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Dive into the research topics where Yukio Miyamoto is active.

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Featured researches published by Yukio Miyamoto.


The Journal of Rheumatology | 2010

Clinical Significance of Serum Levels of Vascular Endothelial Growth Factor, Angiopoietin-1, and Angiopoietin-2 in Patients with Rheumatoid Arthritis

Daitaro Kurosaka; Kenichiro Hirai; Makiko Nishioka; Yukio Miyamoto; Ken Yoshida; Kentaro Noda; Maimi Yanagimachi; Kazuhiro Furuya; Eigo Takahashi; Isamu Kingetsu; Kunihiko Fukuda; Akio Yamada

Objective. To evaluate the clinical significance of serum levels of vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1), and angiopoietin-2 (Ang-2) in patients with rheumatoid arthritis (RA). Methods. The subjects were 70 patients with RA. Serum VEGF, Ang-1, and Ang-2 levels were determined by ELISA. As indices of disease activity, serum levels of C-reactive protein (CRP) and matrix metalloprotease (MMP)-3 were examined, and the 28-joint count Disease Activity Score (DAS28)-CRP was calculated. Power Doppler ultrasonography was performed in the bilateral wrists, elbows, shoulders, knees and ankles. The synovial blood flow signals were scored using a 3-grade scale (0–2), and the total of the scores in the 10 joints was regarded as the total signal score (TSS). Results. Serum VEGF level showed significant correlations with serum CRP and MMP-3 levels, DAS28-CRP, and TSS. Serum Ang-1 level showed significant correlations with serum MMP-3 level and DAS28-CRP. Serum Ang-2 level showed significant correlations with serum CRP level and TSS. Conclusion. The serum VEGF level is important as an index of the activity of RA based on angiogenesis and a prognostic factor regarding joint destruction. Serum Ang-1 level may be useful as an index of sustained arthritis based on the maintenance of newly formed vessels. Serum Ang-2 level may reflect a state of marked angiogenesis.


Journal of Ultrasound in Medicine | 2001

Color/Power Doppler Sonographic Differential Diagnosis of Superficial Lymphadenopathy Metastasis, Malignant Lymphoma, and Benign Process

Takako Shirakawa; Yukio Miyamoto; Jiro Yamagishi; Kunihiko Fukuda; Shimpei Tada

Differentiation of lymph nodes as metastasis, malignant lymphoma, and benign lesions by gray scale and color/power Doppler ultrasonography has been reported. In this study we sought to determine patterns of abnormal vascularity, the relationship between diagnostic criteria and node size, and which vessel in the node was best suited for Doppler spectral analysis. Extrahilar vessels, defined as vessels entering through the lymphatic surface and not through the hilus, were also investigated.


American Journal of Roentgenology | 2014

Efficacy of Sonazoid (Perflubutane) for Contrast-Enhanced Ultrasound in the Differentiation of Focal Breast Lesions: Phase 3 Multicenter Clinical Trial

Yukio Miyamoto; Toshikazu Ito; Etsuo Takada; Kiyoka Omoto; Toshiko Hirai; Fuminori Moriyasu

OBJECTIVE The objective of our study was to compare the efficacy of contrast-enhanced ultrasound (CEUS) using the ultrasound contrast agent Sonazoid (perflubutane) with unenhanced ultrasound and supplementary contrast-enhanced MRI in the differential diagnosis (benign vs malignant) of focal breast lesions. The safety of Sonazoid was also assessed in this study. SUBJECTS AND METHODS A total of 127 patients with focal breast lesions were enrolled in this study at five centers in Japan. Three reviewers who were blinded to the patient characteristics independently assessed the ultrasound images and MR images in a randomized sequence. The accuracy, sensitivity, and specificity of CEUS, unenhanced ultrasound, and supplementary contrast-enhanced MRI for the differential diagnosis were compared using generalized estimating equation analyses. Diagnostic confidence was also assessed. RESULTS The accuracy of CEUS was significantly higher than that of unenhanced ultrasound (87.2% vs 65.5%, respectively; p < 0.001). In addition, CEUS showed significantly higher specificity, although the improvement in sensitivity was not statistically significant. The accuracy and specificity were significantly higher with CEUS than with contrast-enhanced MRI, but the improvement in sensitivity was not statistically significant. The area under the curve in a receiver operating characteristic analysis was significantly greater with CEUS than with unenhanced ultrasound. The incidence of adverse events was 11.4% and the incidence of adverse drug reactions was 3.3%. All adverse drug reactions were mild. CONCLUSION CEUS using Sonazoid was confirmed to be superior to unenhanced ultrasound for the differential diagnosis (benign vs malignant) of focal breast lesions in terms of diagnostic accuracy with no serious adverse reactions.


Journal of Clinical Ultrasound | 1998

Breast masses: Color Doppler, power Doppler, and spectral analysis findings

Nobuharu Hayashi; Yukio Miyamoto; Norio Nakata; Takeo Irie; Masahiro Ikegami; Keiko Asao; Shimpei Tada

To determine the diagnostic efficacy of power Doppler sonography (PDS) with spectral analysis for breast diseases, we retrospectively compared PDS and color Doppler sonography (CDS) in patients with breast lesions.


Journal of Ultrasound in Medicine | 2000

Power Doppler sonography of breast masses: correlation of Doppler spectral parameters with tumor angiogenesis and histologic growth pattern.

Mitsuhiro Tozaki; Masakazu Toi; Yukio Miyamoto; Kunihiko Fukuda

The purpose of this study was to examine the relationship between spectral analysis on power Doppler sonography and microvessel density. Power Doppler sonography was performed in 71 patients with breast masses (36 invasive carcinomas and 35 benign lesions). Microvessel density was measured in surgical specimens from all breast carcinomas using anti‐factor VIII‐related antibody. Invasive carcinomas were divided into two groups according to their growth pattern (solid type, scirrhous type). The pulsatility index and resistive index were high in malignant tumors compared with those in benign lesions (P < 0.001). The maximum velocity had weak statistical significance (P < 0.05). Although the correlation of maximum velocity with microvessel density was strong in solid tumors (P < 0.001), the maximum intensity in scirrhous tumors had no correlation with microvessel density. In conclusion, solid tumors showed a tendency toward correlation of maximum velocity with microvessel density. High maximum velocity with high microvessel density suggests breast carcinoma and could be predictive of a poor prognosis in invasive breast carcinoma.


Seminars in Ultrasound Ct and Mri | 2001

Ultrasound virtual endoscopic imaging

Norio Nakata; Yukio Miyamoto; Fumio Tsujimoto; Junta Harada; Simpei Tada; Kunihiko Fukuda

Volume data acquisition, three dimensional (3D) imaging, and multiplanar reformatting have become widely used for computed tomography (CT) and magnetic resonance imaging (MRI). As an extension of this technology, virtual endoscopic visualization of hollow organs has become a reality that is now finding its way into clinical CT practice. The same methods of computer processing as are used for CT and MRI can be applied to an ultrasound (US) volume image data set with the same potential output; namely, 3D, multiplanar, and virtual endoscopic images. The use of this image processing technology for US applications has lagged behind the CT and MRI applications, but considerable progress in applying these methods to US has occurred in recent years. As a result, US virtual endoscopic imaging now can be performed on a clinical basis by using standard US instruments and commercially available computer software. The use of newer US imaging methods, such as tissue harmonic and power Doppler imaging, has enhanced the potential for US virtual endoscopy. This article reviews the technology of US virtual endoscopy. In addition, our preliminary experience of using this method for abdominal and vascular diagnosis is described. Finally, we speculate on technical improvements and potential applications that are likely in the future.


Radiographics | 2012

Informatics in Radiology: Intuitive User Interface for 3D Image Manipulation Using Augmented Reality and a Smartphone as a Remote Control

Norio Nakata; Naoki Suzuki; Asaki Hattori; Naoya Hirai; Yukio Miyamoto; Kunihiko Fukuda

Although widely used as a pointing device on personal computers (PCs), the mouse was originally designed for control of two-dimensional (2D) cursor movement and is not suited to complex three-dimensional (3D) image manipulation. Augmented reality (AR) is a field of computer science that involves combining the physical world and an interactive 3D virtual world; it represents a new 3D user interface (UI) paradigm. A system for 3D and four-dimensional (4D) image manipulation has been developed that uses optical tracking AR integrated with a smartphone remote control. The smartphone is placed in a hard case (jacket) with a 2D printed fiducial marker for AR on the back. It is connected to a conventional PC with an embedded Web camera by means of WiFi. The touch screen UI of the smartphone is then used as a remote control for 3D and 4D image manipulation. Using this system, the radiologist can easily manipulate 3D and 4D images from computed tomography and magnetic resonance imaging in an AR environment with high-quality image resolution. Pilot assessment of this system suggests that radiologists will be able to manipulate 3D and 4D images in the reading room in the near future. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.324115086/-/DC1.


Journal of Medical Ultrasonics | 2010

Sonographic hemodynamic evaluation of spleno-renal shunt using the Valsalva maneuver

Yukio Miyamoto; Kaoru Onoue; Makiko Nishioka; Norio Nakata

PurposeThe purpose of this study was to assess the characteristic features of hemodynamic changes in portal venous hypertension with spleno-renal shunt on conventional B-mode and color Doppler imaging before and after the Valsalva maneuver.Materials and methodsA total of 11 patients with portal venous hypertension underwent conventional B-mode and color Doppler ultrasound during follow-up examinations. Sonographic imaging of the splenic vein and the left renal vein was performed before and after the Valsalva maneuver.ResultsIn the six patients with spleno-renal shunt formation, dilated left renal veins were depicted after the Valsalva maneuver. In the five patients without spleno-renal shunt, there was no apparent dilatation of the left renal vein either before or after the Valsalva maneuver. In all six patients with spleno-renal shunt, color flow mapping of the left renal veins was emphasized during the Valsalva maneuver. In the five patients without spleno-renal shunt formation, there were no apparent changes on color flow mapping of the left renal vein before or after the Valsalva maneuver.ConclusionThe sonographic findings of the splenic vein and the left renal vein on conventional B-mode and color Doppler imaging before and after the Valsalva maneuver are useful for diagnosis of spleno-renal shunt and for grading the hemodynamic changes caused by spleno-renal shunt.


Journal of Medical Ultrasonics | 2014

Usefulness of contrast-enhanced ultrasonography for intracystic breast tumors: a report of three cases

Kumiko Kato; Hiroko Nogi; Tomoyuki Ohta; Makiko Kamio; Yasuo Toriumi; Norio Nakata; Ken Uchida; Yukio Miyamoto; Hiroshi Takeyama

Cystic breast lesions are caused by a wide spectrum of breast diseases and can range from simple cysts to malignant tumors. Ultrasonography is a good tool for evaluation of the morphology and vascularity of cystic breast lesions. We report three patients in whom contrast-enhanced ultrasonography (CEUS) was used to evaluate intracystic tumors. One of the three patients was diagnosed with intracystic papilloma. Compared with conventional ultrasonography alone, CEUS more clearly demonstrated that the solid component within the mass was lobulated with a narrow base. The other two patients were diagnosed with intracystic papillary carcinoma, and CEUS clearly revealed the presence of widely elevated solid components within both masses, suggesting malignancy. Therefore, CEUS simplified morphological evaluation by enhancing the solid components within the cystic masses.


Journal of Medical Ultrasonics | 2013

A case of focal nodular hyperplasia with a new characteristic finding on contrast-enhanced ultrasonography using Levovist

Kaoru Onoue; Yukio Miyamoto; Makiko Nishioka; Norio Nakata; Toru Sekiya; Kunihiko Fukuda

We used contrast-enhanced ultrasound with Levovist, a microbubble contrast agent, to diagnose a case of hepatic focal nodular hyperplasia (FNH). A new characteristic finding of heartbeat-synchronized centrifugal enhancement was discovered. We call this enhancement pattern the “sonographic fireworks sign.” It is expected to be useful for diagnosing FNH, especially when the lesions are small and it is difficult to depict a spoke-wheel pattern.

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Norio Nakata

Jikei University School of Medicine

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Kunihiko Fukuda

Jikei University School of Medicine

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Shimpei Tada

Jikei University School of Medicine

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Takeo Irie

Jikei University School of Medicine

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Fumio Tsujimoto

Jikei University School of Medicine

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Kaoru Onoue

Jikei University School of Medicine

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Kiyoka Omoto

Jichi Medical University

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Takako Shirakawa

Tokyo Metropolitan University

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Akio Yamada

Jikei University School of Medicine

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