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Dive into the research topics where Kazunori Myojin is active.

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Featured researches published by Kazunori Myojin.


American Journal of Roentgenology | 2012

Balloon-Occluded Retrograde Transvenous Obliteration of Gastric Varices: Use of CT-Guided Foam Sclerotherapy to Optimize Technique

Jun Koizumi; Takeshi Hashimoto; Kazunori Myojin; Chihiro Itou; Tatehiro Kagawa; Toshiya Nishibe; Bertrand Janne d’Othée

OBJECTIVE Balloon-occluded retrograde transvenous obliteration has been traditionally based on liquid sclerotherapy. However, overdose and systemic spillage of liquid sclerosant can cause severe complications, such as hemolysis, which lead to hemoglobinuria, allergy, acute respiratory distress syndrome, and other disorders. The purpose of this study was to evaluate the performance of foam sclerotherapy with C-arm CT guidance to reduce the amount of sclerosant and to optimize the safety of balloon-occluded retrograde transvenous obliteration while preserving its efficacy. MATERIALS AND METHODS Twenty consecutively registered patients with gastric varices underwent balloon-occluded retrograde transvenous obliteration with polidocanol foam. C-arm CT guidance was used to confirm gas filling of the target vessels. In this retrospective analysis of a prospectively encoded database, total net doses of polidocanol used for transvenous obliteration and of contrast medium used for venography before transvenous obliteration were compared, and subsequent complications, including hemoglobinuria, were documented. RESULTS In all patients, foam was observed in the target vessels at C-arm CT. The mean dose of polidocanol used for balloon-occluded retrograde transvenous obliteration (3.9 ± 1.5 mL) was significantly smaller (p < 0.001) than the dose of contrast medium used for venography (16.4 ± 7.9 mL). Hemoglobinuria was found in only one patient. Except in one instance of recanalization, full variceal thrombosis was confirmed at contrast-enhanced CT 1 week after transvenous obliteration (success rate, 95%). In one patient, air migrated into the liver during transvenous obliteration but was spontaneously absorbed. No serious complication occurred. CONCLUSION Balloon-occluded retrograde transvenous obliteration with polidocanol foam under C-arm CT guidance allowed significant reduction of sclerosant dose and resulted in a low complication rate while a high technical success rate and efficacy were maintained.


Journal of Vascular and Interventional Radiology | 2010

C-arm CT-guided Foam Sclerotherapy for the Treatment of Gastric Varices

Jun Koizumi; Takeshi Hashimoto; Kazunori Myojin; Tomokazu Fukushima; Tamaki Ichikawa; Tatehiro Kagawa; Seiichiro Kojima; Norihito Watanabe; Tetsuya Mine; Toshiya Nishibe; Bertrand Janne d'Othée

The authors describe here the use of foam sclerotherapy under C-arm computed tomography (CT) guidance for the treatment of gastric varices via balloon-occluded retrograde transvenous obliteration in seven patients and percutaneous transhepatic obliteration in one patient. All gastric varices were occluded successfully after replacement of blood by foam, which was trapped in the gastric varices as shown by C-arm CT. It also helped reduce the amount of sclerosant, an issue that is associated with severe complications, such as hemolysis, allergy, acute respiratory distress syndrome, and others. Foam sclerotherapy under C-arm CT guidance is a promising tool in the therapeutic armamentarium against gastric varices.


Japanese Journal of Radiology | 2011

Diffusion magnetic resonance imaging with gadofosveset trisodium as a negative contrast agent for lymph node metastases assessment.

Tomohiro Yamashita; Taro Takahara; Thomas C. Kwee; Shuichi Kawada; Chie Inomoto; Kazunobu Hashida; Hiroshi Yamamuro; Kazunori Myojin; Peter R. Luijten; Yutaka Imai

PurposeThe aim of this study was to assess the feasibility of using intravenously administered gadofosveset trisodium as a negative contrast agent for lymph node (LN) assessment with diffusion-weighted imaging (DWI) using a VX2 tumor model in rabbits.Materials and methodsVX2 cells were injected in the right hind limb of five Japanese white rabbits to induce ipsilateral popliteal LN metastasis. DWI was performed before and every 7.5 min (until 1 h) after intravenous gadofosveset trisodium administration, at 1.5 T. Signal intensities (SIs) of right (metastatic) and left (nonmetastatic) popliteal LNs at each time point were measured and compared to each other using two-sided unpaired t-tests.ResultsThe SIs of metastatic lymph nodes were significantly higher (P < 0.05) than those of nonmetastatic LNs at each time point after intravenous gadofosveset trisodium administration. Although the SI of metastatic LNs was significantly higher (P = 0.0237) than that of nonmetastatic LNs before contrast injection, this difference became even more significant (P ≤ 0.0105) after gadofosveset trisodium administration.ConclusionThe SI of metastatic LNs at DWI is less suppressed than that of nonmetastatic LNs after the intravenous administration of gadofosveset trisodium. Therefore, intravenously administered gadofosveset trisodium shows promise for use as a negative contrast agent for discriminating metastatic from nonmetastatic LNs at DWI.


American Journal of Roentgenology | 2015

Balloon-Occluded Retrograde Transvenous Obliteration for the Treatment of Gastric Varices: Polidocanol Foam Versus Liquid Ethanolamine Oleate

Chihiro Itou; Jun Koizumi; Takeshi Hashimoto; Kazunori Myojin; Tatehiro Kagawa; Tetsuya Mine; Yutaka Imai

OBJECTIVE The purpose of this study was to evaluate the clinical results of the management of gastric varices by balloon-occluded retrograde transvenous obliteration with polidocanol foam versus ethanolamine oleate. MATERIALS AND METHODS Twenty patients treated with ethanolamine oleate and 21 patients treated with polidocanol foam were enrolled in this study. Early therapeutic effects were assessed mainly by dynamic contrast-enhanced CT. Subjective symptoms, objective findings associated with the procedures, and changes in laboratory data during the obliteration process were evaluated. Rebleeding from gastric varices was assessed after the procedures. RESULTS Complete obliteration was confirmed in all but one case of early recanalization after treatment with polidocanol foam. One patient died of acute respiratory distress syndrome after treatment with ethanolamine oleate. The total sclerosant volume was significantly lower for 3% polidocanol foam (13.5 ± 6.8 mL) than for 5% ethanolamine oleate (30.6 ± 15.6 mL) (p < 0.01). Polidocanol foam caused fewer severe reactions, including pain, during and after injection. High body temperature, hemoglobinuria, and reactive pleural effusion were not observed with polidocanol foam. The variance in laboratory data values associated with hemolysis was significantly greater with ethanolamine oleate. No postprocedural rebleeding from the gastric varices was observed during a median follow-up time of 39.5 months after procedures with ethanolamine oleate and 34 months after procedures with polidocanol foam. CONCLUSION Polidocanol foam can achieve obliteration of gastric varices comparable to that of ethanolamine oleate but with a significantly lower sclerosant dose and reduced risk of hemolysis-induced complications and harmful reactions, including pain and fever.


Journal of Vascular and Interventional Radiology | 2012

Carbon Dioxide (CO2) vs Iodinated Contrast Digital Subtraction Angiography during Balloon-occluded Retrograde Transvenous Obliteration (BRTO) Using Foam Sclerosant for Gastric Varices

Jun Koizumi; Takeshi Hashimoto; Kazunori Myojin; Chihiro Itou; Takuya Hara; Tatsuya Sekiguchi; Tamaki Ichikawa; Yutaka Imai; Tatehiro Kagawa; Naruhiko Nagata; Norihito Watanabe; Tetsuya Mine; Toshiya Nishibe; Toru Saguchi; Bertrand Janne d'Othée

PURPOSE To compare the visualization of the target gastric varices (GV) on balloon-occluded retrograde transvenous venography (BRTV) using iodinated contrast material vs carbon dioxide (CO(2)) in preparation for subsequent balloon-occluded retrograde transvenous obliteration (BRTO) using foam sclerotherapy. MATERIALS AND METHODS In 16 consecutive patients with nonruptured GV, BRTV was performed first using iodinated contrast material and then with CO(2). BRTV was repeated whenever there were changes in the catheter or patient position or when coil embolization of collaterals was needed. Each visualization grade of GV (grade 1 = GV only; grade 2 = GV > collaterals; 3 = GV < collaterals; grades 4-5 = collaterals only) was determined by two observers in consensus. During foam BRTO, the GV visualization grade was recorded again and confirmed by C-arm computed tomography (CT). RESULTS In 38 pairs of BRTV, GV grades were significantly (P < .0001) lower (ie, favoring BRTO) on CO(2) BRTV (mean ± standard deviation, 1.8 ± 0.8) than on iodine BRTV (3.4 ± 0.8). GV grades on foam BRTO (1.4 ± 0.7) were similar to the grades obtained on the most recent CO(2) BRTV (1.3 ± 0.5) but were significantly smaller (P < .0001) than on iodinated BRTV (3.1 ± 0.9). GV were opacified by foam on initial C-arm CT in 14 patients (87.5%), and complete thrombosis of GV was obtained without any complication in all 16 patients (100%). CO(2) reached the GV even when iodinated contrast material could not (grade 4) in seven of our 16 patients (43.8%), leading to successful BRTO. CONCLUSIONS CO(2) BRTV visualized GV better than did iodine BRTV and changed the management of more than 40% of patients by enabling successful foam BRTO in patients in which conventional liquid BRTO could not be performed.


Annals of Vascular Diseases | 2012

Mycotic Celiac Artery Aneurysm Following Infective Endocarditis: Successful Treatment Using N-butyl Cyanoacrylate with Embolization Coils.

Akira Aki; Toshihiko Ueda; Jun Koizumi; Yoshinori Cho; Shinichiro Shimura; Hidekazu Furuya; Kazunori Myojin; Kimiaki Okada; Chiharu Tanaka

Mycotic celiac artery aneurysm following infective endocarditis is extremely rare and, to our knowledge, only four cases have been reported in the literature to date. We describe the case of a 60 year-old man who developed a mycotic aneurysm of the celiac artery, which was detected by computed tomography (CT) following an episode of infective endocarditis. He successfully underwent endovascular isolation and packing of the aneurysm using N-butyl cyanoacrylate (NBCA) with embolization coils.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 2017

Pulmonary artery hypoplasia associated with posterior mediastinal hematoma accompanied by a ruptured pseudoaneurysm of the esophageal branch of the left gastric artery

Miho Nitta; Soji Ozawa; Junya Oguma; Akihito Kazuno; Yamato Ninomiya; Takayuki Nishi; Hideo Shimada; Kazunori Myojin

A 65-year-old woman with no significant medical history visited the emergency department complaining of epigastric discomfort. A computed tomography of the thorax and abdomen showed the attenuation of the pulmonary artery and a posterior mediastinal hematoma. Angiography showed a tortuous esophageal branch of the left gastric artery and a pseudoaneurysm, and during the later phase, the left lower lobe of the lung was enhanced, and finally, the left pulmonary vein was enhanced. We considered that the patient was exhibiting hypoperfusion of the left pulmonary artery arising from left pulmonary artery hypoplasia, since the left lung was supplying the systemic circulation. Transcatheter arterial embolization was performed. The patient has not experienced any recurrence of a ruptured pseudoaneurysm or epigastric discomfort. Here, we report the first documented case of pulmonary artery hypoplasia associated with posterior mediastinal hematoma accompanied by a ruptured aneurysm of the left gastric artery.


Nutrition | 2007

Kurozu moromimatsu inhibits tumor growth of Lovo cells in a mouse model in vivo

Naoto Fukuyama; Shio Jujo; Isao Ito; Toru Shizuma; Kazunori Myojin; Kazuo Ishiwata; Masanobu Nagano; Hiroe Nakazawa; Hidezo Mori


Japanese Journal of Radiology | 2013

A case of refractory chylous ascites after nephrectomy successfully treated with percutaneous obliteration using adhesive glue

Chihiro Itou; Jun Koizumi; Kazunori Myojin; Tomohiro Yamashita; Naoko Mori; Yutaka Imai


CardioVascular and Interventional Radiology | 2014

Foam Sclerotherapy for a Symptomatic Hepatic Cyst: A Preliminary Report

Chihiro Itou; Jun Koizumi; Takeshi Hashimoto; Kazunori Myojin; Tatehiro Kagawa; Tetsuya Mine; Yutaka Imai

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Rick Wray

Johns Hopkins University

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