Yoshiko Hayashida

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BACKGROUND AND PURPOSE On diffusion-weighted imaging (DWI), metastatic tumors of the brain may exhibit different signal intensities (SI) depending on their histology and cellularity. The purpose of our study was to verify the hypotheses (1) that SI on DWI predict the histology of metastases and (2) that apparent diffusion coefficient (ADC) values reflect(More)
PURPOSE To retrospectively evaluate whether the minimum apparent diffusion coefficient (ADC) of the tumor seen on pretreatment magnetic resonance (MR) images is of prognostic value in patients with malignant supratentorial astrocytoma. MATERIALS AND METHODS The study was approved by the institutional review board; the requirement for informed patient(More)
BACKGROUND AND PURPOSE Although the prognostic value of perfusion MR imaging in various gliomas has been investigated, that in high-grade astrocytomas alone has not been fully evaluated. The purpose of this study was to evaluate retrospectively whether the tumor maximum relative cerebral blood volume (rCBV) on pretreatment perfusion MR imaging is of(More)
The purpose of this study was to compare the visibility of the normal subthalamic nucleus (STN) between fast spin-echo T2-weighted (FSE T2-W) images and fast short inversion time inversion-recovery (FSTIR) images, and to assess the age-related changes of the STN at 3.0 T. We evaluated high-resolution FSE T2-W and FSTIR images in 24 neurologically normal(More)
PURPOSE To evaluate the potential of diffusion-weighted imaging (DWI) in distinguishing chronic expanding hematomas (CEHs) from malignant soft tissue tumors. MATERIALS AND METHODS We performed conventional MRI and DWI of six CEHs and 31 malignant soft tissue tumors from 37 patients seen between May 2000 and November 2006. DWI was obtained with a(More)
We report a 75-year-old man with radiological evidence of a 4.5 × 3.0 cm cystic mass and polypoid masses in the left hepatic lobe. Study of surgical specimens returned a definitive diagnosis of intraductal papillary mucinous neoplasm of the bile duct (IPMN-B). IPMN-B, thought to be the counterpart of intraductal papillary mucinous neoplasm of the pancreas(More)
PURPOSE To assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). METHODS A total of 46 patients with(More)
The purpose of our study was to investigate whether quantitative diffusion-weighted images (DWI) were useful for monitoring the therapeutic response of primary bone tumors. We encountered 18 osteogenic and Ewing sarcomas. Magnetic resonance (MR) images were performed in all patients before and after therapy. We measured the apparent diffusion coefficient(More)
PURPOSE To determine whether quantitative diffusion-weighted imaging (DWI) is useful for characterizing poorly contrast-enhanced and T2-prolonged bone masses. MATERIALS AND METHODS We studied 20 bone masses that showed high signal intensity on T2-weighted images and poor enhancement on contrast-enhanced T1-weighted images. These included eight solitary(More)
Shifts in scalp-recorded direct current (DC) potential were studied in relation to the changes in end-tidal partial CO2 (PACO2) or O2 (PAO2) of the expired gas either during hyperventilation (HV), hypoventilation (HYPO) or inhalation of high CO2 content air during HV or HYPO in 10 healthy subjects. The DC potential was obtained through a chopper stabilized(More)