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Dive into the research topics where Naoyuki Toyota is active.

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Featured researches published by Naoyuki Toyota.


CardioVascular and Interventional Radiology | 2005

Radiofrequency Ablation Therapy Combined with Cementoplasty for Painful Bone Metastases: Initial Experience

Naoyuki Toyota; Akira Naito; Hideaki Kakizawa; Masashi Hieda; Nobuhiko Hirai; Toshihiro Tachikake; Tomoki Kimura; Hideki Fukuda; Katsuhide Ito

The purpose of this study was to assess the efficacy and safety of percutaneous radiofrequency (RF) ablation therapy combined with cementoplasty under computed tomography and fluoroscopic guidance for painful bone metastases. Seventeen adult patients with 23 painful bone metastases underwent RF ablation therapy combined with cementoplasty during a 2-year period. The mean tumor size was 52 × 40 × 59 mm. Initial pain relief, reduction of analgesics, duration of pain relief, recurrence rate of pain, survival rate, and complications were analyzed. The technical success rate was 100%. Initial pain relief was achieved in 100% of patients (n = 17). The mean VAS scores dropped from 63 to 24 (p < 0.001) (n = 8). Analgesic reduction was achieved in 41% (7 out of 17 patients). The mean duration of pain relief was 7.3 months (median: 6 months). Pain recurred in three patients (17.6%) from 2 weeks to 3 months. Eight patients died and 8 patients are still alive (a patient was lost to follow-up). The one-year survival rate was 40% (observation period: 1–30 months). No major complications occurred, but one patient treated with this combined therapy broke his right femur 2 days later. There was transient local pain in most cases, and a hematoma in the psoas muscle (n = 1) and a hematoma at the puncture site (n = 1) occurred as minor complications. Percutaneous RF ablation therapy combined with cementoplasty for painful bone metastases is effective and safe, in particular, for bulky tumors extending to extraosseous regions. A comparison with cementoplasty or RF ablation alone and their long-term efficacies is needed.


Journal of Gastroenterology | 2007

The long-term outcome of patients with bleeding gastric varices after balloon-occluded retrograde transvenous obliteration

Nobuhiko Hiraga; Shintaro Takaki; Hideaki Kodama; Hiroo Shirakawa; Michio Imamura; Yoshiiku Kawakami; Shoichi Takahashi; Naoyuki Toyota; Katsuhide Ito; Shinji Tanaka; Mikiya Kitamoto; Kazuaki Chayama

BackgroundThe purpose of our study was to evaluate the long-term outcome and complications of balloon-occluded retrograde transvenous obliteration (B-RTO) in patients with hemorrhage from gastric fundal varices.MethodsThirty-four consecutive patients with bleeding from gastric varices who were treated with B-RTO were enrolled in this study between December 1994 and September 2005 (urgent cases, n = 12; elective cases, n = 22). The long-term outcome, complications, and various liver functions were evaluated.ResultsComplete obliteration was achieved in 31 of 34 (91%) patients with an acute bleeding episode. In one of the remaining patients, there was a technical failure, and the other two had only partial obliteration. The two patients with partial obliteration did not obtain hemostasis. Thus, the rate of hemostasis was 94% (31/33). Gastric varices disappeared in all patients with complete obliteration during the treatment. The rate of gastric variceal eradication was 91%. Variceal rebleeding from esophageal varices occurred in three patients. The rate of rebleeding was 10% (3/31). Rebleeding from gastric varices was not observed after complete obliteration. None of the patients showed worsening of their Child-Pugh score. Although the 5-year cumulative worsening rate of esophageal varices was 52%, neither portal hypertensive gastropathy nor ectopic varices were observed. The patients with worsening esophageal varices were successfully treated with an endoscopic procedure. The 5-year survival rate was 68%.ConclusionsB-RTO is useful for treatment of bleeding gastric varices, achieving high eradication of gastric varices, a low rebleeding rate, and a fairly good prognosis with improved hepatic function.


Journal of Gastroenterology and Hepatology | 2010

Percutaneous radiofrequency ablation as first‐line treatment for small hepatocellular carcinoma: Results and prognostic factors on long‐term follow up

Koji Waki; Yoshio Katamura; Tomokazu Kawaoka; Shintaro Takaki; Akira Hiramatsu; Shoichi Takahashi; Naoyuki Toyota; Katsuhide Ito; Kazuaki Chayama

Background and Aims:  We evaluated the prognosis and associated factors in patients with small hepatocellular carcinoma (HCC; up to 3 nodules, each up to 3cm in diameter) treated with percutaneous radiofrequency ablation (RFA) as first‐line treatment.


Journal of Gastroenterology | 2007

Pretreatment predictor of response, time to progression, and survival to intraarterial 5-fluorouracil/interferon combination therapy in patients with advanced hepatocellular carcinoma

Kiminori Uka; Shintaro Takaki; Daiki Miki; Tomokazu Kawaoka; Soo Cheol Jeong; Shoichi Takahashi; Naoyuki Toyota; Katsuhide Ito; Kazuaki Chayama

BackgroundSeveral studies have reported survival benefits of combination therapy with intraarterial 5-fluorouracil (5-FU) and subcutaneous interferon (IFN) α for advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT). We investigated the pretreatment predictive factors of early response, time to progression (TTP), and survival in response to intraarterial 5-FU/IFN combination therapy.MethodsPatients with nonresectable HCC and variable PVTT grades (without PVTT to PVTT in the trunk) received intraarterial 5-FU/IFN combination therapy (n = 55).ResultsAfter two courses of the combination therapy, 1 (2%), 15 (27%), 16 (29%), 12 (22%), and 11 (20%) of 55 patients showed complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD), or had dropped out (DO), respectively, when their early response to treatment was assessed. Univariate analysis identified only hepatitis C virus (HCV) antibody positivity as having significantly influenced the early response (P = 0.028) and TTP (P = 0.021). Multivariate analysis identified performance status (P = 0.003) and HCV antibody positivity (P = 0.007) as significant and independent determinants of survival. PVTT grade did not influence early response, TTP, or survival. The survival rate was significantly higher in patients who achieved CR or PR than in those that assessed as SD or PD, or DO (P < 0.0001, each).ConclusionsHCV antibody positivity may be a significant pretreatment predictor of early response, TTP, and survival of patients with advanced HCC treated with 5-FU/IFN. CR or PR as the early response to the combination therapy might indicate a more favorable prognosis in patients with advanced HCC. PVTT grade did not seem to influence the efficacy of combination therapy.


Hepatology Research | 2009

FDG positron emission tomography/computed tomography for the detection of extrahepatic metastases from hepatocellular carcinoma

Tomokazu Kawaoka; Shintaro Takaki; Kiminori Uka; Takahiro Azakami; Hiromi Saneto; Soo Cheol Jeong; Yoshiiku Kawakami; Shoichi Takahashi; Naoyuki Toyota; Katsuhide Ito; Yutaka Hirokawa; Kazuaki Chayama

Aims:  To compare the efficacy of positron emission tomography (PET) computed tomography (CT), multi‐detector helical computed tomography (MDCT) and bone scintigraphy for the detection of extrahepatic metastases in patients with hepatocellular carcinoma (HCC).


Liver International | 2007

Similar effects of recombinant interferon-α-2b and natural interferon-α when combined with intra-arterial 5-fluorouracil for the treatment of advanced hepatocellular carcinoma

Kiminori Uka; Shintaro Takaki; Daiki Miki; Soo Cheol Jeong; Akira Hiramatsu; Hideaki Kodama; Hiroo Shirakawa; Yoshiiku Kawakami; Shoichi Takahashi; Naoyuki Toyota; Katsuhide Ito; Kazuaki Chayama

Aim: Intra‐arterial 5‐fluorouracil (5‐FU) plus interferon (IFN) combination therapy is effective against advanced hepatocellular carcinoma (HCC) with portal vein tumour thrombosis. In this study, we compared the efficiency and safety of recombinant IFN‐α‐2b with natural IFN‐α as components of the combination therapy.


Journal of Computer Assisted Tomography | 2011

Clinical significance of the transitional phase at gadoxetate disodium-enhanced hepatic MRI for the diagnosis of hepatocellular carcinoma: Preliminary results

Yuko Nakamura; Naoyuki Toyota; Shuji Date; Seitaro Oda; Tomohiro Namimoto; Yasuyuki Yamashita; Toru Beppu; Kazuo Awai

Objectives To investigate the clinical significance of the “transitional phase” at gadoxetate disodium (Gd-EOB)–enhanced magnetic resonance imaging for diagnosing hepatocellular carcinoma (HCC). Methods We studied 54 patients with 70 histologically diagnosed HCC. Transitional- and hepatobiliary-phase (TP, HBP) images were acquired 3 and 20 minutes after Gd-EOB injection, respectively. Radiologists measured the size of the hepatic tumors on images and surgical specimens and qualitatively evaluated the signal intensity of the hepatic tumors during TP and HBP independently. Results In 4 patients with portal tumor embolism who had undergone percutaneous transhepatic portal embolization and who manifested arterioportal (AP) shunts, the low-intensity area was larger during HBP than TP. Of the 70 HCCs, 4 were of high signal intensity during HBP and 2 were of slightly low intensity during TP. Conclusion Tumor extension seen during TP rather than HBP more accurately reflected histological findings in patients with HCC with portal tumor thrombi, percutaneous transhepatic portal embolization, or AP shunt.


CardioVascular and Interventional Radiology | 1995

Embolization of a ruptured middle colic artery aneurysm

Akira Naito; Naoyuki Toyota; Katsuhide Ito

Middle colic artery aneurysms are very uncommon. A few cases of occlusion of superior mesenteric artery aneurysms without bowel ischemia are reported. We describe successful uncomplicated embolization of a ruptured middle colic artery aneurysm with a Gelfoam plug.


Journal of Computer Assisted Tomography | 2015

Radiation dose reduction at coronary artery calcium scoring by using a low tube current technique and hybrid iterative reconstruction.

Noriaki Matsuura; Masaki Urashima; Wataru Fukumoto; Hiroshi Sunamori; Fuminari Tatsugami; Naoyuki Toyota; Kazuo Awai

Purpose The aim of this study was to compare the accuracy of coronary artery calcium scoring (CACS) on cardiac computed tomographic images using hybrid iterative reconstruction (hIR) and a low tube current as well as on images acquired with a filtered back projection (FBP) algorithm and a normal tube current. Subjects and Methods Patients (N = 77) with suspected coronary artery disease were subjected to 2 CACS evaluations based on their Agatston, volume, and mass scores. One CACS evaluation was performed on images obtained with a 364-mA tube current and reconstructed with FBP; the other was performed on images obtained with a 73-mA tube current and reconstructed with hIR at iDose4. All scans were performed with the prospective electrocardiogram-triggered method using a 256-slice computed tomographic scanner (Brilliance iCT; Philips). We assessed agreement between calcium scores obtained with FBP and with IR using the percentage difference and Bland-Altman analysis. Results The effective radiation doses for CACS at 80 mA s with FBP and at 16 mA s with IR were 1.20 and 0.24 mSv, respectively (k = 0.014). The mean Agatston, volume, and mass scores at 80 mA s with FBP as well as at 16 mA s with IR were 390.7, 146.5, and 63.2 as well as 377.7, 142.5, and 62.2, respectively. The percentage difference between FBP and hIR for the Agatston, volume, and mass score was 20.7%, 20.7%, and 27.1%, respectively. Bland-Altman analysis showed that there was no systemic bias. Conclusions The radiation dose for CACS can be reduced at a low tube current and hIR without affecting the calcium score.


Oncology | 2007

Efficacy of Percutaneous Cementoplasty for Bone Metastasis from Hepatocellular Carcinoma

Hideaki Kodama; Kiminori Uka; Shintaro Takaki; Nami Mori; Koji Waki; Soo Cheol Jeong; Yoshiiku Kawakami; Hiroo Shirakawa; Shoichi Takahashi; Naoyuki Toyota; Katsuhide Ito; Kazuaki Chayama

Objective: To assess the efficacy of percutaneous cementoplasty for painful bone metastasis from hepatocellular carcinoma (HCC). Methods: Cementoplasty was performed for 22 metastatic bone tumors in 13 patients. All patients had intractable pain and were diagnosed as metastatic bone tumor from HCC. The ostyneedle was inserted in the center of the site of bone metastasis under CT guidance. VAS score, Tokuhashi score and Frankel score were used for assessment of the efficacy of cementoplasty. We also assessed the response to treatment, adverse events and prognosis. Results: Only the VAS score, but not Tokuhashi and Frankel scores, improved after cementoplasty. Cementoplasty for painful bone metastasis provided relief of severe pain but did not improve prognosis, neurological function or survival. Eleven of 13 (85%) patients showed CR or PR and the mean pain-free period was 5 months, including a 10-month pain-free period in one case. No major complications were encountered. Conclusions: Percutaneous cementoplasty can provide pain relief and improvement of quality of life, though without survival benefits, for HCC patients with painful bone metastasis.

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