D. Bittner

Prospectively ECG-triggered high-pitch coronary angiography with third-generation dual-source CT at 70 kVp tube voltage: Feasibility, image quality, radiation dose, and effect of iterative reconstruction

BACKGROUNDnLow tube voltage reduces radiation exposure in coronary CT angiography (CTA). Using 70 kVp tube potential has so far not been possible because CT systems were unable to provide sufficiently high tube current with low voltage.nnnOBJECTIVEnWe evaluated feasibility, image quality (IQ), and radiation dose of coronary CTA using a third-generation dual-source CT system capable of producing 450 mAs tube current at 70 kVp tube voltage.nnnMETHODSnCoronary CTA was performed in 26 consecutive patients with suspected coronary artery disease, selected for body weight <100 kg and heart rate <60 beats/min. High-pitch spiral acquisition was used. Filtered back projection (FBP) and iterative reconstruction (IR) algorithms were applied. IQ was assessed using a 4-point rating scale (1 = excellent, 4 = nondiagnostic) and objective parameters.nnnRESULTSnMean age was 62 ± 9 years (46% males; mean body mass index, 27.7 ± 3.8 kg/m(2); mean heart rate, 54 ± 5 beats/min). Mean dose-length product was 20.6 ± 1.9 mGy × cm; mean estimated effective radiation dose was 0.3 ± 0.03 mSv. Diagnostic IQ was found in 365 of 367 (FBP) and 366 of 367 (IR) segments (P nonsignificant). IQ was rated excellent in 53% (FBP) and 86% (IR) segments (P = .001) and nondiagnostic in 2 (FBP) and 1 segment (IR) (P nonsignificant). Mean IQ score was lesser in FBP vs IR (1.5 ± 0.4 vs 1.1 ± 0.2; P < .001). Image noise was lower in IR vs FBP (60 ± 10 HU vs 74 ± 8 HU; P < .001).nnnCONCLUSIONnIn patients <100 kg and with a regular heart rate <60 beats/min, third-generation dual-source CT using high-pitch spiral acquisition and 70 kVp tube voltage is feasible and provides both robust IQ and very low radiation exposure.

The Prognostic Value of Coronary Artery Calcium in the PROMISE Study

Background —Coronary artery calcium (CAC) is an established predictor of future major adverse atherosclerotic cardiovascular events in asymptomatic individuals. However limited data exist as to how CAC compares to functional testing (FT) in estimating prognosis in symptomatic patients. Methods —In the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) trial, patients with stable chest pain (or dyspnea) and intermediate pre-test probability for obstructive coronary artery disease (CAD) were randomized to FT (exercise electrocardiography, nuclear stress, or stress echocardiography) or anatomic testing. We evaluated those who underwent CAC testing as part of the anatomic evaluation (n=4,209) and compared to results of FT (n=4,602). We stratified CAC and FT results as normal or mildly, moderately or severely abnormal (for CAC: 0, 1-99 Agatston Score [AS], 100-400 AS and >400 AS, respectively; for FT: normal, mild=late positive treadmill, moderate=early positive treadmill or single-vessel ischemia and severe=large ischemic region abnormality). The primary endpoint was all-cause death, myocardial infarction or unstable angina hospitalization over a median follow-up of 26.1 months. Cox regression models were used to calculate hazard ratios and C-statistic to determine predictive and discriminatory value. Results — Overall, the distribution of normal or mildly, moderately or severely abnormal test results was significantly different between FT and CAC (FT = normal 3588 [78.0%], mild 432 [9.4%], moderate 217 [4.7%], severe 365 [7.9%]; CAC = normal 1,457 [34.6%], mild 1340 [31.8%], moderate 772 [18.3%], severe 640 [15.2%], p 0) whereas less than half of events occurred in patients with mild, moderate or severely abnormal FT (n=57/132; 43%) (p Conclusion —Among stable outpatients presenting with suspected CAD, most patients experiencing clinical events have measurable CAC at baseline while less than half have any abnormalities on FT. However, an abnormal FT was more specific for cardiovascular events, leading to overall similarly modest discriminatory abilities of both tests. Clinical Trial Registration —URL: https://clinicaltrials.gov; Unique Identifier: NCT01174550Background: Coronary artery calcium (CAC) is an established predictor of future major adverse atherosclerotic cardiovascular events in asymptomatic individuals. However, limited data exist as to how CAC compares with functional testing (FT) in estimating prognosis in symptomatic patients. Methods: In the PROMISE trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain), patients with stable chest pain (or dyspnea) and intermediate pretest probability for obstructive coronary artery disease were randomized to FT (exercise electrocardiography, nuclear stress, or stress echocardiography) or anatomic testing. We evaluated those who underwent CAC testing as part of the anatomic evaluation (n=4209) and compared that with results of FT (n=4602). We stratified CAC and FT results as normal or mildly, moderately, or severely abnormal (for CAC: 0, 1–99 Agatston score [AS], 100–400 AS, and >400 AS, respectively; for FT: normal, mild=late positive treadmill, moderate=early positive treadmill or single-vessel ischemia, and severe=large ischemic region abnormality). The primary end point was all-cause death, myocardial infarction, or unstable angina hospitalization over a median follow-up of 26.1 months. Cox regression models were used to calculate hazard ratios (HRs) and C statistics to determine predictive and discriminatory values. Results: Overall, the distribution of normal or mildly, moderately, or severely abnormal test results was significantly different between FT and CAC (FT: normal, n=3588 [78.0%]; mild, n=432 [9.4%]; moderate, n=217 [4.7%]; severe, n=365 [7.9%]; CAC: normal, n=1457 [34.6%]; mild, n=1340 [31.8%]; moderate, n=772 [18.3%]; severe, n=640 [15.2%]; P<0.0001). Moderate and severe abnormalities in both arms robustly predicted events (moderate: CAC: HR, 3.14; 95% confidence interval, 1.81–5.44; and FT: HR, 2.65; 95% confidence interval, 1.46–4.83; severe: CAC: HR, 3.56; 95% confidence interval, 1.99–6.36; and FT: HR, 3.88; 95% confidence interval, 2.58–5.85). In the CAC arm, the majority of events (n=112 of 133, 84%) occurred in patients with any positive CAC test (score >0), whereas fewer than half of events occurred in patients with mildly, moderately, or severely abnormal FT (n=57 of 132, 43%; P<0.001). In contrast, any abnormality on FT was significantly more specific for predicting events (78.6% for FT versus 35.2% for CAC; P<0.001). Overall discriminatory ability in predicting the primary end point of mortality, nonfatal myocardial infarction, and unstable angina hospitalization was similar and fair for both CAC and FT (C statistic, 0.67 versus 0.64). Coronary computed tomographic angiography provided significantly better prognostic information compared with FT and CAC testing (C index, 0.72). Conclusions: Among stable outpatients presenting with suspected coronary artery disease, most patients experiencing clinical events have measurable CAC at baseline, and fewer than half have any abnormalities on FT. However, an abnormal FT was more specific for cardiovascular events, leading to overall similarly modest discriminatory abilities of both tests. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01174550.

CT SIZING OF LEFT ATRIAL APPENDAGE PRIOR TO PERCUTANEOUS CLOSURE USING WATCHMAN DEVICE: FEASIBILITY AND INITIAL EXPERIENCE

We assessed the feasibility of CT sizing of the LAA prior to closure using the Watchman device.nn16 patients referred for interventional LAA closure were examined using Dual Source CT prior to the interventional procedure. Multiplanar reconstructions were aligned with the plane of the LAA ostium and

THIRD GENERATION DUAL SOURCE COMPUTED TOMOGRAPHY FOR EVALUATION OF PATIENTS PRIOR TO TRANSCATHETER AORTIC VALVE REPLACEMENT: COMPREHENSIVE IMAGING WITH AN ULTRA LOW-DOSE OF CONTRAST AGENT

Chronic renal insufficiency is a common comorbidity in patients referred for transcatheter aortic valve replacement (TAVR). Pre-procedural CT evaluation of the aortic root as well as the aortic and peripheral arterial anatomy is recommended and provides crucial information prior to TAVR. We

CT-derived left ventricular global strain in aortic valve stenosis patients: A comparative analysis pre and post transcatheter aortic valve implantation

INTRODUCTIONnWe assessed the potential of CT strain to detect changes in myocardial function in patients referred for TAVI pre and post intervention.nnnPATIENTS AND METHODSn25 consecutive patients with symptomatic aortic valve stenosis in whom TAVI had been performed were included in this analysis. Functional CT data sets acquired before and 3 to 6 months after TAVI were available. Multiphase reconstructions in increments of 10% of the cardiac cycle were rendered and transferred to a dedicated workstation (Ziostation2, Ziosoft Inc., Tokyo, Japan). For quantification of left ventricular strain, multiplanar reconstructions of the left ventricle in standard 4 chamber, 2 chamber as well as apical 3 chamber views were rendered. The perimeter of the left ventricle was traced dynamically through the cardiac cycle. Peak strain was calculated for each patient pre and post intervention. Furthermore, for quantification of 3-dimensional maximum principal strain, 2 volumetric regions of interests (VOI) were placed per each basal, mid and apical segment of the previously mentioned MPRs and peak maximal principal strain was calculated. Maximum principal strain as well as perimeter-derived longitudinal strain values in the three standard windows were averaged to obtain global strain.nnnRESULTSn25 patients were included in this analysis (mean age 78u202f±u202f9 years, 13 males). Peak global maximum principal strain was significantly higher at follow-up compared to baseline (0.46u202f±u202f0.19 vs. 0.59u202f±u202f0.18, respectively, pu202f=u202f0.001). Similarly global longitudinal strain derived by perimeter was significantly lower - implying better contraction - compared to baseline (-8.6%u202f±u202f2.8% vs. -9.8%u202f±u202f2.6%, respectively, pu202f=u202f0.006).nnnCONCLUSIONnUsing dedicated software, assessment of CT derived left ventricular strain is feasible. In patients treated with transcatheter aortic valve replacement, CT-derived parameters of global myocardial strain improve onshort-term follow-up.

LOW-DOSE CORONARY CTA AT 70 KV: EFFECT OF ITERATIVE RECONSTRUCTION ON IMAGE QUALITY AND CORONARY ATHEROSCLEROTIC PLAQUE DETECTION

Low tube voltage is one approach to limit radiation exposure in coronary CTA. Third generation dual source CT newly permits to use 70 kVp. We evaluated the influence of reconstruction parameters, including iterative reconstruction, on image quality and coronary atherosclerotic plaque when performing

RELATIONSHIP BETWEEN HOMOCYSTEINE, HYPOVITAMINOSIS AND PERICARDIAL FAT MEASURED BY CORONARY COMPUTED TOMOGRAPHY

Pericardial fat is discussed to be an independent risk factor for CAD. There is close relation between the amount of calcium in the coronary arteries and the amount of pericardial fat. Pericardial fat is correlated to traditional risk factors like BMI, hypertension, male gender and higher age. The