Application of low tube potentials in CCTA results from the PROTECTION VI study

OBJECTIVES The aim of this study was to assess the use of low tube potentials for coronary computed tomography angiography (CCTA) in worldwide clinical practice and its influence on radiation exposure, contrast agent volume, and image quality.BACKGROUND CCTA is frequently used in clinical practice. Lowering of tube potential is a potent method to reduce radiation exposure and to economize contrast agent volume.METHODS CCTAs of 4,006 patients from 61 international study sites were analyzed regarding very-tow (= 130 kVp) tube potentials. The impact on dose-length product (DLP) and contrast agent volume was analyzed. Image quality was determined by evaluation of the diagnostic applicability and assessment of the objective image parameters signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR).RESULTS When compared with conventional tube potentials, low tube potentials were used in 56% of CCTAs (<= 80 kVp 9%; 90 to 100 kVp: 47%), which varied among sites from 0% to 100%. Tube potential reduction was associated with low-cardiovascular risk profile, low body mass index (BMI), and new-generation scanners. Median radiation exposure was lowered by 68% or 50% and median contrast agent volume by 25% or 13% for tube potential protocols of <= 80 kVp or 90 to 100 kVp when compared with conventional tube potentials, respectively (all p < 0.001). With the use of lower tube potentials, the frequency of diagnostic scans was maintained (p = 0.41), whereas SNR and CNR significantly improved (both p < 0.001). Considering BMI eligibility criteria, 58% (n = 946) of conventionally scanned patients would have been suitable for low tube potential protocols, and 44% (n = 831) of patients scanned with 90 to 100 kVp would have been eligible for very-low tube potential CCTA imaging of <= 80 kVp.CONCLUSIONS This large international registry confirms the feasibility of tube potential reduction in clinical practice leading to rower radiation exposure and lower contrast volumes. The current registry also demonstrates that this strategy is stilt underused in daily practice. (C) 2020 by the American College of Cardiology Foundation.Cardiolog

Reduction in Radiation Exposure in Cardiovascular CT Imaging

Advances of cardiac computed tomography angiography (CTA) have been developed for dose reduction, but their efficacy in clinical practice is largely unknown. This study was designed to evaluate radiation dose exposure and utilization of dose-saving strategies for contrast-enhanced cardiac CTA in daily practice

LONG-TERM PREDICTION OF ALL-CAUSE MORTALITY AND MYOCARDIAL INFARCTION USING QUANTIFIED CORONARY PLAQUE VOLUME AND HIGH-RISK PLAQUE FEATURES

Cardiovascular Aspects of Radiolog

Quantification of coronary low-attenuation plaque volume for long-term prediction of cardiac events and reclassification of patients

Background: To investigate the incremental prognostic value of low-attenuation plaque volume (LAPV) from coronary CT angiography datasets.Methods: Quantification of LAPV was performed using dedicated software equipped with an adaptive plaque tissue algorithm in 1577 patients with suspected CAD. A combination of death and acute coronary syndrome was defined as primary endpoint. To assess the incremental prognostic value of LAPV, parameters were added to a baseline model including clinical risk and obstructive coronary artery disease (CAD), a baseline model including clinical risk and calcium scoring (CACS) and a baseline model including clinical risk and segment involvement score (SIS).Results: Patients were followed for 5.5 years either by telephone contact, mail or clinical visits. The primary endpoint occurred in 30 patients. Quantified LAPV provided incremental prognostic information beyond clinical risk and obstructive CAD (c-index 0.701 vs. 0.767, p<.001), clinical risk and CACS (c-index 0.722 vs. 0.771, p<.01) and clinical risk and SIS (c-index 0.735 vs. 0.771, p<.01. A combined approach using quantified LAPV and clinical risk significantly improved the stratification of patients into different risk categories compared to clinical risk alone (categorical net reclassification index 0.69 with 95% CI 0.27 and 0.96, p<.001). The combined approach classified 846 (53.6%) patients as low risk (annual event rate 0.04%), 439 (27.8%) patients as intermediate risk (annual event rate 0.5%) and 292 (18.5%) patients as high risk (annual event rate 0.99%).Conclusion: Quantification of LAPV provides incremental prognostic information beyond established CT risk patterns and permits improved stratification of patients into different risk categories.Cardiovascular Aspects of Radiolog

Changes in coronary plaque components over time assessed by serial coronary computed tomographic angiography

Cardiovascular Aspects of Radiolog

Association of low-attenuation Plaque Volume with cardiovascular risk factors

Cardiovascular Aspects of Radiolog

Coronary plaque volume and predictors for fast plaque progression assessed by serial coronary CT angiography-A single-center observational study

Purpose: The rationale of this study was to identify patients with fast progression of coronary plaque volume PV and characterize changes in PV and plaque components over time.Method: Total PV (TPV) was measured in 350 patients undergoing serial coronary computed tomography angiography (median scan interval 3.6 years) using semi-automated software. Plaque morphology was assessed based on attenuation values and stratified into calcified, fibrous, fibrous-fatty and low-attenuation PV for volumetric measurements. Every plaque was additionally classified as either calcified, partially calcified or non-calcified.Results: In total, 812 and 955 plaques were detected in the first and second scan. Mean TPV increase was 20 % on a per-patient base (51.3 mm(3) [interquartile range (IQR): 14.4, 126.7] vs. 61.6 mm(3) [IQR: 16.7, 170.0]). TPV increase was driven by calcified PV (first scan: 7.6 mm(3) [IQR: 0.2, 33.6] vs. second scan: 16.6 mm(3) [IQR: 1.8, 62.1], p 1.3 mm(3) increase of TPV per month. Male sex (odds ratio 3.1, p = 0.02) and typical angina (odds ratio 3.95, p = 0.03) were identified as risk factors for fast TPV progression, while high-density lipoprotein cholesterol had a protective effect (odds ratio per 10 mg/dl increase of HDL cholesterol: 0.72, p 50 % stenosis at follow-up was observed in 34 of 327 (10.4 %) calcified plaques, in 13 of 401 (3.2 %) partially calcified plaques and 2 of 221 (0.9 %) non-calcified plaques (p < 0.01).Conclusion: Fast plaque progression was observed in male patients and patients with typical angina. High HDL cholesterol showed a protective effect.Cardiovascular Aspects of Radiolog

Impact of diabetes on coronary artery plaque volume by coronary CT angiography and subsequent adverse cardiac events

Background: To investigate the impact of diabetes on coronary artery total plaque volume (TPV) and adverse events in long-term follow-up.Methods: One-hundred-and-eight diabetic patients were matched to 324 non-diabetic patients, with respect to age, sex, body-mass index, hypertension, smoking habits, LDL and HDL cholesterol, family history for CAD as well as aspirin and statin medication. In all patients, TPV was quantified from coronary CT angiographies (CTA) using dedicated software. All-cause mortality, acute coronary syndrome and late revascularisation ( > 90 days) served as combined endpoint.Results: Patients were followed for 5.6 years. The endpoint occurred in 18 (16.7%) diabetic and 26 (8.0%) nondiabetic patients (odds ratio 2.3, p = 0.03). Diabetic patients had significantly higher TPV than non-diabetic patients (55.1 mm 3 [IQR: 6.2 and 220.4 mm(3)] vs. 24.9 mm 3 [IQR: 0 and 166.7 mm(3)], p = 0.02). A TPV threshold of 110.5 mm(3) provided good separation of diabetic and non-diabetic patients at higher and lower risk for adverse events. Noteworthy, diabetic and non-diabetic patients with a TPV 110.5 mm(3) had significantly higher incidence of adverse events (hazard ratio 2.3, p = 0.03) compared to non-diabetic patients with TPV > 110.5 mm(3). There was incremental prognostic value in diabetic and non-diabetic patients over the Framingham Risk Score (Integrated Discrimination Improvement: 0.052 and 0.012, p for both < 0.05).Conclusion: Diabetes is associated with significantly higher TPV, which is independent of other CAD risk factors. Quantification of TPV improves the identification of diabetic patients at higher risk for future adverse events.Cardiovascular Aspects of Radiolog

Quantified coronary total plaque volume from computed tomography angiography provides superior 10-year risk stratification

Aims Automated coronary total plaque volume (TPV) quantification derived from coronary computed tomographic angiography (CTA) datasets provide exact and reliable assessment of calcified and non-calcified coronary atheroscler- osis burden. The aim of this analysis was to investigate the long-term predictive value of TPV.Methods and results TPV was quantified in 1577 patients undergoing coronary CTA and cardiovascular events were collected during 10.5 years (interquartile range 6.0-11.4) of follow-up. The study endpoint comprised cardiac death and acute cor- onary syndrome and occurred in 59 (3.7%) patients. Coronary TPV provided additive prognostic value over clinical risk assessed with the Morise Score and coronary artery disease severity (rise in C-index from 0.744 to 0.769, P=0.03). A category-based reclassification approach combining the Morise Score and TPV revealed superior risk stratification (categorical net reclassification improvement: 0.48 with 95% CI 0.13-0.68, P< 0.001) and resulted in reclassification of 800 (51%) patients compared with the Morise Score alone. The 10-year risk for the study endpoint was 0.6% (95% CI 0-1.3) for patients classified as low risk (n = 807), 4.8% (95% CI 2.4-7.2) for patients at intermediate risk (n = 400), and 10.3% (95% CI 6.6-13.9) for patients at high risk (n = 370) using the combined reclassification approach.Conclusion Quantification of TPV from coronary CTA permits an improved 10-year cardiovascular risk stratification.Cardiovascular Aspects of Radiolog