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Dive into the research topics where Ayumi Ohya is active.

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Featured researches published by Ayumi Ohya.


European Journal of Radiology | 2014

Usefulness of free-breathing readout-segmented echo-planar imaging (RESOLVE) for detection of malignant liver tumors: Comparison with single-shot echo-planar imaging (SS-EPI)

Hirokazu Tokoro; Yasunari Fujinaga; Ayumi Ohya; Kazuhiko Ueda; Aya Shiobara; Yoshihiro Kitou; Hitoshi Ueda; Masumi Kadoya

PURPOSE We aimed to clarify the usefulness of free-breathing readout-segmented echo-planar imaging (RESOLVE), which is multi-shot echo-planar imaging based on a 2D-navigator-based reacquisition technique, for detecting malignant liver tumor. MATERIALS AND METHODS In 77 patients with malignant liver tumors, free-breathing RESOLVE and respiratory-triggered single-shot echo-planar imaging (SS-EPI) at 3-T MR unit were performed. We set a scan time up to approximately 5 min (300s) before examination, measured actual scan time and assessed (1) susceptibility and (2) motion artifacts in the right and left liver lobes (3, no artifact; 1, marked), and (3) detectability of malignant liver tumors (3, good; 1, poor) using a 3-point scale. RESULTS The median actual scan time of RESOLVE/SS-EPI was 365/423s. The median scores of each factor in RESOLVE/SS-EPI were as following in this order: (1) 3/2 (right lobe); 3/3 (left lobe), (2) 2/3 (right lobe); 1/2 (left lobe), and (3) 3/3, respectively. Significant differences were noted between RESOLVE and SS-EPI in all evaluated factors (P<0.05) except for susceptibility of left lobe and detectability of the lesions. CONCLUSION Despite the effect of motion artifacts, RESOLVE provides a comparable detectability of the lesion and the advantage of reducing scanning time compared with SS-EPI.


Pancreas | 2013

Periductal induction of high endothelial venule-like vessels in type 1 autoimmune pancreatitis.

Masafumi Maruyama; Motohiro Kobayashi; Yasuhiro Sakai; Nobuyoshi Hiraoka; Ayumi Ohya; Shunsuke Kageyama; Eiji Tanaka; Jun Nakayama; Toshio Morohoshi

Objectives Type 1 autoimmune pancreatitis (AIP) is histologically characterized by dense lymphoplasmacytic infiltration and marked storiform fibrosis, manifestations associated with pancreatic ducts. Such periductal lymphocyte recruitment is thought to be elicited by dysregulation of mechanisms governing physiological lymphocyte homing. The present study was undertaken to determine whether vascular addressins including peripheral lymph node addressin and mucosal addressin cell adhesion molecule 1 (MAdCAM-1) play a role in type 1 AIP histogenesis. Methods Tissue sections of type 1 AIP and tumor-associated non-AIP chronic pancreatitis, as well as normal pancreas, were subjected to immunohistochemical analysis using vascular addressin-related antibodies. Results The number of periductal mouse endothelial cell antigen 79–positive high endothelial venule (HEV)-like vessels was increased in type 1 AIP relative to that seen in non-AIP chronic pancreatitis, whereas the number of MAdCAM-1–positive HEV-like vessels did not differ between the 2 conditions. Mouse endothelial cell antigen 79 antigens are expressed on duct-forming epithelial cells not only in pancreas but also in salivary glands, which often harbor extrapancreatic lesions in type 1 AIP. Conclusions Type 1 AIP can be characterized by periductal induction of MECA-79–positive HEV-like vessels. MECA-79–positive 6-sulfo sialyl Lewis X-related carbohydrate antigens expressed on duct-forming epithelial cells could be associated with type 1 AIP pathogenesis.


Gynecologic and Obstetric Investigation | 2013

Placental Mesenchymal Dysplasia: Chronological Observation of Placental Images during Gestation and Review of the Literature

Satoshi Ohira; Nao Ookubo; Kyoko Tanaka; Akiko Takatsu; Hisanori Kobara; Norihiko Kikuchi; Ayumi Ohya; Makoto Kanai; Tanri Shiozawa

Placental mesenchymal dysplasia (PMD) is characterized by multiple hypoechoic vesicles which are similar to molar changes in the placenta; however, the process of such morphological changes of PMD during pregnancy has not been fully understood. We performed a review of all PMD cases published in English and identified 49 articles including 110 cases. With regard to the gestational age at which the multicystic pattern was seen, approximately 70% of cases were diagnosed at 13-20 weeks of gestation. Another characteristic feature of PMD is varicose dilation of fetal chorionic vessels. As many as 90% of cases were diagnosed as placenta with dilated fetal chorionic vessels in the third trimester. We also report a case of PMD which was found at 10 weeks of gestation according to ultrasonic molar patterns. Serial observations of the placenta using ultrasound and magnetic resonance imaging revealed that multicystic lesions became smaller after 23 weeks. In contrast, dilated placental vessels on the fetal side became apparent at 38 weeks. The present review highlights that placental vesicular lesions of PMD may precede dilation of fetal chorionic vessels during pregnancy. It also indicates the potential of a gradual reduction in size of PMDs placental vesicular lesions by serial study of placental images.


Japanese Journal of Radiology | 2011

Effect of hepatobiliary uptake of Gd-EOB-DTPA on the hepatic venous phase of dynamic magnetic resonance imaging on a 3.0-T apparatus: comparison between Gd-EOB-DTPA and Gd-DTPA.

Yasunari Fujinaga; Ayumi Ohya; Tsuyoshi Matsushita; Masahiro Kurozumi; Kazuhiko Ueda; Yoshihiro Kitou; Hitoshi Ueda; Masumi Kadoya

PurposeWe aimed to reveal the difference in contrast enhancement of the abdominal organs and major vessels on dynamic contrast-enhanced magnetic resonance imaging (DCM-MRI) using gadoxetic sodium (Gd-EOB-DTPA) and gadopentetate dimeglumine (Gd-DTPA) in the same patients.Materials and methodsDCM-MRI using Gd-EOBDTPA and Gd-DTPA were performed in the same 17 patients. Precontrast and DCM-MRI images [arterial phase (AP), portal venous phase (PP), hepatic venous phase (HP)] were acquired before and after bolus injection of each contrast agent. The organ-to-muscle ratio [liver (L/M), spleen (S/M), aorta (A/M), portal vein (P/M), hepatic vein (V/M)] were calculated at each phase and analyzed statistically.ResultsThere was no significant difference between Gd-EOB-DTPA and Gd-DTPA images regarding the L/M or V/M mean on precontrast images or the mean of L/M at AP and L/M at the PP. At the AP, PP, and HP, the means of S/M, A/M, P/M, and V/M with Gd-EOBDTPA were lower than those with Gd-DTPA. On HP, The mean L/M with Gd-EOB-DTPA was higher than that with Gd-DTPA.ConclusionOn 3-T DCM-MRI using Gd-EOB-DTPA, contrast enhancement of the organs, except for the liver, was lower than that on DCM-MRI using Gd-DTPA. The HP was already affected by hepatobiliary uptake in Gd-EOB-DTPA.


Pathology | 2013

Lymphocyte recruitment via high endothelial venules in lymphoid stroma of Warthin’s tumour

Ayumi Ohya; Motohiro Kobayashi; Yasuhiro Sakai; Hiroto Kawashima; Shunsuke Kageyama; Jun Nakayama

Aims: Warthins tumour is composed of bilayered oncocytic epithelium and organised lymphoid stroma, which resembles mucosa-associated lymphoid tissue (MALT); however, the histogenesis of the lymphoid stroma is not fully understood. We hypothesised that lymphocytes consisting of the stroma are recruited via high endothelial venules (HEVs) by the mechanism operating in normal lymphocyte homing in secondary lymphoid organs. The aim of this study was to determine immunohistochemically the molecules expressed on these HEVs. Methods: Tissue sections of Warthins tumour (n = 10) were immunostained for vascular addressin-related antigens including peripheral lymph node addressin (PNAd) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1). An L-selectin·IgM chimera in situ binding assay was also carried out. Triple immunostaining for PNAd, CD3, and CD20/CD79&agr; was performed to determine which lymphocyte subsets are closely associated with these HEVs. Results: HEVs in the lymphoid stroma of Warthins tumour express PNAd, which is detected by MECA-79 as well as recently developed monoclonal antibodies S1 and S2. These HEVs were bound by L-selectin·IgM chimeras in a calcium-dependent manner, and numbers of lymphocytes, particularly T cells, attached to these HEVs. Conclusions: The lymphoid stroma of Warthins tumour is most likely developed by lymphocytes recruited via HEVs.


Cancer Science | 2017

Gastric gland mucin-specific O -glycan expression decreases with tumor progression from precursor lesions to pancreatic cancer

Ayumi Ohya; Kazuhiro Yamanoi; Hisashi Shimojo; Chifumi Fujii; Jun Nakayama

Pancreatic cancer is lethal, as it is often detected late. Thus, novel biomarkers of precursor lesions are needed to devise timely therapies. Pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN) are major precursors of pancreatic cancer. In normal gastric mucosa, gastric gland mucin‐specific O‐glycans are unique in having α1,4‐linked N‐acetylglucosamine (αGlcNAc) residues attached to MUC6. Recently we reported that αGlcNAc functions as a tumor suppressor for differentiated‐type gastric adenocarcinoma (Karasawa et al., J Clin Invest 122, 923, 2012). MUC6 is also expressed in pancreatic neoplasms, including PanIN and IPMN, but the role of αGlcNAc expression in pancreatic neoplasms remains unknown. Here, we analyze expression patterns of αGlcNAc, MUC6 and MUC5AC in pancreatic neoplasms and compare them with progression from PanIN to invasive ductal adenocarcinoma (IDAC) (the PanIN‐IDAC sequence; 20 cases) and from IPMN to IPMN with associated invasive carcinoma (IPMNAIC) (the IPMN‐IPMNAIC sequence; 20 cases). At both sequences, the frequency of MUC6‐positive and αGlcNAc‐positive lesions decreased with tumor progression. We then compared expression levels of αGlcNAc and MUC6 at each step of the progression. At the PanIN‐IDAC sequence, αGlcNAc expression significantly decreased relative to MUC6 in low‐grade PanIN (P = 0.021), high‐grade PanIN/intraductal spread of IDAC (P = 0.031) and IDAC (P = 0.013). At the IPMN‐IPMNAIC sequence, decreased αGlcNAc expression was also observed in low‐grade IPMN exhibiting gastric‐type morphology (P = 0.020). These results suggest that decreased expression of αGlcNAc relative to MUC6 occurs early and marks the initiation of tumor progression to pancreatic cancer.


Journal of Obstetrics and Gynaecology Research | 2014

Polypoid endometriosis of the ovary mimicking ovarian carcinoma dissemination: A case report and literature review

Yasushi Yamada; Tsutomu Miyamoto; Akiko Horiuchi; Ayumi Ohya; Tanri Shiozawa

Polypoid endometriosis is a rare type of endometriosis. We report a case of polypoid endometriosis of the ovary mimicking ovarian carcinoma with peritoneal dissemination. Computed tomography and magnetic resonance imaging showed a left ovarian endometriotic cyst containing several nodules in the cystic wall that displayed enhancement, and pelvic nodules on the right ovary. A preoperative or intraoperative diagnosis to avoid the unnecessary extended operation is important for such disease. Retrospective magnetic resonance imaging analysis identified a peculiar finding for polypoid endometriosis: all solid nodules had a round and smooth shape and displayed a low‐signal‐intense marginal edge on T2‐weighted images, suggesting that this is an important finding for differentiating polypoid endometriosis from ovarian carcinoma arising from endometriosis.


Journal of Obstetrics and Gynaecology Research | 2018

Uterine cervical adenocarcinoma associated with lobular endocervical glandular hyperplasia: Radiologic–pathologic correlation

Ayumi Ohya; Shiho Asaka; Yasunari Fujinaga; Masumi Kadoya

We aimed to identify the radiologic features of uterine cervical adenocarcinoma associated with lobular endocervical glandular hyperplasia (LEGH).


Journal of Obstetrics and Gynaecology Research | 2017

Epithelioid trophoblastic tumor of the uterus: A case report with radiologic–pathologic correlation

Ayumi Ohya; Kayoko Higuchi; Hisashi Shimojo; Yasunari Fujinaga; Masumi Kadoya; Shigeki Shiohara

Herein, we report a rare case of an epithelioid trophoblastic tumor of the uterus with radiologic–pathologic correlation in a 56‐year‐old postmenopausal woman. On T2‐weighted magnetic resonance (MR) imaging, the tumor appeared as a hypointense irregular mass compared with the surrounding myometrium of the uterine corpus and encircled the cavity of the lower uterine segment. On dynamic contrast‐enhanced MR images, the tumor appeared as a hypovascular mass and an inhomogeneously hyperintense mass in the delayed phase. In addition, non‐contrast computed tomography images showed some spotty areas of very high density within the tumor. These radiologic findings were well correlated with the histological features, such as abundant hyalinization and calcification within the tumor. Accurate interpretation of MR and computed tomography findings was helpful to differentiate epithelioid trophoblastic tumor from other gestational trophoblastic diseases and uterine carcinomas.


Gynecologic and Obstetric Investigation | 2013

Contents Vol. 75, 2013

Satoshi Ohira; Nao Ookubo; Kyoko Tanaka; Akiko Takatsu; Hisanori Kobara; Norihiko Kikuchi; Carlo Vecchioli-Scaldazza; Carolina Morosetti; Azizi Berouz; Willy Giannubilo; Vincenzo Ferrara; Young Eun Jeon; Kyung Eun Lee; Ji Ann Jung; Su Youn Yim; HyeYeon Kim; Seok Kyo Seo; SiHyun Cho; Young Sik Choi; Byung Seok Lee; Tatjana Gazibara; Goran Trajkovic; Ilma Kurtagic; Nikolina Kovacevic; Selmina Nurkovic; Darija Kisic-Tepavcevic; Tatjana Pekmezovic; Ayumi Ohya; Makoto Kanai; Tanri Shiozawa

M.A. Belfort, Provo, Utah J. Bornstein, Nahariya H.L. Brown, Durham, N.C. C. Chapron, Paris J. de Haan, Maastricht G.A. Dekker, Adelaide, S.A. J.A. Deprest, Leuven K. Hecher, Hamburg S. Kahhale, São Paulo H. Kliman, New Haven, Conn. T.F. Kruger, Tygerberg J.A. Kuller, Raleigh, N.C. M.J. Kupferminc, Tel Aviv H. Minkoff , Brooklyn, N.Y. J. Moodley, Congella J.M. Mwenda, Nairobi H. Odendaal, Tygerberg J.T. Repke, Hershey, Pa. G.R. Saade, Galveston, Tex. B.M. Sibai, Cincinnati, Ohio Founded 1895 as ‘Monatsschrift für Geburtshilfe und Gynäkologie’, continued 1946–1969 as ‘Gynaecologia’ and 1970–1977 as ‘Gynecologic Investigation’

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