Filmy Cloud Removal on Satellite Imagery with Multispectral Conditional Generative Adversarial Nets

In this paper, we propose a method for cloud removal from visible light RGB satellite images by extending the conditional Generative Adversarial Networks (cGANs) from RGB images to multispectral images. Satellite images have been widely utilized for various purposes, such as natural environment monitoring (pollution, forest or rivers), transportation improvement and prompt emergency response to disasters. However, the obscurity caused by clouds makes it unstable to monitor the situation on the ground with the visible light camera. Images captured by a longer wavelength are introduced to reduce the effects of clouds. Synthetic Aperture Radar (SAR) is such an example that improves visibility even the clouds exist. On the other hand, the spatial resolution decreases as the wavelength increases. Furthermore, the images captured by long wavelengths differs considerably from those captured by visible light in terms of their appearance. Therefore, we propose a network that can remove clouds and generate visible light images from the multispectral images taken as inputs. This is achieved by extending the input channels of cGANs to be compatible with multispectral images. The networks are trained to output images that are close to the ground truth using the images synthesized with clouds over the ground truth as inputs. In the available dataset, the proportion of images of the forest or the sea is very high, which will introduce bias in the training dataset if uniformly sampled from the original dataset. Thus, we utilize the t-Distributed Stochastic Neighbor Embedding (t-SNE) to improve the problem of bias in the training dataset. Finally, we confirm the feasibility of the proposed network on the dataset of four bands images, which include three visible light bands and one near-infrared (NIR) band

Characteristics of Advanced Colorectal Cancer Detected by Fecal Immunochemical Test Screening in Participants with a Negative Result the Previous Year

Background: There is sufficient evidence to show the mortality reduction effect of colorectal cancer (CRC) screening programs using the fecal occult blood test (FOBT). However, we see cases that are found to be advanced CRC despite yearly FOBT screening. Methods: The aim of this study was to investigate the characteristics of advanced CRC detected by a fecal immunochemical test (FIT) screening program in participants with a negative screening result the previous year, which we call “Negative advanced CRC”. A total of 109,639 participants (10.0% required colonoscopy, of whom 76.9% received one) underwent a CRC screening program using a FIT from fiscal 2009 to 2017. Negative advanced CRC was compared with advanced CRC (First advanced CRC) found at the first visit in a person who had not had a FIT screening history for more than 3 years. In addition, we compared the characteristics of Negative advanced CRC with those of interval cancer: cancer cases detected after a negative screening result and before the date of the next recommended screening. Results: A total of 339 cases of CRC (175 male: 164 female, 173 early stage: 166 advanced stage) were detected in the nine-year CRC screening period. The rate of right-sided CRCs was significantly higher in female (P < 0.01), advanced stage (P < 0.01), negative result previous year (P < 0.01), and symptom-negative (P < 0.01) participants than in each counterpart, respectively. The ratio of female (22/35; 62.9%) patients in Negative advanced CRCs tended to be high compared with that (40/83; 48.2%) in First advanced CRCs (P = 0.145). Overall, 22 (62.9%) of 35 Negative advanced CRCs and 28 (33.7%) of 83 First advanced CRCs were located in the right-sided colon, and the rate was significantly higher in Negative advanced CRCs (P < 0.01). In addition, the frequency of female patients was significantly higher in right-sided Negative advanced CRCs than in right-sided First advanced CRCs (P = 0.03). Conclusion: The characteristics of Negative advanced CRC cases (female and right-sided colon) were similar to those of interval cancer reported so far. In the future, it will be necessary to introduce a screening program that is highly sensitive to right-sided CRC

ミスマッチ修復遺伝子発現欠損を伴う子宮体癌のMRI所見と臨床像

Purpose: The purpose of this study was to identify the magnetic resonance imaging (MRI) features of uterine endometrial carcinoma (EC) with DNA mismatch repair (MMR) deficiency. Materials and methods: This was a retrospective study approved by our institutional review board. The study included 118 patients pathologically diagnosed as having EC in our institution from April 2014 to December 2016. Of 118 patients, 8 were excluded because of insufficient data. Immunohistochemical analysis of MMR was performed retrospectively to observe the expressions of MLH1, MSH2, MSH6, and PMS2. A tumor with MMR deficiency was detected in 17 of 110 cases (15%). Clinical background characteristics and MRI findings were reviewed. These findings were compared between MMR deficiency group and the other group as a control group. Statistical significance was determined using the Fisher's exact test and the Mann-Whitney U test, as appropriate. Results: The clinical background characteristics of patients with EC with MMR deficiency were not significantly different from those of other patients. On MRI, the tumor was significantly more often located in the lower uterine site (MMR(-) vs. MMR(+): 29.4 vs. 8.9% [p = 0.0366]). Conclusion: EC with MMR deficiency tends to be located lower in the uterus, though most other findings were not significantly different from those of EC without MMR deficiency.博士（医学）・甲第749号・令和2年6月30日© Japan Radiological Society 2018© 2018 Springer Nature Switzerland AG. Part of Springer Nature.This is a post-peer-review, pre-copyedit version of an article published in Japanese journal of radiology. The final authenticated version is available online at: http://doi.org/10.1007/s11604-018-0741-4