Compared with the traditional iterative reconstruction method, deep learning image reconstruction improved image quality and lung nodule detection at ultra–low-dose chest CT (0.07–0.14 mSv, similar... Background Ultra–low-dose (ULD) CT could facilitate the clinical implementation of large-scale lung cancer screening while minimizing the radiation dose. However, traditional image reconstruction m...

Background—: Coronary calcium score (CS), traditionally based on electrocardiography-triggered computed tomography (CT), predicts cardiovascular risk. Currently, nontriggered thoracic CT is extensively used, such as in lung cancer screening. The purpose of the study was to determine the correlation in CS between nontriggered and electrocardiography-triggered CT, and to evaluate the prognostic performance of the CS derived from nontriggered CT. Methods and Results—: PubMed, Embase, and Web of Knowledge were searched until November 2012. Two reviewers independently screened 2120 records to identify studies reporting the CS in nontriggered CT and extracted information. Study quality was evaluated by standardized assessment tools. Cohen κ was extracted for agreement of CS categories between nontriggered and electrocardiography-triggered CT (validation). Hazard ratio (HR) was extracted for prognostic performance. Five studies about validation comprising 1316 individuals were included. Five studies about prognosis comprising 34 028 cardiac asymptomatic individuals, mainly from lung cancer screening trials, were included. All studies were of high quality. Meta-analysis could only be performed for validation studies because studies on prognostic performance were highly heterogeneous. Pooled Cohen κ for agreement between the 2 techniques was 0.89 (95% confidence interval, 0.83–0.95) for increasing CS categories. Increasing CS categories were associated with increasing risk of cardiovascular death or events. Nontriggered CT yielded false-negative CS in 8.8% of individuals and underestimated high CS in 19.1% of individuals. Conclusions—: Our analysis shows the prognostic value and potential role of nontriggered assessment of coronary calcium, but it does not suggest that electrocardiography-triggered CT should be replaced by nontriggered examinations.

Objective To determine the accuracy of iodine quantification with dual energy computed tomography (DECT) in two high-end CT systems with different spectral imaging techniques. Methods Five tubes with different iodine concentrations (0, 5, 10, 15, 20 mg/ml) were analysed in an anthropomorphic thoracic phantom. Adding two phantom rings simulated increased patient size. For third-generation dual source CT (DSCT), tube voltage combinations of 150Sn and 70, 80, 90, 100 kVp were analysed. For dual layer CT (DLCT), 120 and 140 kVp were used. Scans were repeated three times. Median normalized values and interquartile ranges (IQRs) were calculated for all kVp settings and phantom sizes. Results Correlation between measured and known iodine concentrations was excellent for both systems (R = 0.999–1.000, p < 0.0001). For DSCT, median measurement errors ranged from −0.5% (IQR −2.0, 2.0%) at 150Sn/70 kVp and −2.3% (IQR −4.0, −0.1%) at 150Sn/80 kVp to −4.0% (IQR −6.0, −2.8%) at 150Sn/90 kVp. For DLCT, median measurement errors ranged from −3.3% (IQR −4.9, −1.5%) at 140 kVp to −4.6% (IQR −6.0, −3.6%) at 120 kVp. Larger phantom sizes increased variability of iodine measurements (p < 0.05). Conclusion Iodine concentration can be accurately quantified with state-of-the-art DECT systems from two vendors. The lowest absolute errors were found for DSCT using the 150Sn/70 kVp or 150Sn/80 kVp combinations, which was slightly more accurate than 140 kVp in DLCT. Key Points • High-end CT scanners allow accurate iodine quantification using different DECT techniques. • Lowest measurement error was found in scans with largest photon energy separation. • Dual-source CT quantified iodine slightly more accurately than dual layer CT.

Objectives: To determine normal pericoronary adipose tissue mean attenuation (PCAT_MA) values for left the anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) in patients without plaques on coronary CT angiography (cCTA), taking into account tube voltage influence. Methods: This retrospective study included 192 patients (76 (39.6%) men; median age 49 years (range, 19–79)) who underwent cCTA with third-generation dual-source CT for the suspicion of CAD between 2015 and 2017. We selected patients without plaque on cCTA. PCAT_MA was measured semi-automatically on cCTA images in the proximal segment of the three main coronary arteries with 10 mm length. Paired t-testing was used to compare PCAT_MA between combinations of two coronary arteries within each patient, and one-way ANOVA testing was used to compare PCAT_MA in different kV groups. Results: The overall mean ± standard deviation (SD) PCAT_MA was − 90.3 ± 11.1 HU. PCAT_MA in men was higher than that in women: − 88.5 ± 10.5 HU versus − 91.5 ± 11.3 HU (p = 0.001). PCAT_MA of LAD, LCX, and RCA was − 92.4 ± 11.6 HU, − 88.4 ± 9.9 HU, and − 90.2 ± 11.4 HU, respectively. Pairwise comparison of the arteries showed significant difference in PCAT_MA: LAD and LCX (p < 0.001), LAD and RCA (p = 0.009), LCX and RCA (p = 0.033). PCAT_MA of the 70 kV, 80 kV, 90 kV, 100 kV, and 120 kV groups was − 95.6 ± 9.6 HU, − 90.2 ± 11.5 HU, − 87.3 ± 9.9 HU, − 82.7 ± 6.2 HU, and − 79.3 ± 6.8 HU, respectively (p < 0.001). Conclusions: In patients without plaque on cCTA, PCAT_MA varied by tube voltage, with minor differences in PCAT_MA between coronary arteries (LAD, LCX, RCA). PCAT_MA values need to be interpreted taking into account tube voltage setting. Key Points: • In patients without plaque on cCTA, PCAT_MAdiffers slightly by coronary artery (LAD, LCX, RCA). • Tube voltage of cCTA affects PCAT_MAmeasurement, with mean PCAT_MAincreasing linearly with increasing kV. • For longitudinal cCTA analysis of PCAT_MA, the use of equal kV setting is strongly recommended.

Objective Aortic stiffness can lead to low diastolic blood pressure, thereby possibly limiting coronary perfusion. Therefore, the simultaneous occurrence of both aortic stiffness and coronary atherosclerosis can lead to an increased risk of subendocardial ischaemia. The aim of the present study was to investigate the association between aortic stiffness and coronary atherosclerosis. Methods The study was performed in 1757 subjects of the Rotterdam Study, a population-based study of elderly individuals. Aortic stiffness was assessed by measuring carotid-femoral pulse wave velocity (PWV). Coronary atherosclerosis was assessed by measuring coronary calcification using electron beam tomography and expressed as a total calcium score. The total calcium score was log-transformed because of its skewed distribution. The association between PWV and coronary calcification was first evaluated after adjustment for age, sex, mean arterial blood pressure and heart rate. Results Linear regression analyses showed that increased PWV was associated with a higher log total coronary calcium score [β-regression coefficient 0.11, 95% confidence interval (CI) 0.07–0.15]. Compared with the lowest quartile of PWV, multivariate odds ratios and corresponding 95% CI for advanced coronary calcification in the second, third and fourth highest quartiles were 1.17 (0.79–1.74), 1.58 (1.07–2.34) and 2.12 (1.40–3.20), respectively. Conclusions In this large population-based study performed in elderly subjects aortic stiffness was strongly and independently associated with coronary atherosclerosis.

OBJECTIVE. Interest in dual-energy CT (DECT) for evaluating the myocardial blood supply, as an addition to coronary artery assessment, is increasing. Although it is still in the early clinical phase, assessment of myocardial ischemia and infarction by DECT constitutes a promising step toward comprehensive evaluation of coronary artery disease with a single noninvasive modality. CONCLUSION. Compared with dynamic CT approaches, DECT has advantages regarding radiation dose and clinical applicability. In this review, the literature on DECT of the heart is discussed.