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Assess image quality and radiation dose of ECG-triggered High-Pitch Dual-Source CTA for the evaluation central vascular stents in children. We included all children ≤ 21 years old with one or more central vascular stents and available prospective ECG-triggered High-Pitch Dual-Source CTA performed at our institution between January 2015 and August 2017. Demographic and scanner information was retrieved. Two board-certified pediatric radiologists blinded to the clinical data, independently reviewed and scored each case using a four-point quality score. Scores 1, 2 and 3 were considered of diagnostic image quality. Inter-observer agreement and non-parametric test were used. 18 patients (10 girls, 8 boys) with a mean age of 9.47 ± 7.38 years (mean ± SD) met inclusion criteria. Thirty-two central vascular stents were evaluated. Mean quality score was 2.07 ± 0.94 with 12.5% (4/32) of the cases classified as unevaluable. Interobserver agreement was excellent (k = 0.86). There is no significant difference between quality score and stent location (p = 0.07). There is a significant difference with stent material as all non-diagnostic scores were only seen in covered stents made of platinum-iridium (p < 0.001). There was no association between image quality and age, height, weight, BSA, heart rate, radiation dose or stent lumen size (p > 0.05). ECG-triggered high-pitch spiral DS-CTA offers appropriate image quality for assessment of central vascular stents in children. [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively compare the image noise, signal-to-noise ratio (SNR), and subjective image quality between CT images acquired with a dual-source, split-dose imaging protocol reconstructed at full and half doses with weighted filtered back projection (wFBP) and an improved sinogram-affirmed iterative reconstruction algorithm (SAFIRE*).Methods: Fifty-three consecutive patients underwent contrast-enhanced CT of the abdomen using a standardized dual-source, single energy CT protocol. Half-dose images were retrospectively generated using data from one detector only. Full-dose datasets were reconstructed with wFBP, while half-dose datasets were reconstructed with wFBP and SAFIRE* strengths 1-5. Region of interest analysis was performed to assess SNR and noise. Diagnostic acceptability, subjective noise, and spatial resolution were graded on a 10-point scale by two readers. Statistical analysis was carried out with repeated measures analysis of variance, Wilcoxon signed rank test, and Cohen's κ test.Results: With the increasing strengths of SAFIRE*, a progressive reduction in noise and increase in SNR (p < 0.01) was observed. There was a statistically significant decrease in objective noise and increase in SNR in half-dose SAFIRE* strength 4 and 5 reconstructions compared to full-dose reconstructions using wFBP (p < 0.01). Qualitative analysis revealed a progressive increase in diagnostic acceptability, decrease in subjective noise and increase in spatial resolution for half-dose images reconstructed with the increasing strengths of SAFIRE* (p < 0.01).Conclusions: Half-dose CT images reconstructed with SAFIRE* at strength 4 and 5 have superior image quality compared to full-dose images reconstructed with wFBP. SAFIRE* potentially allows dose reductions in the order of 50% over wFBP. [ABSTRACT FROM AUTHOR]

Abstract Ductal adenocarcinoma of the pancreas is one of the most aggressive forms of cancer, with only a minority of cases being resectable at the moment of their diagnosis. The accurate detection and characterization of pancreatic carcinoma is very important for patient management. Multidetector-row computed tomography (MDCT) has become the cross-sectional modality of choice in the diagnosis, staging, treatment planning, and follow-up of patients with pancreatic tumors. However, approximately 11% of ductal adenocarcinomas still remain undetected at MDCT because of the lack of attenuation gradient between the lesion and the adjacent pancreatic parenchyma. In this systematic literature review we investigate the current evolution of the CT technique, limitations, and perspectives in the evaluation of pancreatic carcinoma.

Background and Objective: In order to achieve early detection of myocardial ischemia and improve the diagnosis of coronary heart disease (CHD), it is necessary to find a convenient, non-invasive and effective examination method. This study aimed to explore the application value of dual-source computed tomography (CT) by using advanced modeled iterative reconstruction (ADMIRE) combined with computed tomography-fractional flow reserve (CT-FFR) technique in CHD, which provides imaging basis for early diagnosis of CHD and myocardial ischemia., Methods: Seventy-five CHD patients were examined by coronary computed tomography angiography (CCTA). Their CCTA images were reconstructed by iterative algorithm in ADMIRE 1-5 using post-processing workstation. The standard deviation (SD), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of proximal vascular images in right coronary artery (RCA), left main coronary artery (LM), left anterior descending artery (LAD) and left circumflex artery (LCX) were analyzed and compared. Invasive coronary angiography (ICA) was adopted in patients with ≥50% stenosis of coronary artery diameter. Taking ICA as the gold-standard method to accurately assess coronary arterial stenosis degree, the diagnostic efficiency of dual-source CT to diagnose coronary artery stenosis was analyzed. Some patients were subjected to myocardial CT perfusion (CTP) scanning and CT-FFR analysis, which facilitated analyzing the correlation and consistency between the diagnostic results of CTP and analysis results of CT-FFR., Results: There was no statistical difference in the CT values of RCA, LM, LAD and LCX in groups with different ADMIRE reconstruction intensities ( p > 0.05). But the noise, SNR and CNR interval were different among the iterative intensity groups ( p < 0.05). Kappa consistency analysis was used to analyze the subjective evaluation results of image quality under different iterative reconstruction grades. The independent sample t -test performed on the subjective scores revealed that the scores on images were the best at ADMIRE 4. CCTA has sensitivity, specificity, positive predictive value, and negative predictive value of 91.52%, 97.59%, 97.98%, and 96.42% for identifying coronary artery stenosis, respectively. The diagnostic efficacy of CT-FFR, the Kappa analysis of myocardial CTP and CT-FFR results, which yields a Kappa value of 0.830 ( p < 0.05). Spearman correlation analysis was used to statistically analyze the results of myocardial CTP and CT-FFR (correlation coefficient r = 0.774, p < 0.05). Diagnostic sensitivity and specificity were 93% and 95%, respectively., Conclusions: The dual-source CT using ADMIRE iterative algorithm has the best display of coronary vessels and higher image quality when the intensity is 4, and CT-FFR can be used as a non-invasive method for early detection of myocardial ischemia, which is worthy of clinical application.

Abstract Objective Assess the image quality of ECG-triggered High-Pitch Dual-Source CTA for the evaluation of native coronaries in children. Materials and methods Between August 2014 and September 2017, 45 children with morphologically normal cardiac chambers had cardiac prospective ECG-triggered High-Pitch Dual-Source CTA. Two pediatric radiologists blinded to clinical data, independently reviewed each case. The coronary arteries were evaluated using a four-point scale quality score according to the coronary segment. Attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured using values from the air, inter-ventricular septum and ascending aorta at the level of the sinuses of Valsalva. Results 225 coronary segments were assessed showed a mean score of 2.40 ± 0.73, 94.2% had diagnostic image quality. The best and worst average quality were seen in segment 5 and 2, respectively. Inter-observer agreement was moderate for all segments except for segment 1, which was excellent. Worse quality scores were significantly associated with younger patients and low body mass index as well as with higher heart rates in all segments. The mean observed heart rate and BSA in patients with diagnostic image quality were below 77 bpm and over 1.4 m2 respectively. There is no significant association between attenuation, SNR and CNR with image quality. Conclusions Prospective ECG-triggered High-Pitch Dual-Source Computed Tomography Angiography achieves consistent and diagnostic image quality for coronary artery assessment at a low effective dose in pediatric patients. Highlights • ECG-triggered High-Pitch Dual-Source CTA offers good image quality for coronary artery assessment • The left main coronary artery showed the best subjective image quality compared to other coronary segments • Image quality declines in younger and smaller patients as well as those with high heart rate during the CTA • Good image quality can be achieve in patients with a heart rate up to 77 bpm and a body mass index as low as 1.4 m2 • ECG-triggered High-Pitch Dual-Source CTA yields lower effective dose compared to first generation scanners [ABSTRACT FROM AUTHOR]

Background Image quality benefits from high-pitch scanning in agitated patients by reducing acquisition time. Purpose To compare image quality and exposure parameters in patients with maxillofacial trauma on second- and third-generation dual-source computed tomography (DSCT). Material and Methods Four groups were compared. Group 1 was examined on second-generation DSCT (120 kV/50 mAs, pitch 3.0). The other three groups were examined on third-generation DSCT. Group 2 was scanned with 120 kV/50 mAs, pitch 2.2. Automated exposure control (AEC) was used in group 3 and group 4 with pitch factors of 2.2 and 3.0, respectively. Images of third-generation DSCT were reconstructed with iterative reconstruction (IR), of second-generation DSCT with filtered back-projection. CTDIvol, acquisition time, and image quality were compared. Results Thirty patients were included in each group. Average CTDIvol (2.76 ± 0.00 mGy, 2.66 ± 0.00 mGy, 0.74 ± 0.23 mGy, and 0.75 ± 0.17 mGy) was significantly lower on third-generation DSCT with AEC ( P < 0.001). Subjective image quality was rated worst in group 4 due to strong high-pitch artifacts, while in the remaining three groups it was rated good or very good with good inter-observer agreement (k > 0.64). Average acquisition time was significantly shorter with third-generation DSCT (0.47 s, 0.36 s, 0.38 s, 0.30 s; P < 0.001). Conclusion Third-generation DSCT yields faster acquisition times and substantial dose reduction with AEC. A pitch of 2.2 should be preferred, as it results in fewer artifacts. If AEC is used, latest IR ensures that diagnostic image quality is guaranteed. [ABSTRACT FROM AUTHOR]

Rationale and Objective: To identify the influence of various parameters for reducing artifacts in computed tomography (CT) of commonly used pacemakers or implantable cardioverter-defibrillator (ICD) lead tips.Materials and Methods: This ex vivo phantom study compared two CT techniques (Dual-Energy CT [DECT] vs. Dual-Source CT [DSCT]), as well as the influence of incremental alterations of current-time product and pacemaker lead-tip angle with respect to the gantry plane. Four pacemaker leads and one ICD lead were evaluated. The images were assessed visually on a five-point Likert scale (1 = artifact free to 5 = massive artifacts). Likert values 1-3 represent clinically relevant, diagnostic image quality.Results: 344 of 400 total images were rated with diagnostic image quality. The DECT and dual-source DSCT technique each scored 86% diagnostic image quality. Statistically, DECT images showed significantly improved image quality (P < .05). Concerning the current-time product, no statistically significant change was found. Regarding lead-tip positioning, an angle of ≤70° yielded 100% diagnostic image quality. Pacemaker and ICD leads were assessed to have statistically significant differences.Conclusions: Surprisingly, the lead-tip angle of 70° has been established as the key angle under which diagnostic image quality is always ensured, regardless of the imaging technique. Thus, we call 70° the "Magic angle" in CT pacemaker imaging. [ABSTRACT FROM AUTHOR]

Purpose: As an extremely rare abnormity, type IIA pulmonary artery sling (PAS) tracheobronchial anomalies should be differentiated from normal airway for therapeutic decision-making. This study aimed to investigate the quantitative characteristics of type IIA PAS tracheobronchial anomalies using dual-source computed tomography (DSCT).Materials and Methods: From January 2009 to December 2016, there were 11 type IIA PAS patients enrolled for analysis and compared with 32 controls. The areas of the trachea, right upper lobar bronchus, left main bronchus, right intermediate bronchus [bridging bronchus (BB) in patients], and subcarinal angle [subpseudocarinal angle in patients] were measured. Measurements other than that for the angle were standardized with body surface area.Results: Significant differences were found between the type IIA PAS patients and controls in terms of DSCT measurements in the trachea (0.51 ± 0.32 cm2/m2 vs. 0.92 ± 0.18 cm2/m2, P < 0.001); left main bronchus (0.29 ± 0.14 cm2/m2 vs. 0.43 ± 0.18 cm2/m2, P = 0.01); right intermediate bronchus [BB in patients] (0.36 ± 0.13 cm2/m2 vs. 0.47 ± 0.12 cm2/m2, P = 0.02); and subcarinal angle [subpseudocarinal angle in patients] (116.27 ± 16.45° vs. 79.41 ± 15.71°, P < 0.001). Receiver operating characteristic analysis further revealed that these parameters may be indicators to differentiate tracheobronchial anomalies due to type IIA PAS from controls (AUC, 0.88-0.98; sensitivity, 81.7%-100%; specificity, 91.7%-100%).Conclusions: DSCT is an alternative technique to detect tracheobronchial anomalies in pediatric patients with type IIA PAS. It can provide accurate anatomic details for surgeons to determine therapeutic strategies. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the impact of an adaptive detector collimation on the dose parameters and accurateness of scan length adaption at prospectively ECG-triggered sequential cardiac CT with a wide-detector third-generation dual-source CT.Methods: Ideal scan lengths for human hearts were retrospectively derived from 103 triple-rule-out examinations. These measures were entered into the new scanner operated in prospectively ECG-triggered sequential cardiac scan mode with three different detector settings: (1) adaptive collimation, (2) fixed 64 × 0.6-mm collimation, and (3) fixed 96 × 0.6-mm collimation. Differences in effective scan length and deviation from the ideal scan length and dose parameters (CTDIvol, DLP) were documented.Results: The ideal cardiac scan length could be matched by the adaptive collimation in every case while the mean scanned length was longer by 15.4% with the 64 × 0.6 mm and by 27.2% with the fixed 96 × 0.6-mm collimation. While the DLP was almost identical between the adaptive and the 64 × 0.6-mm collimation (83 vs. 89 mGycm at 120 kV), it was 62.7% higher with the 96 × 0.6-mm collimation (135 mGycm), p < 0.001.Conclusion: The adaptive detector collimation for prospectively ECG-triggered sequential acquisition allows for adjusting the scan length as accurate as this can only be achieved with a spiral acquisition. This technique allows keeping patient exposure low where patient dose would significantly increase with the traditional step-and-shoot mode.Key Points: • Adaptive detector collimation allows keeping patient exposure low in cardiac CT. • With novel detectors the desired scan length can be accurately matched. • Differences in detector settings may cause 62.7% of excessive dose. [ABSTRACT FROM AUTHOR]

Purpose: Virtual single source computed tomography (VSS-CT) acquisition on a dual source CT (DSCT) has been demonstrated to allow for dose-neutral intra-individual comparison of three acquisition protocols at different radiation dose levels (RDL) within one acquisition in a phantom. The purpose of this study was twofold: first to evaluate the applicability of VSS-CT in patients and second to optimize the task-dependent trade-off between radiation dose and image quality of lower extremity CT angiography (run-off CTA).Material and Methods: In this IRB-approved prospective study 52 patients underwent run-off CTA between 06/2012 and 06/2013. VSS-CT acquisition was conducted using a first generation DSCT applying equal X-ray tube settings (120 kVp), collimation (2 × 32 × 0.6 mm), and slice thickness (1.0 mm) but different effective tube current-time products (tube A: 80 mAs, tube B: 40 mAs). Three different image datasets representing three different radiation dose levels (RDL40, RDL80, RDL120) were reconstructed using a soft kernel from the raw data of tube B, tube A or both tubes combined. Dose length products (DLP) of each raw data set were documented. Quantitative image quality (IQ) was assessed for five anatomical levels using image noise and contrast-to-noise ratio (CNR). To investigate dose efficiency of each acquisition, the dose-weighted CNR (CNRD) was determined. Qualitative IQ was evaluated by two blinded readers in consensus using a 5-point Likert scale and compared with a Friedman- and posthoc Wilcoxon test.Results: Mean DLP was 200 ± 40, 400 ± 90 and 600 ± 130 mGy·cm for the RDL40, RDL80 and RDL120, respectively. Image noise and CNR were best for RDL120 and decreased significantly for RDL80 and RDL40, independent of the anatomic level (p < 0.001). CNRD showed no significant differences at the abdominal and pelvic level between the investigated radiation dose levels. However, for thigh to foot level a significant increase of CNRD was noted between RDL120, RDL80 and RDL40. Significant differences of qualitative IQ were observed between RDL120 and RDL40 from the abdominal to the foot level, whereas no difference was seen for the other dose levels.Conclusion: Radiation dose splitting with VSS-CT can be applied to run-off CTA facilitating intra-individual comparison of different acquisition protocols without additional radiation exposure. Furthermore, a radiation dose reduction potential for run-off CTA of approximately 1/3 as compared to the acquisition protocol recommended by the manufacturer could be identified in this study. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effect of dual-source dual-energy CT versus single-energy CT on DNA double-strand breaks (DSBs) in blood lymphocytes at CT pulmonary angiography (CTPA).Methods and Materials: Sixty-two patients underwent either dual-energy CTPA (Group 1: n = 21, 80/Sn140 kVp, 89/38 mAs; Group 2: n = 20, 100/Sn140 kVp, 89/76 mAs) or single-energy CTPA (Group 3: n = 21, 120 kVp, 110 mAs). Blood samples were obtained before and 5 min after CTPA. DSBs were assessed with fluorescence microscopy and Kruskal-Walls tests were used to compare DSBs levels among groups. Volume CT dose index (CTDIvol), dose length product (DLP) and organ radiation dose were compared using ANOVA.Results: There were increased excess DSB foci per lymphocyte 5 min after CTPA examinations in three groups (Group 1: P = .001; Group 2: P = .001; Group 3: P = .006). There were no differences among groups regarding excess DSB foci/cell and percentage of excess DSBs (Group 1, 23%; Group 2, 24%; Group 3, 20%; P = .932). CTDIvol, DLP and organ radiation dose in Group 1 were the lowest among the groups (all P < .001).Conclusion: DSB is increased following dual-source and single-source CTPA, while dual-source dual-energy CT protocols do not increase the estimated radiation dose and also do not result in a higher incidence of DNA DSBs in patients undergoing CTPA. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate image quality of coronary artery imaging on non-electrocardiography (ECG)-gated high-pitch dual-source computed tomography (DSCT) in children with congenital heart disease (CHD) and to assess factors affecting image quality. We retrospectively reviewed the records of 142 children with CHD who underwent non-ECG-gated high-pitch DSCT. The subjective image quality of the proximal coronary segments was graded using a five-point scale. A score <3 represented a non-diagnostic image. Age, body weight, and heart rate were compared between the two groups: patients with good diagnostic image quality in all four segments and patients with at least one segment with non-diagnostic image quality. Predictors of image quality were assessed by multivariate logistic regression, including age, body weight, and heart rate. Four-hundred-fifty-seven of the 568 segments (80.5%) had diagnostic image quality. Patients with non-diagnostic segments were significantly younger (21.6 ± 25.5 months), had lower body weight (7.82 ± 5.00 kg), and a faster heart rate (123 ± 23.7 beats/min) (each p < 0.05) than patients with diagnostic image quality in all four segments (30.6 ± 20.7 months, 10.3 ± 4.00 kg, and 113 ± 21.6 beats/min, respectively; each p < 0.05). The multivariate logistic regression revealed that body weight (odds ratio 1.228; p = 0.029) was a significant predictor of image quality. Non-ECG-gated high-pitch DSCT provided adequate image quality of the proximal coronary segments in children with CHD. Lower body weight was a factor that led to poorer image quality of the coronary arteries. [ABSTRACT FROM AUTHOR]

Background Clinical-radiological correlation of myocardial bridge (MB) remains unclear. Purpose To correlate clinical symptoms and outcomes of MBs with computed tomography (CT) coronary angiography findings. Material and Methods A total of 2092 patients with CT coronary angiography were collected. Patients were divided into symptomatic and asymptomatic groups, adverse heart events (AHE) and non-AHE groups, MB and non-MB groups, as well as left anterior descending (LAD)-MB and non-LAD-MB groups. Statistical analyses were performed to identify inter-group differences, and clinical-radiological correlations of MBs or mural coronary arteries (MCAs). Results The prevalence of MB, the MCA stenosis either in systole or in diastole, and the ratio of LAD-MB were significantly higher in the symptomatic group than in the asymptomatic group, and higher in the AHE group than in the non-AHE group ( P all <0.05). MB thickness, systolic MCA stenosis, and diastolic MCA stenosis were independent variables predicting clinical symptoms ( P < 0.05), with diastolic MCA stenosis having the highest diagnostic performance, when cutting at 24.6%. The corresponding sensitivity and specificity were 87.8% and 90.6%, respectively. Diastolic MCA stenosis independently indicated outcome of AHE (odds ratio, 1.047; P < 0.001). Conclusion Measurements of MB-MCA by CT predict the presence of clinical symptoms and outcomes of AHE, with diastolic MCA stenosis possessing the greatest performance. [ABSTRACT FROM AUTHOR]

Background: The usage of coronary CT angiography (CTA) is appropriate in patients with acute or chronic chest pain; however the diagnostic accuracy may be challenged with increased Agatston score (AS), increased heart rate, arrhythmia and severe obesity. Thus, we aim to determine the potential of the recently introduced third-generation dual-source CT (DSCT) for CTA in a 'real-life' clinical setting. Methods: Two hundred and sixty-eight consecutive patients (age: 67 ± 10 years; BMI: 27 ± 5 kg/m²; 61% male) undergoing clinically indicated CTA with DSCT were included in the retrospective single-center analysis. A contrast-enhanced volume dataset was acquired in sequential (SSM) ( n = 151) or helical scan mode (HSM) ( n = 117). Coronary segments were classified in diagnostic or non-diagnostic image quality. A subset underwent invasive angiography to determine the diagnostic accuracy of CTA. Results: SSM (96.8 ± 6%) and HSM (97.5 ± 8%) provided no significant differences in the overall diagnostic image quality. However, AS had significant influence on diagnostic image quality exclusively in SSM ( B = 0.003; p = 0.0001), but not in HSM. Diagnostic image quality significantly decreased in SSM in patients with AS ≥2,000 ( p = 0.03). SSM (sensitivity: 93.9%; specificity: 96.7%; PPV: 88.6%; NPV: 98.3%) and HSM (sensitivity: 97.4%; specificity: 94.3%; PPV: 86.0%; NPV: 99.0%) provided comparable diagnostic accuracy ( p = n.s.). SSM yielded significantly lower radiation doses as compared to HSM (2.1 ± 2.0 vs. 5.1 ± 3.3 mSv; p = 0.0001) in age and BMI-matched cohorts. Conclusion: SSM in third-generation DSCT enables significant dose savings and provides robust diagnostic image quality in patients with AS ≤2000 independent of heart rate, heart rhythm or obesity. [ABSTRACT FROM AUTHOR]

Purpose: To investigate diagnostic accuracy of 3rd-generation dual-source CT (DSCT) coronary angiography in obese and non-obese patients.Methods: We retrospectively analyzed 76 patients who underwent coronary CT angiography (CCTA) and invasive coronary angiography. Prospectively ECG-triggered acquisition was performed with automated tube voltage selection (ATVS). Patients were dichotomized based on body mass index in groups A (<30 kg/m2, n = 37) and B (≥30 kg/m2, n = 39) and based on tube voltage in groups C (<120 kV, n = 46) and D (120 kV, n = 30). Coronary arteries were assessed for significant stenoses (≥50 % luminal narrowing) and diagnostic accuracy was calculated.Results: Per-patient overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 96.9 %, 95.5 %, 93.9 %, 97.7 % and 96.1 %, respectively. Sensitivity and NPV were lower in groups B and D compared to groups A and C, but no statistically significant differences were observed (group A vs. B: sensitivity, 100.0 % vs. 93.3 %, p = 0.9493; NPV, 100 % vs. 95.5 %, p = 0.9812; group C vs. D: sensitivity, 100.0 % vs. 92.3 %, p = 0.8462; NPV, 100.0 % vs. 94.1 %, p = 0.8285).Conclusion: CCTA using 3rd-generation DSCT and (ATVS) provides high diagnostic accuracy in both non-obese and obese patients.Key Points: • Coronary CTA provides high diagnostic accuracy in non-obese and obese patients. • Diagnostic accuracy between obese and non-obese patients showed no significant difference. • <120 kV studies were performed in 44 % of obese patients. • Current radiation dose-saving approaches can be applied independent of body habitus. [ABSTRACT FROM AUTHOR]

Purpose: To investigate feasibility, image quality and safety of low-tube-voltage, low-contrast-volume comprehensive cardiac and aortoiliac CT angiography (CTA) for planning transcatheter aortic valve replacement (TAVR).Materials and Methods: Forty consecutive TAVR candidates prospectively underwent combined CTA of the aortic root and vascular access route (270 mgI/ml iodixanol). Patients were assigned to group A (second-generation dual-source CT [DSCT], 100 kV, 60 ml contrast, 4.0 ml/s flow rate) or group B (third-generation DSCT, 70 kV, 40 ml contrast, 2.5 ml/s flow rate). Vascular attenuation, noise, signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were compared. Subjective image quality was assessed by two observers. Estimated glomerular filtration (eGFR) at CTA and follow-up were measured.Results: Besides a higher body-mass-index in group B (24.8±3.8 kg/m2 vs. 28.1±5.4 kg/m2, P=0.0339), patient characteristics between groups were similar (P≥0.0922). Aortoiliac SNR (P=0.0003) was higher in group B. Cardiac SNR (P=0.0003) and CNR (P=0.0181) were higher in group A. Subjective image quality was similar (P≥0.213) except for aortoiliac image noise (4.42 vs. 4.12, P=0.0374). TAVR-planning measurements were successfully obtained in all patients. There were no significant changes in eGFR among and between groups during follow-up (P≥0.302).Conclusion: TAVR candidates can be safely and effectively evaluated by a comprehensive CTA protocol with low contrast volume using low-tube-voltage acquisition.Key Points: • Third-generation dual-source CT facilitates low-tube-voltage acquisition. • TAVR planning can be performed with reduced contrast volume and radiation dose. • TAVR-planning CT did not result in changes in creatinine levels at follow-up. • TAVR candidates can be safely evaluated by comprehensive low-tube-voltage CT angiography. [ABSTRACT FROM AUTHOR]

Objectives To investigate the diagnostic value of first-pass myocardial perfusion defects visualised in non-gated high-pitch computed tomography angiography (CTA) in patients admitted to the emergency department (ED) for suspected aortic dissection. Methods We recruited 174 ED patients who underwent high-pitch CTA of the aorta because of suspected aortic dissection. We divided these patients into two groups (diseased and control groups) based on whether their clinical data fulfilled the third universal definition of acute myocardial infarction (AMI), specifically an increase in cardiac troponin (cTn) with at least one of the following: (a) symptoms of ischemia; (b) new ST-segment-T wave (ST-T) changes or new left bundle branch block (LBBB); (c) development of pathological Q wave; (d) new loss of viable myocardium or new regional wall motion abnormality; or (e) identification of an intracoronary thrombus by angiography or autopsy. Twenty-two patients with a clinical diagnosis of AMI were placed in the diseased group. Myocardial perfusion defects were evaluated qualitatively and quantitatively on the late arterial phase obtained 50 s post-threshold. Results Of the 22 patients with a final diagnosis of AMI, visually identifiable perfusion defects were observed in 12 patients. The sensitivity, specificity, negative predictive value, and positive predictive value of any perfusion defect for predicting AMI were 54.6%, 94.7%, 93.5%, and 60.0%, respectively. Quantitative analysis indicated that CT attenuation was significantly lower within perfusion defects than within the normal myocardium (67.6 ± 29.5 HU vs. 92.2 ± 19.7 HU; p < 0.001). Conclusions In patients with acute chest pain, the presence of myocardial perfusion defect observed on nongated high-pitch CTA of the aorta can be used to identify individuals with AMI with high specificity, but low sensitivity. [ABSTRACT FROM AUTHOR]

Coronary CT angiography (CCTA) suffers from a reduced diagnostic accuracy in patients with heavily calcified coronary arteries or prior myocardial revascularisation due to artefacts caused by calcifications and stent material. CT myocardial perfusion imaging (CTMPI) yields high potential for the detection of myocardial ischemia and might help to overcome the above mentioned limitations. We analysed CT single-phase perfusion using high-pitch helical image acquisition technique in patients with prior myocardial revascularisation. Thirty-six patients with an indication for invasive coronary angiography (28 with coronary stents, 2 with coronary artery bypass grafts and 6 with both) were included in this prospective study at two study sites. All patients were examined on a 2nd generation dual-source CT system. Stress CT images were obtained using a prospectively ECG-triggered single-phase high-pitch helical image acquisition technique. During stress the tracer for myocardial perfusion (MP) SPECT imaging was administered. Rest CT images were acquired using prospectively ECG-triggered sequential CT. MP-SPECT imaging and invasive coronary angiography served as standard of reference. In this heavily diseased patient cohort CCTA alone showed a low overall diagnostic accuracy for detection of hemodynamically relevant coronary artery stenosis of only 31% on a per-patient base and 60% on a per-vessel base. Combining CCTA and CTMPI allowed for a significantly higher overall diagnostic accuracy of 78% on a per-patient base and 92% on a per-vessel base (p < 0.001). Mean radiation dose for stress CT scans was 0.9 mSv, mean radiation dose for rest CT scans was 5.0 mSv. In symptomatic patients with known coronary artery disease and prior myocardial revascularization combining CCTA and CTMPI showed significantly higher diagnostic accuracy in detection of hemodynamically significant coronary artery stenosis when compared to CCTA alone. [ABSTRACT FROM AUTHOR]

Purpose: To assess image quality and accuracy of CT angiography (CTA) for transcatheter aortic valve replacement (TAVR) planning performed with 3rd generation dual-source CT (DSCT).Material and Methods: We evaluated 125 patients who underwent TAVR-planning CTA on 3rd generation DSCT. A two-part protocol was performed including retrospectively ECG-gated coronary CTA (CCTA) and prospectively ECG-triggered aortoiliac CTA using 60mL of contrast medium. Automated tube voltage selection and advanced iterative reconstruction were applied. Effective dose (ED), signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated. Five-point scales were used for subjective image quality analysis. In patients who underwent TAVR, sizing parameters were obtained.Results: Image quality was rated good to excellent in 97.6% of CCTA and 100% of aortoiliac CTAs. CTA studies at >100kV showed decreased objective image quality compared to 70-100kV (SNR, all p≤0.0459; CNR, all p≤0.0462). Mean ED increased continuously from 70 to >100kV (CCTA: 4.5±1.7mSv-13.6±2.9mSv, all p≤0.0233; aortoiliac CTA: 2.4±0.9mSv-6.8±2.7mSv, all p≤0.0414). In 39 patients TAVR was performed and annulus diameter was within the recommended range in all patients. No severe cardiac or vascular complications were noted.Conclusion: 3rd generation DSCT provides diagnostic image quality in TAVR-planning CTA and facilitates reliable assessment of TAVR device and delivery option while reducing radiation dose. [ABSTRACT FROM AUTHOR]

Ductal adenocarcinoma of the pancreas is one of the most aggressive forms of cancer, with only a minority of cases being resectable at the moment of their diagnosis. The accurate detection and characterization of pancreatic carcinoma is very important for patient management. Multidetector-row computed tomography (MDCT) has become the cross-sectional modality of choice in the diagnosis, staging, treatment planning, and follow-up of patients with pancreatic tumors. However, approximately 11% of ductal adenocarcinomas still remain undetected at MDCT because of the lack of attenuation gradient between the lesion and the adjacent pancreatic parenchyma. In this systematic literature review we investigate the current evolution of the CT technique, limitations, and perspectives in the evaluation of pancreatic carcinoma. [ABSTRACT FROM AUTHOR]

Objective To determine the diagnostic accuracy of dual- source computed tomography coronary angiography (DSCT-CA) for detecting various degrees of coronary artery stenosis. Methods A total of 278 patients with coronary atherosclerotic heart disease (CHD) were selected for DSCT-CA examination. The coronary angiography (CAG) examination was carried out within 30 days in these patients. The result of CAG was used as the gold standard. The coronary artery stenosis of 50% and 75% was used as the sector. Based on the data of patients, DSCT- CA was calculated for quantitative assessment of the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of coronary stenosis for the coronary blood vessels and coronary artery segments. Kappa consistence test was used to analyze the results of two methods. Results The 50% and 75% of coronary artery stenosis was used for the sector, based on the patients, the sensitivities of DSCT- CA were 99.6% and 99.1% , specificities were 84.2% , 89.6% , diagnostic accuracies were 98.6% and 97.5%, and the Kappa values were 0.88 and 0.91. Based on coronary vessels, the sensitivities were 92.0% and 96.9%, specificities were 89.9% and 94.8%, diagnostic accuracies were 91.0% and 95.8%, and the Kappa values were 0.88 and 0.92. Based on coronary artery segments, the sensitivities were 97.3%, 96.5%, specificities were 93.3%, 98.1%, diagnostic accuracies were 94.2% and 97.9%, and the Kappa values were 0.84 and 0.91. Conclusion Based on patient's coronary artery analysis, DSCT-CA can accurately assess the different degrees of coronary stenosis, but based on the analysis of the coronary artery segment, the false-positive results may occur in the diagnosis of DACT-CA, which suggests that DSCT-CA can partly replace the CAG, still cannot completely replace the CAG. [ABSTRACT FROM AUTHOR]

Purpose This study aimed to validate standard deviations of lung densities obtained using high-pitch dual-source computed tomography (DSCT) densitometry as indices of bronchopulmonary dysplasia (BPD) severity in premature infants. Methods Data of preterm, late preterm group, and early term groups were evaluated. Mean and median standard deviations (SDmean, SDmedian) of CT lung density (CTLD) were calculated from CT images. Results SDmean of CTLD in infants with severe BPD was significantly higher than that of infants without BPD (198.1 vs. 140.9, respectively; P = .002). Conclusions Study results support using high-pitch DSCT for BPD diagnosis and quantitative evaluation in prematurity. [ABSTRACT FROM AUTHOR]

Persistent truncus arteriosus is a rare congenital cardiac disease with variable presentation. The exact preoperative diagnosis and delineation of anatomy are very important because the optimal timing and procedure for truncus arteriosus repair are decided on the basis of the morphological characteristics. Moreover, the presence of associated anomalies influences the surgical outcome and mortality in these patients. Dual-source computed tomographic evaluation with three-dimensional post-processing is highly valuable for delineating its precise morphology and to identify and characterize the associated anomalies. Also depiction of the precise aortic arch morphology and simultaneous evaluation of the airway are very useful in treatment planning. This pictorial review provides an overview of the imaging spectrum of truncus arteriosus and various associated anomalies as seen on dual-source computed tomography. [ABSTRACT FROM AUTHOR]

Objective: Evaluation of the intimal flap visibility comparing 2nd and 3rd generation dual-source high-pitch CT. Methods: Twenty-five consecutive patients with aortic dissection underwent CT angiography on a second and third generation dual-source CT scanner using prospective ECG-gated high-pitch dual-source CT acquisition mode. Contrast material, saline flush and flow rate were kept equal for optimum comparability. The visibility of the intimal flap as well as the delineation of the different vascular structures was evaluated. Results: In 3rd generation dual-source high-pitch CT we could show a significant improvement of intimal flap visibility in aortic dissection. Especially, the far end of the dissection membrane could be better evaluated in 3rd generation high-pitch CT, reaching statistical significance ( P < 0.01). Conclusion: 3rd Generation high-pitch CT angiography shows a better delineation of the aortic intimal flap in a small patient cohort, especially in the far ends of the dissection membrane. This might be due to higher tube power in this CT generation. However, to generalise these findings larger trials are needed. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the reliability of ungated, high-pitch dual-source CT for coronary artery calcium (CAC) screening.Materials and Methods: One hundred and eighty-five smokers underwent a dual-source CT examination with acquisition of two sets of images during the same session: (a) ungated, high-pitch and high-temporal resolution acquisition over the entire thorax (i.e., chest CT); (b) prospectively ECG-triggered acquisition over the cardiac cavities (i.e., cardiac CT).Results: Sensitivity and specificity of chest CT for detecting positive CAC scores were 96.4 % and 100 %, respectively. There was excellent inter-technique agreement for determining the quantitative CAC score (ICC = 0.986). The mean difference between the two techniques was 11.27, representing 1.81 % of the average of the two techniques. The inter-technique agreement for categorizing patients into the four ranks of severity was excellent (weighted kappa = 0.95; 95 % CI 0.93-0.98). The inter-technique differences for quantitative CAC scores did not correlate with BMI (r = 0.05, p = 0.575) or heart rate (r = -0.06, p = 0.95); 87.2 % of them were explained by differences at the level of the right coronary artery (RCA: 0.8718; LAD: 0.1008; LCx: 0.0139; LM: 0.0136).Conclusion: Ungated, high-pitch dual-source CT is a reliable imaging mode for CAC screening in the conditions of routine chest CT examinations.Key Points: • CAC is an independent risk factor for major cardiac events. • ECG-gated techniques are the reference standard for calcium scoring. • Great interest is directed toward calcium scoring on non-gated chest CT examinations. • Reliable calcium scoring can be obtained with dual-source CT in a high-pitch mode. [ABSTRACT FROM AUTHOR]

To evaluate the feasibility of low-concentration contrast medium (CM) for vascular enhancement, image quality, and radiation dose on computed tomography aortography (CTA) using a combined low-tube-voltage and iterative reconstruction (IR) technique. Ninety subjects underwent dual-source CT (DSCT) operating in dual-source, high-pitch mode. DSCT scans were performed using both high-concentration CM (Group A, n = 50; Iomeprol 400) and low-concentration CM (Group B, n = 40; Iodixanol 270). Group A was scanned using a reference tube potential of 120 kVp and 120 reference mAs under automatic exposure control with IR. Group B was scanned using low-tube-voltage (80 or 100 kVp if body mass index ≥25 kg/m(2)) at a fixed current of 150 mAs, along with IR. Images of the two groups were compared regarding attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), iodine load, and radiation dose in various locations of the CTA. In comparison between Group A and Group B, the average mean attenuation (454.73 ± 86.66 vs. 515.96 ± 101.55 HU), SNR (25.28 ± 4.34 vs. 31.29 ± 4.58), and CNR (21.83 ± 4.20 vs. 27.55 ± 4.81) on CTA in Group B showed significantly greater values and significantly lower image noise values (18.76 ± 2.19 vs. 17.48 ± 3.34) than those in Group A (all Ps < 0.05). Homogeneous contrast enhancement from the ascending thoracic aorta to the infrarenal abdominal aorta was significantly superior in Group B (P < 0.05). Low-concentration CM and a low-tube-voltage combination technique using IR is a feasible method, showing sufficient contrast enhancement and image quality. [ABSTRACT FROM AUTHOR]

Purpose: To compare, on an intra-individual basis, the effect of automated tube voltage selection (ATVS), integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of aortic CTA studies using 2nd and 3rd generation dual-source CT (DSCT). Material and Methods: We retrospectively evaluated 32 patients who had undergone CTA of the entire aorta with both 2nd generation DSCT at 120kV using filtered back projection (FBP) (protocol 1) and 3rd generation DSCT using ATVS, an integrated circuit detector and advanced iterative reconstruction (protocol 2). Contrast-to-noise ratio (CNR) was calculated. Image quality was subjectively evaluated using a five-point scale. Radiation dose parameters were recorded. Results: All studies were considered of diagnostic image quality. CNR was significantly higher with protocol 2 (15.0±5.2 vs 11.0±4.2; p<.0001). Subjective image quality analysis revealed no significant differences for evaluation of attenuation (p=0.08501) but image noise was rated significantly lower with protocol 2 (p=0.0005). Mean tube voltage and effective dose were 94.7±14.1kV and 6.7±3.9mSv with protocol 2; 120±0kV and 11.5±5.2mSv with protocol 1 (p<0.0001, respectively). Conclusion: Aortic CTA performed with 3rd generation DSCT, ATVS, integrated circuit detector, and advanced iterative reconstruction allow a substantial reduction of radiation exposure while improving image quality in comparison to 120kV imaging with FBP. [ABSTRACT FROM AUTHOR]

Background: All studies involving use of ionizing radiation should be performed in accordance with the ALARA (As Low As Reasonably Achievable) principle, especially in children. In this study, the prospective ECG triggering technique with low voltage was used in dual-source computed tomography (DSCT) angiography to investigate if image quality with low radiation dose could be satisfactory in pediatric patients with congenital heart disease.Methods: Sixty pediatric patients with suspected congenital cardiovascular anomalies were enrolled prospectively in the study. They were randomly assigned to two groups for DSCT angiography. Group A were scanned by prospective ECG-triggering computed tomography angiography (CTA) with 80 kV tube voltage, while group B by used non-ECG-gated CTA with the same tube voltage. The anomaly accuracy was evaluated based on the surgical and/or conventional cardiac angiography findings. The overall image quality was assessed on a five-point scale. And the diagnostic accuracy and radiation dose was evaluated in both groups.Results: There were 127 cardiovascular anomalies in Group A and 108 in Group B. The mean subjective image quality and diagnostic accuracy between these two groups were significantly different (P = 0.007 and 0.011, respectively). The mean effective dose in Group A and Group B was 0.38 ± 0.13 mSv and 0.35 ± 0.17 mSv, respectively. But there was no significant difference between two groups (P = 0.197).Conclusions: The prospective ECG triggering technique in DSCT scan can offer better image quality and diagnostic accuracy with low radiation exposure in pediatric patients with congenital heart diseases. This technique has potential to become a new clinical routine in pediatric cardiac computed tomography (CT) imaging. [ABSTRACT FROM AUTHOR]

Purpose: We evaluated the ability of dual source CT (DSCT) with ECG-triggered high-pitch spiral acquisition (Flash Spiral Cardio mode) to depict the morphological features of ventricles in pediatric patients with congenital heart defects (CHD).Materials and Methods: Between July 2013 and April 2015, 78 pediatric patients with CHD (median age 4 months) were examined using DSCT with the Flash Spiral Cardio mode. The types of ventricular abnormalities were ventricular septal defect (VSD) in 42 (the malaligned type in 11, perimembranous type in 23, supracristal type in 2, atrioventricular type in 2, and muscular type in 4), single ventricle (SV) in 11, and congenital corrected transposition of the great arteries (ccTGA) in 4. We evaluated the accuracy of the diagnosis of the VSD type. In cases of SV and ccTGA, we assessed the detectability of the anatomical features of both ventricles for a diagnosis of ventricular situs.Results: DSCT confirmed the diagnoses for all VSDs. The type of defect was precisely diagnosed for all patients. The anatomical features of both ventricles were also depicted and ventricular situs of SV and ccTGA was correctly diagnosed.Conclusion: The results suggest that DSCT has the ability to clearly depict the configuration of ventricles. [ABSTRACT FROM AUTHOR]

Purpose: To assess the effect of a noise-optimized image-based virtual monoenergetic imaging (VMI+) algorithm in direct comparison with the traditional VMI technique and standard linearly-blended images emulating 120-kVp acquisition (M_0.3) on image quality at dual-energy CT in patients with lung cancer.Materials and Methods: Dual-source dual-energy CT examinations of 48 patients with biopsy-proven primary (n=31) or recurrent (n=20) lung cancer were evaluated. Images were reconstructed as M_0.3, and VMI+ and traditional VMI series at 40, 55, and 70keV. Attenuation of tumor, descending aorta, pulmonary trunk, latissimus muscle, and noise were measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used by three observers to subjectively evaluate general image impression, tumor delineation, image sharpness, and image noise.Results: Background noise was consistently lower with VMI+ compared to VMI at all keV levels (all p<0.0001) and M_0.3 (all p≤0.0004). Tumor SNR and CNR peaked in the 40keV VMI+ series, significantly higher compared to all VMI and M_0.3 series (all p<0.0008). Observers preferred the 55keV VMI+ series regarding general image impression and tumor delineation compared to all other series (all p<0.0001). Image sharpness and image noise ratings were highest in the 55keV VMI+ and 70keV VMI and VMI+ reconstructions.Conclusions: Tumor CNR peaked at 40keV VMI+ while observers preferred 55keV VMI+ series overall other series for dual-energy CT of lung cancer. The noise-optimized VMI+ technique showed significantly lower background noise and higher SNR and CNR compared to the traditional VMI technique at matching keV levels. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of temporal resolution (TR) on cardiogenic artefacts at the level of bronchial walls.Material and Methods: Ninety patients underwent a dual-source, single-energy chest CT examination enabling reconstruction of images with a TR of 75 ms (i.e., optimized TR) (Group 1) and 140 ms (i.e., standard TR) (Group 2). Cardiogenic artefacts were analyzed at the level of eight target bronchi, i.e., right (R) and left (L) B1, B5, B7, and B10 (total number of bronchi examined: n = 720).Results: Cardiogenic artefacts were significantly less frequent and less severe in Group 1 than in Group 2 (p < 0.0001) with the highest scores of discordant ratings for bronchi in close contact with cardiac cavities: RB5 (61/90; 68%); LB5 (66/90; 73%); LB7 (63/90; 70%). In Group 1, 78% (560/720) of bronchi showed no cardiac motion artefacts, whereas 22% of bronchi (160/720) showed artefacts rated as mild (152/160; 95%), moderate (7/160; 4%), and severe (1/160; 1%). In Group 2, 70% of bronchi (503/720) showed artefacts rated as mild (410/503; 82%), moderate (82/503; 16%), and severe (11/503; 2%).Conclusion: At 75 ms, most bronchi can be depicted without cardiogenic artefacts.Key Points: • Quantitative CT helps analyze morphologic changes in COPD patients • Cardiogenic artefacts may hamper precise analysis of bronchial dimensions • Temporal resolution of CT acquisitions is an important parameter for bronchial imaging. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: To investigate motion artifacts, image quality, and practical differences in electrocardiographic (ECG)-gated versus non-ECG-gated high-pitch dual-source computed tomography angiography (CTA) of the whole aorta. Materials and Methods: Two groups, each including 40 patients, underwent either ECG-gated or non-ECG-gated high-pitch dual-source CTA of the whole aorta. The aortic annulus, aortic valve, coronary ostia, and the presence of motion artifacts of the thoracic aorta as well as vascular contrast down to the femoral arteries were independently assessed by two readers. Additional objective parameters including image noise and signal-to-noise ratio were analyzed. Results: Subjective and objective scoring revealed no presence of motional artifacts regardless of whether the ECG-gated or the non-ECG-gated protocol was used (P > 0.1). Image acquisition parameters (examination length, examination duration, radiation dose) were comparable between the two groups without significant differences. The aortic annulus, aortic valve, and coronary ostia were reliably evaluable in all patients. Vascular contrast was rated excellent in both groups. Conclusions: High-pitch dual-source CTA of the whole aorta is a robust and dose-efficient examination strategy for the evaluation of aortic pathologies whether or not ECG gating is used. [ABSTRACT FROM AUTHOR]

Objectives: To investigate to what extent 3rd generation dual-source computed tomography (DSCT) can reduce radiation dose in coronary artery calcium scoring.Methods: Image acquisition was performed using a stationary calcification phantom. Prospectively electrocardiogram (ECG)-triggered 120 kV sequential, and 120 and Sn100 kV ultra-high pitch (UHP) acquisitions were performed with different tube currents (80, 60, 40, 20 mA). Images were reconstructed using filtered back projection (FBP) and 3rd generation iterative reconstruction (IR). Contrast-to-noise ratio (CNR), Agatston score, calcium volume, and radiation dose were assessed. For statistical analysis Friedman tests and Wilcoxon rank sum tests were used.Results: Even at reduced tube currents, the three acquisition techniques did not show significant differences in Agatston score (p=0.4) or calcium volume (p=0.08) with FBP reconstruction. Calcium volumes were significantly lower for 3rd generation IR compared to FBP reconstructions (p<0.01). CTDIvol for the 120 kV sequential, 120 and Sn100 kV UHP acquisitions at 80 and 20 mA were 1.2-0.37, 0.48-0.17, and 0.07-0.02 mGy, respectively.Conclusion: 3rd generation DSCT enabled a reduction of tube current in both the sequential and UHP acquisitions without significantly affecting coronary calcium scoring. Tin filtered 100 kV scanning may allow accurate quantification of calcium score without correction of the HU threshold. [ABSTRACT FROM AUTHOR]

To define the optimal systolic phase for dual-source computed tomography angiography using an absolute reconstruction delay time after the R-R interval based on the coronary artery motion, we analyzed images reconstructed between 200 and 420 miliseconds (ms) after the R wave at 20 ms increments in 21 patients. Based on the American Heart Association coronary segmentation guidelines, the origin of six coronary artery landmarks (RCA, AM1, PDA, LM, OM1, and D2) were selected to calculate the coronary artery motion velocity. The velocity of the given landmark was defined as the quotient of the route and the length of the time interval. The x, y and z-coordinates of the selected landmark were recorded, and were used for the calculation of the 3D route of coronary artery motion by using a specific equation. Differences in velocities were assessed by analysis of variance for repeated measures; Bonferroni post hoc tests were used for multiple pair wise comparisons. 1488 landmarks were measured (6 locations at 12 systolic time points) in 21 patients and were analyzed. The mean values of the minimum velocities were calculated separately for each heart rate group (i.e. <65; 65-80; and >80 bpm). The mean lowest coronary artery velocities in each segment occurred in the middle period of each time interval of the acquired systolic phase i.e. 280-340 ms. No differences were found in the minimal coronary artery velocities between the three HR groups, with the exception of the AM1 branch (p = 0.00495) between <65 and >80 bpm (p = 0.03), and at HRs of 65-80 versus >80 bpm (p = 0.006). During an absolute delay of 200-420 ms after the R-wave, the ideal reconstruction interval varies significantly among coronary artery segments. Decreased velocities occur between 280 to 340 ms. Therefore a narrow range of systolic intervals, rather than a single phase, should be acquired. [ABSTRACT FROM AUTHOR]

We report a case of an anomalous course of the right coronary artery (RCA) through the right atrium, which was evaluated using dual-source CT angiography. There have been a few cases described previously in literature, but most of them were found either during surgery or at autopsy. Although this variant is clinically benign, it has significant consequences during interventional procedures or bypass surgery.

Dual-energy computed tomography (DECT) uses different energy spectrum x-ray beams for differentiating materials with similar attenuation at a certain energy. Compared with single-energy CT, it provides images with better diagnostic performance and a potential reduction of contrast agent and radiation doses. There are different commercially available DECT technologies, with machines that may display two x-ray sources and two detectors, a single source capable of fast switching between two energy levels, a specialized detector capable of acquiring high- and low-energy data sets, and a filter splitting the beam into high- and low-energy beams at the output. Sequential acquisition at different tube voltages is an alternative approach. This narrative review describes the DECT technique using a Q&A format and visual representations. Physical concepts, parameters influencing image quality, postprocessing methods, applicability in daily routine workflow, and radiation considerations are discussed. Differences between scanners are described, regarding design, image quality variabilities, and their advantages and limitations. Additionally, current clinical applications are listed, and future perspectives for spectral CT imaging are addressed. Acknowledging the strengths and weaknesses of different DECT scanners is important, as these could be adapted to each patient, clinical scenario, and financial capability. This technology is undoubtedly valuable and will certainly keep improving.

Objective To explore the feasibility of dual-source computed tomography (DSCT) in the evaluation of coronary in-stent restenosis (ISR) by comparing the results of DSCT and selective coronary angiography (CAG). Methods In-stent restenosis examination results from DSCT were compared with those obtained using CAG. Results Among 173 stents studied, 156 yielded good quality images when evaluated with DSCT. CAG identified 38 ISR cases, while DSCT found 40. Among the 112 stents in the study with an inner diameter ≥3.0 mm, CAG identified 29 as having ISR, while DSCT reported the same finding in 30; among the 44 stents with inner diameter <3.0 mm, CAG identified ISR in 9, while DSCT found ISR in 10. Conclusions Stent inner diameter is a key factor influencing the imaging of the stent lumen. DSCT demonstrated a higher negative predictive value in ISR assessment, suggesting that it could replace CAG for assessing the patency of stents with a larger inner diameter (≥3 mm). [ABSTRACT FROM AUTHOR]

Background: Lower tube voltage has advantages for CT angiography, such as improved contrast Objective: To evaluate the image quality of low-voltage (70 kV) CT for congenital heart disease and the ability of sinogram-affirmed iterative reconstruction to improve image quality. Materials and methods: Forty-six children with congenital heart disease (median age: 109 days) were examined using dual-source CT. Scans were performed at 80 kV and 70 kV in 21 and 25 children, respectively. A nonionic iodinated contrast medium (300 mg I/ml) was used for the 80-kV protocol. The contrast medium was diluted to 75% (225 mgI/mL) with saline for the 70-kV protocol. Image noise was measured in the two protocols for each group by extracting the standard deviations of a region of interest placed on the descending aorta. We then determined whether sinogram-affirmed iterative reconstruction reduced the image noise at 70 kV. Results: There was more noise at 70 kV than at 80 kV (29 ± 12 vs 20 ± 4.8; P < 0.01). Sinogram-affirmed iterative reconstruction with grade 4 strength settings improved the noise (20 ± 5.9; P < 0.01) for the 70-kV group. Conclusion: Sinogram-affirmed iterative reconstruction improved the image quality of CT in congenital heart disease. [ABSTRACT FROM AUTHOR]

Rationale and Objectives To investigate the diagnostic performance of a comprehensive computed tomography (CT) protocol for both cardiac and aortoiliac evaluation of patients considered for transcatheter aortic valve replacement (TAVR) using a single, low-volume contrast medium (CM) injection. Materials and Methods Forty-four TAVR candidates were retrospectively analyzed. All underwent retrospectively electrocardiogram-gated cardiac CT followed by high-pitch CT angiography of the aortoiliac vasculature using one of two single injection protocols of 320 mgI/mL iodine CM: group A ( n = 22), iodine delivery rate-based (1.28 gI/s), 60-mL CM volume, 4.0 mL/s flow rate; group B ( n = 22), clinical routine protocol, 100-mL CM volume, 4.0 mL/s flow rate. Mean arterial attenuation, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was assessed. Results Aortic root and iliofemoral dimensions could be analyzed in all cases. Patient characteristics showed no significant differences. Mean attenuation at the levels of the aortic root (285.8 ± 83.0 HU vs 327.5 ± 70.8 HU, P = .080) and the iliofemoral access route (256.8 ± 88.5 HU vs 307.5 ± 93.2 HU, P = .071), as well as SNR and CNR were nonsignificantly lower in group A compared to group B. Subjective image quality was equivalent. Conclusions In multimorbid TAVR patients, the performance of a combined CT protocol using a single low-volume CM bolus is feasible with maintained image quality compared to a standard protocol. [ABSTRACT FROM AUTHOR]

Objectives To investigate the clinical value of dual source CT （DSCT） dual energy （DE） technique in the cervical lymph nodes．Methods The contrast images in two phases of 94 cervical lymph nodes were retrospectively analyzed. The degree of enhancement of enlarged lymph nodes in arterial and parenchymal phases on iodine-enhanced and weighted fusion 120kV images were evaluated. The mean CT values of benign and malignant lymph nodes in the two phases on iodine-enhanced and weighted fusion 120 kV images for were measured to evaluate the effect of mean CT values for differentiating the benign and malignant cervical lymph nodes. The mean CT values of dual-phase enhancemen on iodine-enhanced image for the enlarged lymph nodes derived from different pathological change were compared to conclude the enhanced characteristics for the different pathological enlarge lymph nodes．Results （ 1） The mean CT values of benign and malignant enlarged lymph nodes on iodine-enhanced images in arterial and parenchymal phase was no difference between them （ ＞0.05） .2.There were statistical differces in CTvalues among different pathological types in arterial and parenchymal phase （F=8. 558， ＜0.001） ．Conclusions The mean CT value of different pathological types of lymph nodes on iodine-enhanced image has statistically significant difference on dual-phase mode．Measuring the mean CT value of dual-phase iodine-enhanced images was helpful to make qualitative diagnosis of lymph nodes lesions [ABSTRACT FROM AUTHOR]

Objective: To measure and analyze the tibia and femur tunnel location after single-bundle reconstruction of anterior cruciate ligament using dual-source CT. Methods: DSCT scanning of the knee joint was performed in the 92 patients who underwent single-bundle ACL reconstruction from January 2013 to June 2014. These patients included 64 men and 28 women, with an average of31.2 years. The centers of bone tunnels were marked with Adobe Photoshop CS6. The tibial tunnel center was measured with Lorenz method(relative position represented with Tx\Ty in percentage) and femoral tunnel center was measured with Bernard method(relative position represented with Fx\Fy in percentage). Results: The average Tx and Ty were(54.54±3.42)% and(39.58±6.72)%, while the average Fx and Fy were(28.98±6.51)% and(28.04±8.70)%. There was no significant difference between male and female, left and right knee(P>0.05). Conclusion: Dual-source CT can clearly, three-dimensional display the operative tunnel of anterior cruciate ligament.It also can be used to evaluate tunnel location, help improve operation method and provide individualized anatomic reconstruction for the injury of anterior cruciate ligament. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the utility of dual-source computed tomography (DSCT) for quantification of the mitral valve area (MVA) in patients with atrial fibrillation (AF) and mitral stenosis (MS) and to compare the results of DSCT with those of cardiovascular magnetic resonance (CMR) and transthoracic echocardiography (TTE). One hundred-two patients with AF and MS who had undergone electrocardiography-gated DSCT, TTE and CMR prior to operation were retrospectively enrolled. The MVA was planimetrically determined by DSCT, CMR, and TTE, as well as by Doppler TTE using the pressure half-time method (TTE-PHT). Agreement, relationship between measurements, and the highest accuracy were evaluated using Bland-Altman, Pearson correlation, and receiver operating characteristic analyses. The MVA on DSCT (mean, 1.27 ± 0.27 cm) was significantly larger than that on CMR (1.15 ± 0.28 cm, P < 0.05), TTE-planimetry and TTE-PHT (1.16 ± 0.28 and 1.07 ± 0.30 cm, respectively; P < 0.05). TTE-planimetry had better correlation with planimetry on DSCT and CMR ( r = 0.65 and 0.67, respectively; P < 0.05) than TTE-PHT ( r = 0.51 and 0.55, respectively; P < 0.05). Using an MVA of 1.0 cm on TTE-planimetry and TTE-PHT as the reference, the optimal thresholds for detecting severe MS on DSCT was 1.19 cm. The planimetry of the MVA measured by DSCT may be a reliable, alternative method for the quantification of MS in patients with AF. [ABSTRACT FROM AUTHOR]

Objective To evaluate the application value of Dual-Source CT in diagnosis of ascending aorta lesion combined aortic regurgitation before and after Carbrol's procedure. Methods A retrospective analysis was performed in 11 cases of diagnosed aortic lesion with aortic valve insufficiency who had preoperative and postoperative dual-source CT examination. Results Preoperative 11 cases showed the ascending aorta in different degree of expansion, aortic valve insufficiency, left ventricular enlargement; 7 cases of ascending aortic aneurysm with aortic valve insufficiency; 4 cases of dissection aneurysm with aortic volve insufficiency, 1 (1/7) case of bicuspid aortic valve abnormalities; 2 cases showed coronary arteries stenosis; 1 case showed aortic valve calcification with neoplasm and affected the openings of right coronary artery. 1 (1/4) case showed right coronary sinus endomembrane tear and right coronary artery originated in the false lumen, postoperative CTA showed after aortic valve replacement, the ascending aorta replacement for artificial blood vessels, artificial blood vessels around the thrombus organization; 6 cases were visible autologous aneurysmal wall surrounding the artificial blood vessels and the right auricle of dantian flow, including 1 case of disc fistula and 1 case of right coronary bypass surgery. 4 cases showed trunk stent implantation. Conclusion Dual-source CT Cardiovascular Imaging has very important value in preoperative and post operative evaluation of Carbrol's procedure. [ABSTRACT FROM AUTHOR]