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Dive into the research topics where Nobuhiro Iwasaki is active.

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Featured researches published by Nobuhiro Iwasaki.


Journal of Medical Ultrasonics | 2002

The Efferent Blood Flow of Early Hepatocellular Carcinoma and Borderline Lesions : Demonstration by Color Doppler Imaging

Hitoshi Tochio; Tomita S; Masatoshi Kudo; Nobuhiro Iwasaki; Syuji Tamura; Hitomi Nakamura; Toshiko Soga; Toyokazu Fukunaga; Yoshihiro Okabe; Hiroshi Kashida; Masahiro Hirasa; Yasuyosi Ibuki; Morimoto Y; Akio Orino

We performed waveform analysis of the efferent signal detected within early hepatocellular carcinomas and borderline lesions, in which portal flow was demonstrated. Continuity of this flow with the surrounding vessels was also analyzed. Nine nodules in 7 patients with early hepatocellular carcinomas and borderline lesions were included in this study. Tumor diameter ranged from 1.2 to 3.5 cm; average, 2.1 cm. Waveform of the efferent flow signal from within these nodules was continuous in 5 nodules and biphasic venous in 4 nodules. Outside the nodules, the waveform of the efferent flow signal was that of a biphasic venous wave. All efferent signals were confirmed to continue in the hepatic vein. These findings thus suggest that the draining vessel in early hepatocellular carcinomas and their borderline lesions is the hepatic vein.


Oncology | 2017

CD68-Positive Cells in Hepatic Angiomyolipoma

Hitoshi Tochio; Eriko Tamaki; Yukihiro Imai; Nobuhiro Iwasaki; Kazushi Minowa; Hobyung Chung; Yoshiki Suginoshita; Tetsurou Inokuma; Masatoshi Kudo

Four resected specimens of hepatic angiomyolipoma in which uptake of Sonazoid was observed in the postvascular phase of Sonazoid-enhanced ultrasonography were analyzed. Macrophage localization in the tumor was revealed pathologically by immunohistochemical staining for CD68. CD68-positive cells were observed in the tumor in all cases. The density of CD68-positive cells was 100/mm2, and the ratio of CD68-positive cell density in the tumor to that in the surrounding parenchyma was 32-171%. These results suggested that the uptake of the contrast agent Sonazoid was related to the density of CD68-positive cells.


Journal of Medical Ultrasonics | 2005

Evaluation of intratumoral hemodynamics with color Doppler imaging in patients with colorectal carcinoma: comparison between waveform analysis and histopathologic characteristics

Nobuhiro Iwasaki; Yoshihiro Okabe; Hitoshi Tochio; Yukie Ohshita; Hitomi Nakamura; Toshiko Soga; Toshiaki Fujimoto; Masaya Wada; Akio Orino

PurposeWe studied the relation between intratumoral hemodynamics and histopathologic characteristics in patients with colorectal carcinoma.MethodsA series of 82 patients with 28 well-differentiated adenocarcinomas, 40 moderately differentiated adenocarcinomas, 10 poorly differentiated adenocarcinomas, and 4 mucinous adenocarcinomas underwent color Doppler examination and surgical treatment. The waveform of blood flow in the thickened wall of the colon was analyzed by determining the maximum velocity (Vmax) and resistance index (RI). These parameters were compared with histopathologic findings of the resected specimens: gross form, tumor size, depth of invasion, histologic stage, and histopathologic classification.ResultsBoth Vmax and RI were higher in the invasive tumors rather than the expansive ones. Vmax and tumor size were not correlated; however, the RI increased proportionately with tumor size in tumors larger than 4 cm in diameter. Both parameters increased with depth of invasion and histologic stage through stage IIIb. Both were markedly higher in mucinous adenocarcinomas than in the other histopathologic types. Furthermore, Vmax in well, moderately, and poorly differentiated adenocarcinomas did not differ significantly, although RI was negatively associated with the degree of differentiation.ConclusionsWe concluded that blood-flow analysis is closely associated with histopathologic findings of colorectal carcinomas and that it provides information useful in the clinical management of these patients.


Journal of Medical Ultrasonics | 2002

Proximal bifurcation of hepatic artery: Novel findings on hepatic arteries demonstrated by ultrasound Doppler imaging, B-flow, and US angiography.

Hitoshi Tochio; Nobuhiro Iwasaki; Hitomi Nakamura; Keiko Nakayama; Toshiko Soga; Shinichi Nishiuma; Toyokazu Fukunaga; Yoshihiro Okabe; Hiroshi Kashida; Masahiro Hirasa; Yasuyoshi Ibuki; Toshiaki Fujimoto; Morimoto Y; Masatoshi Kudo; Tomita S; Yutaka Konishi; Akio Orino

PurposeIt has generally been held that each portal branch is always accompanied by a single arterial branch in the liver. During Doppler ultrasound examination, however, we sometimes encounter a portal branch that appears to be associated with two arterial branches, a phenomenon referred to below asthis finding orthis phenomenon. Here we attempt to confirm that this finding is based on a correct interpretation of the image and to disclose its basic mechanism.Material and MethodsFive cases of chronic liver disease in which this phenomenon appeared were analyzed with B-flow imaging. Videotapes obtained from 30 patients who had chronic liver disease and had undergone ultrasound angiography (USAG) with arterial infusion of CO2 micro bubbles were reviewed in order to look for similar findings. Sixty-nine healthy controls were also examined with Doppler sonography for this purpose. Histopathologic specimens from 7 patients who had undergone hepatectomy (3 with hepatocellular carcinoma, 3 with metastatic tumor, and 1 with focal nodular hyperplasia) were examined to study the basic structure of the hepatic vessels.Results and DiscussionThree parallel color signals (two pulsatile and one of a constant waveform) observed on Doppler examination were confirmed by the B-flow method to be three independent vessels in all five cases in which both Doppler sonography and B-flow imaging were used. In 13 (43%) of the 30 cases of USAG, two vessels along a portal branch were visualized by the inflow of micro bubbles, indicating that the two vessels were arteries. The trio of one portal and two arterial branches was also detected with Doppler sonography in 12 (17%) of the 69 healthy controls. In 10 (59%) of the 17 cases (5 of liver disease and 12 normal) that showed this finding on Doppler examination, bifurcations of the hepatic artery and portal vein were both visualized. Hepatic arterial branches were found to bifurcate slightly more proximal to the hepatic hilus than the accompanying portal branch. Histopathologic study revealed Glisson’s areas that contained one portal branch and two arterial vessels in nontumorous parts of specimens from all 7 patients with hepatectomy.ConclusionTwo arterial branches can be demonstrated along a portal branch as a result of a more-proximal bifurcation of the hepatic artery than of the portal vein.


Oncology | 2017

Subject Index Vol. 92, Suppl. 1, 2017

Hirokazu Chishina; Masashi Kono; Kazuomi Ueshima; Yoriaki Komeda; Tadaaki Arizumi; Eisuke Enoki; Takuya Nakai; Tsutomu Kumabe; Osamu Nakashima; Fukuo Kondo; Masatoshi Kudo; Yasunori Minami; Mina Iwanishi; Tomohiro Minami; Toshiharu Sakurai; Masahiro Takita; Norihisa Yada; Hiroshi Ida; Satoru Hagiwara; Naoshi Nishida; Eriko Tamaki; Yukihiro Imai; Nobuhiro Iwasaki; Kazushi Minowa; Hobyung Chung; Yoshiki Suginoshita; Tetsurou Inokuma; Tomohiro Watanabe; Wing Yee Kwok; Hitoshi Tochio


Kanzo | 2016

Localization of CD68-positive cells in hepatic angiomyolipoma observed by residual contrast agent on Sonazoid-enhanced ultrasonography

Hitoshi Tochio; Eriko Tamaki; Yukihiro Imai; Nobuhiro Iwasaki; Hiroshi Tei; Yoshiki Suginoshita; Kazushi Minowa; Tetsurou Inokuma


Choonpa Igaku | 2008

A case of hepatic venous thrombosis type of Budd-Chiari Syndrome with multiple liver nodules

Nobuhiro Aoki; Nobuhiro Iwasaki; Yukihiro Imai; Yoshihiro Okabe; Tsutomu Chiba


Japanese journal of medical ultrasonics = 超音波医学 | 2005

A Novel Method of Extra couporeal Ultrasonography in combination with endoscopy

Nobuhiro Iwasaki; Yukinobu Takimoto; Hitosi Tochio; Shinobu Kadonaga; Yukie Ooshita; Hitomi Nakamura; Syuji Yamamoto; Akihiko Okada; Tiharu Kawanami; Naoya Kimoto; Yoshihiro Okabe; Akio Orino


Japanese journal of medical ultrasonics = 超音波医学 | 2005

A case of fulminant hepatitis(type B) in whom abnormal hepatic blood flow was observed by ultrasound Doppler imaging

Hitoshi Tochio; Yoshihiro Okabe; Akio Orino; Nobuhiro Iwasaki; Hitomi Nakamura; Kazumi Hamada; Masaya Wada; Misako Obata; Keiko Ogata; Shinobu Kadonaga; Ichiro Sasaki; Mayumi Kuroda


Journal of Medical Ultrasonics | 2000

Hemodynamic Differential Diagnosis of Breast Masses by Ultrasonic Doppler Imaging:Significance of Pulsatile Blood Flow with Resistance Index≧1.0

Hitoshi Tochio; Yutaka Konishi; Hitomi Nakamura; Nobuhiro Iwasaki; Shuji Tamura; Keiko Ohta; Toshiko Soga; Morimoto Y; Takashi Hashimoto; Tatehiro Kajiwara

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