ECG-gated Scan Research Articles

Feasibility of Simple Evaluation of Coronary Artery Calcium Using a Number of Chest Computed Tomography Slices: A Multicenter Study

Objective: We aimed to evaluate the visual measurements of coronary artery calcium (CAC) on nonelectrocardiogram (ECG)-gated chest computed tomography (CT) using a simple scoring method that involves counting the number of CT slices containing CAC. Materials and Methods: We analyzed 163 participants who underwent both coronary and chest CT examinations at six centers within 3 months. Agatston scores were calculated on standard ECG-gated scans and classified as none (0), mild (1-99), moderate (100-400), or severe (>400). Next, chest CT images were reconstructed to standard 5.0 mm axial slices. Then, CAC on chest CT scans was measured using two methods: the Weston score (sum of the assigned score of each vessel, range: 0-12) and number of slices showing CAC (Ca-slice#). Results: When the Weston score and Ca-slice# were divided into four levels according to the optimal divisional levels corresponding to the Agatston score classes, good agreements with the 4-grade Agatston score were observed (kappa value=0.610 and 0.794, respectively). The sensitivity and specificity of Ca-slice# ≥9 to identify severe Agatston scores of >400 were 86% and 96%, respectively. Conclusion: The Ca-slice#, a simple scoring method using chest CT scans, was in good agreement with the ECG-gated Agatston score.

Cardiac motion and its dosimetric impact during radioablation for refractory ventricular tachycardia.

Cardiac radioablation (CR) is a noninvasive treatment option for patients with refractory ventricular tachycardia (VT) during which high doses of radiation, typically 25Gy, are delivered to myocardial scar. In this study, we investigate motion from cardiac cycle and evaluate the dosimetric impact in a cohort of patients treated with CR. This retrospective study included eight patients treated at our institution who had respiratory-correlated and ECG-gated 4DCT scans acquired within 2 weeks of CR. Deformable image registration was applied between maximum systole (SYS) and diastole (DIAS) CTs to assess cardiac motion. The average respiratory-correlated CT (AVGresp ) was deformably registered to the average cardiac (AVGcardiac ), SYS, and DIAS CTs, and contours were propagated using the deformation vector fields (DVFs). Finally, the original treatment plan was recalculated on the deformed AVGresp CT for dosimetric assessment. Motion magnitudes were measured as the mean (SD) value over the DVFs within each structure. Displacement during the cardiac cycle for all chambers was 1.4 (0.9) mm medially/laterally (ML), 1.6 (1.0) mm anteriorly/posteriorly (AP), and 3.0 (2.8) mm superiorly/inferiorly (SI). Displacement for the 12 distinct clinical target volumes (CTVs) was 1.7 (1.5) mm ML, 2.4 (1.1) mm AP, and 2.1 (1.5) SI. Displacements between the AVGresp and AVGcardiac scans were 4.2 (2.0) mm SI and 5.8 (1.4) mm total. Dose recalculations showed that cardiac motion may impact dosimetry, with dose to 95% of the CTV dropping from 27.0 (1.3) Gy on the AVGresp to 20.5 (7.1) Gy as estimated on the AVGcardiac . Cardiac CTV motion in this patient cohort is on average below 3mm, location-dependent, and when not accounted for in treatment planning may impact target coverage. Further study is needed to assess the impact of cardiac motion on clinical outcomes.

Differences in Cardiac-Pulsatility-Induced Displacement and Geometry Changes between the Cook ZBIS and Gore IBE: Postoperative Comparison Using ECG-Gated CTA Scans.

To what extent the stentgraft design of iliac branch devices (IBDs) relates to dynamic deformation is currently unknown. Therefore, this study aimed to quantify and compare displacement and geometry changes during the cardiac cycle of two common IBDs. This paper presents a two-center trial with patients treated with a Zenith bifurcated iliac side (ZBIS) or Gore iliac branch endoprosthesis (IBE). All patients underwent a retrospective electrocardiogram (ECG)-gated computed tomographic angiography (CTA) during follow-up. Cardiac-pulsatility-induced displacement was quantified for the following locations: (neo) bifurcation of the aorta, IBD flow divider, distal markers of the internal iliac artery (IIA) component and first IIA bifurcation. Geometrical parameters (length, tortuosity index, curvature and torsion) were quantified over centerlines. Displacement was more pronounced for the IBE than the ZBIS, e.g., craniocaudal displacement of 0.91 mm (0.91-1.13 mm) vs. 0.57 mm (0.40-0.75 mm, p = 0.004), respectively. The IBDs demonstrated similar geometrical parameters in the neo-common iliac artery and distal IIA, except for the larger dynamic curvature and torsion of the distal IIA in IBEs. The IBEs showed more dynamic length and curvature change compared to the ZBIS in the stented IIA. The IIA trajectory showed more pronounced deformation during the cardiac cycle after placement of an IBE than a ZBIS, suggesting the IBE is more conformable than the ZBIS.

The influence of electrocardiogram-gated computed tomography reconstruction into 8 or 10 cardiac phases on cardiac-pulsatility-induced motion quantification of stent grafts in the aorta

ObjectiveThe goal of this study was to determine to what extent aortic stent graft motion quantification is comparable between electrocardiogram (ECG)-gated computed tomography (CT) scans with reconstructions into 8 and 10 cardiac phases on CT scanners from two different vendors. MethodsAn experimental setup that induces motion of an aortic stent graft, according to a predefined aortic blood pressure wave, was placed in two CT scanners of different vendors. The stent graft motion was captured using an ECG-gated CT technique and quantified using dedicated analysis algorithms. The calculated motion amplitudes and total traveled path lengths of stent segmentations were compared between scans reconstructed into 8 and 10 phases and between the scanners, after validation with sensor measurements and repeated measurements. ResultsNo difference in motion amplitudes in z-direction (craniocaudal direction) was observed between the reconstructions into 8 and 10 phases (0.02 mm; 95% confidence interval [CI], –0.01 to 0.05 mm; P = .358). The z-amplitudes differed by 0.04 mm (95% CI, 0.01-0.07 mm; P = .003) between the different CT scanners. Path lengths differed 0.07 mm (95% CI, 0.01-to 0.13 mm; P = .013) between the reconstructions into 8 and 10 phases and 0.13 mm (95% CI, 0.06-0.17 mm; P < .001) between the different scanners. ConclusionsThe motion amplitudes can accurately be compared between 8 and 10 phases and between the two scanners, without differences larger than the voxel size of 0.3 × 0.3 × 0.5 mm. Clinical motion analysis results of different ECG-gated CT scans and CT scanners can be compared up to the accuracy of the CT scan.

Diagnostic accuracy of lower-dose cardiac CT in evaluating young infants with non-coronary complex congenital heart disease on a 64-slice multidetector CT scanner.

Redoable precise and non-invasive diagnostic imaging modality with the least radiation dose is essential for infants with congenital heart disease (CHD) . To investigate the accuracy and estimate the radiation dose of our cardiac computed tomography (CCT) protocol. A total of 82 infants with CHD underwent non-ECG-gated CCT without contrast timing scanning techniques and were retrospectively studied. The image quality and radiation dose were estimated. The radiation dose was compared statistically to virtual retrospective ECG-gated and prospective ECG-triggering scanning modes. The diagnostic accuracy was assessed assuming the surgical results as the diagnostic gold standard. Most exams showed a high quality with low radiation doses compared to previous studies. The mean effective dose (ED) was 0.39 ± 1.2, significantly lower than that of the virtual retrospective ECG-gated and prospective ECG-triggering scanning and lower than in previous studies. Our CCT protocol has achieved a diagnostic accuracy of 99.52% with a sensitivity of 94.83% and specificity of 99.91%. Non-ECG-gated CCT without contrast timing techniques can detect the non-coronary cardiovascular defects of CHD in infants with an ultralow radiation dose and a high diagnostic accuracy.

Opportunistic deep learning powered calcium scoring in oncologic patients with very high coronary artery calcium (≥ 1000) undergoing 18F-FDG PET/CT

Our aim was to identify and quantify high coronary artery calcium (CAC) with deep learning (DL)-powered CAC scoring (CACS) in oncological patients with known very high CAC (≥ 1000) undergoing 18F-FDG-PET/CT for re-/staging. 100 patients were enrolled: 50 patients with Agatston scores ≥ 1000 (high CACS group), 50 patients with Agatston scores < 1000 (negative control group). All patients underwent oncological 18F-FDG-PET/CT and cardiac SPECT myocardial perfusion imaging (MPI) by 99mTc-tetrofosmin within 6 months. CACS was manually performed on dedicated non-contrast ECG-gated CT scans obtained from SPECT-MPI (reference standard). Additionally, CACS was performed fully automatically with a user-independent DL-CACS tool on non-contrast, free-breathing, non-gated CT scans from 18F-FDG-PET/CT examinations. Image quality and noise of CT scans was assessed. Agatston scores obtained by manual CACS and DL tool were compared. The high CACS group had Agatston scores of 2200 ± 1620 (reference standard) and 1300 ± 1011 (DL tool, average underestimation of 38.6 ± 26%) with an intraclass correlation of 0.714 (95% CI 0.546, 0.827). Sufficient image quality significantly improved the DL tool’s capability of correctly assigning Agatston scores ≥ 1000 (p = 0.01). In the control group, the DL tool correctly assigned Agatston scores < 1000 in all cases. In conclusion, DL-based CACS performed on non-contrast free-breathing, non-gated CT scans from 18F-FDG-PET/CT examinations of patients with known very high (≥ 1000) CAC underestimates CAC load, but correctly assigns an Agatston scores ≥ 1000 in over 70% of cases, provided sufficient CT image quality. Subgroup analyses of the control group showed that the DL tool does not generate false-positives.

Evaluation of non-breath-hold, ultra-fast, low-dose high-pitch (flash) CT scan as a practical alternative to standard spiral scan for pre-TAVI patients: a real-world single-center experience

Abstract Introduction and aim Aortic annulus dimensions change during the cardiac cycle. A retrospective ECG-gated (Spiral) scan is the default technique for pre TAVR evaluation since it includes systolic phases considered optimal for aortic annulus assessment. Ultra-fast, Low-Dose High-Pitch (FLASH) offers faster, potentially low radiation and low contrast dose scans. However, it lacks the ability to time data acquisition to the systole. Therefore, measurements derived from FLASH scan are considered suboptimal for reporting. The effect of this potential annular measurement difference on procedural success and safety was not evaluated. Therefore, we aimed to assess the feasibility and safety of FLASH vs. Spiral scan before TAVI. Methods We conducted a retrospective, single-center study. 409 patients underwent CT-TAVI scan with either FLASH or SPIRAL acquisition. Baseline characteristics, CT study, procedural and f/u data were acquired from the EMR. Outcomes defined by Valve Academic Research Consortium3 (VARC-2) endpoint definitions included in-hospital mortality, bleeding, vascular complications, acute kidney injury (AKI), conduction disorders, mechanical complications, and prosthetic aortic valve regurgitation. Composite endpoints such as device success were also examined. Results Of the 409 patients, 55.7% underwent FLASH scans. The median age was 80 years, and males accounted for 55%. The FLASH-protocol patients had higher rate of chronic kidney disease, their CT-measured aortic annulus area and diameter were smaller, and they were exposed to a smaller amount of contrast agent and radiation than the SPIRAL group. There was no statistically significant difference in primary clinical and safety endpoints between the two groups, including mechanical complications (such as annular rupture and valve malposition) and conduction disorders. Conclusions FLASH CT scan is a pragmatic and safe approach that potentially may replace spiral scan for the evaluation before TAVI procedure in the appropriate patients. Funding Acknowledgement Type of funding sources: None.

Clinical impact of novel pericoronary adipose tissue measurement on ECG-gated non-contrast chest CT scan

Abstract Background Pericoronary adipose tissue (PCAT) quantified from coronary computed tomography angiography (CCTA) is a new predictor of CT-derived high-risk plaque (HRP) and adverse cardiac events. There has been no report investigating the method to assess PCAT from non-contrast CT so far. In this present study, we developed a brand-new method to quantify the value of PCAT from electrocardiogram (ECG)-gated non-contrast CT (NC-PCAT). Purpose To develop a brand-new method to quantify NC-PCAT accurately, and evaluate its prognostic value. Methods We retrospectively studied two independent cohorts of patients undergoing CCTA and ECG-gated non-contrast CT for clinical indication of coronary artery disease (CAD). For former cohort of consecutive 300 patients, we validated the agreement between the NC-PCAT and PCAT, and evaluated the association between NC-PCAT and the prevalence of HRP. For latter cohort of consecutive 333 patients, we dichotomized them into two groups with median NC-PCAT, and assessed the prognostic value of NC-PCAT. To quantify NC-PCAT, we placed 15x15mm region of interest at epicardial fat tissue dorsally adjacent to right coronary ostium in axial slice of ECG-gated non-contrast CT, and defined NC-PCAT as the mean CT value of each 1x1mm pixel there. PCAT was quantified from CCTA using conventional method as described in former researches. Primary endpoint was defined as major adverse cardiac events (MACE), composite of all-cause death and non-fatal myocardial infarction. HRP was defined as coronary artery plaque which has two or more following features; positive remodeling, low attenuation, spotty calcification, and napkin-ring sign. Results NC-PCAT was well-correlated with PCAT (r=0.68, p&amp;lt;0.0001). In former cohort, we found HRP in 34 (11.3%) patients. In multivariable logistic regression analysis, higher NC-PCAT (OR 1.06, 95% CI 1.03–1.10, p=0.0001), coronary artery calcium score (CACS) (OR 1.01 per 10 CACS increase, 95% CI 1.00–1.02, p=0.013), and current smoking (OR 2.58, 95% CI 1.03–6.49, p=0.044) were independent predictors of the prevalence of HRP. Among patients with CACS more than zero (n=193), NC-PCAT (OR 1.06, 95% CI 1.03–1.10, p=0.0002), current smoking (OR 3.02, 95% CI 1.17–7.82, p=0.027), and male (OR 2.81, 95% CI 1.06–7.48, p=0.028) were independent predictors of the prevalence of HRP, whereas CACS was not (p=0.15). In latter cohort, the median duration of follow-up was 2.9 years (IQR 1.9–3.9), and 16 (4.8%) cases of MACE were identified. The cumulative incidence of MACE was significantly higher in high NC-PCAT group. Multivariable cox hazard regression analysis revealed that higher NC-PCAT was an independent predictor of primary endpoint, even after adjustment for sex and age (HR 4.28, 95% CI 1.20–12.52, p=0.012). Conclusions There was a positive correlation between NC-PCAT and PCAT. Higher NC-PCAT is significantly associated with not only the prevalence of HRP, but also worse clinical outcome. Funding Acknowledgement Type of funding sources: None.

Diagnostic Value of Fully Automated Artificial Intelligence Powered Coronary Artery Calcium Scoring from 18F-FDG PET/CT.

Objectives: The objective of this study was to assess the feasibility and accuracy of a fully automated artificial intelligence (AI) powered coronary artery calcium scoring (CACS) method on ungated CT in oncologic patients undergoing 18F-FDG PET/CT. Methods: A total of 100 oncologic patients examined between 2007 and 2015 were retrospectively included. All patients underwent 18F-FDG PET/CT and cardiac SPECT myocardial perfusion imaging (MPI) by 99mTc-tetrofosmin within 6 months. CACS was manually performed on non-contrast ECG-gated CT scans obtained from SPECT-MPI (i.e., reference standard). Additionally, CACS was performed using a cloud-based, user-independent tool (AI-CACS) on ungated CT scans from 18F-FDG-PET/CT examinations. Agatston scores from the manual CACS and AI-CACS were compared. Results: On a per-patient basis, the AI-CACS tool achieved a sensitivity and specificity of 85% and 90% for the detection of CAC. Interscore agreement of CACS between manual CACS and AI-CACS was 0.88 (95% CI: 0.827, 0.918). Interclass agreement of risk categories was 0.8 in weighted Kappa analysis, with a reclassification rate of 44% and an underestimation of one risk category by AI-CACS in 39% of cases. On a per-vessel basis, interscore agreement of CAC scores ranged from 0.716 for the circumflex artery to 0.863 for the left anterior descending artery. Conclusions: Fully automated AI-CACS as performed on non-contrast free-breathing, ungated CT scans from 18F-FDG-PET/CT examinations is feasible and provides an acceptable to good estimation of CAC burden. CAC load on ungated CT is, however, generally underestimated by AI-CACS, which should be taken into account when interpreting imaging findings.

Reproducibility of quantitative coronary calcium scoring from PET/CT attenuation maps: comparison to ECG-gated CT scans.

We sought to evaluate inter-scan and inter-reader agreement of coronary calcium (CAC) scores obtained from dedicated, ECG-gated CAC scans (standard CAC scan) and ultra-low-dose, ungated computed tomography attenuation correction (CTAC) scans obtained routinely during cardiac PET/CT imaging. From 2928 consecutive patients who underwent same-day 82Rb cardiac PET/CT and gated CAC scan in the same hybrid PET/CT scanning session, we have randomly selected 200 cases with no history of revascularization. Standard CAC scans and ungated CTAC scans were scored by two readers using quantitative clinical software. We assessed the agreement between readers and between two scan protocols in 5 CAC categories (0, 1-10, 11-100, 101-400, and > 400) using Cohen's Kappa and concordance. Median age of patients was 70 (inter-quartile range: 63-77), and 46% were male. The inter-scan concordance index and Cohen's Kappa for readers 1 and 2 were 0.69; 0.75 (0.69, 0.81) and 0.72; 0.8 (0.75, 0.85) respectively. The inter-reader concordance index and Cohen's Kappa (95% confidence interval [CI]) was higher for standard CAC scans: 0.9 and 0.92 (0.89, 0.96), respectively, vs. for CTAC scans: 0.83 and 0.85 (0.79, 0.9) for CTAC scans (p = 0.02 for difference in Kappa). Most discordant readings between two protocols occurred for scans with low extent of calcification (CAC score < 100). CAC can be quantitatively assessed on PET CTAC maps with good agreement with standard scans, however with limited sensitivity for small lesions. CAC scoring of CTAC can be performed routinely without modification of PET protocol and added radiation dose.

Epicardial Adipose Tissue Attenuation and Fat Attenuation Index: Phantom Study and In Vivo Measurements With Photon-Counting Detector CT.

BACKGROUND. Epicardial adipose tissue (EAT) attenuation is a vascular inflammation marker predictive of adverse cardiac events. The fat attenuation index (FAI) assesses fat attenuation for predefined coronary segments. Photon-counting detector (PCD) CT uses routine virtual monoenergetic image (VMI) reconstructions. VMI energy level may affect EAT attenuation and FAI measurements. OBJECTIVE. The purpose of this article was to assess EAT attenuation and FAI measurements at different monoenergetic energy levels in patients undergoing coronary CTA using a first-generation whole-body dual-source PCD CT scanner. METHODS. An anthropomorphic phantom at two sizes with a fat insert was imaged on a first-generation dual-source PCD CT scanner and, as a reference, on a conventional energy-integrating detector (EID) CT scanner at 120 kV. Thirty patients (11 women, 19 men; mean age, 48 ± 10 years; Agatston score < 60) who underwent an ECG-gated unenhanced calcium-scoring scan and contrast-enhanced coronary CTA by PCD CT were retrospectively evaluated. VMIs from 55 to 80 keV at 5-keV increments were reconstructed. EAT attenuation was manually measured on unenhanced and contrast-enhanced images. FAI was calculated using semiautomated software. RESULTS. The attenuation of the phantom fat insert was -69 HU for the reference EID CT; the closest attenuation for PCD CT was observed at 70 keV for the small (-69 HU) and large (-70 HU) phantoms. In patients, EAT attenuation increased for unenhanced acquisition from -111 ± 11 HU at 55 keV to -82 ± 9 HU at 80 keV and for contrast-enhanced acquisition from -104 ± 11 HU at 55 keV to -81 ± 9 HU at 80 keV. The mean attenuation difference between unenhanced and contrast-enhanced scans decreased with increasing energy level (from 7 ± 12 HU to 1 ± 10 HU). The FAI increased from -89 ± 8 HU at 55 keV to -77 ± 12 HU at 80 keV for the right coronary artery, -95 ± 11 HU at 55 keV to -85 ± 11 HU at 80 keV for the left anterior descending artery, and -87 ± 10 HU at 55 keV to -80 ± 12 HU at 80 keV for the circumflex artery. CONCLUSION. EAT attenuation and FAI measurements using PCD CT are impacted by VMI energy level and contrast enhancement. Use of VMI reconstruction at 70 keV provides fat attenuation approximating conventional polychromatic measurements. CLINICAL IMPACT. The findings may help standardize evaluation of pericoronary inflammation by PCD CT as a measure of patients' cardiac risk.

Reduced Radiation Exposure Protocol during Computer Tomography of the Left Atrium Prior to Catheter Ablation in Patients with Atrial Fibrillation.

(1) Background: Computer tomography (CT) is an imaging modality used in the pre-planning of radiofrequency catheter ablation (RFA) procedure in patients with cardiac arrhythmias. However, it is associated with a considerable ionizing radiation dose for patients. This study aims to develop and validate low-dose CT scanning protocols of the left atrium (LA) for RFA guidance. (2) Methods: 68 patients scheduled for RFA of atrial fibrillation were sequentially assigned to four groups of ECG-gated scanning protocols, based on the set tube current (TC): Group A (n = 20, TC = 33 mAs), Group B (n = 18, TC = 67 mAs), Group C (n = 10, TC = 135 mAs), and control Group D (n = 20, TC = 600 mAs). We used a 256-row multidetector CT with body weight-dependent tube voltage of 80 kVp (<70 kg), 100 kVp (70–90 kg), and 120 kVp (>90 kg). We evaluated scanning parameters including radiation dose, total scanning procedure time and signal-to-noise ratio (SNR). (3) Results: The average effective radiation dose (ED) was lower in Group A in comparison to Group B, C and D (0.83 (0.76–1.10), 1.55 (1.36–1.67), 2.91 (2.32–2.96) and 9.35 (8.00–10.04) mSv, p < 0.05). The total amount of contrast media was not significantly different between groups. The mean SNR was 6.5 (5.8–7.3), 7.1 (5.7–8.2), 10.8 (10.1–11.3), and 12.2 (9.9–15.7) for Group A, B, C and D, respectively. The comparisons of SNR in group A vs. B and C vs. D were without significant differences. (4) Conclusions: Optimized pre-ablation CT scanning protocols of the LA can reduce an average ED by 88.7%. Three dimensional (3D) models created with the lowest radiation protocol are useful for the integration of electro-anatomic-guided RFA procedures.

Evaluation of coronary arteries in congenital heart disease in children: diagnostic comparison of electrocardiogram-gated and non-electro-cardiogram-gated computed tomography cardiac angiography.

To compare the visualization and anatomy of coronary arteries in children (≤ 2 years) with congenital heart disease (CHD) on non-electrocardiogram (ECG)-gated and ECG-gated computed tomography angiography (CTA). In this retrospective study, approved by the Ethics Committee of our institute, evaluation of coronary arteries in CHD was performed in 40 children on non-ECG-gated CTA and in 42 children on ECG-gated CTA. The origin and course of the right coronary artery (RCA), left main coronary artery (LMCA), left anterior descending (LAD) artery, and left circumflex (LCX) artery were evaluated by 2 paediatric radiologists independently. ECG-gated CT scans yielded increased (additional) visualization of all the coronary arteries, when compared to non-ECG-gated CT scans. The RCA, LMCA, LAD artery, and LCX artery were visualized in 47.5%, 62.5%, 55%, and 32.5% of children, respectively, on non-ECG-gated studies, while they were visualized in 64.3%, 92.8%, 80.9%, and 62% children, respectively, on ECG-gated studies. The coronary artery anatomical variations were also supplementarily detected more in the ECG-gated group (23.8%) than in the non-ECG gated group (2.5%). ECG-gated CT cardiac angiography studies yield enhanced diagnostic outcomes for the evaluation of the coronary arteries in comparison to non-ECG-gated studies.

Accuracy of non-gated low-dose non-contrast chest CT with tin filtration for coronary artery calcium scoring

ObjectiveThe study investigated the accuracy of coronary artery calcium scores (CACS) and the potential for reducing radiation dose using non-gated low-dose non-contrast chest computed tomography (CT) scanning with tin filtration for one-stop screening of the lungs and heart. MethodsA prospective study was conducted,193 Patients received two scans for determining CACS, including an ECG-gated CT at 120 kV (ECG-gated CT), followed by a non-gated low-dose chest CT using 100 kV with tin filtration (non-gated Sn100 kV-LDCT). The Agatston score (AS), risk stratification, and radiation dose were compared between the scan types. ResultsThere was good consistency in the AS from both an ECG-gated CT and a non-gated low-dose chest CT scan, which had a high correlation (r = 0.970). The Kappa value of risk stratification of the two scan types was 0.549. The area under the ROC curve (AUC) of the CACS was used to develop a new risk stratification standard for non-gated Sn100 kV-LDCT evaluation of CACS. In comparison to the CACS measured by ECG-gated CT, non-gated Sn100 kV-LDCT had an AUC of 0.951 and an optimal critical value of 4.6 in the low-risk category. The AUC of low-medium risk was 0.966, and the optimal critical value was 41.2. The AUC of the medium-high risk category was 0.968, and the optimal critical value was 230. The consistency in CACS measured by ECG-gated CT and non-gated Sn100 kV-LDCT had a Kappa value of 0.831. The Effective dose (ED) of non-gated Sn100 kV-LDCT and ECG-gated CT was 0.056 ± 0.017 mSv and 0.685 ± 0.455 mSv, respectively (p < 0.05). ConclusionThe Agatston score of CACS using non-gated low-dose chest CT was accurate, but there was an underestimation in risk stratification. This study developed a new risk stratification standard for non-gated Sn100 kV-LDCT evaluation of CACS, which is in closer agreement with CACS derived from ECG-gated CT scans.

Coronary Calcium Scoring with First Generation Dual-Source Photon-Counting CT-First Evidence from Phantom and In-Vivo Scans.

We evaluated the accuracy of coronary artery calcium (CAC) scoring on a dual-source photon-counting detector CT (PCD-CT). An anthropomorphic chest phantom underwent ECG-gated sequential scanning on a PCD-CT at 120 kV with four radiation dose levels (CTDIvol, 2.0–8.6 mGy). Polychromatic images at 120 kV (T3D) and virtual monoenergetic images (VMI), from 60 to 75 keV without quantum iterative reconstruction (no QIR) and QIR strength levels 1–4, were reconstructed. For reference, the same phantom was scanned on a conventional energy-integrating detector CT (120 kV; filtered back projection) at identical radiation doses. CAC scoring in 20 patients with PCD-CT (120 kV; no QIR and QIR 1–4) were included. In the phantom, there were no differences between CAC scores of different radiation doses (all, p > 0.05). Images with 70 keV, no QIR (CAC score, 649); 65 keV, QIR 3 (656); 65 keV; QIR4 (648) and T3D, QIR4 (656) showed a <1% deviation to the reference (653). CAC scores significantly decreased at increasing QIR levels (all, p < 0.001) and for each 5 keV-increase (all, p < 0.001). Patient data (median CAC score: 86 [inter-quartile range: 38–978] at 70 keV) confirmed relationships and differences between reconstructions from the phantom. First phantom and in-vivo experience with a clinical dual-source PCD-CT system shows accurate CAC scoring with VMI reconstructions at different radiation dose levels.

Evaluation of complex congenital heart disease with prospective ECG-gated cardiac CT in a single heartbeat at low tube voltage (70kV) and adaptive statistical iterative reconstruction in infants: a single center experience.

The purpose of this study is to evaluate the radiation dose, image quality, and diagnostic accuracy of prospective ECG-gated cardiac CT at 70kV and adaptive statistical iterative reconstruction (ASIR), with a single source, 512 slice MDCT in the diagnosis of complex congenital heart disease in infants. We retrospectively evaluated 47 infants (ages 1day to 353days) with prospective ECG-gated cardiac CT that was performed on a single source 512 slice CT at low tube voltage (70kV) using a wide detector aperture, adaptive statistical iterative reconstruction algorithm (ASIR), and specific reconstruction software reducing coronary motion artifacts (SnapShot Freeze). All cardiac images were obtained during the first pass of contrast material through the anatomic structures of interest and the targets for the center of the acquisition window were set 45% of the R-R interval during one cardiac cycle without sedation and breath-hold. The median effective dose measured in our study was 0.64 ± 0.16mSv. The average subjective overall image quality score was 4.34 ± 0.31 (range 3-5). For the determination of objective image quality, Mean Noise (HU), SNR, and CNR values ​​emerged as 20.8, 28.7(for pulmonary artery), and 27.1, respectively. Diagnostic accuracy was 100% for the main purposes for the main clinical indication. During cardiac CT examination, pathologies in addition to cardiac anomalies were found in 9/47 of cases (7 severe airway obstructions,1 posterior diaphragmatic hernia, 1 vertebral anomaly).Prospective ECG-gated cardiac CT scan at 70kV and ASIR in infants with complex CHD provides low radiation dose (submillisievert) in a single heartbeat with a good objective and subjective image quality. It also provides important benefits in the diagnosis of additional pathology.

Reduced Pulmonary Artery Distensibility Is Independently Associated With 2-year Mortality In Transcatheter Aortic Valve Replacement Patients: A Retrospective Longitudinal Study

Introduction: Recent studies have shown that pulmonary artery (PA) distensibility on pre-TAVR ECG-gated CTA scans can detect PH due to left heart disease. In this longitudinal study we sought to evaluate whether PA distensibility measured on pre-procedural CTA is associated with 2-year mortality after TAVR.

Evaluating the Independent Impact of Renal Function Decline on Coronary Artery Calcification in Patients Undergone Cardiac CT Scan

Background: Cardiovascular events are the leading global cause of death. Calcification of coronary arteries is a common complication of renal failure and the leading cause of death in this population. However, its multifactorial mechanism is not fully understood. Objectives: The current study aimed to, firstly, investigate the association between renal dysfunction and the calcification of coronary arteries in patients with severe and milder stages of renal failure and, secondly, to determine the role of this variable by eliminating the effect of established confounding factors. Methods: Following a retrospective design, 261 patients with cardiovascular risk factors or atypical symptoms were investigated. Estimated GFR (glomerular filtration rate) was calculated using both Cockcroft-Gault and MDRD equations. An ECG-gated multidetector CT scan was performed to calculate CACS (coronary artery calcification score) using the Agatston method. The presence of significant CAC (coronary artery calcification) was defined as CACS &gt; 100. Univariate and multivariate analyses were performed using binary logistic regression. Results: A total of 134 cases were diagnosed with CAC, and the mean CACS was 83.4 ± 18. According to univariate analysis, older age, male gender, systolic and diastolic blood pressure, and higher TG levels were correlated with the degree of CAC. HbA1C showed a weak correlation with CACS (P-value = 0.04). Renal insufficiency resulted in increased CAC, and lower eGFR (calculated with both Cockgraft-Gault and MDRD equations) was associated with higher calcification (P-value &lt; 0.01). Our analysis shows that serum Ca, P, LDL, and HDL levels do not have a significant influence on calcification changes. After adjusting for confounding factors, male sex, age, triglyceride level, and eGFR were recognized as independent risk factors for CACS ≥ 100, a marker of coronary artery atherosclerosis. However, HbA1C and systolic and diastolic blood pressure were no longer considered as factors that contribute to the risk of CAC. Conclusions: We observed a gradual and independent association between lower eGFR and higher CAC scores.

Application of prospective ECG-gated multiphase scanning for coronary CT in children with different heart rates.

To investigate the application of prospective ECG-gated multiphase scanning in coronary CT imaging in children with different heart rates. In the control group, 160 children aged 2-4 years who underwent a coronary CT examination in our hospital from May 2016 to December 2017 were retrospectively selected. They were divided into five subgroups according to their heart rate frequency: 75-85 beats/min, 86-95 beats/min, 96-105 beats/min, and 106-120 beats/min. There were 40 children in each subgroup. Each child was treated with retrospective ECG-gated scanning technology. Six groups of phase images were reconstructed: 40%, 45%, 50%, 70%, 75% and 80%. The optimal phase was selected for coronary artery reconstruction. In the study group, 240 children aged 2-4 years who underwent coronary artery CT examination in our hospital from January 2018 to May 2019 were prospectively selected and divided into five subgroups according to the heart rate frequency: 75-85 beats/min, 86-95 beats/min, 96-105 beats/min, and 106-120 beats/min. There were 60 children in each subgroup. A prospective ECG-gated multiphase scanning technique was used to reconstruct 70%, 75% and 80% phase images in the subgroups with heart rates < 85/min. In the remaining subgroups, 40%, 45% and 50% phase images were reconstructed, and the optimal phase was selected for coronary artery reconstruction. The scanning parameters, dosage of contrast medium and injection mode of contrast medium were the same in both groups. The radiation dose and image quality of the coronary artery were compared between the two groups at the same heart rate. When comparing the two groups at the same heart rate, the radiation dose in the study group was 72% lower than that in the control group (P < 0.05). There was no significant difference in coronary artery image quality between the two groups at the optimal phase (P > 0.05). Applying prospective ECG-gated multiphase scanning technology to children's coronary CT imaging can significantly reduce the scanning radiation dose without affecting the quality of the coronary artery image.

Cardiac 18F-FDG Positron Emission Tomography: An Accurate Tool to Monitor In vivo Metabolic and Functional Alterations in Murine Myocardial Infarction.

Cardiac monitoring after murine myocardial infarction, using serial non-invasive cardiac 18F-FDG positron emissions tomography (PET) represents a suitable and accurate tool for in vivo studies. Cardiac PET imaging enables tracking metabolic alterations, heart function parameters and provides correlations of the infarct size to histology. ECG-gated 18F-FDG PET scans using a dedicated small-animal PET scanner were performed in mice at baseline, 3, 14, and 30 days after myocardial infarct (MI) by permanent ligation of the left anterior descending (LAD) artery. The percentage of the injected dose per gram (%ID/g) in the heart, left ventricular metabolic volume (LVMV), myocardial defect, and left ventricular function parameters: end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and the ejection fraction (EF%) were estimated. PET assessment of the defect positively correlates with post-infarct histology at 3 and 30 days. Infarcted murine hearts show an immediate decrease in LVMV and an increase in %ID/g early after infarction, diminishing in the remodeling process. This study of serial cardiac PET scans provides insight for murine myocardial infarction models by novel infarct surrogate parameters. It depicts that serial PET imaging is a valid, accurate, and multimodal non-invasive assessment.