Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Yasunari Yamada is active.

Publication


Featured researches published by Yasunari Yamada.


Journal of Clinical Oncology | 2004

Comparison of the Efficacy, Toxicity, and Pharmacokinetics of a Uracil/Tegafur (UFT) Plus Oral Leucovorin (LV) Regimen Between Japanese and American Patients With Advanced Colorectal Cancer: Joint United States and Japan Study of UFT/LV

Kuniaki Shirao; Paulo M. Hoff; Atsushi Ohtsu; P. J. Loehrer; Ichinosuke Hyodo; S. Wadler; R. G. Wadleigh; P. J. O'Dwyer; Kei Muro; Yasunari Yamada; Narikazu Boku; Fumio Nagashima; James L. Abbruzzese

PURPOSE To compare the efficacy, toxicities, and pharmacokinetics of an oral regimen consisting of uracil/tegafur (UFT) and leucovorin (LV) between Japanese patients and patients in the United States with previously untreated metastatic colorectal cancer. PATIENTS AND METHODS Forty-four Japanese patients and 45 patients in the United States were enrolled in concurrent nonrandomized phase II trials. UFT 300 mg/m2/d and leucovorin 75 mg/d were administered orally for 28 days followed by a 7-day rest period. The total daily dose of each drug was divided into three equal doses. Treatment was repeated every 5 weeks until disease progression. Blood samples for the pharmacokinetic study were obtained after the initial dose on day 1 of the first course. RESULTS The response rate for the Japanese patients and the patients in the United States was 36.4% (95% CI, 22.4% to 52.2%) and 34.1% (95% CI, 20.5% to 49.9%), respectively. The only major toxicity was diarrhea, and other toxicities were mild in both populations. The incidence of grade 3 or higher diarrhea in the Japanese and Americans was 9% and 22%, respectively. Although the area under the curve and maximum concentration of fluorouracil were found to be slightly higher in the Japanese patients than the patients in the United States, and area under the curve-adjusted body surface area appeared to be comparable between the two groups. CONCLUSION The efficacy and pharmacokinetic parameters of UFT and LV are comparable in Japanese and American patients; however, a difference in toxicity profile, specifically diarrhea, was noted. This oral regimen of UFT and LV is considered to have similar activity against metastatic colorectal cancer and to have acceptable toxicity in patients in both countries.


British Journal of Radiology | 2009

Primary malignant lymphoma of the gallbladder: a case report and literature review

Asami Ono; Shuichi Tanoue; Yasunari Yamada; Y Takaji; Fumito Okada; Shunro Matsumoto; Hiromu Mori

Primary malignant lymphoma of the gallbladder is extremely rare and the associated radiological findings are not well described in the literature. We report a case of malignant lymphoma in the gallbladder wall of a 78-year-old woman. Pre-operative CT and MRI showed homogeneous submucosal thickening of the gallbladder wall with a preserved mucosal surface. These unique radiological findings may be useful for diagnosing malignant lymphoma of the gallbladder.


Clinical Radiology | 1998

MRI signal characteristics of progressive massive fibrosis in silicosis

Shunro Matsumoto; Hiromu Mori; Hidetoshi Miyake; Yasunari Yamada; S. Ueda; M. Oga; H. Takeoka; K. Anan

AIM To determine the magnetic resonance imaging (MRI) signal characteristics of progressive massive fibrosis (PMF) in silicosis. SUBJECTS AND METHODS We evaluated prospectively the MR appearances in 17 patients with 34 PMF lesions on the basis of pre-contrast signal intensity (SI) and SI pattern and post-contrast enhancement pattern, using a 0.5-T unit. There were 13 PMF lesions in six patients who had silicosis and 21 PMF lesions in 11 patients who had silicotuberculosis. The SI pattern on T2-weighted image (WI) was classified into four types and the pattern of contrast enhancement on T1-WI was classified into three types. MR appearances of PMF lesions were correlated with the findings of computed tomography (CT). RESULTS The commonest signal intensity characteristic was isointensity (70%) on T1-WI and hypointensity (68%) on T2-WI when compared with skeletal muscle. For signal pattern on T2-WI, a type with only internal high SI areas (46% in silicosis group, 38% in silicotuberculosis group) was most frequent. All of these areas corresponded to the low density areas at CT, suggestive of necrosis. After intravenous contrast medium enhancement, rim enhancement (54% in silicosis group, 52% in silicotuberculosis group) was most frequent, followed by no enhancement. CONCLUSION The most common MRI appearance of PMF was isointensity on T1-WI and hypointensity on T2-WI when compared with skeletal muscle, with internal high SI areas on T2-WI and either rim enhancement or no enhancement.


Radiation Medicine | 2007

Extrapancreatic neural plexus invasion by carcinomas of the pancreatic head region: evaluation using thin-section helical CT

Hui Tian; Hiromu Mori; Shunro Matsumoto; Yasunari Yamada; Hiro Kiyosue; Masayuki Ohta; Seigo Kitano

PurposeThe aim of this study was to determine the computed tomographic (CT) criteria for diagnosing the second portion of the extrapancreatic neural plexus (PLX-II) invasion by carcinoma of the pancreatic head region on thin-section helical CT.Materials and methodsA total of 41 patients with carcinoma of the pancreatic head region (17 in the pancreas, 24 in the lower common bile duct) underwent three-phase helical CT (collimation 5 mm; reconstruction 2.5 mm) before surgery. Two criteria were established for the assessment of the PLX-II running between the superior mesenteric artery (SMA) and the medial margin of the uncinate process: criterion A: assessment of the area around the SMA and inferior pancreaticoduodenal artery; criterion B: assessment of the jejunal trunk.ResultsPLX-II invasion was pathologically confirmed in 19 patients with pancreatobiliary carcinoma. For criterion A, all 19 patients with positive PLX-II invasion and 20 of the 22 with negative PLX-II invasion were correctly diagnosed (sensitivity 100%; specificity 91%; accuracy 95%). For criterion B, 3 of the 17 patients with positive PLX-II invasion and all 20 with negative PLX-II invasion were correctly diagnosed (sensitivity 18%; specificity 100%; accuracy 62%). The two false-positive cases using criterion A were correctly diagnosed using criterion B.ConclusionThin-section helical CT provides sufficient diagnostic ability regarding PLX-II invasion by carcinoma of the pancreatic head region.


Lasers in Surgery and Medicine | 1999

Histopathological features of liver damage induced by laser ablation in rabbits

Yutaka Fujitomi; Kenji Kashima; Shinnya Ueda; Yasunari Yamada; Hiromu Mori; Yuzo Uchida

Possible mechanisms that promote or interfere with the effects of laser ablation of the liver have not been clarified. The aim of this study was to define the chronological alterations in the normal rabbit liver at early stages after laser ablation.


Journal of Computer Assisted Tomography | 2006

Invasive carcinomas derived from intraductal papillary mucinous neoplasms of the pancreas: a long-term follow-up assessment with CT imaging.

Yasunari Yamada; Hiromu Mori; Shunro Matsumoto; Noritaka Kamei; Norio Hongo

Objective: To describe computed tomography (CT) findings of invasive carcinoma derived from intraductal papillary mucinous neoplasms (IPMNs) of the pancreas during long-term follow-up. Methods: Follow-up CT findings of 5 patients with IPMNs progressing to invasive carcinomas were respectively reviewed for 12 to 63 months. All patients underwent thin-section 3-phase helical and/or multislice CT. Results: Invasive carcinomas were detected as hypo- (n = 3) or hyperattenuating (n = 2) solid masses in the pancreatic parenchyma on contrast-enhanced CT. Hypoattenuating masses were mostly visualized on arterial dominant phase images. In 4 branch-duct type IPMNs, the solid masses appeared with (n = 3) or without (n = 1) dilatation of the main pancreatic duct after 3 to 5 years. In the remaining combined-type IPMN, a solid mass was detected on initial CT and progressively increased during the follow-up. Conclusions: Arterial dominant phase CT is useful for detecting invasive carcinoma derived from IPMNs and is an effective follow-up method.


Abdominal Imaging | 2010

Arterial supply to the pancreas; variations and cross-sectional anatomy

Mika Okahara; Hiromu Mori; Hiro Kiyosue; Yasunari Yamada; Yoshiko Sagara; Shunro Matsumoto

The pancreas has complex arterial supplies. Therefore, special attention should be paid in pancreatic arterial intervention for patients with acute pancreatitis and pancreatic carcinomas. Knowledge of pancreatic arterial anatomy and arterial territory is important not only to perform pancreatic arterial intervention, but to read the pancreatic angiography and cross-sectional image. We reviewed 226 selective abdominal angiography and CT scans during selective arteriography (CTA) of common hepatic artery, superior mesenteric artery, splenic artery, or peripancreatic arteries including posterior superior pancreaticoduodenal artery, anterior superior pancreaticoduodenal artery, inferior pancreaticoduodenal artery, and dorsal pancreatic artery. CTA images were evaluated to clarify the cross-sectional anatomy of the pancreatic arterial territory. Variations of the peripancreatic arteries were also investigated. In this exhibit, schemes and illustrative cases demonstrate pancreatic arterial territory and variations.


Journal of Vascular and Interventional Radiology | 2004

Transportal Intravariceal Sclerotherapy with N-Butyl-2-Cyanoacrylate for Gastric Varices

Hiro Kiyosue; Shunro Matsumoto; Yasunari Yamada; Yuzo Hori; Yuriko Okino; Mika Okahara; Hiromu Mori

Four patients with gastric varices without catheterizable draining veins through a systemic vein were treated with transportal intravariceal sclerotherapy with n-butyl-2-cyanoacrylate (NBCA). In all patients, the gastric varices were successfully obliterated with 2-5 mL of NBCA-lipiodol mixture injected via a microcatheter introduced into the varices with transhepatic or transileocolic portal venous access. No complications related to the procedure were encountered. Follow-up gastroendoscopy showed disappearance (n = 3) or marked decrease (n = 1) of the varices. Neither recurrent gastric varices nor variceal bleeding were observed during the follow-up period (6-46 months). Transportal intravariceal sclerotherapy is useful for obliteration of gastric varices in selected cases.


Clinical Imaging | 2004

Intrahepatic porto-hepatic venous shunts in Rendu-Osler-Weber disease. Imaging demonstration

Shunro Matsumoto; Hiromu Mori; Yasunari Yamada; Tomoko Hayashida; Yuzo Hori; Hiro Kiyosue

This study describes the imaging features of the intrahepatic portohepatic venous (PHV) shunt, which is a potential cause of portosystemic encephalopathy in Rendu-Osler-Weber disease. Six patients with Rendu-Osler-Weber disease (two men, four women; age range 42–73 years) were retrospectively studied. There were two from one family and three from another family. Of these patients, one was diagnosed with definitive portosystemic encephalopathy because of a psychiatric disorder. We retrospectively reviewed the radiological examinations, including abdominal angiography (n=6), three-phase dynamic helical computed tomography (CT; n=3), and conventional enhanced CT (n=1). In one patient, CT during angiography and CT angioportography were also performed. Evaluation was placed on the imaging features of intrahepatic PHV shunts. On angiography, intrahepatic PHV shunts showing multiple and small shunts <5 mm in diameter in an apparent network were detected in all patents. In two patients, a large shunt with a size of either 7 or 10 mm was associated. These intrahepatic PHV shunts were predominantly distributed in the peripheral parenchyma. Intrahepatic PHV shunts would be characterized by small and multiple shunts in an apparent network on the periphery with or without a large shunt.


Journal of Computer Assisted Tomography | 2003

Hepatocellular carcinoma: prediction of blood supply from right inferior phrenic artery by multiphasic CT.

Yuriko Okino; Hiro Kiyosue; Shunro Matsumoto; Ryo Takaji; Yasunari Yamada; Hiromu Mori

Objective: Recurrent hepatocellular carcinoma (HCC) often occurs with extrahepatic arterial supply (parasitic supply), essentially due to liver intraarterial chemoembolization, which could potentially hamper retreatment. The right inferior phrenic artery (RIPA) is the most frequent extrahepatic feeding artery. We investigated computed tomography (CT) findings of parasitic supply by the RIPA, and discuss the utility of multiphasic CT for prediction of parasitic supply from RIPA. Method: Medical records, CT scans, and angiograms in 20 patients with HCC fed by RIPA were reviewed. Forty‐two patients with HCC but without parasitic supply were enrolled as the control group. After injection of contrast medium (300 mg I/mL) at a rate of 3 mL/s (total amount, 100 mL), CT images were obtained at 30 seconds, 60 seconds, and 150 seconds with scanning parameters of 7‐mm collimation, 1:1 pitch, and 3.5‐mm reconstruction. Two radiologists evaluated the previous treatment, patency of the hepatic arteries, location of tumors, and detectability and diameter of the RIPA. Results: CT demonstrated at least one portion of RIPA in all patients in both groups. The distal portions of RIPA were detected on CT more frequently in the parasitic group (75%) than in the control group (7.1%). The mean diameter of the RIPA in the parasitic group was 2.3 mm (range; 1.6–3.8), and was larger than that of the control group (mean; 1.3 mm and range; 0–4.1mm) with statistical significance (P < 0.01). Conclusions: Multiphasic CT could demonstrate the presence of parasitic supply to HCCs from RIPA. Visualization of RIPA at the distal portion on CT would be a clue of parasitic supply from RIPA. Index Terms: right inferior phrenic artery, hepatocellular carcinoma, parasitic supply, computed tomography

Collaboration


Dive into the Yasunari Yamada's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge