Low-tube-voltage whole-body CT angiography with extremely low iodine dose: a comparison between hybrid-iterative reconstruction and deep-learning image-reconstruction algorithms

AIM

To evaluate arterial enhancement, its depiction, and image quality in low-tube potential whole-body computed tomography (CT) angiography (CTA) with extremely low iodine dose and compare the results with those obtained by hybrid-iterative reconstruction (IR) and deep-learning image-reconstruction (DLIR) methods.

MATERIALS AND METHODS

This prospective study included 34 consecutive participants (27 men; mean age, 74.2 years) who underwent whole-body CTA at 80 kVp for evaluating aortic diseases between January and July 2020. Contrast material (240 mg iodine/ml) with simultaneous administration of its quarter volume of saline, which corresponded to 192 mg iodine/ml, was administered. CT raw data were reconstructed using adaptive statistical IR-Veo of 40% (hybrid-IR), DLIR with medium- (DLIR-M), and high-strength level (DLIR-H). A radiologist measured CT attenuation of the arteries and background noise, and the signal-to-noise ratio (SNR) was then calculated. Two reviewers qualitatively evaluated the arterial depictions and diagnostic acceptability on axial, multiplanar-reformatted (MPR), and volume-rendered (VR) images.

RESULTS

Mean contrast material volume and iodine weight administered were 64.1 ml and 15.4 g, respectively. The SNRs of the arteries were significantly higher in the following order of the DLIR-H, DLIR-M, and hybrid-IR (p<0.001). Depictions of six arteries on axial, three arteries on MPR, and four arteries on VR images were significantly superior in the DLIR-M or hybrid-IR than in the DLIR-H (p≤0.009 for each). Diagnostic acceptability was significantly better in the DLIR-M and DLIR-H than in the hybrid-IR (p<0.001-0.005).

CONCLUSION

DLIR-M showed well-balanced arterial depictions and image quality compared with the hybrid-IR and DLIR-H.

Influence of the coronavirus disease 2019 pandemic on the post-graduate career paths of medical students: a cross-sectional study

BACKGROUND

The World Health Organization first declared the coronavirus disease 2019 (COVID-19) pandemic in March 2020 and announced the end of the emergency in May 2023. Additionally, the COVID-19 pandemic significantly impacted individuals globally, including medical students. Although the COVID-19 pandemic increased online education, it restricted clinical training, extracurricular activities, and interprovincial travel. Therefore, this study aimed to examine whether the COVID-19 pandemic influenced the choice of training hospitals and career paths among 3rd- to 6th-year medical students in Japan.

METHODS

We developed a questionnaire comprising 21 multiple-choice and 1 open-ended questions, which was administered anonymously via online platforms. The survey targeted Japanese medical students to obtain insights into their preferences for training hospitals and career paths during the COVID-19 pandemic. Participants included 4th- to 6th-year medical students from 51 medical schools in Japan. The survey was conducted through student networks from 8 February 2022 to 20 March 2022.

RESULTS

Overall, 507 medical students participated in the survey, with representation from various academic years as follows: 102 (20.1%), 134 (26.4%), 121 (23.9%), and 150 (29.6%) students from the 3rd, 4th, 5th, and 6th year, respectively. Of these, 338 (66.6%) students reported that the COVID-19 pandemic had influenced their choice of training hospitals. The degree of the influence varied based on the university region and the student year. However, most of the students (473, 93.3%) did not change their course for clinical, basic research, or administrative pathways due to the COVID-19 pandemic. Among the clinically oriented students, 391 (77.2%) did not change their preferred speciality.

CONCLUSIONS

The COVID-19 pandemic influenced medical students' choice of training hospitals. Although many students believed that the pandemic would not change their career choices, our results indicate a potential subconscious trend to avoid internal medicine, which is the speciality most directly involved in treating patients with COVID-19.

Prevention of atopic dermatitis in high-risk neonates via different types of moisturizer application: A randomized, blinded, parallel, three-group, phase II trial (PAF study)

BACKGROUND

The effectiveness of moisturizers in preventing infant atopic dermatitis (AD) remains unclear. We previously showed that using 2e moisturizer of commercial moisturizer (Shiseido Japan Co., Ltd.) at least once a day significantly prevented AD in infants as compared with as-needed petroleum jelly. This trial aimed to determine the effectiveness of twice- or once-daily application of Fam's Baby moisturizer (Fam's Inc.) in preventing AD compared with once-daily 2e moisturizer.

METHODS

This trial was a single-centre, three-parallel-group, assessor-blinded, superiority, individually randomized, controlled, phase II trial that was conducted from 25 August 2020 to 28 September 2021. We randomly assigned 60 newborns with at least one parent or sibling who has AD to receive Fam's Baby moisturizer twice daily (Group A) or once daily (Group B), or 2e once daily (Group C) in a 1:1:1 ratio until they were 32 weeks old. The primary outcome was the time of AD onset.

RESULTS

Atopic dermatitis was observed in 11/20 (55%), 5/20 (25%) and 10/20 (50%), infants in Groups A, B and C, respectively. Cumulative incidence values for AD according to the Kaplan-Meier method showed that infants in Group B tended to maintain an intact skin for a longer period than those in Group C (median time, not reached [NR] vs. 212 days, log-rank test, p = 0.064). Cox regression analysis showed that the risk of AD tended to be lower in Group B (hazard ratio with group C as control, 0.36; 95% confidential intervals: 0.12-1.06). No serious adverse events occurred in any of the enrolled infants.

CONCLUSION

Fam's Baby moisturizer may better prevent AD than 2e. Further large-scale trials should be performed to confirm the efficacy of Fam's Baby moisturizer in preventing AD in infants.

The effectiveness of simulation-based education combined with peer-assisted learning on clinical performance of first-year medical residents: a case-control study

BACKGROUND

Simulation-based education and peer-assisted learning (PAL) are both known as useful educational methods. Previous research has reported that combining these two methods are effective for training medical residents in short-term evaluation. This study was aimed to evaluate the middle- to long-term effects of simulation-based education combined with PAL on the performance of medical residents during emergency department duties.

METHODS

This study was designed as a case-control study and conducted over three years at Okayama University Hospital in Japan. Postgraduate-year-one medical residents were assigned to three groups: a simulation group that received simulation-based education, a lecture group that received traditional lecture-based education, and a control group that received no such prior trainings. Prior training in emergency department duties using PAL was performed as an educational intervention for the simulation and lecture groups during the clinical orientation period. The residents' medical knowledge was assessed by written examinations before and after the orientation. The performance of residents during their emergency department duties was assessed by self-evaluation questionnaires and objective-assessment checklists, following up with the residents for three months after the orientation period and collecting data on their 1st, 2nd, and 3rd emergency department duties. All the datasets collected were statistically analyzed and compared by their mean values among the three groups.

RESULTS

A total of 75 residents were included in the comparative study: 27 in the simulation group, 24 in the lecture group, and 24 in the control group. The simulation and lecture groups obtained significantly higher written examination scores than the control group. From the self-evaluation questionnaires, the simulation group reported significantly higher satisfaction in their prior training than the lecture group. No significant differences were found in the emergency department performance of the residents among the three groups. However, when evaluating the improvement rate of performance over time, all three groups showed improvement in the subjective evaluation, and only the simulation and lecture groups showed improvement in the objective evaluation.

CONCLUSION

Simulation-based education combined with PAL is effective in improving the knowledge and satisfaction of medical residents, suggesting the possibility of improving work performance during their emergency department duties.

Analysis of COVID-19 in Japan with extended SEIR model and ensemble Kalman filter

We introduce an extended SEIR infectious disease model with data assimilation for the study of the spread of COVID-19. In this framework, undetected asymptomatic and pre-symptomatic cases are taken into account, and the impact of their uncertain proportion is fully investigated. The standard SEIR model does not consider these populations, while their role in the propagation of the disease is acknowledged. An ensemble Kalman filter is implemented to assimilate reliable observations of three compartments in the model. The system tracks the evolution of the effective reproduction number and estimates the unobservable subpopulations. The analysis is carried out for three main prefectures of Japan and for the entire country of Japan. For these four communities, our estimated effective reproduction numbers are more stable than the corresponding ones estimated by a different method (Toyokeizai). We also perform sensitivity tests for different values of some uncertain medical parameters, like the relative infectivity of symptomatic/asymptomatic cases. The regional analysis results suggest the decreasing efficiency of the states of emergency.

Neurodevelopmental outcome after antenatal therapy for fetal supraventricular tachyarrhythmia: 3-year follow-up of multicenter trial

OBJECTIVES

Although many studies have supported the efficacy of transplacental treatment for fetal supraventricular tachyarrhythmia, the long-term neurodevelopmental outcome after antenatal antiarrhythmic treatment is not well understood. The aim of this study was to investigate the prognosis and neurodevelopmental outcome at 36 months of corrected age and the incidence of tachyarrhythmia after birth, following protocol-defined antenatal therapy for fetal supraventricular tachyarrhythmia.

METHODS

This was a 3-year follow-up study of a multicenter trial that evaluated the efficacy and safety of protocol-defined transplacental treatment for fetal supraventricular tachycardia (SVT) and atrial flutter (AFL). The primary endpoints were mortality and neurodevelopmental impairment (NDI) at 36 months of corrected age. NDI was defined as any of the following outcomes: cerebral palsy, bilateral blindness, bilateral deafness or neurodevelopmental delay. Neurodevelopmental delay was evaluated using appropriate developmental quotient scales, mainly the Kyoto Scale of Psychological Development, or examination by pediatric neurologists. The detection rate of tachyarrhythmia at birth and at 18 and 36 months of corrected age was also evaluated as the secondary endpoint. In addition, the association of NDI at 36 months with perinatal and postnatal factors was analyzed.

RESULTS

Of 50 patients enrolled in the original trial, one withdrew consent and in two there was fetal death, leaving 47 patients available for enrollment in this follow-up study. Of these, 45 cases were available for analysis after two infants were lost to follow-up. The mortality rate was 2.2% (1/45) during a median follow-up of 3.2 (range, 2.1-9.4) years. The infant died at the age of 2.1 years. Another infant had missing neurodevelopmental assessment data. In the remaining 43 infants, at 36 months of corrected age, NDI was detected in 9.3% (4/43) overall and in two of three (66.7%) cases with fetal hydrops with subcutaneous edema. Cerebral palsy was noted in two infants with severe subcutaneous edema or ascites at an early gestational age. Neurodevelopmental delay was found in two infants with severe congenital abnormalities (one with tuberous sclerosis and the other with heterotaxy syndrome). Tachyarrhythmia was present in 31.9% (15/47) cases in the neonatal period and decreased to 8.9% (4/45) and 4.5% (2/44) at 18 and 36 months of corrected age, respectively. The median ventricular rate at diagnosis was significantly higher in infants with NDI compared to those without (265 vs 229 bpm; P = 0.003). In infants with NDI, compared to those without, fetal hydrops with subcutaneous edema at diagnosis was more common (50.0% vs 2.6%; P = 0.019) and the duration of fetal effusion was longer (median, 10.5 vs 0 days; P = 0.013). Postnatal arrhythmia and physical development abnormalities were not associated with NDI.

CONCLUSIONS

This multicenter 3-year follow-up study is the first to demonstrate the long-term mortality and morbidity of infants born following protocol-defined transplacental treatment for fetal SVT and AFL. NDI was associated with the presence of fetal hydrops with subcutaneous edema at diagnosis and longer duration of fetal effusion. Neurodevelopmental delay was detected only in infants with severe congenital abnormalities. Therefore, in infants that have undergone antenatal treatment for fetal tachyarrhythmia and in which there are no comorbidities, the risk of NDI is low. However, in those with fetal hydrops with subcutaneous edema and/or associated severe congenital abnormalities, the risk for long-term neurologic morbidity might be considered somewhat increased. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Effects of Yoga and Mindfulness Programs on Self-Compassion in Medical Professionals during the COVID-19 Pandemic: An Intervention Study

Stress among healthcare workers (HCWs) increased during the coronavirus disease 2019 pandemic. We aimed to determine whether a yoga and mindfulness program could alleviate burnout and other psychological and physical distress in HCWs, and how this might affect their empathy for patients. A weekly one-hour yoga and mindfulness program was conducted for three months in 2021. Participants were 18 consenting HCWs and, the final analysis included 13 participants. They responded to online questionnaires before and after the program. We measured salivary cortisol levels before and after the program on the first and last days. Self-measured pulse rates (PRs) were taken before and after each session, which decreased significantly in both cases (before, after the first program: 72, 65 bpm, p < 0.05; before, after the last program: 75, 66, p < 0.05), but salivary cortisol levels did not change. No significant changes were observed in Patient Health Questionnaire-9, Maslach Burnout Inventory, Sense of Coherence, Connor-Davidson Resilience Scale, Self-compassion Scale, or Jefferson Scale of Empathy. However, common humanity, a subscale of self-compassion, increased significantly (before the first program: 5.6, after the last program: 6.5, p < 0.05), and over-identification decreased significantly (7.9, 6.7, p < 0.01). Yoga and mindfulness programs may help improve the sense of common humanity and reduce over-identification in HCWs.

Prevalence of psychological distress on public health officials amid COVID-19 pandemic

OBJECTIVES

While the coronavirus disease 2019 (COVID-19) pandemic has led to increased burnout among frontline healthcare workers (HCWs), little research has been done regarding the potential psychological burden among public health officials who have worked tirelessly to tackle the pandemic from an administrative perspective. This study aimed to determine the prevalence of burnout, depression, and job-related stress in Japanese public health officers amid the COVID-19 pandemic.

METHODS

We conducted an anonymous, self-administered web-based cross-sectional survey including basic demographics, work-related questions, the Maslach Burnout Inventory, Patient Health Questionnaire-9, Utrecht Work Engagement Scale-3, and Brief Job Stress Questionnaire. 100 public health officers working in the public health centers (PHCs) in Okayama, Japan, answered the survey in December 2021 when the 5th surge in the number of COVID-19 was over.

RESULTS

The prevalence of burnout, depression, and job-related stress was 27%, 43%, and 62%, respectively. The multivariate logistic analysis demonstrated that females, public health nurses, and those who suffered from a lack of support from their workplaces were significantly associated with psychological distress.

CONCLUSIONS

While we tend to focus on mitigation plans to help alleviate burnout of frontline HCWs, more focus is needed to help public health officers, and public health nurses, in particular, to alleviate their psychological distress and job-related stress to prevent further staff shortages and secure sustainable health systems.

Deep-learning image-reconstruction algorithm for dual-energy CT angiography with reduced iodine dose: preliminary results

AIM

To evaluate the computed tomography (CT) attenuation values, background noise, arterial depiction, and image quality in whole-body dual-energy CT angiography (DECTA) at 40 keV with a reduced iodine dose using deep-learning image reconstruction (DLIR) and compare them with hybrid iterative reconstruction (IR).

MATERIAL AND METHODS

Whole-body DECTA with a reduced iodine dose (200 mg iodine/kg) was performed in 22 patients, and DECTA data at 1.25-mm section thickness with 50% overlap were reconstructed at 40 keV using 40% adaptive statistical iterative reconstruction with Veo (hybrid-IR group), and DLIR at medium and high levels (DLIR-M and DLIR-H groups). The CT attenuation values of the thoracic and abdominal aortas and iliac artery and background noise were measured. Arterial depiction and image quality on axial, multiplanar reformatted (MPR), and volume-rendered (VR) images were assessed by two readers. Quantitative and qualitative parameters were compared between the hybrid-IR, DLIR-M, and DLIR-H groups.

RESULTS

The vascular CT attenuation values were almost comparable between the three groups (p=0.013-0.97), but the background noise was significantly lower in the DLIR-H group than in the hybrid-IR and DLIR-M groups (p<0.001). The arterial depictions on axial and MPR images and in almost all arteries on VR images were comparable (p=0.14-1). The image quality of axial, MPR, and VR images was significantly better in the DLIR-H group (p<0.001-0.015).

CONCLUSION

DLIR significantly reduced background noise and improved image quality in DECTA at 40 keV compared with hybrid-IR, while maintaining the arterial depiction in almost all arteries.

Burnout of Healthcare Workers Amid the COVID-19 Pandemic: A Follow-Up Study

The coronavirus disease 2019 (COVID-19) pandemic has posed a significant challenge to the modern healthcare system and led to increased burnout among healthcare workers (HCWs). We previously reported that HCWs who engaged in COVID-19 patient care had a significantly higher prevalence of burnout (50.0%) than those who did not in November 2020 (period 1). We performed follow-up surveys in HCWs in a Japanese national university hospital, including basic demographics, whether a participant engaged in care of COVID-19 patients in the past 2 weeks, and the Maslach Burnout Inventory in February 2021 (period 2) and May 2021 (period 3). Periods 1 and 3 were amid the surges of COVID-19 cases, and period 2 was a post-surge period with a comparatively small number of COVID-19 patients requiring hospitalization. Response rates to the surveys were 33/130 (25.4%) in period 1, 36/130 (27.7%) in period 2, and 56/162 (34.6%) in period 3, respectively. While no consistent tendency in the prevalence of burnout based on variables was observed throughout the periods, the prevalence of burnout tends to be higher in periods 1 and 3 in those who engaged in COVID-19 patient care in the last 2 weeks (50.0%, 30.8%, 43.1% in period 1, 2, and 3, respectively). Given the prolonged pandemic causing stigmatization and hatred against HCWs leading to increased prevalence of burnout, high-level interventions and supports are warranted.

Sacubitril/valsartan ameliorates doxorubicin-induced cardiomyocyte toxicity through inhibiting oxidative stress in rats

Background

Doxorubicin (DOX)-based chemotherapy induces cardiotoxicity, which is considered the main limitation of its clinical application.

Purpose

The present study investigated the potential protective effect of sacubitril/valsartan, an angiotensin receptor–neprilysin inhibitor, against DOX-induced cardiotoxicity in rats and H9c2 cells, and whether the underlying mechanism for any such protection involves its antioxidant activity.

Methods

Male Sprague-Dawley rats were randomly divided into four groups: DOX (1.5 mg/kg/day intraperitoneally for 10 days), DOX+valsartan (31 mg/kg/day by gavage from day 1 to day 18), DOX+sacubitril/valsartan (68 mg/kg/day by gavage from day 1 to day 18), and control (saline intraperitoneally for 10 days). There were 15 rats in each group. At the end of the treatment period, samples were collected and analysed. Cardiac function, tissue morphology, and reactive oxygen species (ROS) were evaluated in rats. Serum levels of Malondialdehyde (MDA) and cardiac troponin T were also measured. Mitochondrial ROS production and cell viability were evaluated in H9c2 cells.

Results

DOX-induced cardiac dysfunction was not prevented by valsartan and sacubitril/valsartan in this model. However, the serum level of cardiac troponin T on day 18 was increased in the DOX group (0.046±0.006 ng/mL, p&lt;0.01 vs. control) and significantly reduced in the DOX+sacubitril/valsartan group (0.039±0.007 ng/mL, p=0.03 vs. DOX), but not in the DOX+valsartan group (0.046±0.005 ng/mL, p=1.00 vs. DOX). Regarding the effect of sacubitril/valsartan on fibrosis in rat myocardium, Masson's trichrome staining showed increased intestinal fibrosis in the DOX group compared to that in the control group (1.35±0.07% and 0.49±0.04%, p&lt;0.01) and significantly decreased intestinal fibrosis in the DOX+sacubitril/valsartan group (1.08±0.08%), but not in the DOX+ valsartan group (1.15±0.05%) compared to that in the DOX group (p=0.01 and p=0.15, respectively). The fluorescence intensity of dihydroethidium as a measure of ROD production in left ventricle, which was increased in the DOX group (1.56±0.07), was significantly reduced in the DOX+sacubitril/valsartan group (1.44±0.05, p=0.03), but not in the DOX+valsartan group (1.29±0.06, p=1.00). On day 11, the serum MDA level, which was increased in the DOX group, was significantly reduced in the DOX+ sacubitril/valsartan group (p=0.02), but not in the DOX+ valsartan group (p=0.75). In H9c2 cells, sacubitril/valsartan reduced DOX-induced mitochondrial ROS generation by 25%, which was more marked than valsartan-induced ROS generation (p&lt;0.01 and p=0.01, respectively). Sacubitril/valsartan improved cell viability more markedly than valsartan. Thus, DOX-induced cytotoxicity in H9c2 cells was improved by sacubitril/valsartan, but not valsartan.

Conclusions

Sacubitril/valsartan protected rat hearts from DOX-induced cardiotoxicity in vivo and in vitro by decreasing oxidative stress.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This work was supported by Novartis Pharma K.K.

Association between adherence to home-based walking exercise with a pedometer and one-year adverse outcomes among lower extremity peripheral artery disease patients with endovascular treatment

Background

Home-based exercise after endovascular treatment (EVT) for lower extremity peripheral artery disease (LE-PAD) patients with intermittent claudication is suggested as an alternative therapy for supervised exercise; however, an association of adherence to home-based exercise with clinical adverse events has not been fully investigated.

Purpose

We aimed to investigate the association of adherence to home-based exercise with 1-year major adverse events (MAE), patency, and leg symptoms after EVT in a contemporary Japanese registry.

Methods

A total of 500 patients with LE-PAD within the Long Term Outcome of Endovascular Therapy for PAD with Intermittent Claudication Observational Prospective Multicenter (ASHIMORI-IC) registry (UMINCTR, UMINehab724.203718753) who underwent EVT between January 2016 and March 2019 were included in the analysis. After EVT, all patients were instructed to do home-based walking exercise with a pedometer. The study population was divided and compared between 2 groups according to adherence to home-based exercise: well-adherence and poor-adherence. The adherence of home-based exercise was as defined by step count derived from a pedometer on sites. The primary outcome was MAE defined as composite of all-cause death, myocardial infarction, stroke, target vessel revascularization, and major amputation of target lower limb for one year. The main secondary outcome was 1-year primary patency of the treated lesion, and the improvement of leg symptom (6-minute walk distance [6MWD] and claudication distance). The study followed the Consensus definitions from peripheral academic research consortium criteria.

Results

Overall, the mean age was 72.8 years, and 78% were men. At 1 year, MAE occurred in 45 patients (9.0%), and the primary patency rate was 85.3% (94.2% of EVT for aortoiliac and 71.9% of EVT for femoropopliteal). A significant difference in the incidence of MAE was observed between the well-adherence group and the poor-adherence group (10 of 233 patients [4.3%] vs. 35 of 267 patients [13.1%]; P&lt;0.001). After multivariate Cox regression analysis, patients in the well-adherence group showed the lower hazard ratio for 1-year MAE (0.30; 95% confidence interval, 0.15–0.58; P&lt;0.001) compared to those in the poor-adherence group. In the well-adherence group, compared with the poor-adherence group, higher primary patency rate (88.9% vs 81.5%; p=0.015), longer claudication onset distance (370 m [IQR 240–453 m] vs 240m [IQR 126–324 m]; P&lt;0.001), and longer 6MWD (422 m [IQR 359–483 m] vs 325 m [IQR 213–400 m]; P&lt;0.001) were observed even after adjusting for each baseline value.

Conclusion

Our study demonstrates the importance of adherence to home-based walking exercise after EVT in LE-PAD patients.

Funding Acknowledgement

Type of funding sources: None.

Cardio-ankle vascular index is useful screening method to detect obstructive coronary artery disease in asymptomatic diabetes patients with subclinical atherosclerosis

Background

Patients with diabetes mellitus are at very high risk for obstructive coronary artery disease; however, invasive coronary angiography is not allowed to apply in all patients. Cardio-ankle vascular index (CAVI), a marker of arterial stiffness has been reported to reflect atherosclerotic burden.

Purpose

To assess the diagnostic performance of CAVI vs. coronary calcium score for detecting obstructive coronary artery disease determined by Coronary CT angiography (CCTA) in asymptomatic diabetes patients.

Methods

During May 2015 to December 2019, 816 patients with diabetes mellitus were evaluated. First, intima-media thickness of carotid artery was measured in all subjects. Then, patients with intima-media thickness over 11mm underwent CAVI. Finally, 209 patients who have one or more cardiovascular risk factors other than diabetes mellitus were enrolled (68±11 years, 68% men). Patients were excluded if they had a disorder of the kidney, a prior history of coronary artery revascularization, atrial fibrillation, LV ejection fraction &lt;50%, ABI &lt;0.9 or allergy to contrast. Diagnostic performance of CAVI was evaluated with coronary stenosis &gt;50% by CCTA.

Results

CAVI, Agatston score, and intima-media thickness of carotid artery were 9.2±1.3, 396±621 and 2.0±0.7mm, respectively. CAVI was significantly correlated with age (r=0.530, p&lt;0.001), coronary artery calcification (r=0.182, p=0.008), and intima-media thickness of carotid artery (r=0.195, p=0.005). Among them, 108 patients (48%) had coronary stenosis. CAVI, Agatston score and intima-media thickness of carotid artery in patients with coronary stenosis were higher than that without coronary stenosis, respectively (9.8±1.1 vs 8.5±1.0, p&lt;0.001, 526±676 vs. 255±525, p=0.001, 2.2±0.7 vs. 1.8±0.6, p&lt;0.001). The ROC curve analysis of CAVI for discriminating coronary stenosis showed that the sensitivity 75.0% and specificity 77.2% at the cut off value of 9.23 (AUC=0.812, p&lt;0.001). Contrastingly, diagnostic performance of coronary calcium score and intima-media thickness of carotid artery were less than CAVI (sensitivity: 91.7%, specificity: 56.4%, AUC=0.753, p&lt;0.05 vs. CAVI, sensitivity: 68.5%, specificity: 59.4%, AUC=0.663, p&lt;0.05 vs. CAVI). Multivariate logistic analysis demonstrated that CAVI was significantly associated with coronary stenosis (OR=4.133, p&lt;0.001) after adjustment of conventional risk factors, although coronary calcium score was not correlated with coronary stenosis.

Conclusion

CAVI could be informative to select patients having obstructive coronary artery disease in asymptomatic diabetes patients with thick intima-media thickness.

Funding Acknowledgement

Type of funding sources: None.

Fragmented qrs as a predictor of cardiac events in patients with cardiac sarcoidosis

Background

Multiple spikes within the QRS complex (fragmented QRS [fQRS]) are associated with occurrences of ventricular arrhythmic events (VAEs) in Brugada syndrome and hypertrophic cardiomyopathy. However, association between fQRS and occurrences of VAEs in cardiac sarcoidosis (CS) has not been elucidated.

Purpose

We investigated the association between fQRS and cardiac events in patients with CS.

Methods

We evaluated the association between existence of fQRS (Figure 1A) and cardiac events including VAEs (non-sustained ventricular tachycardia (NSVT), sustained ventricular tachycardia (VT) and ventricular fibrillation (VF)), hospitalization for heart failure and all cause death in 68 patients with CS for 5 years (30 patients with fQRS vs 38 patients without fQRS).

Results

All cardiac events (NSVT, VT, VF, hospitalization for heart failure and all cause death) occurred in 22 patients with fQRS and 18 patients without fQRS (73% vs 47%; P=0.031). Among cardiac events, occurrences of VAEs (NSVT/VT/VF) in patients with baseline fQRS were higher than those in patients without fQRS (VAEs: 70% vs 45%, P=0.037), whereas there were no significant differences in hospitalization for heart failure and all cause death between patients with and without fQRS (hospitalization for heart failure: 6.7% vs 5.3%, P=0.80 and all cause death: 6.7% vs 5.3%, P=0.80). Kaplan-Meier method also showed significant difference in occurrences of VAEs between with and without fQRS (Log rank: P=0.015) (Figure 1B). Multivariable analysis showed that the existence of fQRS in baseline ECG was associated with VAEs (Hazard ratio [HR]: 2.21, 95% confidence interval [CI]:1.15 to 4.25, P=0.017).

Conclusions

fQRS represents a predictor of VAEs in patients with CS.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Unveiling unconventional magnetism at the surface of Sr2RuO4

Materials with strongly correlated electrons often exhibit interesting physical properties. An example of these materials is the layered oxide perovskite Sr₂RuO₄, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in Sr₂RuO₄ is still ongoing, a deeper understanding of the Sr₂RuO₄ normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in Sr₂RuO₄ in its normal state. We detect static weak dipolar fields yet manifesting at an onset temperature higher than 50 K. We ascribe this unconventional magnetism to orbital loop currents forming at the reconstructed Sr₂RuO₄ surface. Our observations set a reference for the discovery of the same magnetic phase in other materials and unveil an electronic ordering mechanism that can influence electron pairing with broken time reversal symmetry.

Deep-learning-based image reconstruction in dynamic contrast-enhanced abdominal CT: image quality and lesion detection among reconstruction strength levels

AIM

To evaluate the use of deep-learning-based image reconstruction (DLIR) algorithms in dynamic contrast-enhanced computed tomography (CT) of the abdomen, and to compare the image quality and lesion conspicuity among the reconstruction strength levels.

MATERIALS AND METHODS

This prospective study included 59 patients with 373 hepatic lesions who underwent dynamic contrast-enhanced CT of the abdomen. All images were reconstructed using four reconstruction algorithms, including 40% adaptive statistical iterative reconstruction-Veo (ASiR-V) and DLIR at low, medium, and high-strength levels (DLIR-L, DLIR-M, and DLIR-H, respectively). The signal-to-noise ratio (SNR) of the abdominal aorta, portal vein, liver, pancreas, and spleen and the lesion-to-liver contrast-to-noise ratio (CNR) were calculated and compared among the four reconstruction algorithms. The diagnostic acceptability was qualitatively assessed and compared among the four reconstruction algorithms and the conspicuity of hepatic lesions was compared between <5 and ≥5 mm lesions.

RESULTS

The SNR of each anatomical structure (p<0.0001) and CNR (p<0.0001) were significantly higher in DLIR-H than the other reconstruction algorithms. Diagnostic acceptability was significantly better in DLIR-M than the other reconstruction algorithms (p<0.0001). The conspicuity of hepatic lesions was highest when using 40% ASiR-V and tended to lessen as the reconstruction strength level was getting higher in DLIR, especially in <5 mm lesions; however, all hepatic lesions could be detected.

CONCLUSIONS

DLIR improved the SNR, CNR, and image quality compared with 40% ASiR-V, while making it possible to decrease lesion conspicuity using higher reconstruction strength.

Food allergy in nursery children of Kawasaki city, Japan

BACKGROUND

Food allergies are often life threatening. In order to establish appropriate food allergy measures in nursery children, it is important to analyze local epidemiological data on the food allergy prevalence in nursery children. However, no such data are currently available for the city of Kawasaki, Japan.

OBJECTIVE

The present study retrospectively evaluated food allergy prevalence among nursery children in Kawasaki city.

METHODS

Data from children with food allergies requiring food avoidance in the nurseries of Kawasaki city between 2007 and 2016 were evaluated.

RESULTS

From 2007 to 2016, the prevalence of food allergies among nursery children in Kawasaki city increased from 2.7% to 5.3%. The increase of food allergy prevalence was higher in 2-5 year-old children than in 0-1 year-old children (2.0% to 4.7% vs. 5.3% to 7.0%, respectively). The top five most common food allergies were hen's egg (73.0%), cow's milk (29.3%), nuts (9.7%), soy (8.9%), and wheat (6.5%). Hen's egg was consistently identified as a causative food of food allergy in more than 70% (73.0-89.1%) of food avoidance cases over the 10 year period. The increase of egg allergy prevalence was higher in 2-5 year-old children than in 0-1 year-old children (1.7% to 3.2% vs. 5.2% to 6.0%, respectively).

CONCLUSIONS

Food allergies, to hen's egg in particular, have increased considerably among nursery children in the city of Kawasaki, Japan, and that increase was higher among older children.

Feasibility and safety of early initiation of a PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor in patients with acute myocardial infarction undergoing primary PCI

Background

Recent ESC/EAS Guidelines for the management of dyslipidemia stated that the treatment goal of LDL cholesterol (LDL-C) in very high-risk patients is less than 55mg/dl. PCSK9 inhibitors in addition to strong statins could be a useful strategy for rapid and aggressive lowering of LDL-C. However, the feasibility and safety of early initiation of a PCSK9 inhibitor for AMI patients undergoing primary PCI remain unclear.

Objectives

We examined the effects of early initiation of a PCSK9 inhibitor, evolocumab, on lipid profile and inflammatory markers and its safety in AMI patients undergoing primary PCI.

Methods

This study is a single center, randomized, controlled trial involving 102 patients hospitalized for AMI. The patients were randomly assigned 1:1 to the evolocumab group and the control group. Evolocumab (140 mg) was subcutaneously injected within 24 hours after PCI and then every two weeks. All patients received pitavastatin (2mg/day) in addition to the allocated treatment. The primary endpoints were changes in lipid profile and inflammatory markers from baseline to 4 weeks.

Results

102 patients were enrolled between October 2017 and December 2019. 89 patients were ST-segment elevation myocardial infarction (STEMI), 13 patients were non-STEMI. Primary PCI was successfully performed in all patients. 76 patients were statin-naïve. 2 patients were excluded from analyses because they died severe heart failure in acute phase. Finally, 100 patients (evolocumab; n=51 and control; n=49) were analyzed. Baseline LDL-C was 121.6±30.3 mg/dl in the evolocumab group and 124.7±33.6 mg in the control group. Change in LDL-C from the baseline to 4 weeks was −92.4±32.4 mg/dl (−75%) in the evolocumab group and −44.8±32.1 mg/dl (−33.1%) in the control group (mean difference; 47.6mg/dl, 95% CI; 34.8 to 60.4 mg/dl, p&lt;0.001). LDL-C &lt;70mg/dl at 4 weeks was achieved in 96.0% of the evolocumab group as compared with 26.5% of the control group. Further, in the evolocumab group. LDL &lt;55mg/dl was achieved in 92.1% at 2 weeks and 92.1% at 4 weeks. Regarding inflammatory markers, there were no significant difference in change in high-sensitivity C-reactive protein (p=0.49) and tumor necrosis factor-alpha (p=0.63) between two groups even after adjustment of baseline value. No adverse event associated with evolocumab was observed during this study.

Conclusion

In patients with AMI undergoing primary PCI, early initiation of evolocumab rapidly reduced LDL-C without no adverse event, and achieved LDL-C&lt;55mg/dl in most patients within 2 weeks. Early administration of a PCSK9 inhibitor combined with a strong statin could be a feasible and safe treatment for AMI patients undergoing PCI.

Funding Acknowledgement

Type of funding source: None

Cardio-ankle vascular index as an arterial stiffness marker improves on cardiovascular events by adding to framingham risk score

Background

The cardio-ankle vascular index (CAVI) is a non-invasive measurement that evaluates arterial stiffness using the analysis of oscillometric waveform during cuff-Inflation. Several studies reported that CAVI is associated with cardiovascular risk factors, while the clinical prognostic value of CAVI as a surrogate marker of atherosclerosis has not been fully elucidated. Meanwhile, the Framingham risk score (FRS) is an established marker of cardiovascular outcomes.

Purpose

To investigate whether adding CAVI to Framingham risk score improves the prediction of cardiovascular events.

Methods

This prospective observational study included consecutive 422 patients with cardiovascular risk factors but without known coronary artery disease (69±8 years, 63% men). CAVI was measured by the oscillometric method with VaSera vascular screening system. Patients with atrial fibrillation, left ventricular ejection fraction &lt;50%, both ABI&lt;0.9, severe valvular diseases, or hemodialysis were excluded. Primacy outcomes were cardiovascular death, myocardial infarction, stroke, hospitalization for heart failure and revascularization.

Results

During a median follow-up of 3.1 years, cardiovascular events occurred in 12.8% (3.3%, 15.7%, and 19.1% in the low, intermediate and high-risk group of stratification by FRS, respectively). The ROC curve analysis for discriminating cardiovascular events showed that the AUC of CAVI added to Framingham risk score was the highest compared to Framingham risk score and CAVI alone (CAVI added to Framingham risk score: AUC 66.9, 95% CI 59.6–74.2, Framingham risk score alone: AUC 61.5, 95% CI 53.8–69.1, CAVI alone: AUC 62.3, 95% CI 54.1–70.6). The logistic regression analysis demonstrated that CAVI and Framingham risk score were independent predictors of cardiovascular events (CAVI: OR 1.381, 95% CI 1.164–1.597, p=0.004, Framingham risk score: OR 1.135, 95% CI 1.044–1.225, p=0.007). Next, when logistic regression analysis was performed simultaneously on Framingham risk factor and CAVI, CAVI was an independent predictor of cardiovascular events (OR 1.347, 95% CI 1.124–1.569, p=0.009). Furthermore, in the likelihood ratio test, CAVI added to Framingham risk score significantly improved the cardiovascular event prediction ability than Framingham risk factor alone. Next, when patients with intermediate risk (n=217) were divided into two groups based on CAVI of 9.0, the Kaplan-Meier estimate showed that events occurred more frequently in higher CAVI group (9.3% and 29.1%, log-rank, P=0.009) and the C-statistic was 0.662. Multiple Cox analysis showed that, in the intermediate risk group, CAVI was an independent predictor of primary outcomes (HR 1.387 per 1 index, 95% CI 1.081–1.779, p=0.010).

Conclusion

The measurement of CAVI could be a useful predictor for cardiovascular events. In addition, the combination of CAVI and Framingham risk score could improve the predictability compared to the Framingham risk score alone.

Funding Acknowledgement

Type of funding source: None

Triglyceride to HDL-cholesterol ratio is a predictor of future coronary events: a possible role of high-risk coronary plaques detected by coronary CT angiography

Background

For the prevention of future cardiovascular events, control of residual risks such as triglyceride rich lipoproteins and HDL-cholesterol is an emerging problem beyond LDL-cholesterol. Triglyceride to HDL-cholesterol ratio (TG/HDL ratio) has been reported to be useful for risk classification of cardiovascular diseases. Meanwhile, several studies showed that high-risk plaque characteristics evaluated with coronary CT angiography (cCTA) was associated with the incidence of acute coronary syndrome. However, the relationship of TG/HDL ratio with coronary plaque characteristics and its impact of this association on future coronary events have not been fully elucidated.

Purpose

The aim of this study was to evaluate the association between TG/HDL ratio and high-risk plaque detected by cCTA and its impact on future coronary events.

Methods

A total of 944 patients suspected stable coronary artery disease who underwent cCTA at our institution were analyzed (mean 64-year-old, 55% male). Patients were divided into two groups by the median value of TG/HDL ratio (higher TG/HDL: TG/HDL ratio ≥2.0, lower TG/HDL: TG/HDL ratio &lt;2.0). Coronary high-risk plaques were defined as a plaque with all three components; low attenuation plaque (&lt;50H.U.), positive remodeling (remodeling index &gt;1.1) and spotty calcification. Cardiovascular event was defined as cardiovascular death, acute coronary syndrome, and late coronary revascularization after 30 days of CT acquisition.

Results

The higher TG/HDL ratio was significantly associated with male gender (63% vs. 48%, P&lt;0.001), body mass index (24.8±3.8 vs. 22.9±4.0, p&lt;0.001), the prevalence of hypertension (65% vs. 54%, P&lt;0.001), dyslipidemia (60% vs. 42%, P&lt;0.001), diabetes mellitus (38% vs. 27%, P=0.001) and current smoking (26% vs. 10%, p&lt;0.001). Regarding cCTA findings, the prevalence of significant stenosis, calcified plaque, non-calcified plaque, coronary plaques with low attenuation plaque, positive remodeling and spotty calcification in the higher TG/HDL group were greater than those in the lower group (Figure 1A). Of note, the difference in high-risk plaque between two groups was significant. (18% vs. 11%, p=0.004). Multivariate logistic analysis revealed that the TG/HDL ratio was an independent risk factor for high-risk plaque even after adjustment (OR, 1.35; 95% CI, 1.01–1.81; p=0.049). Regarding coronary events (median follow-up duration; 48 months), Kaplan-Meier curve showed poor event-free rate in the higher TG/HDL group (Figure 1B). At Cox proportional hazard analysis, higher TG/HDL ratio (HR, 1.94; 95% CI, 1.01–3.70; p=0.046) and CT-verified high-risk plaque (HR, 2.36; 95% CI, 1.27–4.38; p=0.006) were independent predictive factors for coronary events even after adjustment.

Conclusion

TG/HDL ratio is involved in the vulnerability of CT-verified coronary plaque characteristics. This association may play an important role in the prognostic impact of TG/HDL ratio on future cardiovascular events.

Funding Acknowledgement

Type of funding source: None

Efficacy of early intravenous landiolol, an ultrashort-acting beta-blocker on infarct size and its safety in patients with myocardial infarction undergoing primary PCI: a randomized, controlled study

Background

Previous clinical studies showed that early intravenous metoprolol before reperfusion in patients with ST-elevation myocardial infarction (STEMI) undergoing primary PCI reduced infarct size. However, intravenous beta-blockers in acute phase of STEMI can be associated with adverse effects such as cardiogenic shock and atrioventricular block. Landiolol is an ultrashort-acting beta-blocker with a half-life of 3 min that is eight times more cardioselective than esmolol.

Purpose

We evaluate the efficacy of intravenous infusion of landiolol on infarct size and its safety in STEMI patients undergoing primary PCI.

Methods

This study is a multicenter randomized control trial. A total of 47 patients with Killip class II or less STEMI undergoing PCI within 12 hours of symptoms onset were randomized to receive intravenous landiolol (n=23) or not (control, n=24). Patients allocated to landiolol group delivered an intravenous continuous dose of 3μg/min/kg before reperfusion and then continued until a total dose of 50mg. All patients started oral metoprolol or carvedilol within 12 hours. The primary end point was myocardial salvage index (MSI) on magnetic resonance imaging performed 5 to 7 days after PCI. MSI was defined as the difference between the area at risk and the area of necrosis analyzed using a commercial software.

Results

Magnetic resonance imaging was performed in 35 patients (17 patients in landiolol group and 18 patients in the control group), and ischemia duration time was 229 minutes in the landiolol group and the 242 minutes in control. In adjusting for confounding variables, the areas of myocardium at risk were not difference in both groups (54.4g in the landiolol group, and 46.8g in the control group; p=0.31). However, MSI in the landiolol group was significantly reduced than that in the control group (36.8% and 57.0%; p&lt;0.001).

In both group blood pressure was not difference in recruitment (142mmHg in landiolol group, and 144 in control) and starting PCI (163mmHg in landiolol group, and 165 in control). Regarding safety, the composite of death, malignant ventricular arrhythmia, cardiogenic shock, and atrioventricular block at 24 hours did not differ between the landiolol and the control groups (8.7% and 8.3%, respectively, p=0.93).

Conclusion

Early intravenous landiolol before starting primary PCI reduced infarct size in STEMI patients without significant hemodynamic adverse effects.

Funding Acknowledgement

Type of funding source: None

Pemafibrate protects the rupture of experimental aortic aneurysm in mice through anti-oxidative stress with induced catalase

Background

Abdominal aortic aneurysm (AAA) is a life-threatening disease, while effective and preventive medical treatments remain unestablished.

Purpose

The aim of this study was to evaluate the effect of selective peroxi- some proliferator-activated receptor alpha (PPARα) modulator pemafibrate on AAA formation in mice.

Methods

AAA was induced by subcutaneous infusion of angiotensin II (AngII) in apolipoprotein E-deficient mice for 4 weeks. Treatment by pemafibrate or vehicle was started one week before AngII infusion. Oxidative stress was evaluated by dihydroethidium (DHE) staining.

Results

Prognosis after AngII infusion in pemafibrate-treated mice was significantly better than that in vehicle-treated mice (log-rang test, p=0.035) by reducing the occurrence of fatal AAA rupture. Meanwhile pemafibrate did not significantly reduce maximal diameter of the aorta. Histological findings demonstrated that the expression of collagen in adventitia in pemafibrate-treated mice was significantly greater than that in vehicle-treated mice (p&lt;0.05). Oxidative stress in aorta of pemafibrate-treated mice was significantly reduced comparing to vehicle-treated mice, accompanying by the reduction of mRNA expression of matrix metalloproteinase 2, tumor necrosis factor-α, and interleukin-6 (all p&lt;0.05). Catalase expression in abdominal aortic tissue was increased 1.5-fold in mice treated with pemafibrate than in mice treated with vehicle (p=0.032). In human vascular smooth muscle cells (hVSMC), pemafibrate attenuated AngII-induced oxidative stress (p&lt;0.001), which was canceled by administrating small interfering RNA (siRNA) of PPARα (p&lt;0.001). Furthermore, in hVSMC, pemafibrate increased catalase expression significantly (p&lt;0.001), while this increase was significantly suppressed by knockdown of PPAR-α with siRNA. (p&lt;0.001).

Conclusion

Pemafibrate reduced the rupture of AAA in this murine model, which is associated with anti-oxidative stress via catalase induction.

Funding Acknowledgement

Type of funding source: None

Clinical Relevance of Serum Prolactin Levels to Inflammatory Reaction in Male Patients

To clarify the relevance of prolactin (PRL) to clinical parameters in patients who visited our general medicine department, medical records of 353 patients in whom serum PRL levels were measured during the period from 2016 to 2018 were retrospectively reviewed. Data for 140 patients (M/F: 42/98) were analyzed after excluding patients lacking detailed records and patients taking dopaminergic agents. Median serum PRL levels were significantly lower in males than females: 6.5 ng/ml (IQR: 4.2-10.3) versus 8.1 ng/ml (5.9-12.9), respectively. Pain and general fatigue were the major symptoms at the first visit, and past histories of hypertension and dyslipidemia were frequent. Male patients with relatively high PRL levels (≥ 10 ng/ml) had significantly lower levels of serum albumin and significantly higher levels of serum LDH than those with low PRL (< 10 ng/ml). There were significant correlations of male PRL level with the erythrocyte sedimentation rate (R=0.62), serum LDH level (R=0.39) and serum albumin level (R=-0.52), while the level of serum CRP (R=0.33) showed an insignificant but weak positive correlation with PRL level. Collectively, these results show that PRL levels had gender-specific relevance to various clinical factors, with PRL levels in males being significantly related to inflammatory status.

Antibiotic literacy among Japanese medical students

Antimicrobial resistance (AMR) is an urgent global issue. After the AMR action plan was introduced in 2016, a study on antibiotic literacy (i.e., awareness, knowledge, and attitude relating to antimicrobial use) among clinicians and lay people was conducted in Japan. However, no studies have hitherto targeted medical students who are expected to have a high level of antibiotic literacy. The present study was conducted between September 2019 and February 2020, enrolling undergraduate students at Okayama University Medical School. We collected data using a paper-based questionnaire form with 11 questions about antibiotic literacy. The response rate was 93.8% (661/705 students). Overall, 92.6% of the students knew that antibiotics inhibit the growth of bacteria. Student reporting that antibiotics could treat the common cold accounted for 77.0% (Year 1), 50.9% (Year 2), 48.2% (Year 3), 49.1% (Year 4), 23.8% (Year 5), and 26.2% (Year 6). Only 43 (6.5%) had heard about the AMR action plan. The study data suggested that medical students' level of literacy on antimicrobial use should be further enhanced to address AMR and promote antimicrobial stewardship.

P1766 Comparison of left ventricular stroke volume in healthy adults among regions around the world: results from the World Alliance of Societies of Echocardiography (WASE) Normal Values Study

Funding Acknowledgements

WASE Normal Values Study is sponsored by American Society Echocardiography Foundation.

OnBehalf

the WASE Investigators

Background

The American Society of Echocardiography (ASE) and the European Association of Cardiovascular Imaging (EACVI) chamber quantification guidelines provide normal reference values for a variety of size and function parameters. While used worldwide, these were predominantly obtained from American and European Caucasian populations and may not represent individuals from other regions around the world. Accordingly, ASE in collaboration with its International Alliance Partners conducted the World Alliance of Societies of Echocardiography (WASE) Normal Values Study to establish and compare normal echocardiographic values across races, ethnicities and countries worldwide. While most previous studies focused on left ventricular (LV) size and ejection fraction, LV stroke volume (SV) in healthy normal subjects has not been well defined. In this report, we aim to examine similarities and differences in normal LV SV indexed by body surface area (SVI) among regions around the world.

Methods

WASE Normal Values Study is a multinational, observational, cross-sectional study. Individuals free from known cardiac, lung and renal disease were prospectively enrolled with even distribution among age groups and gender. Echocardiographic images were acquired following a standardized protocol. LV SV was assessed by Doppler-derived (LVOT diameter and VTI) and two-dimensional (2D) biplane Simpson’s methods. LV SVI was calculated to account for differences in body size. These measurements were analyzed (TOMTEC) in a single core laboratory following ASE/EACVI Guidelines.

Results

As of May 2019, LV SV has been analyzed in 1164 cases from 13 countries, representing 8 distinct regions worldwide. In this population, age, body surface area and 2D LV ejection fraction were 47 ± 17 years old (range 18-87 years old), 1.76 ± 0.22 m² (range 0.95-2.44 m²) and 63.2 ± 2.9 % (range 52.7-73.7 %), respectively. LV SV and SVI by Doppler were larger than those obtained by 2D method in all regions. LV SV and SVI in both methods had significant differences among regions (p&lt; 0.0001, Kruskal-Wallis test). LV SV and SVI in South Asia (India) were smallest in both methods and were also significantly smaller than other Asian regions (Figure). North America and Europe had largest LV SV and SVI by Doppler method, while Oceania had largest values by 2D.

Conclusions

The WASE Normal Values Study shows geographical variability in LV SVI across continents and countries. This information should be considered when determining normative values for SV and SVI.

Abstract P1766 Figure.

104 Left ventricular stroke volume differences among echocardiographic methods in healthy adults from the World Alliance of Societies of Echocardiography (WASE) Normal Values Study

Funding Acknowledgements

WASE Normal Values Study is sponsored by American Society Echocardiography Foundation.

OnBehalf

the WASE Investigators

Background

Left ventricular (LV) stroke volume (SV) can be determined by multiple ultrasound methods, including Doppler, two- (2D) and three-dimensional (3D) echocardiography. However, how methods compare to each other is not well understood. In this report from the WASE study, we aim to examine and compare normal reference ranges for SV and SV index (SVI) obtained from healthy adults by Doppler, 2D Simpson’s and 3D methods.

Methods

WASE Normal Values Study is a multinational, observational, cross-sectional study. Individuals free from known cardiac, lung and renal disease were prospectively enrolled with even distribution among age groups and gender. Doppler, 2D and 3D datasets were acquired at the enrolling centers, following a standardized protocol. LV SV was measured by three methods: Doppler (LV outflow tract diameter and velocity time integral), 2D biplane Simpson’s rule and 3D volume method. SV was indexed by body surface area (SVI). All measurements were analyzed (TOMTEC) in two core laboratories (for 2D and 3D) following ASE Guidelines. Methods were compared by Friedman test and Bland-Altman analysis.

Results

As of May 2019, 646 cases have been analyzed in both 2D and 3D datasets. In this population, age was 45 ± 16 years old (range 18-85) and body surface area was 1.76 ± 0.22 m² (range 0.95-2.44). LV EF by 2D Simpson’s rule and 3D method were 63.2 ± 2.9 and 62.3 ± 5.0 %, respectively (p &lt; 0.0001, Wilcoxon test). SVI by Doppler, 2D and 3D were 39.6 ± 7.6, 33.8 ± 6.5 and 41.0 ± 9.4 ml/m², respectively. There were significant differences between the three methods (p &lt; 0.0001, Friedman test). 2D underestimated SVI compared to Doppler by 14.6% (mean of differences 5.8 ml/m², p &lt; 0.0001) and 3D by 17.6% (7.2 ml/m², p &lt; 0.001). The difference between Doppler and 3D was smaller (3.4% lower by Doppler) but still statistically significant (1.4 ml/m², p = 0.0008). The results are shown in the figure.

Conclusions

Comparing 3 modalities in a large population of healthy individuals, SV and SVI are underestimated by 2D Simpson’s method. Given the large differences, combining 2D and Doppler or 3D measurements for hemodynamic calculations (such as regurgitant volumes and fraction) should be done with caution.

Abstract 104 Figure.

Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction

Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e^{'}pω, at central Q^{2} values of 1.60, 2.45  GeV^{2}, at W=2.21  GeV. The results of our pioneering -u≈-u_{min} study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^{2}=2.45  GeV^{2}, the observed dominance of σ_{T} over σ_{L}, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.

P2238Prognostic value and incremental benefit of ischaemic myocardial burden subtended by non-invasive CT-derived fractional flow reserve (FFRCT) significant stenoses

Background

Fractional flow reserve derived from CT-coronary angiography (FFRCT) accurately identifies ischaemic vessels which may be associated with clinical outcomes. Its predictive value in grey zone FFRCT values between 0.7–0.8 is not defined. The technique permits estimation of burden of ischaemic myocardium subtended by FFRCT significant vessels.

Purpose

To evaluate the prognostic value and incremental benefit of FFRCT defined ischaemic myocardial burden when compared to FFRCT alone.

Methods

This is a subanalysis of NXT (Analysis of Coronary Blood-Flow Using CTA:Next-Steps), a prospective study of stable coronary artery disease (CAD) patients referred for invasive angiography (ICA) undergoing invasive FFR, CTA and FFRCT in whom treating physicians had been blinded to FFRCT results. Primary endpoint, defined as a composite of non-fatal myocardial infarction and any revascularisation, was determined in 206 patients (age 64±9.5 years, 64% male) and 618 vessels. Burden of ischaemic myocardium was defined as percentage of myocardium subtended beyond the point at which a vessel's FFRCT becomes ≤0.8 as estimated by APPROACH score (FFRCT-APPROACH). In significant FFRCT vessels, the predictive value and incremental benefit of FFRCT-APPROACH was compared with significant FFRCT (≤0.8) for primary endpoint as measured by area under the receiver operator characteristic curve (AUC). Significant ischaemic myocardial burden was defined as >10%. The incidence and relationship between the primary endpoint with each 10% increase in FFRCT-APPROACH and 0.05-unit decrease in FFRCT values ≤0.8 was determined.

Results

Significant FFRCT was identified in 52.9% of patients (109/206) and 29.3% of vessels (181/618). At 4.7 years median follow-up the incidence of the primary endpoint in vessels with significant FFRCT-APPROACH was 58.9% (96/163) which was comparable with vessels with significant FFRCT (55.2%,100/181; P=0.50). The predictive value of FFRCT-APPROACH for the primary endpoint was comparable with FFRCT (AUC 0.72 [95% CI 0.65–0.79] vs 0.71 [0.63–0.78], P=0.79). When combined, there was significant predictive improvement compared with FFRCT alone (AUC 0.77 [0.70–0.84]; P=0.01). The largest incremental benefit upon FFRCT was observed in vessels with FFRCT values in the grey zone between 0.70–0.80 (AUC 0.76 [0.65–0.86] vs 0.62 [0.48–0.74]; P<0.01). Each 10% increase in FFRCT-APPROACH (Adjusted-HR 1.36; 95% CI 1.16–1.60; P<0.001) and each 0.05-unit FFRCT decrease (Adjusted-HR 1.42; 1.19–1.70; P<0.001) were independently associated with significant increase in the incidence of the primary-endpoint.

Conclusion

In patients with stable CAD referred for ICA, the burden of ischaemic myocardium subtended by FFRCT significant vessels predicted non-fatal myocardial infarction and future revascularisation. This provided significant incremental benefit when used in combination with FFRCT particularly at FFRCT values in the grey zone between 0.7 to 0.8.

1407Drug effect of luseogliflozin and voglibose on heart failure with preserved ejection fraction in diabetic patients: a multicenter randomized-controlled trial

Background

Recent randomized, placebo-controlled trial in patients with type 2 diabetes demonstrated that the sodium-glucose cotransporter 2 inhibitors reduced mortality, cardiovascular events and hospitalization for heart failure. However, those trials were not specialized design to investigate the effect of sodium-glucose cotransporter 2 inhibitors in patients with heart failure, in particular with heart failure with preserved ejection fraction.

Purpose

The aim of this study was to evaluate the drug efficacy of luseogliflozin, a sodium-glucose cotransporter 2 inhibitor, compared with voglibose, an alpha-glucosidase inhibitor, using brain natriuretic peptide (BNP) in type 2 diabetes patients with heart failure with preserved ejection fraction.

Methods

This study was a prospective, multicenter, open-label, randomized-controlled trial, comparing luseogliflozin 2.5 mg once daily or voglibose 0.2 mg three times daily in patients with type 2 diabetes suffering from heart failure with preserved ejection fraction (left ventricular ejection fraction >45% and BNP ≥35 pg/ml2) in a 1:1 randomization fashion. Randomization was undertaken using a computer-generated random sequence web response system. The primary outcome was the difference from baseline in BNP after 12 weeks of treatment between two drugs. The key secondary outcomes were the change from baseline in left ventricular ejection fraction and E/e' in echocardiographic parameters, body weight, glycohemoglobin level after 12 weeks of treatment. The safety outcomes included the incidence of major adverse cardiovascular events, hypoglycemic adverse events, and urinary tract infection.

Results

Between December 2015 and September 2018, 173 patients from 16 hospitals and clinics have been included in this study. Of those, 83 patients were assigned to receive luseogliflozin and 82 to receive voglibose. There was no significant difference in the reduction in the BNP concentration after 12 weeks from baseline between the two groups; the ratio of the average values at week 12 to the baseline value was 0.91 in the luseoglifllzin group as compared with 0.98 in the voglibose group (percent change, −9.0% vs. −1.9%, ratio of change with luseogliflozin vs. voglibose, 0.93; 95% confidence interval, 0.78 to 1.10; p=0.26). The key secondary outcomes including left ventricular ejection fraction, E/e', body weight, glycohemoglobin level and the safety outcomes did not differ significantly between the two groups.

Conclusions

In type 2 diabetes patients with heart failure with preserved ejection fraction, the administration of luseogliflozin did not lead to a significant reduction in the BNP concentration than that of voglibose. Left ventricular ejection fraction, E/e', body weight and glycohemoglobin level after 12 weeks of treatment, comparing with at baseline did not differ significantly between the two groups. (UMIN Clinical Trial Registry number, UMINehz748.005618395)

Acknowledgement/Funding

Novartis

P5305Oxidized high-density lipoprotein is associated with progression of coronary artery calcification

Introduction

As a residual cardiovascular risk, high-density lipoprotein (HDL) is of great interest in lipid management. Native HDL has an anti-atherogenic role, while oxidized HDL (oxHDL) has atherogenic property because of reduced anti-inflammatory properties compared with native HDL. Meanwhile, recent studies showed that rapid progression of coronary artery calcification (CAC), a marker of subclinical atherosclerosis, was associated with greater incidence of cardiovascular events. However, the role of oxHDL in the pathogenesis of CAC remains unclear.

Purpose

The purpose of this study was to examine the association between the annual change in oxHDL and the progression of CAC (Agatston score) in a substudy of prospective multicenter randomized study.

Methods

In the principal study, patients with a CAC score of 1 to 999 were treated with pitavastatin with/without eicosapentaenoic acid. Measurement of CAC with MDCT and a blood test were performed at baseline and at the 1-year follow-up. The principal study showed 30–40% of annual change in CAC in all patients and no difference in the progression of CAC among treatment groups. In this substudy (n=140), patients were divided into 2 groups: CAC progression (change in Agatston score of >0, n=103) and no CAC progression (n=37). The serum concentration of oxHDL was measured using an antibody against oxidized human apoA-I with ELISA. The difference in oxHDL between patients with hypercholesterolemia and healthy subjects (n=30) was also evaluated.

Results

OxHDL levels were significantly lower in healthy subjects than in patients with hypercholesterolemia (150 [107–176] and 167 [132–246], respectively; median [25th-75th percentile], U/ml) (p=0.006). The baseline log-transformed oxHDL level was correlated with total cholesterol (r=0.21, p=0.01), HDL-cholesterol (r=0.33, p<0.01), and triglycerides (r=−0.21, p=0.01), but not correlated with age, body mass index, hemoglobinA1c, LDL-cholesterol, serum creatinine, or high-sensitivity C-reactive protein. After treatment, the oxHDL level significantly decreased from 167 (132–246) at baseline to 122 (103–149) (median [25th–75th percentile], U/ml) (p<0.001). The annual change in CAC was significantly positively associated with changes in oxHDL (r=0.17, p=0.04), triglycerides (r=0.17, p=0.04), and hsCRP (r=0.22, p=0.01) but not associated with changes in LDL-C or HDL-C. Multiple logistic analysis demonstrated that the decrease in oxHDL per 10 U/ml was independently associated with CAC progression after adjusting for variables including baseline oxHDL, LDL-cholesterol, Agatston score and current smoking (odds ratio, 0.95; 95% confidence interval, 0.90–0.99; p=0.04).

Conclusion

The decrease in oxHDL is associated with the attenuation of CAC progression, suggesting that oxHDL is a potential target for preventing atherosclerosis.

P692Chemoradiation therapy to patients with lung cancer exacerbates thoracic aortic calcification

Introduction

Development of chemoradiation therapy (CRT) has improved mortality in patients with cancer. Whereas, it is emerging problem that cancer-survivors suffer from cardiovascular diseases, and the association between modern CRT and the increase in future cardiovascular events is suggested. Meanwhile, previous studies showed that thoracic aortic calcification (TAC) detected by computed tomography (CT), a marker of atherosclerosis, was associated with all-cause mortality and cardiovascular events. However, the influence of CRT on TAC progression remains unclear.

Purpose

The purpose of this study was to evaluate whether CRT would exacerbate TAC.

Methods

A total of 68 patients who treated lung cancer at our hospital between 2011 and 2015 were retrospectively analyzed (mean 62 year-old, male 78%): 35 patients underwent surgical treatment after induction CRT (CRT group) and 33 patients underwent surgical treatment alone (control group), extracted by propensity score matching by age, sex, smoking status, and diseased side. The volume of TAC between 2nd and 12th thoracic vertebrae was quantitatively measured with CT imaging, at baseline and at 1 year follow-up. The annual percent change in TAC was compared between the CRT and the control group. Moreover, the independent relationship between implementation of CRT and the progression of TAC was assessed by multivariate logistic regression analysis, adjusting for age, gender, conventional atherosclerotic risk factors and baseline aortic calcification volume.

Results

Patients in the CRT group received radiation (mean 47.3±4.0 Gy) and chemotherapy: 2 courses of cisplatin with docetaxel (34 cases) or vinorelbine (1 case). The prevalence of dyslipidemia, taking statins and diabetes drugs were significantly higher in the control groups (17% vs. 39%; p=0.041, 11% vs. 33%; p=0.029, 3% vs. 18%; p=0.044, respectively). Baseline C-reactive protein level was significantly higher in the CRT group (0.255 vs. 0.115; p=0.034). In univariate analysis, the annual percent change in TAC volume was significantly increased in the CRT group compared with the control group (37.6% vs. 23.3%; p=0.006). Multivariate logistic regression analysis demonstrated that CRT was an independent factor associated with the progression of TAC volume, even after adjustment for baseline calcification volume and coronary risk factors (OR, 3.90; 95% CI, 1.32–11.47; p=0.014).

Conclusion

CRT to patients with lung cancer exacerbates thoracic aortic calcification, which may result in future cardiovascular events.

Energy consumption in a baffled membrane bioreactor (B-MBR): estimation based on long-term continuous operation

We investigated the operating conditions of a baffled membrane bioreactor (B-MBR) under which long-term stable operation can be achieved through the continuous operation of a pilot-scale B-MBR. Under appropriate operating conditions, the B-MBR was capable of achieving excellent treated water quality in terms of biochemical oxygen demand and concentration of total nitrogen. Excellent removal of total phosphorus was also achieved. In addition, the degree of membrane fouling was acceptable, indicating that stable continuous operation of a B-MBR is possible under the operating conditions adopted in the present study. Estimation of the specific energy consumption in hypothetical full-scale B-MBRs operated under the conditions recommended by the findings was also performed in this study. The results suggest that energy consumption in full-scale B-MBRs would be in the range of 0.20-0.22 kWh/m³. These results strongly suggest that energy consumption in MBR operation can be significantly reduced by applying the concept of a B-MBR.

Clinical and biochemical characteristics of patients having general symptoms with increased serum IgG4

Objective: To differentiate patients with IgG4-related diseases (RD) from patients with other hyper IgG4 conditions who visit general medicine department.Methods: Fifty-six patients with high serum IgG4 levels (>135 mg/dL) were classified into three groups based on the final diagnosis: definite and possible IgG4-RD and others. Clinical and laboratory characteristics of the three groups of patients were retrospectively analyzed.Results: Major manifestations were renal dysfunction and general malaise, while thirst was the most frequent symptom in the definite group, in which submandibular glands and lymph nodes were likely to be affected. Biopsy of minor salivary glands was the least diagnostic for IgG4-RD despite the high frequency of biopsy. In the definite group, serum levels of IgG4 and IgG, IgG4/IgG ratio and basophil number were increased, while serum levels of CRP, IgA and complements were decreased. A negative correlation between serum levels of IgG4 and IgM was found in the definite group.Conclusion: The results indicated that in patients with renal dysfunction, malaise, thirst or weight loss, measurements of the levels of basophils, immunoglobulins and complements are helpful for diagnosing IgG4-RD. Considering distribution of affected tissues and localization of diagnostic biopsies, physical examination and laboratory workup are required for early diagnosis.

Factors related to burnout in resident physicians in Japan

OBJECTIVES

We explore the prevalence and characteristics of burnout among Japanese resident physicians and identifies factors associated with burnout.

METHODS

A cross-sectional study was conducted three times between April 2017 and March 2018 at a Japanese teaching hospital. Resident physicians were invited to answer an online survey that included existing valid instruments related to burnout, depression, and empathy. Demographic, background, occupational, and socioeconomic data were also collected. Participants were prompted to report the average daily work hours and the specialty they wish to pursue.

RESULTS

Overall, 39/76 (51%), 27/76 (36%), and 21/76 (28%) resident physicians responded to surveys in April 2017, October 2017, and March 2018, respectively. The percentages of participants with burnout for surveys in April 2017, October 2017, and March 2018 were 7/39 (18%), 6/27 (22%), and 7/21 (33.3%). Emotional exhaustion (EE) was the only burnout component strongly correlated with the severity of depression (r = .615, p < .001; r = .706, p < .001; r = .601, p < .01). EE and depersonalization (DP) had no significant correlation with average daily working hours (β = .156, p = .343 for EE; β = .061, p = .711 for DP).

CONCLUSIONS

The results suggest that capping working hours alone may not be effective in reducing burnout in Japanese resident physicians. Medical educators might need to consider not only working hours but also individual job quality and satisfaction to address burnout. Future studies may need to incorporate qualitative methods to explore the characteristics of burnout.

SAT-LB068 Involvement of Serum Dehydroepiandrosterone Sulfate in Male Erythropoietic Activity

Dehydroepiandrosterone (DHEA) is a steroid hormone produced in the adrenal cortex. It is synthesized from pregnenolone and further metabolized to androstenedione, testosterone, and estrogen. DHEA and its sulfated ester (DHEAS) are the most abundant circulating steroids in humans. DHEAS is converted to DHEA in a linear manner. Since its serum concentration is 300-500 times higher than that of DHEA, DHEAS serves as a circulating reservoir for DHEA. DHEAS secretion increases during adrenarche, peaks between the ages of 15-25 years, and decreases steadily with age thereafter. This age-related decline in DHEAS secretion is termed adrenopause and is presumably the result of the normal aging processes.DHEAS has recently attracted widespread attention because of its anti-aging effects. However, since studies of the physiological effects of DHEAS in specific organ systems are limited, it is unclear how DHEAS contributes to anti-aging. DHEAS may also extend lifespan: several prospective population-based studies associate low DHEAS levels with high mortality rates, especially in elderly men. Toward the goal of determining a mechanistic basis for these actions of DHEAS, we assessed the relationships between serum DHEAS levels and various patient characteristics. The aim of the present study was to determine how age-related decreases in serum DHEAS levels affect various physiological processes.We retrospectively reviewed the medical records of patients in whom serum DHEAS levels were measured in our department, and assessed the relationships between serum DHEAS levels and various patient characteristics. Among the 149 patients included in our analysis (mean age: 52.7±17.6 years, range: 15-84 years), 54 (36.2%) were men. Serum DHEAS levels inversely correlated with age in men (R = -0.810, p < 0.01) and to a lesser extent in women (R = -0.391, p < 0.01). In women, age better correlated with DHEAS/ACTH ratios (R = -0.444, p < 0.01) than DHEAS levels. Of note, there was a significant positive association between DHEAS levels and hemoglobin (R = 0.419, p < 0.01) and hematocrit (R = 0.375, p < 0.01) levels in men but not women.Collectively, our data indicate that reduced DHEAS secretion inhibits erythropoietic activity in aging men, possibly owing to the erythropoietic androgenic actions of DHEAS. Importantly, these findings suggest that the age-associated decline in DHEAS secretion might decrease erythropoietic activity in aging men. It is also possible that the adrenal cortex, the source of DHEAS, is dysfunctional in anemic men. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

Effects on postgraduate-year-I residents of simulation-based learning compared to traditional lecture-style education led by postgraduate-year-II residents: a pilot study

BACKGROUND

Simulation-based learning plays an important role in contemporary medical education, although there are problems providing tutors. Peer-assisted learning has begun being formally adopted in medical education. Although it is considered useful for simulation-based learning, its effectiveness remains unclear. This study was designed to compare the effect of simulation-based learning with that of traditional lectures conducted by postgraduate-year (PGY)-II residents on PGY-I residents.

METHODS

This study was conducted at Okayama University Hospital over three years, for one week each year, before residents entered clinical practice. The study enrolled 76 PGY-I residents, who were randomized into two groups: simulation and lecture groups. PGY-II residents volunteered to conduct simulations and lectures. Knowledge evaluation was performed using pre- and post-tests, and self-evaluation of competence and behaviour-change and program evaluations were conducted using questionnaires.

RESULTS

In both groups, knowledge test scores were found to improve significantly, and the score difference between pre- and post-tests in both the groups was not significant. Self-evaluation of competence and behaviour-change was found to be higher in the simulation group than the lecture group. The trainees in the simulation group valued the program and the PGY-II residents as teaching staff more than those in the lecture group.

CONCLUSIONS

The combination of simulation-based learning and peer-assisted learning led by PGY-II residents is potentially more effective in improving the postgraduate education of PGY-I residents than the combination of lecture and peer-assisted learning.

Plasma natriuretic peptide levels in fetuses with congenital heart defect and/or arrhythmia

OBJECTIVE

Diagnosing fetal heart failure remains challenging because it is difficult to know how well the fetal myocardium will perform as loading conditions change. In adult cardiology, natriuretic peptides (NPs) are established markers of heart failure. However, the number of studies investigating NP levels in fetuses is quite limited. The aim of this study was to evaluate the significance of plasma NP levels in the assessment of heart failure in fetuses with a congenital heart defect (CHD) and/or arrhythmia.

METHODS

This was a prospective observational study conducted at a tertiary pediatric cardiac center. A total of 129 singletons with CHD and/or arrhythmia and 127 controls were analyzed between 2012 and 2015. Umbilical cord plasma atrial NP, brain NP and N-terminal pro-brain NP levels at birth were compared with ultrasonography findings indicating fetal heart failure, such as cardiovascular profile (CVP) score and morphological characteristics.

RESULTS

Fetuses with CHD and/or arrhythmia had higher NP levels than did controls (P < 0.01). NP levels of fetuses with CHD and/or arrhythmia were correlated inversely with CVP score (P for trend < 0.01). No differences in NP levels were found in fetuses with CHD and/or arrhythmia and a CVP score of ≥ 8 in comparison to controls. Multivariate analysis showed that a CVP score of ≤ 5, tachy- or bradyarrhythmia at birth, preterm birth and umbilical artery pH < 7.15 were associated independently with high NP levels (P < 0.01). Among fetuses with a CVP score of ≤ 7, abnormal venous Doppler sonography findings were significantly more common and more severe in fetuses with tachy- or bradyarrhythmia than in those with CHD, and those with tachy- or bradyarrhythmia had higher NP levels than did those with CHD (P = 0.01). Fetuses with right-heart defect and moderate or severe tricuspid valve regurgitation had significantly higher NP levels than did fetuses with other types of CHD (P < 0.01).

CONCLUSIONS

Plasma NP levels in fetuses with CHD and/or arrhythmia are correlated with the severity of fetal heart failure. Elevated NP levels are attributed mainly to an increase in central venous pressure secondary to arrhythmia or atrioventricular valve regurgitation due to CHD, rather than to the morphological abnormality itself. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

EVALUATION OF PATIENT EXPOSURE IN FAST kVp SWITCHING DUAL ENERGY COMPUTED TOMOGRAPHY: PHANTOM STUDY

The aim of this study was to evaluate the suitability of size specific dose estimates (SSDE) to estimate patient dose in Fast kVp switching dual energy CT. An anthropomorphic phantom (RAN-110) was repeatedly scanned (chest, abdomen and the pelvis) using a 64 detector row MDCT (Discovery CT750 HD, GE Healthcare, Milwaukee, WI, USA) with various CT parameters, including Fast kVp switching. Dosimetry was performed using thermo-luminescent dosimeters, positioned both superficially and within the phantom. SSDE was calculated for all slices of the anthropomorphic phantom using both the localiser and axial images. In Fast kVp switching, SSDE underestimated the measured absorbed dose for the chest/abdomen region ~35% at the maximum, but were in closer agreement for the pelvic region about within 10%. In single energy techniques, SSDE could not be applied in the estimation of organ doses, but in Fast kVp switching dual energy techniques, SSDE could be applied for anatomical regions with larger thicknesses.

Effects of recirculation and separation times on nitrogen removal in baffled membrane bioreactor (B-MBR)

In this study, we investigated the effects of recirculation and separation times on removals of organic matter, nitrogen, and phosphorus in a baffled membrane bioreactor (B-MBR) treating real municipal wastewater. A pilot-scale B-MBR experimental apparatus was operated under two different sets of recirculation and separation times. The results revealed that, irrespective of operating conditions, the biochemical oxygen demand (BOD) and concentration of total nitrogen (T-N) in the treated water can be lowered to less than 3 and 5 mg/L, respectively. Although T-N was effectively removed in the two different operating conditions, increase in the fraction of recirculation time results in tiny deterioration of nitrogen removal efficiency in the B-MBR. Phosphorus removal efficiency was also slightly decreased as the fraction of recirculation time (ratio between recirculation and separation times) was increased. The results of the measurement of dissolved oxygen (DO) profiles at different points of the B-MBR apparatus indicate that the increase in DO concentration in the anoxic zone of the B-MBR becomes much more pronounced by increasing recirculation intensity. On the basis of the results obtained in this study, it can be concluded that efficient removal of BOD, T-N, and total phosphorus can be achieved by the B-MBR as long as appropriate recirculation intensity is selected.