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Dive into the research topics where Shiro Onozawa is active.

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Featured researches published by Shiro Onozawa.


American Journal of Roentgenology | 2006

Management of Pancreaticoduodenal Artery Aneurysms: Results of Superselective Transcatheter Embolization

Satoru Murata; Hiroyuki Tajima; Tsuyoshi Fukunaga; Yutaka Abe; Pascal Niggemann; Shiro Onozawa; Tatsuo Kumazaki; Masayuki Kuramochi; Kemmei Kuramoto

OBJECTIVE The purpose of our study was to assess the efficacy of transcatheter arterial embolization for pancreaticoduodenal artery aneurysms. CONCLUSION We concluded that transcatheter arterial embolization is the initial and definitive therapeutic choice for pancreaticoduodenal artery aneurysms, with a possible option to perform surgery after embolization.


European Radiology | 2009

Initial experience of transcatheter arterial chemoembolization during portal vein occlusion for unresectable hepatocellular carcinoma with marked arterioportal shunts

Satoru Murata; Hiroyuki Tajima; Ken Nakazawa; Shiro Onozawa; Shin-ichiro Kumita; Kazuhiro Nomura

The purpose of this study was to assess the clinical effects of transcatheter arterial chemoembolization (TACE) during the corresponding portal vein occlusion (TACE-PVO) in patients with hepatocellular carcinoma (HCC) and marked arterioportal (AP) shunts. This was a prospective, nonrandomized study of TACE-PVO in patients with HCC who had marked AP shunts. The subjects were 21 patients with unresectable HCC and marked AP shunts who underwent shunt embolization with the use of coils and/or gelatin-sponge particles (group A: n = 7) or by TACE-PVO (group B: n = 14). Clinical parameters and data on embolization of AP shunts and on tumor response were assessed prospectively. No major procedure-related complication occurred in either group. Effectiveness of AP-shunt treatment was significantly better in group B than in group A in terms of both immediate results (P = 0.009) and subsequent results (P = 0.028). Tumor response in the therapeutic target area was significantly (P = 0.002) better in group B than in group A. Survival was significantly better in group B than in group A (P = 0.008). TACE-PVO may be a safe and useful therapy for selected patients with unresectable HCC and marked AP shunts.


World Journal of Gastroenterology | 2014

Interventional treatment for unresectable hepatocellular carcinoma

Satoru Murata; Takahiko Mine; Fumie Sugihara; Daisuke Yasui; Hidenori Yamaguchi; Tatsuo Ueda; Shiro Onozawa; Shin-ichiro Kumita

Hepatocellular carcinoma (HCC) is the sixth most common cancer and third leading cause of cancer-related death in the world. The Barcelona clinic liver cancer classification is the current standard classification system for the clinical management of patients with HCC and suggests that patients with intermediate-stage HCC benefit from transcatheter arterial chemoembolization (TACE). Interventional treatments such as TACE, balloon-occluded TACE, drug-eluting bead embolization, radioembolization, and combined therapies including TACE and radiofrequency ablation, continue to evolve, resulting in improved patient prognosis. However, patients with advanced-stage HCC typically receive only chemotherapy with sorafenib, a multi-kinase inhibitor, or palliative and conservative therapy. Most patients receive palliative or conservative therapy only, and approximately 50% of patients with HCC are candidates for systemic therapy. However, these patients require therapy that is more effective than sorafenib or conservative treatment. Several researchers try to perform more effective therapies, such as combined therapies (TACE with radiotherapy and sorafenib with TACE), modified TACE for HCC with arterioportal or arteriohepatic vein shunts, TACE based on hepatic hemodynamics, and isolated hepatic perfusion. This review summarizes the published data and data on important ongoing studies concerning interventional treatments for unresectable HCC and discusses the technical improvements in these interventions, particularly for advanced-stage HCC.


European Journal of Endocrinology | 2014

Evaluation of right adrenal vein cannulation by computed tomography angiography in 140 consecutive patients undergoing adrenal venous sampling

Shiro Onozawa; Satoru Murata; Hiroyuki Tajima; Hidenori Yamaguchi; Takahiko Mine; Akira Ishizaki; Hitoshi Sugihara; Shinichi Oikawa; Shin-ichiro Kumita

OBJECTIVE As it is now known that primary aldosteronism (PA) is more prevalent than was previously recognized, and is a potentially curable cause of hypertension and related cardiovascular diseases, the search for a safe and effective means of its diagnosis has reemerged as a topic of interest. Adrenal venous sampling is the gold standard for diagnosis of PA, but the technique is challenging and the small right adrenal vein can be particularly difficult to cannulate. Our objective was to evaluate the usefulness of computed tomography during angiography (angio-CT) in increasing the success of adrenal venous sampling and to identify factors associated with cannulation failure. DESIGN Retrospective review. METHODS A total of 140 consecutive patients with suspected PA except Cushings syndrome treated at a single hospital from June 2008 to May 2013 were included. Catheter misplacement and correct cannulation rates before angio-CT and success rate of sampling after angio-CT were calculated. Univariate analysis for factors related to incorrect cannulation included gender, age, height, weight, BMI, and adrenal nodules. Successful sampling was biochemically defined according to cortisol concentrations in the venous blood samples. RESULTS Angio-CT detected misplaced catheters in 13 patients (9.3%). The calculated correct cannulation rate of adrenal vein sampling increased from 86.4% before angio-CT to 95.7% after CT (P<0.001, McNemars test). Univariate analysis showed a tendency for a higher rate of failure of right adrenal venous sampling in taller patients (P=0.052, Mann-Whitneys U test). CONCLUSION Angio-CT improved success of adrenal venous sampling.


Acta Radiologica | 2014

Endovascular embolization strategy for renal arteriovenous malformations.

Satoru Murata; Shiro Onozawa; Ken Nakazawa; Ayako Akiba; Takahiko Mine; Tatsuo Ueda; Daisuke Yasui; Fumie Sugihara; Yukihiro Kondoh; Shin-ichiro Kumita

Background Renal arteriovenous malformations (AVMs) are rare vascular malformations that cause hematuria. Treatment for renal AVMs has evolved from open nephrectomy to transcatheter arterial embolization (TAE). Purpose To retrospectively evaluate efficacy and adverse events of TAE for renal AVMs. Material and Methods We examined 12 patients (three men, nine women; mean age, 56 years) with renal AVM with gross hematuria, who underwent 14 sessions of treatment, using various embolization materials (liquid embolization agents, gelatin sponge, and coils). Among the 12 patients, 10 had cirsoid AVMs, eight of which were high-flow lesions. The remaining two patients had aneurismal AVMs. We assessed technical and clinical success, and also complications. All patients were followed for 7–92 months (mean, 48 months). Results Technical success was obtained in all patients. Primary clinical success was obtained in all patients; however, recurrence was observed in two patients who were treated with coils alone. A second session of TAE led to the sustained relief of symptoms. Clinical success rate was significant better (P = 0.045) when coils combined with other agents or liquid agents were used, than when only coils were used. No major complications occurred in any of patients; post-embolization syndrome and deterioration of renal function were not observed. Conclusion TAE treatment was safe, effective, and provided a good outcome, except when only coils were used as the embolization agent.


The Scientific World Journal | 2013

Transcatheter Arterial Chemoembolization Based on Hepatic Hemodynamics for Hepatocellular Carcinoma

Satoru Murata; Takahiko Mine; Tatsuo Ueda; Ken Nakazawa; Shiro Onozawa; Daisuke Yasui; Shin-ichiro Kumita

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer-related deaths in the world. The Barcelona Clinic Liver Cancer (BCLC) classification has recently emerged as the standard classification system for clinical management of patients with HCC. According to the BCLC staging system, curative therapies (resection, transplantation, and percutaneous ablation) can improve survival in HCC patients diagnosed at an early stage and offer potential long-term curative effects. Patients with intermediate-stage HCC benefit from transcatheter arterial chemoembolization (TACE), and those diagnosed at an advanced stage receive sorafenib, a multikinase inhibitor, or conservative therapy. Most patients receive palliative or conservative therapy only, and approximately 50% of patients with HCC are candidates for systemic therapy. TACE is often recommended for advanced-stage HCC patients all over the world because these patients desire therapy that is more effective than systemic chemotherapy or conservative treatment. This paper aims to summarize both the published data and important ongoing studies for TACE and to discuss technical improvements in TACE for advanced-stage HCC.


Acta Radiologica | 2013

Glue embolization for gastroduodenal ulcer bleeding: contribution to hemodynamics and healing process.

Takahiko Mine; Satoru Murata; Ken Nakazawa; Shiro Onozawa; Tatsuo Ueda; M Miyauchi; S Morita; Shin-ichiro Kumita

Background Although the morbidity of bowel ischemic events after glue embolization has been suggested, a causal relationship between glue and ischemia has not been clearly established. Purpose To evaluate the efficiency and safety of transcatheter arterial embolization with n-butyl cyanoacrylate (NBCA–TAE) for upper gastrointestinal hemorrhage (GIH). Material and Methods Between October 2006 and October 2012, 21 patients with upper GIH underwent NBCA–TAE, and endoscopic data were obtained within 30 days of follow-up. Shock index prior to and immediately after NBCA–TAE were compared to determine changes in hemodynamics. Days to Forrest type III, as assessed by follow-up endoscopy, was used as an indicator of the healing process. Other clinical outcomes included days for starting ingestion and for hospital discharge. Results Sixteen gastric and five duodenal ulcers, classified into Forrest type I, were treated. Immediate hemostasis was achieved in all the patients, and no re-bleeding occurred within the follow-up period. Shock index significantly (P < 0.001) improved from before (0.99 ± 0.076) to immediately after NBCA–TAE (0.67 ± 0.038). Sequential mucosal healing processes were observed in all the patients, and the number of days to Forrest type III was 9.6 ± 7.1. The number of days for starting ingestion and hospital discharge was 9.0 ± 4.5 and 15 ± 7.7 days, respectively. Conclusion NBCA–TAE is an effective and safe method for the control of nonvariceal upper GIH, in terms of contribution to hemodynamics and healing process of the gastroduodenal mucosa.


Journal of Gastroenterology and Hepatology | 2014

Contribution of extrahepatic collaterals to liver parenchymal circulation after proper hepatic artery embolization.

Takahiko Mine; Satoru Murata; Tatsuo Ueda; Minako Takeda; Shiro Onozawa; Hidenori Yamaguchi; Youichi Kawano; Shin-ichiro Kumita

To retrospectively evaluate proper hepatic artery embolization, with respect to the development of extrahepatic collaterals.


The Scientific World Journal | 2012

Comparison of Epirubicin-Iodized Oil Suspension and Emulsion for Transcatheter Arterial Chemoembolization in VX2 Tumor

Tatsuo Ueda; Satoru Murata; Takahiko Mine; Shiro Onozawa; Munehiko Onda; Zenya Naito; Yasuo Amano; Shin-ichiro Kumita

To compare the antitumor efficacy and safety of transcatheter arterial chemoembolization (TACE) by epirubicin suspension (epirubicin suspension: epirubicin-iodized oil mixture without solution) to that by epirubicin emulsion (epirubicin emulsion: epirubicin-iodized oil mixture with solution), the efficacy of treatment by administration of either an epirubicin suspension or emulsion was examined in an animal model. Changes in plasma epirubicin concentration were compared over 24 h immediately after treatment, and enhanced ultrasonographic and histopathological analysis subsequently conducted 7 days after treatment to determine the growth ratio and proportion of viable tumor cells. The growth ratio and proportion of viable tumor cells were found to be significantly lower in the suspension group than in the emulsion group while the plasma epirubicin concentration was found to be significantly higher in the suspension group than in the emulsion group. These results indicate that administration of an epirubicin suspension is a superior form of TACE compared to that of administration of an epirubicin emulsion.


Acta Radiologica | 2014

Negative-balance isolated pelvic perfusion in patients with incurable symptomatic rectal cancer: results and drug dose correlation to adverse events

Satoru Murata; Shiro Onozawa; Chol Kim; Hiroyuki Tajima; Ryoji Kimata; Eiji Uchida; Shin-ichiro Kumita

Background Drug leakage and lack of a drug-removal system have prevented clinical application of isolated pelvic perfusion (IPP). These barriers were overcome with negative-balance IPP (NIPP) in experimental pig models. Here, a phase 1 clinical study of NIPP was performed in patients with incurable symptomatic rectal cancer. Purpose To establish a safe regimen of high-dose regional chemotherapy with NIPP using cisplatin in patients with incurable rectal cancer. Material and Methods Between June 2004 and January 2007, NIPP therapy was performed for 23 patients (11 women, 12 men; mean age, 58 years). NIPP was routinely performed twice over a 4-week interval. Dose-limiting toxicities (DLTs) were defined using a 5 + 3 design, and cisplatin doses were escalated from 170 mg/m2, with a fixed 5-fluorouracil dose of 1000 mg/m2. The grade of adverse events (AEs) at the first and second sessions of NIPP therapy, pharmacokinetics, and antitumor response were evaluated. Results No DLTs were observed during the first session of NIPP. However, at the second session, two patients experienced the DLT of neuropathy after administration of 200 mg/m2 cisplatin. Therefore, 190 mg/m2 cisplatin was indicated as the maximum tolerated dose (MTD). The plasma pelvic-to-systemic exposure ratio was 18.4 based on the maximum concentration and 19.0 based on the concentration-time curve. Solid tumor responses included complete response in two patients, partial response in five patients, stable disease in 15 patients, and progressive disease in one patient. Conclusion NIPP may offer the safe delivery of high-dose regional chemotherapy (MTD of 190 mg/m2 cisplatin) with negligible AEs and effective control of tumor growth in patients with incurable rectal cancer.

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Satoru Murata

Jichi Medical University

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