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Sachiko Yuen

Publications and source records attributed to Sachiko Yuen.

11 recordsLinked to original sources
PubMed2006

Dynamic contrast-enhanced MR imaging in screening detected microcalcification lesions of the breast: is there any value?

PURPOSE: To prospectively evaluate whether dynamic contrast-enhanced magnetic resonance (MR) imaging findings can help predict the presence of malignancy when screening detected microcalcification lesions, and its contribution to patient management of stereotactic vacuum-assisted breast biopsy (SVAB). MATERIALS AND METHODS: Dynamic contrast-enhanced breast MR imaging was performed when screening 100 detected microcalcification lesions not visualized by ultrasonography with 11-gauge SVAB. Definitive surgery was performed on all patients with the biopsy resulting in the diagnosis of breast cancer or atypical ductal hyperplasia (ADH). Positive predictive values (PPVs) and negative predictive values (NPVs) were calculated on the basis of a BI-RADS (Breast Imaging Reporting and Data System) category and the absence or presence of contrast uptake in the area of microcalcification. RESULTS: The BI-RADS mammography category correlated with the diagnosis of breast cancer (ADH excluded): category 3 = 7% (4/55); category 4 = 48% (13/27); category 5 = 94% (17/18). After dynamic contrast-enhanced MR imaging, three of four malignancies with BI-RADS mammography category 3 were diagnosed as true positive. Therefore, the PPV of BI-RADS mammography category 3 with MR imaging was 1.8% (1/55). The PPV of contrast uptake of MR imaging was 86% (32/37), significantly higher than the 67% (30/45) PPV of BI-RADS mammography 4 and 5 (P = 0.033). The NPV of BI-RADS mammography 3 was 93% (51/55) versus 97% (61/63) NPV of MR imaging (P = 0.167). CONCLUSION: In the evaluation of screening detected microcalcification lesions, dynamic contrast-enhanced breast MR imaging provides additional information with high PPV and NPV, and may therefore offer an alternative to SVAB for women who do not want to undergo SVAB with equivocal findings following full diagnostic mammographic assessment, but breast MR imaging with imperfect PPV and NPV cannot replace SVAB. CLINICAL RELEVANCE: Dynamic contrast-enhanced breast MR imaging can demonstrate malignant microcalcifications detected by screening mammography and can be recommended in the evaluation of equivocal microcalcifications prior to SVAB.

Adult↗
PubMed2005

Unusual late pulmonary complication in a child after umbilical cord blood transplantation: high-resolution CT-pathologic correlation.

We encountered a late pulmonary complication after umbilical cord blood transplantation (UCBT) that has not been previously reported. High-resolution CT (HRCT) findings of this disease were compared with the pathology. HRCT obtained on inspiration showed dilated thick-walled bronchioli, and innumerable centrilobular linear and branching structures in the bilateral middle and lower lobes. Neither mosaic perfusion nor air-trapping was seen in HRCT on inspiration and expiration. These HRCT findings were atypical compared with those of former bronchiolitis obliterans (BO) after bone marrow transplant (BMT). Pathologic specimens obtained by open lung biopsy showed thickening of the wall from the distal bronchioli to the alveolar ducts due to submucosal and intraepithelial infiltration of lymphocytes, histiocytes and foamy macrophages, which was not accompanied by organizing changes. These changes resemble lymphocytic bronchiolitis in lung transplant recipients, which was well correlated with HRCT findings. We think that our case was a new late pulmonary complication after UCBT.

Adolescent↗
PubMed2005

Comparison of FDG PET and SPECT for detection of bone metastases in breast cancer.

OBJECTIVE: The purpose of our study was to evaluate the efficacy of FDG PET and bone SPECT for diagnosing bone metastases in breast cancer. SUBJECTS AND METHODS: The study was a prospective series of 15 patients with breast cancer who underwent both PET and bone scanning with SPECT. Comparison was performed on a lesion-by-lesion analysis. MDCT, MRI, and the patient's clinical course were used as references. RESULTS: In the lesion-by-lesion analysis (n = 900), the sensitivity for diagnosing bone metastases was 85% for SPECT and 17% for PET, specificity was 99% for SPECT and 100% for PET, and accuracy was 96% for SPECT and 85% for PET. In the statistical analysis, bone SPECT was significantly superior to FDG PET for its sensitivity (p < 0.0001) and accuracy (p < 0.0001). No statistically significant difference was seen with regard to specificity. When classifying the bone metastases as osteoblastic or osteolytic, bone scanning classified 92% of metastases as osteoblastic and 35% of metastases as osteolytic, whereas PET classified 6% of metastases as osteoblastic and 90% of metastases as osteolytic. CONCLUSION: Bone SPECT is superior to FDG PET in detecting bone metastases in breast cancer. The sensitivity of osteoblastic lesions is limited with FDG PET. Surveillance of metastatic spread to the skeleton in breast cancer patients based on FDG PET alone is not possible.

Adult↗
PubMed2005

Effect of thin-section diffusion-weighted MR imaging on stroke diagnosis.

BACKGROUND AND PURPOSE: Diffusion-weighted (DW) imaging has limited spatial resolution, especially in the z direction. We decreased the section thickness of DW imaging to 3 mm to determine if this change improves the depiction of small infarcts and if it affects stroke diagnosis. METHODS: We studied conventional (5-mm section thickness, 1-mm intersection gap) and thin-section (3-mm section thickness, no intersection gap) DW imaging data in 49 patients with symptoms of acute cerebral ischemia. Two radiologists who were not aware of the clinical findings reviewed all images and diagnosed the stroke subtype according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) method. Accuracies of stroke diagnosis with an experienced neuroradiologist and with a second-year radiology resident were compared. To quantify lesion conspicuity, contrast-to-noise ratios (CNRs) were measured. The CNR of thin-section DW imaging was then divided by the CNR of conventional DW imaging to yield the relative CNR (rCNR). RESULTS: The experienced neuroradiologist made the correct final diagnoses in 78% of cases with conventional DW imaging, improving to 100% with thin-section DW imaging. The resident made the correct diagnoses in 71% of cases with conventional DW imaging, improving to 94% with thin-section DW imaging. Lesion conspicuity was improved on thin-section DW imaging (rCNR = 1.47 +/- 0.63), especially for supratentorial lesions (rCNR = 1.51 +/- 0.63). CONCLUSION: Compared with conventional DW imaging, thin-section DW imaging permitted better lesion conspicuity and more precise stroke diagnosis.

Aged↗
PubMed2004

Equivalent cross-relaxation rate imaging of breast cancer.

PURPOSE: To determine whether equivalent cross-relaxation rate (ECR) imaging is a feasible method for demonstrating breast cancer. MATERIALS AND METHODS: Fifteen breast cancer patients underwent both ECR imaging, with off-resonance saturation pulses at frequency offsets of 7 and 19 ppm (ECR-7 and ECR-19, respectively) from water resonance, and gadolinium (Gd)-enhanced dynamic magnetic resonance imaging (MRI) of the breast. The mean tumor size was 26.5 mm. The tumor outlines defined by their shape and margin on ECR-7 images were compared with the subtraction images produced by the dynamic study, and the distribution of hyperintensity areas and their shapes on ECR-19 images were assessed. All patients had surgery and pathological findings were compared to ECR images. RESULTS: The tumor outline of 13/15 (87%) tumors on ECR-7 images was nearly identical to that on subtraction images; ECR-19 images demonstrated the location and degree of fibrosis. The tumor outline of the other two tumors was less clear on ECR-7 images, and internal hyperintensity on ECR-19 images reflected intratumoral fibrotic foci. ECR-7 and -19 imaging findings allowed identification of four distinct tumor types that reflected the tumor growth patterns and their internal structures associated with fibrosis. CONCLUSION: ECR imaging is a feasible imaging technique for demonstrating breast cancer.

Adult↗
PubMed2004

Picture archiving and communication system introduced to a new Japanese cancer center hospital.

Picture archiving and communication systems (PACS) have been widely introduced as a credible alternative to the traditional film-based radiological service. Shizuoka Cancer Center Hospital (SCCH) introduced PACS and hospital information systems as an alternative to the film- and traditional paper-based hospital system at the opening of the hospital. Using PACS, whole images and their reports can be available at any nearby terminal. Users can select the display format for monitor viewing on the bases of individual preference and navigate through cases by buttons and rollerballs on the mouse with easy handling and quick response. Most clinicians in SCCH evaluated such medical circumstances well. Filmless image management systems will become popular in all hospitals in the near feature. All staff in each hospital should investigate the merits and demerits of this system and how to introduce it effectively.

Cancer Care Facilities↗
PubMed2003

Fiber-tracking method reveals sensorimotor pathway involvement in stroke patients.

BACKGROUND AND PURPOSE: We tested the feasibility of a new MRI technique that provides visualization of the sensorimotor tracts in vivo in a group of stroke victims. SUMMARY OF REPORT: Fourteen patients with small infarctions involving the white matter of the supratentorial brain were evaluated. Sensorimotor tracts on the lesional and contralesional sides were successfully depicted in all cases. The position of the sensorimotor tracts relative to the infarct was in good agreement with clinical symptoms. The overall sensitivity and specificity for sensorimotor tract involvement were 100% and 77%, respectively. CONCLUSIONS: Our proposed fiber-tracking method was shown to be a clinically feasible technique that correlates well with clinical symptoms.

Aged↗
PubMed2003

MR imaging-guided axillary node biopsy for breast cancer: initial findings.

The aim of this study was to evaluate the usefulness and feasibility of preoperative sentinel node needle biopsy of the breast under guidance of open MR imaging, a method that we developed. Nine patients with breast cancer in whom the axillary lymph nodes were not palpable underwent preoperative sentinel node needle biopsy under real-time MR imaging guidance. The sentinel nodes were identified before the biopsy using CT and MR imaging. Diagnostic ability of this method was compared with that of the operative diagnosis. Sentinel nodes were correctly identified in all 9 patients. The MR imaging-guided sentinel node needle biopsy was performed for all of the 9 patients, and, in 7 (77.8%) of the 9, a specimen sufficient for pathologic evaluation was obtained; and in 6, whether malignancy existed was precisely diagnosed. No serious complications were noted. This experience indicates the possibility of a precise diagnosis of whether the sentinel node in breast cancer is benign or malignant without surgery.

Adult↗
PubMed2003

Brain fiber tracking with clinically feasible diffusion-tensor MR imaging: initial experience.

Two technical challenges must be overcome before brain fiber tracking with diffusion-tensor magnetic resonance (MR) imaging can be applied to clinical practice: Imaging time must be shortened, and image distortion must be minimized. Single-shot echo-planar MR imaging with parallel imaging technique enabled both objectives to be accomplished. Twenty-three consecutive patients with brain tumors underwent MR imaging with a 1.5-T whole-body MR system. Fiber tracts on the lesion side in the brain had varying degrees of displacement or disruption as a result of the tumor. Tract disruption resulted from direct tumor involvement, compression on the tract, and vasogenic edema surrounding the tumor. This diffusion-tensor MR imaging method with the parallel imaging technique allows clinically feasible brain fiber tracking.

Adolescent↗
PubMed2002

Effect of intravenous gadolinium-DTPA on diffusion-weighted images: evaluation of normal brain and infarcts.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) is usually done before administration of intravenous contrast agents. Repetition of DWI is occasionally necessary after administration, but the effects of contrast material on DWI and apparent diffusion coefficient (ADC) values have not yet been fully examined. The present study assesses whether administration of gadolinium-based contrast material significantly affects DWI and ADC values. METHODS: We examined DWI data from 39 patients (mean age, 67.9 years; range, 34 to 87 years) who were evaluated with a stroke protocol at our institute. All patients were scanned at the acute or subacute stages of infarct from 3 hours to 5 days after symptom onset. We obtained DWI images using single-shot echo-planar imaging with a b value of 1000 s/mm2. Patients were injected with 0.1 mmol gadopentetate dimeglumine per 1 kg body weight. We examined the signal-to-noise ratio of the normal brain and the infarct and evaluated the contrast-to-noise ratio of each lesion. In addition, we compared the ADC values calculated from the DWI images before and after administration of contrast. The statistical significance of differences between precontrast and postcontrast administration was determined by use of a paired t test. RESULTS: The signal-to-noise and contrast-to-noise ratios of the DW images were not significantly different before and after administration of contrast agent. The ADC values were slightly lower after administration of contrast agent for both normal brain (P=0.0011) and infarcts (P=0.038). The estimated differences in the ADC values were approximately 1.3% and 3.5% for normal brain and infarcts, respectively. CONCLUSIONS: The lack of a significant difference between the signal-to-noise and contrast-to-noise ratios of DW images before and after administration of contrast agent indicates the feasibility of postcontrast DWI.

Adult↗