Search

Abstract: This paper proposes a vehicle detector with an anisotropic magnetoresistive (AMR) sensor and addresses experimental study carried out to show the detector''s characteristics and performance. The detector consists of an AMR sensor and mechanical and electronic apparatuses. Composed of four magnetoresistors, the AMR sensor senses disturbance of the earth''s magnetic field caused by a moving vehicle over the sensor itself and then produces an output indicative of the moving vehicle. Experiments have been carried out with three stages. At the first stage, the outputs of the sensor have been analyzed to show the validity of the detector''s circuit and the detecting method. At the second stage, the detector has been tested on a local highway in Korea. Through the field tests, the outputs of the detector in response to various kinds of moving vehicles have been collected and analyzed. At the final stage, to verify the performance of the detector, traffic volumes on the highway have been measured with the detector and compared with the exact traffic volumes in a highly congested traffic. [Copyright &y& Elsevier]

A practical high curvature path planning algorithm that considers the velocity limit of a mobile robot in joint space is proposed. The existence of obstacles that constrict the smooth movement of mobile robots is inevitable. To avoid incoming collision, the robot is redirected to a new path with respect to the dimensions of the obstacle and a safety factor. The redirected path consists of geometric constraints such as high curvatures on its turning points which cause difficulty in controlling the mobile robot. Thus, a central velocity generation method that considers both velocity limits through a convolution operator and high curvatures at turning points is suggested. The central velocity is able to be within the configured velocity limit, otherwise actual velocity commands in joint space could result. Therefore, interpolation to obtain uniform sampling and velocity downscaling is performed to generate a feasible joint space trajectory. The result shows short travelling time compared with previous methods while satisfying velocity limits in the joint space. [ABSTRACT FROM AUTHOR]

Studies a general method for assigning the structures of nodularins. Inhibitory activity to protein phosphatases; Stereochemistry of amino acid components; Ozonolysis of nodularin.

Cardiac diffusion weighted-magnetic resonance imaging (DWI) has slowly developed due to its technical difficulties. However, this limitation could be overcome by advanced techniques, including a stimulated echo technique and a gradient moment nulling technique. This study aimed to develop and validate a high-order DWI sequence, using echo-planar imaging (EPI) and second-order motion-compensated (M012) diffusion gradient applied to cardiac imaging in small-sized animals with fast heart and respiratory rates, and to investigate the feasibility of cardiac DWI, diagnosing acute myocardial injury in isoproterenol-induced myocardial injury rat models. The M012 diffusion gradient sequence was designed for diffusion tensor imaging of the rat myocardium and validated in the polyvinylpyrrolidone phantom. Following sequence optimization, 23 rats with isoproterenol-induced acute myocardial injury and five healthy control rats underwent cardiac MRI, including cine imaging, T1 mapping, and DWI. Diffusion gradient was applied using a 9.4-T MRI scanner (Bruker, BioSpec 94/20, gradient amplitude = 440 mT/m, maximum slew rate = 3440 T/m/s) with double gating (electrocardiogram and respiratory gating). Troponin I was used as a serum biomarker for myocardial injury. Histopathologic examination of the heart was subsequently performed. The developed DWI sequence using EPI and M012 provided the interpretable images of rat hearts. The apparent diffusion coefficient (ADC) values were significantly higher in rats with acute myocardial injury than in the control group (1.847 ± 0.326 * 10–3 mm2/s vs. 1.578 ± 0.144 * 10–3 mm2/s, P < 0.001). Troponin I levels were increased in the blood samples of rats with acute myocardial injury (P < 0.001). Histopathologic examinations detected myocardial damage and subendocardial fibrosis in rats with acute myocardial injury. The newly developed DWI technique has the ability to detect myocardial injury in small animal models, representing high ADC values on the myocardium with isoproterenol-induced injury. [ABSTRACT FROM AUTHOR]

Cardiac diffusion weighted-magnetic resonance imaging (DWI) has slowly developed due to its technical difficulties. However, this limitation could be overcome by advanced techniques, including a stimulated echo technique and a gradient moment nulling technique. This study aimed to develop and validate a high-order DWI sequence, using echo-planar imaging (EPI) and second-order motion-compensated (M012) diffusion gradient applied to cardiac imaging in small-sized animals with fast heart and respiratory rates, and to investigate the feasibility of cardiac DWI, diagnosing acute myocardial injury in isoproterenol-induced myocardial injury rat models. The M012 diffusion gradient sequence was designed for diffusion tensor imaging of the rat myocardium and validated in the polyvinylpyrrolidone phantom. Following sequence optimization, 23 rats with isoproterenol-induced acute myocardial injury and five healthy control rats underwent cardiac MRI, including cine imaging, T1 mapping, and DWI. Diffusion gradient was applied using a 9.4-T MRI scanner (Bruker, BioSpec 94/20, gradient amplitude = 440 mT/m, maximum slew rate = 3440 T/m/s) with double gating (electrocardiogram and respiratory gating). Troponin I was used as a serum biomarker for myocardial injury. Histopathologic examination of the heart was subsequently performed. The developed DWI sequence using EPI and M012 provided the interpretable images of rat hearts. The apparent diffusion coefficient (ADC) values were significantly higher in rats with acute myocardial injury than in the control group (1.847 ± 0.326 * 10–3 mm2/s vs. 1.578 ± 0.144 * 10–3 mm2/s, P < 0.001). Troponin I levels were increased in the blood samples of rats with acute myocardial injury (P < 0.001). Histopathologic examinations detected myocardial damage and subendocardial fibrosis in rats with acute myocardial injury. The newly developed DWI technique has the ability to detect myocardial injury in small animal models, representing high ADC values on the myocardium with isoproterenol-induced injury. [ABSTRACT FROM AUTHOR]

Background: Although the bismuth breast shield can reduce radiation exposure to the breast during dual-energy computed tomography (DECT), it can potentially affect material quantification on DECT due to artifacts.Purpose: To evaluate the effects of bismuth breast shielding on iodine quantification and radiation exposure in DECT.Material and Methods: Small balloons were made with 0.2%, 0.6% and 1.0% blended iodinated contrast (370 mg/mL of iodine) with water. The balloons were located at both anterior and posterior lungs in an adult anthropomorphic chest phantom. DECT was performed with and without breast shielding. Afterwards, iodine concentration values were measured for each balloon on the iodine maps. Absorbed radiation doses in the breast were measured with the optically stimulated luminescence dosimeter.Results: After shielding, we obtained significantly decreased iodine quantification for all three concentrations with 0.78 ± 0.13 to 0.46 ± 0.13 mg/mL, 2.31 ± 0.17 to 1.68 ± 0.19 mg/mL, and 3.82 ± 0.10 to 2.84 ± 0.20 mg/mL at the anterior location, and 0.72 ± 0.11 to 0.48 ± 0.09 mg/mL, 2.24 ± 0.13 to 1.87 ± 0.21 mg/mL, and 3.75 ± 0.16 to 3.15 ± 0.14 mg/mL at the posterior location for the 0.2%, 0.6%, and 1.0% balloons, respectively ( P = 0.001 for all). After shielding, absorbed radiation doses to the breast significantly decreased by 14.8% (4.32 ± 0.33 to 3.68 ± 0.30 mGy; P = 0.005).Conclusion: Although using the bismuth breast shield may decrease radiation exposure to the breast on DECT, it may also significantly affect iodine quantification. [ABSTRACT FROM AUTHOR]

With the increased availability of magnetic resonance imaging (MRI) and a progressive rise in the frequency of cardiac device implantation, there is an increased chance that patients with implanted cardiac devices require MRI examination during their lifetime. Though MRI is generally contraindicated in patients who have undergone pacemaker implantation with electronic circuits, the recent introduction of MR Conditional pacemaker allows physicians to take advantage of MRI to assess these patients during diagnosis and treatment. When MRI examinations of patients with pacemaker are requested, physicians must confirm whether the device is a conventional pacemaker or an MR Conditional pacemaker by reviewing chest radiographs or the electronic medical records (EMRs). The purpose of this study was to evaluate the utility of a deep convolutional neural network (DCNN) trained to detect pacemakers on chest radiographs and to determine the device's subclassification. The DCNN perfectly detected pacemakers on chest radiographs and the accuracy of the subclassification of pacemakers using the internal and external test datasets were 100.0% (n = 106/106) and 90.1% (n = 279/308). The DCNN can be applied to the radiologic workflow for double-checking purposes, thereby improving patient safety during MRI and preventing busy physicians from making errors. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the effect of the phantom-based correction method for standardizing myocardial native T1 and extracellular volume fraction (ECV) in healthy subjects.Methods: Seventy-one healthy asymptomatic adult (≥ 20 years) volunteers of five different age groups (34 men and 37 women, 45.5 ± 15.5 years) were prospectively enrolled in three academic hospitals. Cardiac MRI including Modified Look - Locker Inversion recovery T1 mapping sequence was performed using a 3-Tesla system with a different type of scanner for each hospital. Native T1 and ECV were measured in the short-axis T1 map and analyzed for mean values of the 16 entire segments. The myocardial T1 value of each subject was corrected based on the site-specific equation derived from the T1 Mapping and ECV Standardization phantom. The global native T1 and ECV were compared between institutions before and after phantom-based correction, and the variation in native T1 and ECV among institutions was assessed using a coefficient of variation (CoV).Results: The global native T1 value significantly differed between the institutions (1198.7 ± 32.1 ms, institution A; 1217.7 ± 39.9 ms, institution B; 1232.7 ± 31.1 ms, institution C; p = 0.002), but the mean ECV did not (26.6-27.5%, p = 0.355). After phantom-based correction, the global native T1 and ECV were 1289.7 ± 32.4 ms and 25.0 ± 2.7%, respectively, and CoV for native T1 between the three institutions decreased from 3.0 to 2.5%. The corrected native T1 value did not significantly differ between institutions (1284.5 ± 31.5 ms, institution A; 1296.5 ± 39.1 ms, institution B; 1291.3 ± 29.3 ms, institution C; p = 0.440), and neither did the ECV (24.4-25.9%, p = 0.078).Conclusions: The phantom-based correction method can provide standardized reference T1 values in healthy subjects.Key Points: • After phantom-based correction, the global native T1 of 16 entire myocardial segments on 3-T cardiac MRI is 1289.4 ± 32.4 ms, and the extracellular volume fraction was 25.0 ± 2.7% for healthy subjects. • After phantom - based correction was applied, the differences in the global native T1 among institutions became insignificant, and the CoV also decreased from 3.0 to 2.5%. [ABSTRACT FROM AUTHOR]

We aimed to determine the effects of deep learning-based reconstruction (DLR) on radiomic features obtained from cardiac computed tomography (CT) by comparing with iterative reconstruction (IR), and filtered back projection (FBP). A total of 284 consecutive patients with 285 cardiac CT scans that were reconstructed with DLR, IR, and FBP, were retrospectively enrolled. Radiomic features were extracted from the left ventricular (LV) myocardium, and from the periprosthetic mass if patients had cardiac valve replacement. Radiomic features of LV myocardium from each reconstruction were compared using a fitting linear mixed model. Radiomics models were developed to diagnose periprosthetic abnormality, and the performance was evaluated using the area under the receiver characteristics curve (AUC). Most radiomic features of LV myocardium (73 of 88) were significantly different in pairwise comparisons between all three reconstruction methods (P < 0.05). The radiomics model on IR exhibited the best diagnostic performance (AUC 0.948, 95% CI 0.880–1), relative to DLR (AUC 0.873, 95% CI 0.735–1) and FBP (AUC 0.875, 95% CI 0.731–1), but these differences did not reach significance (P > 0.05). In conclusion, applying DLR to cardiac CT scans yields radiomic features distinct from those obtained with IR and FBP, implying that feature robustness is not guaranteed when applying DLR. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the quality of radiomics studies using cardiac magnetic resonance imaging (CMR) according to the radiomics quality score (RQS), Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) guidelines, and the standards defined by the Image Biomarker Standardization Initiative (IBSI) and identify areas needing improvement. Materials and methods: PubMed and Embase were searched to identify radiomics studies using CMR until March 10, 2021. Of the 259 identified articles, 32 relevant original research articles were included. Studies were scored according to the RQS, TRIPOD guidelines, and IBSI standards by two cardiac radiologists. Results: The mean RQS was 14.3% of the maximum (5.16 out of 36). RQS were low for the demonstration of validation (−60.6%), calibration statistics (1.6%), potential clinical utility (3.1%), and open science (3.1%) items. No study conducted a phantom study or cost-effectiveness analysis. The adherence to TRIPOD guidelines was 55.9%. Studies were deficient in reporting title (3.1%), stating objective in abstract and introduction (6.3% and 9.4%), missing data (0%), discrimination/calibration (3.1%), and how to use the prediction model (3.1%). According to the IBSI standards, non-uniformity correction, image interpolation, grey-level discretization, and signal intensity normalization were performed in two (6.3%), four (12.5%), six (18.8%), and twelve (37.5%) studies, respectively. Conclusion: The quality of radiomics studies using CMR is suboptimal. Improvements are needed in the areas of validation, calibration, clinical utility, and open science. Complete reporting of study objectives, missing data, discrimination/calibration, how to use the prediction model, and preprocessing steps are necessary. Key Points: • The quality of science in radiomics studies using CMR is currently inadequate. • RQS were low for validation, calibration, clinical utility, and open science; no study conducted a phantom study or cost-effectiveness analysis. • In stating the study objective, missing data, discrimination/calibration, how to use the prediction model, and preprocessing steps, improvements are needed. [ABSTRACT FROM AUTHOR]

Backgrounds: Synthetic late gadolinium enhancement (LGE) images are less sensitive to inversion time (TI) and robust to motion artifact, because it is generated retrospectively by post-contrast T1-mapping images. To explore the clinical applicability of synthetic LGE, we investigated the image quality and diagnostic accuracy of synthetic LGE images, in comparison to that of conventional LGE for various disease groups. Method and materials: From July to November 2019, a total of 98 patients who underwent cardiovascular magnetic resonance imaging (CMR), including LGE and T1-mapping sequences, with suspicion of myocardial abnormality were retrospectively included. Synthetic magnitude inversion-recovery (IR) and phase-sensitive IR (PSIR) images were generated through calculations based on the post-contrast T1-mapping sequence. Three cardiothoracic radiologists independently analyzed the image quality of conventional and synthetic LGE images on an ordinal scale with per-segment basis and the image qualities were compared with chi-square test. The agreement of LGE detection was analyzed on per-patient and per-segment basis with Cohen's kappa test. In addition, the LGE area and percentage were semi-quantitatively analyzed for LGE positive ischemic (n = 14) and hypertrophic cardiomyopathy (n = 13) subgroups by two cardiothoracic radiologists. The difference of quantified LGE area and percentage between conventional and synthetic LGE images were assessed with Mann–Whitney U-test and the inter-reader agreement was assessed with Bland–Altman analysis. Results: The image quality of synthetic images was significantly better than conventional images in both magnitude IR and PSIR through all three observers (P < 0.001, all). The agreements of per-patient and per-segment LGE detection rates were excellent (kappa = 0.815–0.864). The semi-quantitative analysis showed no significant difference in the LGE area and percentage between conventional and synthetic LGE images. In the inter-reader agreement showed only small systematic differences in both magnitude IR and PSIR and synthetic LGE images showed smaller systematic biases compared to conventional LGE images. Conclusion: Compared to conventional LGE images, synthetic LGE images have better image quality in real-life clinical situation. [ABSTRACT FROM AUTHOR]

Objectives: To identify the optimal artery-based method for ordinal grading of coronary artery calcium (CAC) on non-electrocardiogram (ECG)-gated low-dose chest computed tomography (LDCT) among three methods. Methods: A total of 120 asymptomatic subjects who underwent both LDCT and ECG-gated calcium scoring CT on the same day were retrospectively enrolled. Three cardiothoracic radiologists independently assessed CAC severity on LDCT (1.25-mm and 2.5-mm slice thickness) and classified it into four categories (none, mild, moderate, or severe) using three artery-based ordinal scoring methods (extent-based scoring, Weston scoring, and length-based scoring). Inter- and intra-observer CAC severity agreements of each method were assessed by Fleiss kappa statistics. Agreements between each method and ECG-gated calcium scoring CT were assessed by weighted kappa statistics. Results: The inter-observer agreement was highest with length-based method for both 1.25-mm (Fleiss kappa 0.735 for extent-based method, 0.801 for Weston score, and 0.813 for length-based method) and 2.5-mm slice thickness evaluation (Fleiss kappa 0.755 for extent-based method, 0.776 for Weston score, and 0.833 for extent-based method). Agreement across the three grading methods for the same observer was poor to moderate on 1.25-mm (Fleiss kappa 0.379–0.441) and moderate on 2.5-mm thickness evaluation (Fleiss kappa 0.427–0.461). Agreement of CAC severity between each method and ECG-gated calcium scoring CT was highest with the length-based method for all three observers on both 1.25-mm (weighted kappa 0.773–0.786) and 2.5-mm (weighted kappa 0.794–0.825) LDCT images. Conclusion: Among the three artery-based ordinal grading methods, the length-based method appears to be the most reliable for evaluating CAC on non-ECG-gated LDCT. Key Points: • The length-based method showed the highest inter-observer agreement and the highest agreement with the ECG-gated calcium scoring CT, compared with the extent-based method and the Weston score. [ABSTRACT FROM AUTHOR]

Background: Atherosclerosis is a systemic disease. Many ischemic stroke patients may have concomitant coronary artery disease (CAD). Detection and treatment of preclinical CAD in stroke patients may improve long-term outcome and survival because CAD is a major cause of death during follow-up in stroke patients. However, association between coronary and cerebral artery atherosclerosis in stroke patients has not fully been investigated. This study aimed at examining the frequency and high-risk groups of CAD in ischemic stroke patients. Methods: Consecutive patients who were admitted due to acute ischemic stroke between July 2006 and June 2010 were prospectively enrolled in this study. A total of 1,304 patients who underwent MSCT coronary angiography and cerebral angiography were included in this study. By using 64-multislice computed tomography coronary angiography, we investigated the frequency of CAD and association between coronary and cerebral artery atherosclerosis in terms of location and burden (severity and extent) in stroke patients. We also sought to identify high-risk groups for CAD among stroke patients. Results: The frequency of significant (≥50%) CAD was 32.3% and the frequency of any degree of CAD was 70.1%. Diabetes mellitus, serum levels of total cholesterol, high-density lipoprotein cholesterol and triglyceride, and significant stenosis of the extracranial carotid, intracranial vertebral and basilar arteries were independently associated with CAD. However, no association was found between CAD and significant stenosis of the anterior, middle and posterior cerebral arteries. The association between CAD and cerebral atherosclerosis was stronger with increased severity and extent of cerebral atherosclerosis. When compared to patients with <2 risk factors and without significant cerebral atherosclerosis, those with multiple (≥2) risk factors and atherosclerosis in both the carotid and the vertebrobasilar arteries had very high risks of CAD [odds ratio (OR) 8.36; 95% confidence interval (CI) 4.15-16.87]. The risk was also high in patients with multiple risk factors and atherosclerosis in either the carotid or the vertebrobasilar artery (OR 4.13; 95% CI 2.62-6.51), and in those with <2 risk factors but atherosclerosis in both the carotid and the vertebrobasilar arteries (OR 3.40; 95% CI 1.22-9.47). Conclusions: A substantial portion of stroke patients had preclinical CAD, and there was a clear relationship between coronary and cerebral artery atherosclerosis in terms of location and burden. The risk of CAD was particularly high in stroke patients with multiple risk factors and atherosclerosis of the carotid and/or vertebrobasilar arteries. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: Coronary angiography (CAG) is the gold standard method in evaluating graft patency following coronary artery bypass grafting (CABG), even though there are several kinds of non-invasive methods. Recently developed multi-slice CT (m-CT), having effective scan times up to 0.25 s and multi-row detector array systems, enable rapid imaging of cardiac structures, including coronary arteries during one breath-hold. We compared m-CT with CAG for the evaluation of graft patency following CABG. Methods: Forty-two patients having undergone m-CT and CAG within 3 months of CABG were studied. Twenty-three patients underwent conventional CABG and 19 off-pump CABG. A total of 125 grafts were used, including 42 left internal mammary arteries (LIMA), 25 radial arteries (RA), 3 right internal mammary arteries (RIMA) and 55 vein grafts. Results: CAG showed a 96% (120/125) patency rate (1 LIMA, 2 RA and 2 vein grafts were occluded). m-CT showed a 98% (122/125) correct positive ratio with a sensitivity and specificity of 98 and 100%, respectively. The sensitivity in LIMA, RA, RIMA and vein grafts was 98, 91, 100 and 100%, respectively, with 100% specificity for all. There was an equivocal result in the competitive grafts with native coronary artery that were patent in the CAG, but faint opacification with no significant flow in the m-CT. Conclusions: This study showed that m-CT was very simple, useful and accurate in evaluating graft patency during the early post-operative period following CABG, even though there was an equivocal result in the competitive grafts with a native coronary artery. [Copyright &y& Elsevier]

Background: Chemotherapy-induced cardiotoxicity is a well-recognized adverse effect of chemotherapy. Quantitative T1-mapping cardiovascular magnetic resonance (CMR) is useful for detecting subclinical myocardial changes in anthracycline-induced cardiotoxicity. The aim of the present study was to histopathologically validate the T1 and T2 mapping parameters for the evaluation of diffuse myocardial changes in rat models of cardiotoxicity. Methods: Rat models of cardiotoxicity were generated by injecting rats with doxorubicin (1 mg/kg, twice a week). CMR was performed with a 9.4 T ultrahigh-field scanner using cine, pre-T1, post-T1 and T2 mapping sequences to evaluate the left ventricular ejection fraction (LVEF), native T1, T2, and extracellular volume fraction (ECV). Histopathological examinations were performed and the association of histopathological changes with CMR parameters was assessed. Results: Five control rats and 36 doxorubicin-treated rats were included and classified into treatment periods. In the doxorubicin-treated rats, the LVEF significantly decreased after 12 weeks of treatment (control vs. 12-week treated: 73 ± 4% vs. 59 ± 9%, P = 0.01). Increased native T1 and ECV were observed after 6 weeks of treatment (control vs. 6-week treated: 1148 ± 58 ms, 14.3 ± 1% vs. 1320 ± 56 ms, 20.3 ± 3%; P = 0.005, < 0.05, respectively). T2 values also increased by six weeks of treatment (control vs. 6-week treated: 16.3 ± 2 ms vs. 10.3 ± 1 ms, P < 0.05). The main histopathological features were myocardial injury, interstitial fibrosis, inflammation, and edema. The mean vacuolar change (%), fibrosis (%), and inflammation score were significantly higher in 6-week treated rats than in the controls (P = 0.03, 0.03, 0.02, respectively). In the univariable analysis, vacuolar change showed the highest correlation with native T1 value (R = 0.60, P < 0.001), and fibrosis showed the highest correlation with ECV value (R = 0.78, P < 0.001). In the multiple linear regression analysis model, vacuolar change was a significant factor for change in native T1 (P = 0.01), and vacuolar change and fibrosis were significant factors for change in ECV (P = 0.006, P < 0.001, respectively) by adding other histopathological parameters (i.e., inflammation and edema scores) Conclusions: Quantitative T1 and T2 mapping CMR is a useful non-invasive tool reflecting subclinical histopathological changes in anthracycline-induced cardiotoxicity. [ABSTRACT FROM AUTHOR]

Machine learning offers great opportunities to streamline and improve clinical care from the perspective of cardiac imagers, patients, and the industry and is a very active scientific research field. In light of these advances, the European Society of Cardiovascular Radiology (ESCR), a non-profit medical society dedicated to advancing cardiovascular radiology, has assembled a position statement regarding the use of machine learning (ML) in cardiovascular imaging. The purpose of this statement is to provide guidance on requirements for successful development and implementation of ML applications in cardiovascular imaging. In particular, recommendations on how to adequately design ML studies and how to report and interpret their results are provided. Finally, we identify opportunities and challenges ahead. While the focus of this position statement is ML development in cardiovascular imaging, most considerations are relevant to ML in radiology in general. KEY POINTS: • Development and clinical implementation of machine learning in cardiovascular imaging is a multidisciplinary pursuit. • Based on existing study quality standard frameworks such as SPIRIT and STARD, we propose a list of quality criteria for ML studies in radiology. • The cardiovascular imaging research community should strive for the compilation of multicenter datasets for the development, evaluation, and benchmarking of ML algorithms. [ABSTRACT FROM AUTHOR]

Background: Right ventricular (RV) free wall fibrosis is an important component of adverse remodeling with RV dysfunction in pulmonary hypertension (PH). However, no previous reports have compared cardiovascular magnetic resonance (CMR) findings and histological analysis for RV free wall fibrosis in PH. We aimed to assess the feasibility of CMR T1 mapping with extracellular volume fraction (ECV) for evaluating the progression of RV free wall fibrosis in PH, and compared imaging findings to histological collagen density through an animal study. Methods: Among 42 6-week-old Wistar male rats, 30 were classified according to disease duration (baseline before monocrotaline injection, and 2, 4, 6 and 8 weeks after injection) and 12 were used to control for aging (4 and 8 weeks after the baseline). We obtained pre and post-contrast T1 maps for native T1 and ECV of RV and left ventricular (LV) free wall for six animals in each disease-duration group. Collagen density of RV free wall was calculated with Masson's trichrome staining. The Kruskall-Wallis test was performed to compare the groups. Native T1 and ECV to collagen density were analyzed with Spearman's correlation. Results: The mean values of native T1, ECV and collagen density of the RV free wall at baseline were 1541 ± 33 ms, 17.2 ± 1.3%, and 4.7 ± 0.5%, respectively. The values of RV free wall did not differ according to aging (P = 0.244, 0.504 and 0.331, respectively). However, the values significantly increased according to disease duration (P < 0.001 for all). Significant correlations were observed between native T1 and collagen density (r = 0.770, P < 0.001), and between ECV and collagen density for the RV free wall (r = 0.815, P < 0.001) in PH. However, there was no significant difference in native T1 and ECV values for the LV free wall according to the disease duration from the baseline (P = 0.349 and 0.240, respectively). Conclusions: We observed significantly increased values for native T1 and ECV of the RV free wall without significant increase of the LV free wall according to the disease duration of PH, and findings were well correlated with histological collagen density. [ABSTRACT FROM AUTHOR]

Objectives: To determine whether quantitative radiomic features from cardiac CT could differentiate the left atrial appendage (LAA) thrombus from circulatory stasis in patients with valvular heart disease. Methods: Ninety-five consecutive patients with valvular heart disease and filling defects in LAA on two-phase cardiac CT from March 2016 to August 2018 were retrospectively enrolled and classified as having thrombus or stasis by transesophageal echocardiography or cardiac surgery. The ratio of Hounsfield units in the filling defects to those in the ascending aorta (AA) was calculated on early- and late-phase CT (LAA/AAE and LAA/AAL, respectively). Radiomic features were extracted from semi-automated three-dimensional segmentation of the filling defect on early-phase CT. The diagnostic ability of radiomic features for differentiating thrombus from stasis was assessed and compared to LAA/AAE and LAA/AAL by comparing the AUC of ROC curves. Diagnostic performances of CT attenuation ratios and radiomic features were validated with an independent validation set. Results: Thrombus was diagnosed in 25 cases and stasis in 70. Sixty-eight radiomic features were extracted. Values of 8 wavelet-transformed features were lower in thrombus than in stasis (p < 0.001). The AUC value of a radiomic feature, wavelet_LHL, for diagnosing thrombus was 0.78, which was higher than that of LAA/AAE (AUC = 0.54, p = 0.025) and similar to that of LAA/AAL (AUC = 0.76, p = 0.773). In the validation set, the AUC of wavelet_LHL was 0.71, which was higher than that of LAA/AAE (AUC = 0.57, p = 0.391) and similar to that of LAA/AAL (AUC = 0.75, p = 0.707). Conclusions: Quantitative radiomic features from the early phase of cardiac CT may help diagnose LAA thrombus in patients with valvular heart disease. Key Points: • Wavelet-transformed grey-level non-uniformity values from radiomic analysis are significantly lower for LAA thrombus than for circulatory stasis. • Radiomic features may have an additional value for differentiating LAA thrombus from circulatory stasis when interpreting single-phase cardiac CT. • Radiomic features extracted from single-phase images may show similar diagnostic ability as conventional quantitative analysis from two-phase images. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the relationship between coronary artery calcification and subfoveal thicknesses of individual chorioretinal layers in subjects with subclinical atherosclerosis by using enhanced-depth imaging optical coherence tomography. Methods: In this retrospective, noninterventional, cross-sectional study, we included 193 eyes from 193 subjects and divided them into three cardiovascular (CV) risk groups based on coronary artery calcification (CAC) scores calculated from cardiac-gated computed tomography: low (CAC = 0; n = 77), intermediate (CAC = 1–300; n = 83), and high (CAC >300; n = 33). Central macula individual retinal layer thicknesses and subfoveal choroidal thickness were measured and compared among groups. Multivariate linear regression was used to evaluate associations of subfoveal choroidal thickness or central retinal thickness with CAC scores. Results: Average subfoveal choroidal thickness differed significantly among low, intermediate, and high CV risk groups (all p < 0.05). There were no statistically significant changes in segmented retinal layer thickness of the central macula. Multivariate regression analyses showed that higher CAC scores were significantly negatively associated with subfoveal choroidal thickness (β = –2.169, p < 0.001). Conclusions: Higher CAC scores were significantly associated with subfoveal choroidal thinning in subjects with subclinical atherosclerosis. Prominent reductions in the subfoveal choroidal layer could provide a useful biomarker for predicting CV risk in patients of advanced age with subclinical atherosclerosis. [ABSTRACT FROM AUTHOR]

Background: We aimed to assess if quantitative radiomic features can predict programmed death ligand 1 (PD‐L1) expression in advanced stage lung adenocarcinoma. Methods: This retrospective study included 153 patients who had advanced stage (>IIIA by TNM classification) lung adenocarcinoma with pretreatment thin section computed tomography (CT) images and PD‐L1 expression test results in their pathology reports. Clinicopathological data were collected from electronic medical records. Visual analysis and radiomic feature extraction of the tumor from pretreatment CT were performed. We constructed two models for multivariate logistic regression analysis (one based on clinical variables, and the other based on a combination of clinical variables and radiomic features), and compared c‐statistics of the receiver operating characteristic curves of each model to identify the model with the higher predictability. Results: Among 153 patients, 53 patients were classified as PD‐L1 positive and 100 patients as PD‐L1 negative. There was no significant difference in clinical characteristics or imaging findings on visual analysis between the two groups (P > 0.05 for all). Rad‐score by radiomic analysis was higher in the PD‐L1 positive group than in the PD‐L1 negative group with a statistical significance (−0.378 ± 1.537 vs. −1.171 ± 0.822, P = 0.0008). A prediction model that uses clinical variables and CT radiomic features showed higher performance compared to a prediction model that uses clinical variables only (c‐statistic = 0.646 vs. 0.550, P = 0.0299). Conclusions: Quantitative CT radiomic features can predict PD‐L1 expression in advanced stage lung adenocarcinoma. A prediction model composed of clinical variables and CT radiomic features may facilitate noninvasive assessment of PD‐L1 expression. Key points: Significant findings of the study Quantitative CT radiomic features can help predict PD‐L1 expression, whereas none of the qualitative imaging findings is associated with PD‐L1 positivity. What this study adds A prediction model composed of clinical variables and CT radiomic features may facilitate noninvasive assessment of PD‐L1 expression. [ABSTRACT FROM AUTHOR]

Background: Lung cancers are occasionally detected on coronary artery calcium (CAC)-scoring computed tomography (CT). However, the cause of delayed diagnosis and prognostic factors have not been studied. Purpose: To investigate the causes of delayed diagnosis of lung cancer in patients who undergo CAC-scoring CT and to identify predictors of mortality. Material and Methods: A total of 151 patients who were diagnosed with lung cancer and had undergone CAC-scoring CT from January 2010 to December 2014 were retrospectively enrolled. The reasons for delayed diagnosis were reviewed. Follow-up data on all-cause mortality were obtained. Cox proportional hazards regression analysis was used to identify predictors of mortality. Analyses of solid and subsolid subgroups were performed. Results: Among the 151 patients, 86 lesions (56.9%) were solid and 63 (41.7%) were subsolid. The main causes of delayed diagnosis were detection (48%) and interpretation (22%) errors. Age, size, unresectable stage at the time of diagnosis, and stage shift were independent prognostic factors throughout the entire and in the solid subgroup (all P < 0.2). There were no significant prognostic factors in the subsolid subgroup. Conclusion: In conclusion, avoidance of detection and interpretation errors may prevent delayed diagnosis of lung cancer on CAC-scoring CT. Older age, larger tumor size, unresectable stage at the time of diagnosis, and stage shift were associated with poor survival in patients with solid lung cancers but not in those with subsolid lung cancers. [ABSTRACT FROM AUTHOR]

We investigated the predictive value of preoperative computed tomography (CT)-derived tricuspid annular and right ventricular (RV) parameters for postoperative RV dysfunction in patients undergoing tricuspid valve (TV) surgery. We retrospectively reviewed clinical, transthoracic echocardiography (TTE), and CT data of 100 consecutive patients who underwent cardiac CT and subsequently received TV surgery. Preoperative cardiac CT and TTE parameters were analyzed, including TV annulus diameter and RV size. Univariate and multivariate logistic regression analyses were performed to identify significant predictors for postoperative RV dysfunction, both in the entire study population and in the subgroup of patients without preoperative RV dysfunction. Postoperative RV dysfunction occurred in 46% of all patients. In the multivariate logistic regression analysis, longer TV annulus diameter (>29.3 mm/m2 on four-chamber view; (odds ratio [OR] 3.56, 95% confidence interval [CI] 1.13–11.24), larger RV volume (RV end-diastolic volume/body surface area > 128.8 ml/m2) on CT (OR 3.85, 95% CI 1.24–11.98) and presence of preoperative RV dysfunction on TTE (OR 11.96, 95% CI 2.8–50.99) were independent predictors for postoperative RV dysfunction in the entire study population (P < 0.05). Among patients without preoperative RV dysfunction, longer TV annulus diameter (OR 4.02, 95% CI 1.20–13.41) and larger RV volume on CT (OR 6.09, 95% CI 1.87–19.80) were independent predictors for postoperative RV dysfunction (P < 0.05). Preoperative assessment of cardiac CT imaging–based TV annular diameter and RV volume can provide independent information for predicting postoperative RV dysfunction in patients undergoing TV surgery. • Postoperative RV dysfunction occurred in 46% after tricuspid valve surgery. • Longer TV annulus diameter and larger RV volume on CT were predictors. • Predictive information from TV annulus diameter and RV volume on preoperative CT [ABSTRACT FROM AUTHOR]

The coronary artery disease-reporting and data system (CAD-RADS) was recently developed to standardize CAD classifications and incorporate clinical management. We aimed to investigate the prognostic value and additional risk stratification benefits of CAD-RADS compared to coronary artery calcium scores (CACS) and CAD extent classifications in ischemic stroke patients without cardiac symptoms. From January 2013 to December 2014, 762 ischemic stroke patients with risk factors for CAD and without chest pain underwent coronary computed tomography angiography. CACS, CAD extent classification, and CAD-RADS scores were used to evaluate the computed tomography angiography images. The primary endpoint was major adverse cardiovascular events (MACEs), which were defined as cardiovascular death, nonfatal myocardial infarction, unstable angina requiring hospitalization, and revascularization. During the mean follow-up period of 3.36 years, 67 MACEs were recorded. Of the 762 patients, 23.5% were classified as CAD-RADS 0, 19.7% as CAD-RADS 1, 18.2% as CAD-RADS 2, 18.6% as CAD-RADS 3, 15.4% as CAD-RADS 4A, 2.2% as CAD-RADS 4B, and 2.4% as CAD-RADS 5. CACS, CAD extent classification, and CAD-RADS scores independently stratified the risk of future MACEs (all p < 0.05). The C-statistics revealed that both CAD extent classification and CAD-RADS scores improved risk stratification beyond CACS (C-index: 0.767 vs. 0.715; 95% confidence interval [CI] 0.026, 0.105), and 0.781 vs. 0.715; 95% CI 0.015, 0.086). In ischemic stroke patients without chest pain, CAD-RADS had prognostic value for future MACEs and better risk discrimination compared with CACS alone. Image 1 • Ischemic stroke patients have a substantial prevalence of coronary artery disease. • CAD-RADS has prognostic value for future MACEs in stroke patients. • CAD-RADS provides additional risk-prediction over CACS. [ABSTRACT FROM AUTHOR]

Purpose: The preexcited myocardium of Wolff-Parkinson-White (WPW) syndrome would have different characteristics from normal myocardium and these findings might be related to persistent left ventricular systolic dysfunction. We evaluated myocardial tissue characteristics at the preexcited segment in adult WPW syndrome patients and their implicated findings. Methods: For this prospective study, we enrolled 22 adult WPW syndrome patients (16 male, mean 45.4 ± 17.8 years) with echocardiographic findings of regional wall motion abnormality in our electrophysiology clinic. Of these patients, 14 underwent radiofrequency ablation before cardiac magnetic resonance imaging. All patients underwent cardiac magnetic resonance imaging including cine and late gadolinium enhancement. The ventricular morphology, function and myocardial characteristics of the preexcited segment were analyzed. Results: A relatively high prevalence of late gadolinium enhancement (9/22, 40.9%) was observed exclusively at the basal septum. The septal accessory pathway was significantly more prevalent in patients with late gadolinium enhancement (P = 0.011). The prevalences of regional myocardial wall thinning and regional akinesia were significantly higher (P = 0.001 for both) and left ventricular function was significantly decreased in patients with late gadolinium enhancement (P < 0.001). In addition, there were no significant relationships between radiofrequency ablation and regional akinesia (P > 0.999), regional myocardial wall thinning (P > 0.999), late gadolinium enhancement (P = 0.662) and low ejection fraction (P > 0.999). Conclusion: Myocardial fibrosis was observed at the preexcited myocardium of adult WPW syndrome patients with septal accessory pathway, which could accompany regional akinesia and regional myocardial wall thinning and might be related to persistent left ventricular systolic dysfunction even after radiofrequency ablation. [ABSTRACT FROM AUTHOR]

Objectives: The application of SYNTAX score II based on coronary CT angiography (CCTA) for selecting further treatment options has not been studied. This study aimed to investigate the diagnostic performance of CCTA combined with SYNTAX score II for selecting the revascularization method compared with invasive coronary angiography (ICA) based on 2014 European Society of Cardiology (ESC)/European Association for Cardio-Thoracic Surgery (EACTS) guidelines.Methods: From January-May 2011, 160 patients who underwent both CCTA and ICA within 30 interval days were included. The diagnostic performance of CCTA, CCTA plus CT-SYNTAX score I and CT-SYNTAX score II was analysed using ICA counterparts as references.Results: Overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy of CCTA plus CT-SYNTAX I for selecting coronary artery bypass grafting (CABG) candidates using ICA plus ICA-SYNTAX I as reference, were 70.6 %, 95.8 %, 66.7 %, 96.5 % and 93.1 %, respectively. The diagnostic performance of CCTA plus CT-SYNTAX II showed improvement with values of 83.3 %, 97.3 %, 71.4 %, 98.6 % and 96.3 %, respectively, using ICA plus ICA-SYNTAX II as reference.Conclusions: CCTA combined with CT-SYNTAX score II is an accurate method for selecting CABG surgery candidates compared with ICA-SYNTAX score II.Key Points: • SYNTAX plus CCTA can be highly specific for selecting the revascularization method. • SYNTAX II was complemented by including clinical considerations to SYNTAX I. • CCTA plus CT-SYNTAX II is an accurate method for selecting CABG candidates. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate whether the quantitative parameters of dual-energy computed tomography (DECT) can predict the effects of chemotherapy in advanced adenocarcinoma based on the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines.Materials and Methods: A total of 90 patients (59 males, 31 females, age 61.4 ± 12.3 (23-85)) with unresectable lung adenocarcinoma (TNM stage IIIB or IV) who underwent DECT before chemotherapy were prospectively included in this study. By comparing baseline studies with the best response achieved during 1 st line chemotherapy, patients were divided into two groups according to RECIST (version 1.1) guidelines as follows; responders (CR or PR) and non-responders (SD or PD). Quantitative measurements were performed on baseline DECT, and a logistic regression model was used to evaluate predictive factors for a response to chemotherapy.Results: Among 90 patients, 38 were categorized as responders, while 52 patients were non-responders. The mean iodine concentration measurements were significantly higher in responders compared with non-responders (1.81 ± 0.51 vs 1.33 ± 0.76 mg/ml, p < 0.001). On multivariate analysis, EGFR mutation (odds ratio (OR): 3.116, 95% confidential interval (CI):1.182-8.213, p = .019) and iodine concentration (OR: 1.112, 95% CI:1.034-1.196, p = .006) were found to be significant for predicting a treatment response.Conclusions: Dual-energy CT using a quantitative analytic method based on iodine concentration measurements can be used to predict the effects of chemotherapy in patients with advanced adenocarcinoma. [ABSTRACT FROM AUTHOR]

Background: Reduced image quality from increased X-ray scatter and image noise can be problematic when coronary computed tomography angiography (CCTA) imaging is performed in obese patients. The aim of this study was to compare the image quality and radiation dose obtained using automatic tube potential selection with tube current modulation (APSCM) with those obtained using a body mass index (BMI)-based protocol for CCTA in obese patients. Methods: A total of 203 consecutive obese (BMI > 30 kg/m2) patients were retrospectively enrolled, of whom 96 underwent CCTA with APSCM and 107 underwent a BMI-based protocol. After applying the propensity score matching method, the clinical parameters, subjective and objective image quality, and radiation dose were compared between the APSCM group and the matched BMI-based group. These parameters were also compared among different tube potential subgroups. Results: No significant differences were observed between the APSCM group and the BMI-based group with respect to image quality or radiation dose assessment (p > 0.05). Twenty patients (21%) examined with 140 kV in the APSCM group were exposed to significantly more radiation (p < 0.05) than patients in the BMI-based group or patients in the other APSCM kV subgroups; significant improvement in image quality was not observed in the 140 kV subgroup. Patients with a high BMI and a large effective diameter tended to be examined with 140 kV (p < 0.05). Conclusion: The use of APSCM for CCTA in obese patients did not significantly reduce the radiation dose or improve image quality compared with those in the matched BMI-based group. Our data indicate that it is better to avoid using APSCM when 140 kV is automatically selected, due to increased radiation dose and lack of significant improvement in image quality. [ABSTRACT FROM AUTHOR]

Background The clinical significance of pannus in the prosthetic mitral valve (MV) is not well documented. Objectives To investigate the clinical significance of pannus on cardiac computed tomography (CT) in patients with a prosthetic MV. Methods A total of 130 patients with previous MV replacement who underwent cardiac CT were retrospectively included in this study. The presence of pannus, paravalvular leak (PVL) around the prosthetic MV and limitation of motion (LOM) of the MV were analyzed using CT. Between patients with MV pannus and those without pannus, CT, echocardiographic, and redo-surgery findings were compared. The diagnostic performance of CT and transesophageal echocardiography (TEE) for the detection of MV pannus was also compared, using surgical findings as a standard reference. Results MV pannus was observed on cardiac CT in 32.3% of the study population. Patients with MV pannus detected on CT more commonly had LOM (28.2% vs. 15.2%) and less frequently had PVL of the prosthetic MV (16.7% vs. 25%) than patients without MV pannus (P > 0.05). Prosthetic valve obstruction (PVO) due prosthetic MV pannus requiring redo-surgery was present in only five patients (11.9%). Cardiac CT detected MV pannus with sensitivity of 65.2% and specificity of 80.9% and showed better diagnostic performance than TEE (P < 0.05). Conclusions Prosthetic MV pannus can frequently be seen on cardiac CT. However, its clinical significance should be assessed with careful consideration, because PVO due to MV pannus is relatively uncommon, and pannus can be seen in patients without any clinical problems. [ABSTRACT FROM AUTHOR]

A reliable, non-invasive diagnostic method is needed for early detection and serial monitoring of cardiotoxicity, a well-known side effect of chemotherapy. This study aimed to assess the feasibility of T1-mapping cardiac magnetic resonance imaging (CMR) for evaluating subclinical myocardial changes in a doxorubicin-induced cardiotoxicity rabbit model. Adult male New Zealand White rabbits were injected twice-weekly with doxorubicin and subjected to CMR on a clinical 3T MR system before and every 2–4 weeks post-drug administration. Native T1 and extracellular volume (ECV) values were measured at six mid-left ventricle (LV) and specific LV lesions. Histological assessments evaluated myocardial injury and fibrosis. Three pre-model and 11 post-model animals were included. Myocardial injury was observed from 3 weeks. Mean LV myocardium ECV values increased significantly from week 3 before LV ejection fraction decreases (week 6), and ECVs of the RV upper/lower insertion sites and papillary muscle exceeded those of the LV. The mean native T1 value in the mid-LV increased significantly increased from week 6, and LV myocardium ECV correlated strongly with the degree of fibrosis (r = 0.979, p < 0.001). Myocardial T1 mapping, particularly ECV values, reliably and non-invasively detected early cardiotoxicity, allowing serial monitoring of chemotherapy-induced cardiotoxicity. [ABSTRACT FROM AUTHOR]

Objectives: To validate a method for performing myocardial segmentation based on coronary anatomy using coronary CT angiography (CCTA).Methods: Coronary artery-based myocardial segmentation (CAMS) was developed for use with CCTA. To validate and compare this method with the conventional American Heart Association (AHA) classification, a single coronary occlusion model was prepared and validated using six pigs. The unstained occluded coronary territories of the specimens and corresponding arterial territories from CAMS and AHA segmentations were compared using slice-by-slice matching and 100 virtual myocardial columns.Results: CAMS more precisely predicted ischaemic area than the AHA method, as indicated by 95% versus 76% (p < 0.001) of the percentage of matched columns (defined as percentage of matched columns of segmentation method divided by number of unstained columns in the specimen). According to the subgroup analyses, CAMS demonstrated a higher percentage of matched columns than the AHA method in the left anterior descending artery (100% vs. 77%; p < 0.001) and mid- (99% vs. 83%; p = 0.046) and apical-level territories of the left ventricle (90% vs. 52%; p = 0.011).Conclusions: CAMS is a feasible method for identifying the corresponding myocardial territories of the coronary arteries using CCTA.Key Points: • CAMS is a feasible method for identifying corresponding coronary territory using CTA • CAMS is more accurate in predicting coronary territory than the AHA method • The AHA method may underestimate the ischaemic territory of LAD stenosis. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to evaluate the prognostic role of cardiac magnetic resonance imaging (CMR)-based extracellular volume fraction (ECV) in patients with non-ischemic dilated cardiomyopathy (NIDCM) and compare it with late gadolinium enhancement (LGE) parameters.Methods: This was a single-center, prospective, cohort study of 117 NIDCM patients (71 men, 51.9 ± 16.7 years) who underwent clinical 3.0-T CMR. Myocardial ECV and LGE were quantified on the left ventricular myocardium. The presence of midwall LGE was also detected. Nineteen healthy subjects served as controls. The primary end points were cardiovascular (CV) events defined by CV death, rehospitalization due to heart failure, and heart transplantation.Results: During the follow-up period (median duration, 11.2 months; 25th-75th percentile, 7.8-21.9 months), the primary end points occurred in 19 patients (16.2%). The ECV (per 3% and 1% increase) was associated with a hazard ratio of 1.80 and 1.22 (95% confidence interval [CI], 1.48-2.20 and 1.14-1.30, respectively; p < 0.001) for the CV events. Multivariable analysis also indicated that ECV was an independent prognostic factor and had a higher prognostic value (Harrell's c statistic, 0.88) than LGE quantification values (0.77) or midwall LGE (0.80).Conclusion: CMR-based ECV independently predicts the clinical outcome in NIDCM patients.Key Points: • T1-mapping-based ECV is a useful parameter of risk stratification in NIDCM • ECV has a higher prognostic value than LGE • Contrast-enhanced T1-mapping CMR is a feasible and safe method. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the diagnostic value of dual-energy computed tomography (DECT) in differentiating between low- and high-risk thymomas and thymic carcinomas.Materials: Our institutional review board approved this study, and patients provided informed consent. We prospectively enrolled 37 patients (20 males, mean age: 55.6 years) with thymic epithelial tumour. All patients underwent DECT. For quantitative analysis, two reviewers measured the following tumour parameters: CT attenuation value in contrast Hounsfield units (CHU), iodine-related HU and iodine concentration (mg/ml). Pathological results confirmed the final diagnosis.Results: Of the 37 thymic tumours, 23 (62.2 %) were low-risk thymomas, five (13.5 %) were high-risk thymomas and nine (24.3 %) were thymic carcinomas. According to quantitative analysis, iodine-related HU and iodine concentration were significantly different among low-risk thymomas, high-risk thymomas and thymic carcinomas (median: 29.78 HU vs. 14.55 HU vs. 19.95 HU, p = 0.001 and 1.92 mg/ml vs. 0.99 mg/ml vs. 1.18 mg/ml, p < 0.001, respectively).Conclusion: DECT using a quantitative analytical method based on iodine concentration measurement can be used to differentiate among thymic epithelial tumours using single-phase scanning.Key Points: • IHU and IC were lower in high-risk thymomas/carcinomas than in low-risk thymomas • IHU and IC were lower in advanced-stage thymomas than in early-stage thymomas • Dual-energy CT helps differentiate among thymic epithelial tumours. [ABSTRACT FROM AUTHOR]

Background: An optimal method of preoperative localization for pulmonary nodules has yet to be established. This systematic review and meta-analysis aimed to compare the success and complication rates associated with three pulmonary nodule localization methods for video-assisted thoracoscopic surgery (VATS): hook-wire localization, microcoil localization, and lipiodol localization.Methods: We searched the PubMed, MEDLINE, and EMBASE databases for prospective or retrospective English language studies of VATS localization in adult patients. A noncomparative, random effects model-based meta-analysis was performed to obtain pooled success and complication rates for the three localization methods.Results: A total of 46 clinical studies were enrolled, including 30, 9, and 7 studies of hook-wire, microcoil, and lipiodol localization, respectively. The successful targeting rates for hook-wire, microcoil, and lipiodol localization were 0.98 (95% CI, 0.97-0.99), 0.98 (95% CI, 0.96-0.99), and 0.99 (95% CI, 0.98-1.00), respectively, with corresponding successful operative field targeting rates of 0.94 (95% CI, 0.91-0.96), 0.97 (95% CI, 0.95-0.98), and 0.99 (95% CI, 0.98-1.00), respectively. In addition, the successful VATS rates with hook-wire, microcoil, and lipiodol localization were 0.96 (95% CI, 0.94-0.97), 0.97 (95% CI, 0.94-0.99), and 0.99 (95% CI, 0.98-1.00), respectively. Regarding complications, hook-wire, microcoil, and lipiodol localization were associated with pneumothorax rates of 0.35 (95% CI, 0.28-0.43), 0.16 (95% CI, 0.07-0.34), and 0.31 (95% CI, 0.20-0.46), respectively and hemorrhage rates of 0.16 (95% CI, 0.11-0.23), 0.06 (95% CI, 0.03-0.11), and 0.12 (95% CI, 0.05-0.23), respectively.Conclusions: All three localization methods yielded similarly highly successful targeting rates. However, hook-wire localization had a relatively lower successful operative field targeting rate because of dislodgement or migration. Lipiodol localization had the highest overall success rate, and microcoil localization yielded the lowest complication rates. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to determine whether dual-energy computed tomography (DECT) angiography could differentiate pulmonary thromboembolism (PTE) from pulmonary artery sarcoma (PAS).Methods: We prospectively enrolled 19 patients that had a filling defect in the main pulmonary artery on DECT. Six patients who had PAS and underwent DECT were retrospectively enrolled for comparison. Pathological results or follow-up CT after anticoagulation therapy were used to make the final diagnosis. Two investigators measured the following parameters at the filling defect in the main pulmonary artery: CT attenuation density [Hounsfield units (HU)], iodine-related HU (IHU) and iodine concentration (IC, mg/ml).Results: From a total of 25 patients (M:F = 10:15; mean age, 65 years old), 19 were categorised into the PTE group and six were categorised into the PAS group. The mean HU values were not significantly different between the PTE and PAS groups (45.5 ± 15.9 vs 47.1 ± 9.2 HU; P = 0.776). However, the mean IHU and IC values of the lesions were significantly different between the PTE and PAS groups (10.6 ± 7.2 vs 27.9 ± 9.1 HU; P = 0.004, and 0.61 ± 0.39 vs 1.49 ± 0.57; P = 0.001).Conclusions: DECT angiography using a quantitative analytic methodology can be used to differentiate PTE and PAS.Key Points: • DECT can be useful for differentiation of PAS and PTE. • With quantitative analysis, DECT offers tissue characterisation by detecting lesion parameter increases. • The patients without predisposing factors for PTE can be candidates for DECT. [ABSTRACT FROM AUTHOR]

Background: With the development of computed tomography (CT) technology, coronary CT angiography can be acquired with low doses of radiation and contrast agent without a loss of diagnostic performance. The primary objective of the CONCENTRATE study is to prove the noninferiority of the enhancement effect of low-concentration contrast agents compared to a high-concentration contrast agent of the coronary artery and myocardium with coronary CT angiography.Methods/design: The CONCENTRATE study is a prospective, multicenter, noninferiority, randomized trial evaluating the enhancement effect of low-concentration contrast agents (270 and 320 mg iodine/ml) compared with a high-concentration contrast agent (370 mg iodine/ml) in the coronary artery and myocardium of coronary artery CT angiography. The primary efficacy measurement is the enhancement of coronary arteries as measured in Hounsfield units. The target population comprises 318 patients with suspected coronary artery disease who have been referred for clinically indicated nonemergent coronary CT angiography. Eligible participants are randomized for three different concentrations of the contrast agent in a 1:1:1 allocation ratio to one of three arms. The CONCENTRATE trial is a double-blind study, where the subjects and the outcome assessor are blinded to the concentration of the contrast agent used for coronary the CT angiography. Eight clinical sites in Korea are participating in this trial.Discussion: The CONCENTRATE study will determine whether low-concentration contrast agents are able to provide diagnostic image quality in coronary CT angiography.Trial Registration: NCT02549794 . Registered on 14 September 2015. [ABSTRACT FROM AUTHOR]

Background The added value of cardiac computed tomography (CT) with transesophageal echocardiography (TEE) for evaluating mechanical aortic valve (AV) dysfunction has not yet been investigated. The purposes of this study were to investigate the added value of cardiac CT for evaluation of mechanical AVs and diagnoses of pannus compared to TEE, with surgical findings of redo-aortic valve replacement (AVR) used as a standard reference. Methods 25 patients who underwent redo-AVR due to mechanical AV dysfunction and cardiac CT before redo-AVR were included. The presence of pannus, encroachment ratio by pannus, and limitation of motion (LOM) were evaluated on CT. The diagnostic performance of pannus detection was compared using TEE, CT, and CT + TEE, with surgical findings as a standard reference. The added value of CT for diagnosing the cause of mechanical AV dysfunction was assessed compared to TTE + TEE. Results In two patients, CT analysis was not feasible due to severe metallic artifacts. On CT, pannus and LOM were found in 100% (23/23) and 60.9% (14/23). TEE identified pannus in 48.0% of patients (12/25). CT, TEE, and CT + TEE correctly identified pannus with sensitivity of 92.0%, 48.0%, and 92.0%, respectively (P = 0.002 for CT vs. TEE). In 11 of 13 cases (84.6%) with inconclusive or negative TEE results for pannus, CT detected the pannus. Among 13 inconclusive cases of TTE + TEE for the cause of mechanical AV dysfunction, CT suggested 6 prosthetic valve obstruction (PVO) by pannus, 4 low-flow low-gradient PVO, and one LOM without significant PVO. Conclusions Cardiac CT showed added diagnostic value with TEE in the detection of pannus as the cause of mechanical AV dysfunction. [ABSTRACT FROM AUTHOR]

Aims Acne is a common skin disease that originates in the sebaceous gland. The pathogenesis of acne is very complex, involving the increase of sebum production and perifollicular inflammation. In this study, we screened the anti-lipogenic material and demonstrated its effect using cultured human sebocytes. Main methods Normal human sebocytes were cultured by explanting the sebaceous glands. To evaluate the anti-lipogenic effect, sebocytes were treated with test materials and 14 C-acetate incorporation assay was performed. Key findings To screen the anti-lipogenic materials, we tested the effect of many herbal plant extracts. We found that Angelica dahurica extract inhibited the insulin-like growth factor-1 (IGF-1)-induced sebum production in terms of squalene synthesis in sebocytes. Furthermore, imperatorin isolated from A. dahurica showed remarkable inhibitory effect on squalene production as well as squalene synthase promoter activity. To investigate the putative action mechanism, we tested the effect of imperatorin on intracellular signaling. The results showed that imperatorin inhibited IGF-1-induced phosphorylation of Akt. In addition, imperatorin significantly down-regulated PPAR-γ and SREBP-1, the important transcription factors for lipid synthesis. Significance These results suggest that imperatorin has a potential for reducing sebum production in sebocytes, and can be applicable for acne treatment. [ABSTRACT FROM AUTHOR]

Background The long-term prognostic value of the computed tomography (CT)-based SYNTAX score has not yet been investigated. The aim of our study was to investigate the prognostic value of the CT-SYNTAX score in predicting major adverse cardiac events (MACEs) in populations who underwent both coronary computed tomography (CCTA) and invasive coronary angiography (ICA), compared with prognostic values of coronary artery disease (CAD) findings on CCTA and the ICA-based SYNTAX score. Methods We retrospectively included 339 patients (213 men, mean age of 63.8 ± 9.45 years) with suspected CAD who underwent CCTA and ICA. SYNTAX score was obtained based on both CCTA and ICA. Follow-up clinical outcome data regarding composite MACEs were obtained. Cox proportional hazard models were developed to predict MACEs based on clinical variables, number of CAD vessels, and SYNTAX scores based on CCTA and ICA. The time-dependent receiver operating characteristic curve method was used, and the integrated area under the curve (iAUC) was calculated to compare the predictive prognosis of the models. Results During the median follow-up of 1374 days, there were 30 MACEs. In multivariate Cox regression adjusted for clinical variables, SYNTAX score group 4 (≥ 33) on CCTA and SYNTAX score groups 3 (23–32) and 4 (≥ 33) on ICA showed increased hazard ratios for MACEs compared to SYNTAX score group 1 (0). CT-SYNTAX score demonstrated no significant difference in iAUC compared with ICA-SYNTAX score and the number of vessels of CAD on CCTA. Conclusions CT-SYNTAX score can be a useful method for non-invasively predicting MACEs, especially in patients with complex CAD. [ABSTRACT FROM AUTHOR]

Y.J. Hong, T.K. Kim, S.J. Yoo, C.H. Park, P.K. Kim, J.Y. Lee conducted experiment. J. Hur, Y.J. Kim H.Y. Lee, Y.J. Suh edited the manuscript." should read: "Y.J. Hong, B.W. Choi conceived experiment wrote the manuscript. J. Hur, Y.J. Kim H.Y. Lee, Y.J. Suh edited the manuscript". [Extracted from the article]

Objectives The diagnosis and treatment of ground-glass opacity (GGO) lesions have become important issues because subsolid nodules including GGO are known to frequently represent the histologic spectrum of lung adenocarcinoma. Because small GGO lesions cannot usually be palpated or visualized during surgery, several marking techniques have been reported for localization during thoracoscopic surgery, such as lipiodol and hook-wire localization. This study is designed to demonstrate the usefulness and safety of the lipiodol localization technique for individuals undergoing GGO VATS resection compared to the hook-wire localization technique. Methods Two hundred fifty participants will be prospectively enrolled in a 1:1 manner to the lipiodol or hook-wire group according to the inclusion criteria. All study participants will undergo preoperative lung localization using either the lipiodol or hook-wire method. Thoracoscopic surgery will be performed by experienced thoracoscopic surgeons within several hours after marking under general anesthesia. The primary endpoint is the procedure success rate, and the secondary endpoints are the procedure complication rate, procedure time, surgery time and the margin from the lesion in the resected specimen. Results Patient enrollment will be completed within 2 years. We will analyze the procedure success rate and the presence of complications with regard to the CT results. In addition, the procedure and surgery times, and the safety margin will be also compared between the 2 techniques. Conclusion If the aims of this study are achieved, then the use of lipiodol localization technique will be widespread in the localization of non-palpable pulmonary lesions that are indicated for surgical resection. (ClinicalTrials.gov: NCT02180568 ) [ABSTRACT FROM AUTHOR]

Objective : The predictive value of coronary computed tomography angiography (CCTA) in stroke patients has not yet been established. We investigated the prognostic value of coronary artery disease (CAD) detection by CCTA, and determined the incremental risk stratification benefit of CCTA findings as compared to coronary artery calcium scores (CACS) in ischemic stroke patients without chest pain. Methods : Among 914 consecutive ischemic stroke patients, 317 (68.5% were male with a mean age of 64 years) who had at least one clinical risk factor for CAD without chest pain were prospectively enrolled to undergo CCTA. CT images were assessed for CAC, presence of CAD and extent of CAD. The primary endpoint was major adverse cardiac events (MACEs) defined as cardiac death, non-fatal myocardial infarction, unstable angina requiring hospitalization, or revascularization after 90 days from index CCTA. Results : The prevalence of CAC ≥1 was 73.1% (232/317) and the average CACS was 346.6 ± 693.5 (Agatston unit). During the median follow-up period of 409 days, there were a total of 26 MACEs. Both CACS [CAC (101–400, and >400)] and CCTA findings [presence of obstructive CAD, 1-vessel disease (VD), 2-VD, and 3-VD] independently stratified risk of future MACEs (all p < 0.05). The time-dependent receiver operating characteristic curve analysis revealed that CAD findings (presence of obstructive CAD and number of involved vessels) based on CCTA improved risk stratification beyond clinical risk factors and CACS (iAUC: 0.863 vs 0.752, p < 0.05). Conclusion : In ischemic stroke patients without chest pain, CCTA findings of CAD provide additional risk-discrimination over CACS. [ABSTRACT FROM AUTHOR]

As a first step in the development of novel liver-specific contrast agents using ethosomes for computed tomography (CT) imaging applications, we entrapped iodine within ethosomes, which are phospholipid vesicular carriers containing relatively high alcohol concentrations, synthesized using several types of alcohol, such as methanol, ethanol, and propanol. The iodine containing ethosomes that were prepared using methanol showed the smallest vesicle size (392nm) and the highest CT density (1107 HU). The incorporation of cholesterol into the ethosomal contrast agents improved the stability of the ethosomes but made the vesicle size large. The ethosomal contrast agents were taken up well by macrophage cells and showed no cellular toxicity. The results demonstrated that ethosomes containing iodine, as prepared in this study, have potential as contrast agents for applications in CT imaging. [ABSTRACT FROM AUTHOR]

Self-assembled polymeric nanocapsules(NCs) that incorporate dendrimerporphyrin (DP) in the shells and superparamagnetic iron oxide nanoparticles(SPIONs) in the cores are fabricated to create a theragnostic platformfor the application in photodynamic therapy (PDT) and magnetic resonanceimaging (MRI). SPIONs-embedded polystyrene NPs (SPIONs@PS) are usedas a template to build up multilayered NCs. The formation of PAH/DPmultilayer on the SPIONs@PS is monitored by zeta-pential and fluorescenceemission measurement, because the porphyrin unit in the core of DPhas strong red fluorescence emission. NCs have strong enough magneticproperty (>20 emu/g) for MRI application with typical superparamagneticbehavior, where the linear correlation of R2 and Fe concentrationat diluted conditions led to corresponding T2 relaxivity coefficient(r2) value of 93.5 mM–1s–1. Cell viability study upon light irradiation reveals that NCs cansuccessfully work in photosensitizer formulation for PDT. [ABSTRACT FROM AUTHOR]

Objective: Aortic unfolding occurs with aging and reflects proximal aortic dilation, aortic arch widening, and decreased curvature. This study 1) evaluated the relationship between aortic unfolding measured using non-contrast cardiac-gated computed tomography (CT) and age, 2) assessed factors influencing aortic unfolding, and 3) determined the association of this measurement with coronary artery calcium (CAC) score. Methods: We reviewed the charts of 219 subjects (142 men, 77 women; mean age 54.2±9.3 years) who underwent coronary artery calcium scanning during routine health screening from December 2010 to May 2011. Multivariate regression analysis according to cardiovascular risk factors was performed. We also analyzed the relationship between aortic unfolding measurements and CAC score using stepwise multiple linear regression. Results: Mean aortic unfolding was 103.7±13.9 mm (men, 106.5±13.5 mm; women, 98.4±12.9 mm). Age, body surface area, and hypertension were exclusively associated with aortic unfolding. The association between aortic unfolding and CAC score was significant after adjustment for age and gender (β = 1.89, p = 0.017) and for Framingham risk score (β = 2.83, p<0.001). Conclusions: Aortic unfolding defined by measuring aortic width was a reproducible and practical method with non-contrast cardiac CT and associated with age, body surface area, and hypertension. CAC score, a well-established surrogate marker of cardiovascular disease, is positively associated with aortic unfolding. Further study to evaluate aortic unfolding as a potential predictor of cardiovascular risk is warranted. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: To investigate the feasibility of dual-energy computed tomography (DECT) in differentiating malignant from benign mediastinal tumors. Materials and methods: We prospectively enrolled 25 patients (14 males; mean age: 56.7 years) who had suspected mediastinal tumors on chest radiography or non-contrast chest computed tomography (CT). All patients underwent a two-phase DECT using gemstone spectral imaging (GSI) mode (GE HD750). For the quantitative analysis, two investigators measured the following parameters of the tumors in the early and the delayed phases: CT attenuation value in Hounsfield units (HU) and iodine concentration (mg/ml). Pathological results were used for a final diagnosis. Statistical analyses were performed using the Fisher's exact test and the Mann–Whitney t-test. Results: 10 patients (40%) had benign pathology, while 15 (60%) had malignant pathology. The iodine concentration measurements were significantly different between benign and malignant tumors both in the early phase (1.38mg/ml vs. 2.41mg/ml, p =0.001) and in the delayed phase (1.52mg/ml vs. 2.84mg/ml, p =0.001), while mean attenuation values were not significantly different in both phases (57.8HU vs. 69.1HU, p =0.067 and 67.4HU vs. 78.4HU, p =0.086, respectively). Conclusions: Dual-energy CT using a quantitative analytic methodology can be used to differentiate between benign and malignant mediastinal tumors [Copyright &y& Elsevier]

Noninvasive imaging that provides anatomic information while excluding intracardiac thrombus would be of significant clinical value for patients referred for catheter ablation of atrial fibrillation (AF). This study assessed the diagnostic performance of a dualenhancement single-phase cardiac computed tomography (CT) protocol for thrombus and circulatory stasis detection in AF patients before catheter ablation. We studied 101 consecutive symptomatic AF patients (71 men and 30 women; mean age, 61.8 years) who were scheduled to have catheter ablation. All patients had undergone pre-AF ablation CT imaging and transesophageal echocardiography on the same day. CT was performed with prospective electrocardiographic gating, and scanning began 180 seconds after the test bolus. Mean left atrial appendage (LAA)/ascending aorta Hounsfield unit (HU) ratios were measured on CT images. Among the 101 patients, 9 thrombi and 18 spontaneous echo contrasts were detected by transesophageal echocardiography. The overall sensitivity, specificity, positive predictive value, and negative predictive value of CT for the detection of thrombi in the LAA were 89%, 100%, 100%, and 99%, respectively. The mean LAA/ ascending aorta HU ratios were significantly different between thrombus and circulatory stasis (0.17 vs 0.33, p [ 0.002). Dual-enhancement single-scan cardiac CT is a sensitive modality for detecting and differentiating LAA thrombus and circulatory stasis. [ABSTRACT FROM AUTHOR]

Objectives: This study was designed to determine the prognostic value of multidetector coronary computed tomography angiography (CTA) in relation to exercise electrocardiography (XECG) findings. Background: The prognostic usefulness of coronary CTA findings of coronary artery disease in relation to XECG findings has not been explored systematically. Methods: Patients with suspected coronary artery disease who had undergone both coronary CTA and XECG (<90 days between tests) from 2003 through 2009 were enrolled retrospectively. Coronary CTA results were classified according to the severity of maximal stenosis (normal, mild: <40% of luminal stenosis, moderate: 40% to 69%, severe: ≥70%), XECG results were categorized as positive and negative, and Duke XECG score was calculated. Clinical follow-up data were collected for major adverse cardiac events (MACE): cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, and revascularization after 90 days from index coronary CTA. C-statistics were calculated to compare discriminatory values of each test. Results: Among the 2,977 (58 ± 10 years) study patients, 12% demonstrated positive XECG results. By coronary CTA, patients were categorized as normal (56%) or having mild (26%), moderate (13%), or severe (5%) disease. During a median follow-up of 3.3 years (interquartile range: 2.3 to 4.6), 97 MACE were observed and the 5-year cumulative event rate was 3.6% (95% confidence interval: 3.0 to 4.3). Although both XECG (C-statistic: 0.790) and coronary CTA (C-statistic: 0.908) improved risk stratification beyond clinical risk factors (C-statistic: 0.746, p < 0.05 for all), XECG in addition to coronary CTA (C-statistic: 0.907) did not provide better discrimination than coronary CTA alone (p = 0.389). In subgroup analyses, coronary CTA stratified risk of MACE in groups with both positive and negative XECG results (all p < 0.001 for trend). However, positive XECG results predicted risk of MACE on coronary CTA only in the moderate stenosis group (hazard ratio: 2.58, 95% confidence interval: 1.29 to 5.19, p = 0.008) and severe stenosis group (hazard ratio: 2.28, 95% confidence interval: 1.19 to 4.38, p = 0.013). Conclusions: In patients with suspected coronary artery disease, coronary CTA discriminates future risk of MACE in patients independent of XECG results. Compared with coronary CTA, XECG has an additive prognostic value only in patients with moderate to severe stenosis on coronary CTA. [Copyright &y& Elsevier]

An abstract of the conference paper "Epicardial adipose tissue thickness assessed by cardiac magnetic resonance is an independent indicator for coronary artery stenosis in asymptomatic type 2 diabetic patients," by Young Jin Kim, and colleagues is presented.

Recently contrast-enhanced cardiac computed tomography (CT) was found to be useful for imaging the left atrium and pulmonary veins (PVs) before radiofrequency catheter ablation in patients with atrial fibrillation. However, the risks of contrast agent in patients with impaired renal function must be considered. We investigated the accuracy of low-dose electrocardiographically synchronized nonenhanced cardiac CT (NECT) for identifying PV anatomy. One hundred eight consecutive patients who underwent cardiac CT before radiofrequency catheter ablation of atrial fibrillation were included. Nonenhanced cardiac computed tomogram was retrospectively evaluated for each patient by 2 radiologists for the following PV anatomy: conventional pattern, conjoined ostium, and accessory PVs with number and location. Sensitivity and specificity for variations in PVs were calculated using contrast-enhanced cardiac computed tomogram as the reference standard. Detection rates for each variation were also calculated. Twenty-one right PV (RPV) variations and 11 left PV (LPV) variations were observed. NECT showed a high diagnostic performance in detecting variations in PVs for the 2 observers. For RPV variations overall sensitivity was 97.6% and specificity was 96.6%. For LPV variations overall sensitivity was 90.9% and specificity was 97.9%. Overall detection rates for variation between the 2 observers were 97.1% for accessory RPV from the right middle lobe, 100% for 4 ostia with accessory RPV from the right middle lobe and accessory RPV from the superior segment of the right lower lobe, 100% for accessory RPV from the superior segment of the right lower lobe, 88.9% for conjoined ostium of the LPV, and 100% for accessory LPV from the left lingular segment. In conclusion, variations in PV anatomy were detected with great accuracy by NECT. [ABSTRACT FROM AUTHOR]