- 著者
- Hiroyuki MORISAKA Utaroh MOTOSUGI Tomoaki ICHIKAWA Katsuhiro SANO Shintaro ICHIKAWA Tsutomu ARAKI Nobuyuki ENOMOTO
- 出版者
- Japanese Society for Magnetic Resonance in Medicine
- 雑誌
- Magnetic Resonance in Medical Sciences (ISSN:13473182)
- 巻号頁・発行日
- vol.12, no.2, pp.77-86, 2013 (Released:2013-06-25)
- 参考文献数
- 36
- 被引用文献数
- 17 17
Objectives: We evaluated flow parameters measured by phase-contrast magnetic resonance (MR) imaging (PC-MRI) of the portal venous system and liver stiffness measured by MR elastography (MRE) to determine the usefulness of these methods in predicting gastroesophageal varices (GEV) in patients with chronic liver disease (CLD). Methods: In patients with CLD and controls, we performed PC-MRI on the portal (PV) and superior mesenteric veins; calculated mean velocity (V, cm/s), cross-sectional area (S, mm2), and flow volume (Q, mL/min); and determined markers of liver fibrosis (liver stiffness [kPa]) and aspartate aminotransferase (AST) platelet ratio index [APRI]). We visually assessed GEV and development of collateral pathways of the PV on routine contrast-enhanced dynamic MR imaging and compared patient characteristics, flow parameters, liver stiffness markers, and visual analysis among 3GEV groups, those with mild, severe, or no GEV with reference to endoscopic findings. Results: Child-Pugh grade, VPV, SPV, liver stiffness, APRI, and visually identified GEV (visible GEV) differed significantly among the 3 groups (P<0.05). We investigated VPV, SPV, liver stiffness, and visible GEV as independent markers to distinguish patients with and without GEV and examined VPV and visible GEV to predict severe GEV. Visible GEV showed low sensitivity (14 to 30%) and high specificity (98%) for predicting GEV in patients with CLD. A subgroup analysis that excluded cases with collateral pathway demonstrated slightly improved diagnostic performance of VPV and liver stiffness. Conclusions: Portal vein flow parameters and liver stiffness can be useful markers for predicting GEV in patients with CLD.
- 著者
- Akihiko Wada Yuya Saito Shohei Fujita Ryusuke Irie Toshiaki Akashi Katsuhiro Sano Shinpei Kato Yutaka Ikenouchi Akifumi Hagiwara Kanako Sato Nobuo Tomizawa Yayoi Hayakawa Junko Kikuta Koji Kamagata Michimasa Suzuki Masaaki Hori Atsushi Nakanishi Shigeki Aoki
- 出版者
- Japanese Society for Magnetic Resonance in Medicine
- 雑誌
- Magnetic Resonance in Medical Sciences (ISSN:13473182)
- 巻号頁・発行日
- pp.mp.2021-0068, (Released:2021-12-10)
- 参考文献数
- 32
- 被引用文献数
- 5
Purpose: Myelination-related MR signal changes in white matter are helpful for assessing normal development in infants and children. A rule-based myelination evaluation workflow regarding signal changes on T1-weighted images (T1WIs) and T2-weighted images (T2WIs) has been widely used in radiology. This study aimed to simulate a rule-based workflow using a stacked deep learning model and evaluate age estimation accuracy.Methods: The age estimation system involved two stacked neural networks: a target network-to extract five myelination-related images from the whole brain, and an age estimation network from extracted T1- and T2WIs separately. A dataset was constructed from 119 children aged below 2 years with two MRI systems. A four-fold cross-validation method was adopted. The correlation coefficient (CC), mean absolute error (MAE), and root mean squared error (RMSE) of the corrected chronological age of full-term birth, as well as the mean difference and the upper and lower limits of 95% agreement, were measured. Generalization performance was assessed using datasets acquired from different MR images. Age estimation was performed in Sturge–Weber syndrome (SWS) cases.Results: There was a strong correlation between estimated age and corrected chronological age (MAE: 0.98 months; RMSE: 1.27 months; and CC: 0.99). The mean difference and standard deviation (SD) were −0.15 and 1.26, respectively, and the upper and lower limits of 95% agreement were 2.33 and −2.63 months. Regarding generalization performance, the performance values on the external dataset were MAE of 1.85 months, RMSE of 2.59 months, and CC of 0.93. Among 13 SWS cases, 7 exceeded the limits of 95% agreement, and a proportional bias of age estimation based on myelination acceleration was exhibited below 12 months of age (P = 0.03).Conclusion: Stacked deep learning models automated the rule-based workflow in radiology and achieved highly accurate age estimation in infants and children up to 2 years of age.
- 著者
- GEN SUWA YONAS BEYENE HIDEO NAKAYA RAYMOND L. BERNOR JEAN-RENAUD BOISSERIE FAYSAL BIBI STANLEY H. AMBROSE KATSUHIRO SANO SHIGEHIRO KATOH BERHANE ASFAW
- 出版者
- 日本人類学会
- 雑誌
- Anthropological Science (ISSN:09187960)
- 巻号頁・発行日
- pp.150206, (Released:2015-04-14)
- 被引用文献数
- 4 26
The vertebrate fossil localities of the Chorora Formation, Ethiopia, comprise one of only a few sub-Saharan African paleontological research areas that illuminate Late Miocene African mammalian and primate evolution. Field work at Chorora since 2007 has resulted in the establishment of new vertebrate fossil localities and a revised chronostratigraphic framework. The new Chorora Formation fossils include the earliest known records of Cercopithecinae, Hippopotaminae, and Leporidae in Africa. Two lineages of hipparionins are recognized at Chorora, a larger and smaller morph, forming potential phyletic links between the earlier Samburu Hills hipparionins and later Eurygnathohippus turkanensis and E. feibeli from Lothagam, Kenya. The Chorora colobines are larger than the >9 Ma Microcolobus and morphologically conservative with only moderate molar cusp notches. The Chorora cercopithecines represent the earliest documented occurrence of the subfamily.