 59 years, respectively) referred for CT coronary angiography were categorized according to heart rate: less than 65 beats per minute (group A) and 65 beats per minute or greater (group B). Patients were randomized to undergo prospective high-pitch spiral scanning and narrow-window prospective sequential scanning in group A (n = 160) or wide-window prospective sequential scanning and retrospective spiral scanning in group B (n = 112). Image quality was graded (1 = nondiagnostic; 2 = artifacts present, diagnostic; 3 = no artifacts) and compared (Mann-Whitney and Student t tests). RESULTS: In group A, mean image quality grade was significantly lower with high-pitch spiral versus sequential scanning (2.67 ± 0.38 [standard deviation] vs 2.86 ± 0.21; P < .001). In a subpopulation (heart rate, <55 beats per minute), mean image quality grade was similar (2.81 ± 0.30 vs 2.94 ± 0.08; P = .35). In group B, image quality grade was comparable between sequential and retrospective spiral scanning (2.81 ± 0.28 vs 2.80 ± 0.38; P = .54). Mean estimated radiation dose was significantly lower (high-pitch spiral vs sequential scanning) in group A (for 100 kV, 0.81 mSv ± 0.30 vs 2.74 mSv ± 1.14 [P < .001]; for 120 kV, 1.65 mSv ± 0.69 vs 4.21 mSv ± 1.20 [P < .001]) and in group B (sequential vs retrospective spiral scanning) (for 100 kV, 4.07 mSv ± 1.07 vs 5.54 mSv ± 1.76 [P = .02]; for 120 kV, 7.50 mSv ± 1.79 vs 9.83 mSv ± 3.49 [P = .1]). CONCLUSION: A high-pitch spiral CT coronary angiographic protocol should be applied in patients with regular and low (<55 beats per minute) heart rates; a sequential protocol is preferred in all others.

Aortic annulus dimensions and leaflet calcification from contrast MSCT predict the need for balloon post-dilatation after TAVI with the Medtronic CoreValve prosthesis.

AIMS: We compared the measurement of aortic leaflet calcification on contrast and non-contrast MSCT and investigated predictors of the need for balloon post-dilatation after TAVI. METHODS AND RESULTS: In 110 patients, who had TAVI with a Medtronic CoreValve prosthesis (MCS) for symptomatic aortic stenosis, calcification of the aortic root was measured on non-contrast MSCT (conventionally) and on contrast MSCT (signal attenuation >450 Houndsfield units). Calcium volume was underestimated on contrast- when compared to non-contrast MSCT: median (IQ-range)=759 (466 to 1295) vs. 2016 (1376 to 3262) and the difference between the two methods increased with higher calcium volumes (correlation coefficient r=0.90). Calcium mass was only slightly underestimated on contrast vs. non-contrast MSCT: median (IQ-range)=441 (268 to 809) vs. 555 (341 to 950) and there was no association between the differences and increasing calcium mass (r=0.17). Balloon post-dilatation was performed for significant aortic regurgitation after TAVI in 11 of 110 patients. When compared to controls, the patients who required balloon post-dilatation had higher aortic leaflet calcium on contrast CT (p<0.01), higher aortic annulus diameters (p<0.01) and higher annulus to prosthesis area ratio (p=0.01). ROC curves demonstrated that aortic root or aortic leaflet calcium measured on either contrast- or non-contrast MSCT showed excellent discrimination for the requirement of balloon post-dilatation (area under ROC >0.80 for all), whereas the discriminatory value of aortic annulus dimensions was moderate (area under ROC=0.69) and that of prosthesis to annulus ratio was poor (area under ROC=0.36). CONCLUSIONS: Dense aortic leaflet calcification measured on contrast MSCT discerned well the need for balloon post-dilatation after TAVI with an MCS for significant PAR. Non-contrast MSCT may no longer be needed to quantify aortic root calcium before TAVI.

Stable angina pectoris: head-to-head comparison of prognostic value of cardiac CT and exercise testing.

PURPOSE: To determine and compare the prognostic value of cardiac computed tomographic (CT) angiography, coronary calcium scoring, and exercise electrocardiography (ECG) in patients with chest pain who are suspected of having coronary artery disease (CAD). MATERIALS AND METHODS: This study complied with the Declaration of Helsinki, and the local ethics committee approved the study. Patients (n = 471) without known CAD underwent exercise ECG and dual-source CT at a rapid assessment outpatient chest pain clinic. Coronary calcification and the presence of 50% or greater coronary stenosis (in one or more vessels) were assessed with CT. Exercise ECG results were classified as normal, ischemic, or nondiagnostic. The primary outcome was a major adverse cardiac event (MACE), defined as cardiac death, nonfatal myocardial infarction, or unstable angina requiring hospitalization and revascularization beyond 6 months. Univariable and multivariable Cox regression analysis was used to determine the prognostic values, while clinical impact was assessed with the net reclassification improvement metric. RESULTS: Follow-up was completed for 424 (90%) patients; the mean duration of follow-up was 2.6 years. A total of 44 MACEs occurred in 30 patients. Four of the MACEs were cardiac deaths and six were nonfatal myocardial infarctions. The presence of coronary calcification (hazard ratio [HR], 8.22 [95% confidence interval {CI}: 1.96, 34.51]), obstructive CAD (HR, 6.22 [95% CI: 2.77, 13.99]), and nondiagnostic stress test results (HR, 3.00 [95% CI: 1.26, 7.14]) were univariable predictors of MACEs. In the multivariable model, CT angiography findings (HR, 5.0 [95% CI: 1.7, 14.5]) and nondiagnostic exercise ECG results (HR, 2.9 [95% CI: 1.2, 7.0]) remained independent predictors of MACEs. CT angiography findings showed incremental value beyond clinical predictors and stress testing (global χ(2), 37.7 vs 13.7; P < .001), whereas coronary calcium scores did not have further incremental value (global χ(2), 38.2 vs 37.7; P = .40). CONCLUSION: CT angiography findings are a strong predictor of future adverse events, showing incremental value over clinical predictors, stress testing, and coronary calcium scores. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110744/-/DC1.

Detection and quantification of coronary atherosclerotic plaque by 64-slice multidetector CT: a systematic head-to-head comparison with intravascular ultrasound.

OBJECTIVE: We evaluated the ability of 64-slice multidetector computed tomography (MDCT)-derived plaque parameters to detect and quantify coronary atherosclerosis, using intravascular ultrasound (IVUS) as the reference standard. METHODS: In 32 patients, IVUS and 64-MDCT was performed. The MDCT and IVUS datasets of 44 coronary arteries were co-registered using a newly developed fusion technique and quantitative parameters were derived from both imaging modalities. The threshold of >0.5 mm of maximum wall thickness was used to establish plaque presence on MDCT and IVUS. RESULTS: We analyzed 1364 coregistered 1-mm coronary cross-sections and 255 segments of 5-mm length. Compared with IVUS, 64-MDCT enabled correct detection in 957 of 1109 cross-sections containing plaque (sensitivity 86%). In 180 of 255 cross-sections atherosclerosis was correctly excluded (specificity 71%). On the segmental level, MDCT detected 213 of 220 segments with any atherosclerotic plaque (sensitivity 96%), whereas the presence of any plaque was correctly ruled out in 28 of 32 segments (specificity 88%). Interobserver agreement for the detection of atherosclerotic cross-sections was moderate (Cohen's kappa coefficient K=0.51), but excellent for the atherosclerotic segments (K=1.0). Pearson's correlation coefficient for vessel plaque volumes measured by MDCT and IVUS was r=0.91 (p<0.001). Bland-Altman analysis showed a slight non-significant underestimation of any plaque volume by MDCT (p=0.5), with a trend to underestimate noncalcified and overestimate mixed/calcified plaque volumes (p=0.22 and p=0.87 respectively). CONCLUSION: MDCT is able to detect and quantify atherosclerotic plaque. Further improvement in CT resolution is necessary for more reliable assessment of very small and distal coronary plaques.

Transaortic flow velocity from dual-source MDCT for the diagnosis of aortic stenosis severity.

OBJECTIVES: To describe a method for the estimation of transaortic flow from multidetector computer tomography (MDCT). BACKGROUND: Cardiac MDCT may not allow instantaneous flow measurement yet the components of flow, namely, volume change over time and lumenal area are recorded. METHODS: In 36 patients, the transaortic flow velocity was determined on transthoracic echocardiography and also with cardiac MDCT as follows: On MDCT an axial orientation through the aortic root was obtained so that the nadir of all three aortic leaflets could be seen simultaneously in one axial image. Aortic valve area (AVA) was determined by planimetry and left ventricular volumes by endocardial border mapping at every 5% increment of the RR intervals. Flow velocity was then calculated as the incremental ejection volume ÷ duration of the increment ÷ AVA. RESULTS: The transthoracic echocardiography (TTE) peak velocity and MDCT peak velocity were highly correlated (r = 0.75, P < 0.01). Transaortic peak velocity was higher when measured by MDCT as compared to TTE, with respectively a median [IQ-range] of 4.5 [2.9-5.3] and 4.0 [3.0-4.6], P < 0.01. For the diagnosis of severe aortic stenosis greater concordance with TTE peak velocity was seen with MDCT peak velocity (sensitivity 100%, specificity 76%) than with MDCT AVA (sensitivity 74%, specificity 76%). CONCLUSIONS: We show for the first time that transaortic flow velocity can be estimated by dual-source MDCT and has a better sensitivity for the detection of severe aortic stenosis than AVA planimetry when compared to the gold standard of TTE peak flow velocity.

Is there a difference in the diagnostic accuracy of computed tomography coronary angiography between women and men?

OBJECTIVE: To assess the influence of sex on the diagnostic performance of computed tomography coronary angiography (CTCA). METHODS: A total of 916 symptomatic patients (30.5% women) without earlier history of coronary artery intervention underwent both CTCA and invasive coronary angiography. Descriptive diagnostic parameters, to detect obstructive coronary artery disease (CAD; ≥ 50% lumen diameter narrowing) on CTCA, were compared between women and men on a per-patient, per-vessel, and per-segment level. Adjusted values were calculated for clustered segments and differences in sex variables using logistic multivariate regression models in general estimated equations. RESULTS: Women were older, had less typical chest complaints, and had a lower prevalence, extent, and severity of CAD compared with men. Multivariate analysis on a per-patient level revealed no difference in sensitivity (98 vs. 99%, P=0.15), specificity (78 vs. 82%, P=0.65), positive predictive value (PPV; 87 vs. 95%, P=0.10), negative predictive value (NPV; 97 vs. 98%, P=0.63), and diagnostic odds ratio (DOR; 198 vs. 721, P=0.07). No difference was found on per-vessel level analysis (sensitivity 95 vs. 97%, P=0.14; specificity 89 vs. 87%, P=0.93; PPV 73 vs. 79%, P=0.06; NPV 98 vs. 98%, P=0.72; and DOR 143 vs. 240, P=0.08). Per-segment analysis revealed a lower sensitivity (88 vs. 94%, P<0.001) and DOR (163 vs. 302, P=0.002) in women compared with men, without a difference in specificity (96 vs. 95%, P=0.19), PPV (64 vs. 69%, P=0.07), and NPV (99 vs. 99%, P=0.08). CONCLUSION: CTCA can accurately rule out obstructive CAD in both women and men. CTCA is less accurate in women to detect individual obstructive disease.