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Hiroshi Nakahara

Publications and source records attributed to Hiroshi Nakahara.

6 recordsLinked to original sources
PubMed2006

Magnetic resonance-guided focused ultrasound surgery of breast cancer: reliability and effectiveness.

BACKGROUND: Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is a noninvasive technique that has been shown to coagulate benign and malignant tumors. The purpose of this study was to evaluate MRgFUS safety and effectiveness for the ablation of breast carcinomas. STUDY DESIGN: Thirty women with biopsy-proved breast cancer underwent MRgFUS treatment. Gadolinium-enhanced MR images were used for treatment planning and posttreatment radiologic assessment of treated tissue, and temperature-sensitive MR images provided real-time treatment monitoring. After MRgFUS, all 30 women underwent wide excision or mastectomy. The extent of thermal ablation was assessed with tumor histology. RESULTS: Treatment was well tolerated, with a minimum of adverse effects, especially when performed under local anesthesia. On pathologic examination, mean (+/-SD) necrosis of the targeted breast tumors was 96.9 +/- 4% (median 100%, range 78% to 100%) of tumor volume. Fifteen (53.5%) of 28 evaluable patients had 100% necrosis of the ablated tumor; only 3 patients (10.7%) had less than 95% necrosis. In 28 (93.3%) patients, 100% of the malignancy was within the treatment field, and 98% and 95% of tumor lay within the treatment field in 2 remaining patients. Retrospective analysis in two patients with residual tumor showed treatment was not delivered to the full recommended area, reaffirming the need for precise localization and the value of contrast-enhanced images for treatment planning. CONCLUSIONS: MRgFUS has great potential to become a viable noninvasive replacement for lumpectomy. Additional studies focusing on posttreatment image-based evaluation are needed.

Adult↗
PubMed2003

A comparison of MR imaging, galactography and ultrasonography in patients with nipple discharge.

BACKGROUND: The aim of this study is to assess the usefulness of three-dimensional contrast-enhanced magnetic resonance (MR) imaging, compared with galactography and ultrasonography(US). METHODS: Fifty-five patients with bloody nipple discharge were investigated retrospectively. All patients were examined by galactography, ultrasonography and MR imaging. These three sets of findings were compared with the histopathological results from 16 intraductal biopsies, 3 excisional biopsies, 24 microdochectomies and 12 mastectomies. RESULTS: Contrast enhanced MR imaging demonstrated all malignant lesions including ductal carcinoma in situ (DCIS). Four cases of DCIS were not visualized by ultrasonography and three malignant lesions were missed by galactography. In the MR study, segmental clumped enhancement (positive predictive value =100 %), and focal mass with smooth border (negative predictive value =87.5 %) were the statistically significant predictive factors. CONCLUSIONS: Among the three modalities, contrast-enhanced three-dimensional MR imaging demonstrated the location and distribution of the lesions most clearly, especially in cases of ductal carcinoma in situ. It has the potential to be a useful diagnostic tool for patients with nipple discharge.

Adult↗
PubMed2002

Accumulation of 4- and 5-ene steroid sulfates in human breast cyst fluids.

Gross cystic disease of the breast is one of the most common diseases of adult females. Breast cyst fluid contains various steroid hormones. In order to obtain more information about the concentrations of 4- and 5-ene steroids in human breast cyst fluids, levels of pregnenolone sulfate (PREGS), pregnenolone (PREG), dehydroepiandrosterone sulfate (DHEAS) and dehydroepiandrosterone (DHEA) were determined by high-performance liquid chromatography (HPLC). A total of 35 human breast cyst fluid samples, obtained from 35 patients (28-54 years old) were analyzed. Cyst fluid electrolytes were simultaneously determined. Levels of PREGS (mean+/-S.D.) were 26.9+/-20.0 micromol/l (N=35) and of PREG were <0.1 micromol/l. Levels of DHEAS and DHEA were 89.1+/-111.7 micromol/l (N=35) and 0.3+/-0.2 micromol/l (N=35), respectively. Cyst fluids were divided into two groups (types I and II) according to their electrolyte ratio (K(+)/Na(+)). The cysts of the type I group (K(+)/Na(+) >1.5) contained significantly higher levels of PREGS (39.9+/-21.1 micromol/l) and DHEAS (133.2+/-87.9 micromol/l) than those of the type II group (K(+)/Na(+) <1.5), the mean levels of which were 19.8+/-16.2 micromol/dl for PREGS, and 36.3+/-29.0 micromol/dl for DHEAS (P<0.05). PREGS and DHEAS levels in the cysts were significantly correlated (r=0.49; P<0.01). Human breast cyst fluids contain high concentration of DHEAS and PREGS, especially in the cyst fluids containing high K(+)/Na(+) ratios.

Adult↗
PubMedDate not supplied

A case of alpha-thalassemia-2 associated with pulmonary infarction.

Pulmonary infarction is an entity of medical significance that develops concurrently in beta-thalassemia but not in alpha-thalassemia. The reason for this difference is yet to be elucidated. We have evaluated a 21-year-old male alpha-thalassemia-2 patient who had profound microcytic anemia and pulmonary infarction. Analysis of the alpha-globin gene revealed -alpha3.7/alpha alpha genotype. His mother also had the same heterozygous gene deletion, though she had neither anemia nor pulmonary infarction. Since the patient had no other predisposition to pulmonary infarction, it is suggested that there is a close etiologic relationship between morphologic abnormality of the erythrocytes caused by alpha-thalassemia-2 and development of pulmonary infarction.

Adult↗
PubMedDate not supplied

Extension of breast cancer: comparison of CT and MRI.

PURPOSE: To compare three-dimensional (3D) helical CT with 3D MRI in the evaluation of intraductal spread of breast cancer. METHODS: Fifty patients with breast cancer were examined. Tumor size ranged from Tis to T2. The whole breast was scanned by both breath-holding helical CT and MRI with contrast media. Linear or segmental enhancement, and spotty enhancement around the main tumor were considered to indicate ductal carcinoma in situ (DCIS) or ductal spread. These findings were compared with thin section histopathologic data. RESULTS: Seventeen of 35 patients had intraductal spread with invasive cancer and 15 patients had DCIS. The sensitivity, specificity, and accuracy of 3D CT in detecting intraductal spread or DCIS were 71.9%, 83.3%, and 76.0%, respectively, and those of 3D MRI were 87.5%, 61.1%, and 78.0%. Overestimations numbered three (6.0%) on CT and seven (14.0%) on MRI, and underestimations numbered nine (18.0%) on CT and four (8.0%) on MRI. CONCLUSION: 3D helical CT can provide good information about the spread of breast cancer and could be an alternative to 3D MRI for preoperative examination of breast cancer.

Adult↗