Fusion-Extracted Features by Deep Networks for Improved COVID-19 Classification with Chest X-ray Radiography.

Convolutional neural networks (CNNs) have shown promise in accurately diagnosing coronavirus disease 2019 (COVID-19) and bacterial pneumonia using chest X-ray images. However, determining the optimal feature extraction approach is challenging. This study investigates the use of fusion-extracted features by deep networks to improve the accuracy of COVID-19 and bacterial pneumonia classification with chest X-ray radiography. A Fusion CNN method was developed using five different deep learning models after transferred learning to extract image features (Fusion CNN). The combined features were used to build a support vector machine (SVM) classifier with a RBF kernel. The performance of the model was evaluated using accuracy, Kappa values, recall rate, and precision scores. The Fusion CNN model achieved an accuracy and Kappa value of 0.994 and 0.991, with precision scores for normal, COVID-19, and bacterial groups of 0.991, 0.998, and 0.994, respectively. The results indicate that the Fusion CNN models with the SVM classifier provided reliable and accurate classification performance, with Kappa values no less than 0.990. Using a Fusion CNN approach could be a possible solution to enhance accuracy further. Therefore, the study demonstrates the potential of deep learning and fusion-extracted features for accurate COVID-19 and bacterial pneumonia classification with chest X-ray radiography.

The Association between Smoking Exposure and Reflux Esophagitis: A Cross-sectional Study among Men Conducted as a Part of Health Screening.

Objective Gastroesophageal reflux disease (GERD), including reflux esophagitis (RE), is recognized as a common gastrointestinal disease, and its prevalence is reported to be increasing. While current cigarette smoking has been established as a risk factor for RE in several cross-sectional studies, most of these studies did not include details concerning the smoking status in their analyses. Smoking-related conditions, such as chronic lung disease and cough, are reportedly also related to GERD. Methods To investigate the association between RE and detailed smoking habits, we performed a cross-sectional analysis of healthy men enrolled in a comprehensive health checkup program conducted in 2015 that included esophago-gastro-duodenoscopy. Smoking status was assessed using a self-reported questionnaire. Other smoking-related parameters, including the lung function, cough symptoms and presence of chronic lung disease, were also assessed. Unconditional logistic regression was applied to calculate the odds ratio (OR) with 95% confidence intervals (CIs) after adjusting for confounding factors. Results The study included 151 subjects with RE (RE group) and 814 without RE (control group). Compared with never-smokers, former smokers (OR, 1.5; 95% CI, 0.9-2.9) and current smokers (OR, 2.4; 95% CI, 1.5-3.9) showed an increased risk of RE. An increased risk of RE was also observed among subjects with current smoking for 10-20 PYs and more than 20 PYs (OR, 2.8; 95% CI, 1.4-5.8, OR, 3.1; 95% CI, 1.6-5.7 respectively). An elevated risk was observed in former smokers who reported more than 20 PYs (OR, 2.5; 95% CI, 1.3-4.8). When former smokers were stratified according to time since smoking cessation, a significant RE risk was observed in participants who had stopped smoking less than 10 years earlier compared with never smokers (OR, 1.9; 95% CI, 1.1-3.3). No significant associations were observed between chronic cough, FEV1.0%, and RE. Conclusion Cumulative lifetime exposure to smoking plays an important role in the risk of RE.

Impact of arm position on vertebral bone marrow proton density fat fraction in chemical-shift-encoded magnetic resonance imaging: a preliminary study.

Arm positions employed during magnetic resonance imaging (MRI) can affect magnetic field distribution, which may result in variability in proton density fat fraction (PDFF) measurements. This study evaluated the effect of arm position on lumbar PDFF measured using chemical-shift-encoded MRI (CSE-MRI). Fifteen healthy volunteers from a single-center underwent lumbar CSE-MRI at two different arm positions (side and elevated) using a single 3T scanner. Scans were performed twice in each position. PDFFs of the L1-L5 vertebrae were independently measured by two readers, and reader measurements were compared by calculating intraclass correlation coefficients (ICC). We compared PDFF measurements from two arm positions and from two consecutive scans using the Wilcoxon test and Bland-Altman analysis. Measurements from the two readers were in high agreement [ICC =0.999; 95% confidence interval (CI), 0.998-0.999]. No significant difference was observed between PDFFs from the first and second scans of all vertebrae for each reader (all P>0.05); however, PDFF for the elevated arm position was significantly higher than that for the side arm position (37.9-44.8% vs. 37.0-43.8%; all P<0.05), except at the L2 level by reader 2. The mean differences in PDFF measurements from the first and second scans [0.1%; 95% limits of agreement (LoA), -1.8% to 1.9%] and from the side arm and elevated arm positions (0.8%; 95% LoA, -1.6% to 3.2%) were small. In conclusion, these preliminary data suggest that different arm positions during CSE-MRI can slightly affect lumbar PDFF; however, the mean absolute differences were very small.

Mixed Reality Visualization of Radiation Dose for Health Professionals and Patients in Interventional Radiology.

For interventional radiology, dose management has persisted as a crucially important issue to reduce radiation exposure to patients and medical staff. This study designed a real-time dose visualization system for interventional radiology designed with mixed reality technology and Monte Carlo simulation. An earlier report described a Monte-Carlo-based estimation system, which simulates a patient's skin dose and air dose distributions, adopted for our system. We also developed a system of acquiring fluoroscopic conditions to input them into the Monte Carlo system. Then we combined the Monte Carlo system with a wearable device for three-dimensional holographic visualization. The estimated doses were transferred sequentially to the device. The patient's dose distribution was then projected on the patient body. The visualization system also has a mechanism to detect one's position in a room to estimate the user's exposure dose to detect and display the exposure level. Qualitative tests were conducted to evaluate the workload and usability of our mixed reality system. An end-to-end system test was performed using a human phantom. The acquisition system accurately recognized conditions that were necessary for real-time dose estimation. The dose hologram represents the patient dose. The user dose was changed correctly, depending on conditions and positions. The perceived overall workload score (33.50) was lower than the scores reported in the literature for medical tasks (50.60) for computer activities (54.00). Mixed reality dose visualization is expected to improve exposure dose management for patients and health professionals by exhibiting the invisible radiation exposure in real space.

Calculating and estimating second cancer risk from breast radiotherapy using Monte Carlo code with internal body scatter for each out-of-field organ.

Out-of-field organs are not commonly designated as dose calculation targets during radiation therapy treatment planning, but they might entail risks of second cancer. Risk components include specific internal body scatter, which is a dominant source of out-of-field doses, and head leakage, which can be reduced by external shielding. Our simulation study quantifies out-of-field organ doses and estimates second cancer risks attributable to internal body scatter in whole-breast radiotherapy (WBRT) with or without additional regional nodal radiotherapy (RNRT), respectively, for right and left breast cancer using Monte Carlo code PHITS. Simulations were conducted using a complete whole-body female model. Second cancer risk was estimated using the calculated doses with a concept of excess absolute risk. Simulation results revealed marked differences between WBRT alone and WBRT plus RNRT in out-of-field organ doses. The ratios of mean doses between them were as large as 3.5-8.0 for the head and neck region and about 1.5-6.6 for the lower abdominal region. Potentially, most out-of-field organs had excess absolute risks of less than 1 per 10,000 persons-year. Our study surveyed the respective contributions of internal body scatter to out-of-field organ doses and second cancer risks in breast radiotherapy on this intact female model.

Immersive Radiation Experience for Interventional Radiology with Virtual Reality Radiation Dose Visualization Using Fast Monte Carlo Dose Estimation.

For interventional radiology (IR), understanding the precise dose distribution is crucial to reduce the risks of radiation dermatitis to patients and staff. Visualization of dose distribution is expected to support radiation safety efforts immensely. This report presents techniques for perceiving the dose distribution using virtual reality (VR) technology and for estimating the air dose distribution accurately using Monte Carlo simulation for VR dose visualization. We adopted an earlier reported Monte-Carlo-based estimation system for IR and simulated the dose in a geometrical area resembling an IR room with fluoroscopic conditions. Users of our VR system experienced a simulated air dose distribution in the IR room while the irradiation angle, irradiation timing, and lead shielding were controlled. The estimated air dose was evaluated through comparison with measurements taken using a radiophotoluminescence glass dosimeter. Our dose estimation results were consistent with dosimeter readings, showing a 13.5% average mutual difference. The estimated air dose was visualized in VR: users could view a virtual IR room and walk around in it. Using our VR system, users experienced dose distribution changes dynamically with C-arm rotation. Qualitative tests were conducted to evaluate the workload and usability of our VR system. The perceived overall workload score (18.00) was lower than the scores reported in the literature for medical tasks (50.60) and computer activities (54.00). This VR visualization is expected to open new horizons for understanding dose distributions intuitively, thereby aiding the avoidance of radiation injury.

Association between alcohol consumption and mammographic density: a hospital-based cross-sectional study.

BACKGROUND: Mammographic density (MD), the proportion of radiological dense breast, has been reported to be a strong risk factor for breast cancer in many studies. Epidemiological evidence indicates that alcohol consumption increases the risk of breast cancer. In Western countries, a positive association between alcohol consumption and MD has been reported. METHODS: To investigate the effect of alcohol consumption on MD, we conducted a cross-sectional analysis of healthy women enrolled in a breast cancer screening program at the Ebina Health Service Center, Japan, in 2012, comprising 477 premenopausal women and 308 postmenopausal women. Alcohol consumption was assessed using a self-report questionnaire. Unconditional logistic regression was applied to calculate the odds ratio (OR) and 95% confidence intervals (CI) while adjusting for confounders. RESULTS: The study included 497 women with high breast density (HD group) and 288 women with low breast density (LD group). In all women, multivariate analysis revealed that the OR for HD was significantly increased among women with the highest alcohol intake (≥ 140 g/week of ethanol) compared with abstainers (OR 2.1, 95% CI 1.2-3.9 p = 0.01). The linear trend with increasing alcohol consumption was statistically significant (p = 0.009). CONCLUSION: MD was positively associated with alcohol consumption in Japanese women.

Influence of Gd-EOB-DTPA on T1 dependence of the proton density fat fraction using magnetic resonance spectroscopy.

This phantom study assessed the effect of Gd-EOB-DTPA on T1 bias (difference in T1 between water and fat) of the proton density fat fraction when using magnetic resonance spectroscopy. Phantoms containing varying fat percentages, without and with Gd-EOB-DTPA (precontrast and postcontrast, respectively), were scanned with repetition times ranging from 1000 to 5000 ms. The relationship between the proton density fat fraction at a reference repetition time of 5000 ms and that using different repetition times, was evaluated in the precontrast and postcontrast phantoms using linear regression and Bland-Altman analyses. In the precontrast phantom, as the repetition time increased, the slope tended to approach one. In the postcontrast phantom, the slope and intercept were near one and zero, respectively. The mean difference was smaller in the postcontrast phantom (range - 0.24 to - 0.01%) than in the precontrast phantom (range 0.12 to 3.52%). We conclude that I1 bias is minimized by Gd-EOB-DTPA.

Correction to: Influence of Gd-EOB-DTPA on proton density fat fraction using the six-echo Dixon method in 3 Tesla magnetic resonance imaging.

A diameter of glass bottles in phantoms in the above article (2 cm) was incorrect. The correct diameter is 4.5 cm.

Influence of Gd-EOB-DTPA on proton density fat fraction using the six-echo Dixon method in 3 Tesla magnetic resonance imaging.

The purpose of this study was to evaluate whether disodium gadoxetate (Gd-EOB-DTPA) affects proton density fat fractions (PDFFs) during use of the multiecho Dixon (meDixon) method in phantom and simulation magnetic resonance imaging (MRI) studies at 3 T. Fat-water phantoms comprising vegetable fat-water emulsions with varying fat volume percentages (0, 5, 10, 15, 20, 30, 40, and 50) and Gd-EOB-DTPA concentrations (0 and 0.4 mM) were prepared. Phantoms without Gd-EOB-DTPA were defined as precontrast, and those with Gd-EOB-DTPA were defined as postcontrast. All phantoms were scanned with a 3 T MRI system using the meDixon method, and precontrast and postcontrast PDFFs were calculated. Simulated pre and postcontrast PDFFs in the liver were calculated using a theoretical formula. The relationship between PDFFs measured in the pre and postcontrast phantoms was evaluated using linear regression and Bland-Altman analysis. The regression analysis comparing the pre and postcontrast PDFFs yielded a slope of 0.77 (P < 0.001). The PDFFs on the postcontrast phantom were smaller than those on the precontrast phantom. The mean difference between the PDFFs on the pre and postcontrast phantoms was 6.12% (95% confidence interval 3.13 to 9.10%; limits of agreement -0.88 to 13.11%). The simulated PDFF on the postcontrast phantom was smaller than that on the precontrast phantom. We demonstrated that the PDFF measured using the meDixon was smaller on postcontrast than on precontrast at 3 T, if a low flip angle was used. This tendency was also seen in the simulation study results.

[A case of recurrence of breast cancer 36 years after mastectomy treated with endocrine and chemotherapy].

In 2001, a 72-year-old woman, who had undergone left mastectomy for breast carcinoma 36 years ago, was admitted because of dysphagia. Chest CT showed pleural effusion in the right side and no tumor in the breast. Chest drainage was performed. Cytology of chest effusion revealed adenocarcinoma. A high serum CA15-3 level was noted. She was diagnosed with a pleural recurrence of breast cancer, so administration of CAF agents (4 courses) was started. Pleural effusion was improved and the serum CA15-3 level was reduced. She was then clinically followed on medication with oral anastrozole (AI). After 4 years, progression of disease was noted. The serum CA15-3 level was elevated. A tumor measuring 3 cm was confirmed on the right chest wall. The tumor was removed under local anesthesia and pathological findings showed invasive ductal carcinoma expressing estrogen receptor. Chemotherapy with taxane had to be withdrawn because of its side effect. Administration of S-1 was then started. The serum CA15-3 level was gradually elevated. Thereafter, the regimen was switched to combined S-1 and toremifene citrate. The serum CA15-3 level was reduced and sustained for several months. However, she died of multiple organ metastasis in 2008.

[Chemotherapy-naïve advanced malignant fibrohistiocytoma presenting IVC syndrome case report].

The case was a 77-year-old male with swelling of his right leg. Physical examination revealed an ill-defined mass at RLQ. Computed tomography (CT) and 3 dimensional CT showed an 8-cm tumor on the IVC, partially replacing iliac vessels and invading the psoas muscle. A diagnosis of malignant fibrohistiocytoma was made by pathological examination of biopsied specimens at exploratory laparotomy. Five courses of combination chemotherapy of ifosfamide (IFM) and doxorubicin (DXR) resulted in PR. Edema of the lower leg and hydronephrosis were both alleviated. Another 5 courses of chemotherapy with epirubicin and IFM were added. PR lasted 2 years, though the patient succumbed to the disease in 2 years and 8 months.

[A case of small cell carcinoma of the esophagus with SIADH].

The patient was a 63-year-old male admitted for further evaluation of the bleeding esophageal tumor. Endoscopic biopsy revealed small cell carcinoma. CT scan of the abdomen demonstrated nodular enlargement at the celiac axis. Under diagnosis of small cell carcinoma of the esophagus at Stage IVa, neoadjuvant chemotherapy with FP (5-FU+CDDP) was given. Immediately after fluid load, levels of serum sodium decreased to 117 mEq/L and persisted during chemotherapy treatment despite aggressive corrections. Response and shrinkage of the distant nodal metastases were confirmed, and an esophagectomy was conducted. Pathological examination with IHC demonstrated positive staining for CD56, NSE and synaptophysin but negative for ADH. Lymph node and liver metastases recurred. Progression of the disease again triggered hyponatremia.

Prognostic value of extracapsular invasion and fibrotic focus in single lymph node metastasis of gastric cancer.

BACKGROUND: Histological findings of metastatic lymph nodes are important prognosticators in patients with gastric cancer. The aim of this study was to clarify the clinical significance of various pathological characteristics of the early phase of lymph node metastasis in patients with gastric cancer, by selecting patients with tumors that had single lymph node metastases, no serosal invasion, and no metastases to the peritoneum, liver, or distant organs. METHODS: Seventy-eight patients were eligible and were entered in this study. These patients were subdivided according to the following histological characteristics of the one metastatic lymph node: size of the metastasis (i.e., amount of tumor cells [AT]), proliferating pattern (PP), intranodal location (IL), and the presence or absence of extracapsular invasion (ECI) and/or fibrotic focus (FF). Associations between clinicopathological factors, survival, and the nodal findings were examined. RESULTS: There were no correlations between AT or PP and any clinicopathological factors. IL was significantly correlated with venous invasion and the pathological characteristics of the primary tumor. ECI and FF were observed significantly more frequently in pT2 than in pT1 cancer. Overall survival (OS) differed significantly according to depth of invasion, venous invasion, and the presence or absence of ECI or FF, although OS was not affected by AT, PP, or IL. The 10-year overall survival rates of patients with and without ECI were 50% and 80%, respectively, while these rates for patients with and without FF were 50% and 79%, respectively. Multivariate analysis revealed that ECI and FF were significant prognosticators of survival. CONCLUSION: These results strongly suggested that the presence of ECI or FF could affect the survival of patients with gastric cancer.

[Clinical efficacy of image processing of grid detection and suppression (GDS) in computed radiography].

In projection radiography, stationary grids are indispensable accessories to the improvement of diagnostic imaging. On the other hand, they are becoming one of the issues facing digital image processing. The lead foil that composes the grid can produce moiré on printed films and monitors according to the sampling interval at which the image is read by computed radiography (CR), creating a major obstacle to diagnosing images. The subject of this study on Grid Detection and Suppression (GDS) was the development of comprehensive image-processing software to detect and suppress grid lines automatically. Our results showed that applying GDS parameters 3 approximately 5 could provide a sufficient effect on suppression with little impact on images through the use of a multi-purpose grid (grid ratio 8:1, density 34 lp/cm) for general purposes. In projection radiography, it is expected that soft copy diagnosis will increase because the digital transition is proceeding, and the establishment of high-speed networks is becoming easier. Therefore, the digital environment is expected to improve and the choice of grids and monitors to expand, by using software such as GDS that does not require special skills.

Inhibition of peritoneal metastasis in an animal gastric cancer model by interferon-gamma and interleukin-2.

BACKGROUND: The anti-tumor activity of interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) have been shown in human gastric cancer cell lines, however, their therapeutic effects on peritoneal metastasis have not been investigated. MATERIALS AND METHODS: The anti-tumor activity of IFN-gamma and IL-2 against the gastric cancer cell line, MKN45, was evaluated by in vitro antiproliferation assays and in animal-tumor models of intraperitoneal (i.p.) and subcutaneous (s.c.) tumors. RESULTS: Survival of the animals with i.p. tumor was longest in those given IFN-gamma, followed by those given IL-2, IL-2 + IFN-gamma and saline (control) with median survival of 88 +/- 27 days, 73 +/- 30 days, 53 +/- 20 days and 32 +/- 1.1 days, respectively (p < 0.001 vs control). In animals with s.c. tumor, IFN-gamma significantly inhibited tumor growth as compared with the control. In vitro, IFN-gamma alone inhibited the growth of MKN45 and induced apoptosis, while IL-2 had no additional effect. CONCLUSION: IFN-gamma inhibited the growth of gastric cancer cells in vitro and in a peritoneal tumor model. The therapeutic effects were partially antagonized by IL-2.

An anti-apoptosis gene, survivin and telomerase expression in gastric cancer.

BACKGROUND/AIMS: Survivin is frequently expressed in various malignancies as an inhibitor of programmed cell death, while telomerase is associated with cell immortality and consequent accumulation of a malignant genetic property. We surmised that an activation of telomerase in combination with an inhibition of apoptosis might further accelerate growth of malignant tumors. To test this hypothesis, we investigated the expression of survivin and telomerase in stomach cancer. METHODOLOGY: Twenty-five consecutive patients who underwent gastrectomy for stomach cancer were studied including 13 patients at stage 4, 7 of whom had peritoneal metastasis. The expression of survivin and telomerase in the tumors were studied by a reverse transcriptase-polymerase chain reaction. RESULTS: Survivin mRNA was detected in 16 (64%) out of 25 tumors and telomerase mRNA in 24 (96%) of them. Survivin expression was inversely associated with the depth of tumor and peritoneal metastasis, while histology, lymph node metastasis, stage, and telomerase expression were not associated. DNA fragmentation was observed in 8 out of 15 tumors including 4 of 9 survivin positive tumors and 4 of 6 survivin negative tumors (n.s.). CONCLUSIONS: Survivin was not likely to be related with an inhibition of apoptosis or induction of telomerase but may have some role in gastric cancer extension.

[Trial manufacture of subsidiary tool and use of technique for shoulder joint of "Scapula Y"].

The technique of "Scapula Y " is effective for capturing forward/backward dislocation of the humeral head and variation in surgical spine fracture. It is also indispensable for describing images of ossification at the tendon plate of the lower lobe of the acrominon and impingement syndrome. However, owing to large individual variations in body shape and position and shape of the scapula, the conventional method does not lend itself to stable reproduction of position or provide adequate diagnostic information. We measured the central angle of entry from scapula m24 pairs of dried bone (Indian) into the spine of the scapula from horizontal and forehead planes to determine the range of variation together with the clinical data referred to in the next paragraph. We then manufactured a trial subsidiary tool to set the angle of the central entering beam base on the acrominon to the spine of the scapula using data on measured angle from 50 clinical radiographs. We identified improvement in radiography of the scapula by using the subsidiary tool designed and manufactured on the basis of the above measured data.