Publications by authors named "Takayuki Masui"

Article Synopsis
  • The study aimed to compare the effectiveness and safety of low-dose sulfamethoxazole/trimethoprim (SMX/TMP) for preventing Pneumocystis jirovecii pneumonia (PCP) in patients with systemic rheumatic disease (SRD) on glucocorticoids.
  • A total of 186 Japanese patients were analyzed, with no cases of PCP reported in either the low-dose or conventional-dose groups after one year, although two in the low-dose needed an increased dose.
  • The results indicated that low-dose SMX/TMP was as effective as conventional dosage for PCP prevention while resulting in lower discontinuation rates and fewer severe adverse drug reactions.
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Background: To investigate the outcomes of Pneumocystis jirovecii pneumonia (PCP) between patients with rheumatoid arthritis (RA) treated with and without biologics before PCP onset.

Patients And Methods: We retrospectively included rheumatoid arthritis (RA) patients with PCP treated with and without biologics before PCP onset. The primary endpoints were 30-day and 180-day survival rates, and the secondary endpoint was severe PCP, including in-hospital death, intensive care unit admission, and requirement of respiratory support during hospitalization.

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Dynamic contrast-enhanced MR imaging (DCE-MRI) has been widely used for the evaluation of renal arteries. This method is also useful for tumor and renal parenchyma characterization. The very fast MRI may provide stable and precise information regarding vasculature and soft tissues.

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Objectives: To evaluate the diagnostic performance of MRI-based radiomics model for differentiating phyllodes tumors of the breast from fibroadenomas.

Methods: This retrospective study included 88 patients (32 with phyllodes tumors and 56 with fibroadenomas) who underwent MRI. Radiomic features were extracted from T2-weighted image, pre-contrast T1-weighted image, and the first-phase and late-phase dynamic contrast-enhanced MRIs.

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Objective To investigate the risk factors for the development of Pneumocystis jirovecii pneumonia (PCP) in patients with rheumatoid arthritis (RA) undergoing methotrexate (MTX) therapy. Methods This single-center retrospective cohort study included consecutive patients with RA who received MTX for at least one year. The study population was divided into PCP and non-PCP groups, depending on the development of PCP, and their characteristics were compared.

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Background: Subependymal giant cell astrocytoma (SEGA) is occasionally seen in tuberous sclerosis complex (TSC). Two main options are currently available for treating SEGA: surgical resection or pharmacotherapy using mammalian target of rapamycin inhibitors (mTORi). We hypothesized that opportunities for surgical resection of SEGA would have reduced with the advent of mTORi.

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To evaluate the improvement of radiologist performance in detecting bone metastases at follow up low-dose computed tomography (CT) by using a temporal subtraction (TS) technique based on an advanced nonrigid image registration algorithm.Twelve patients with bone metastases (males, 5; females, 7; mean age, 64.8 ± 7.

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Objective: We aimed to clarify the association between magnetic resonance imaging (MRI)-lesion patterns, including cortices and white matters, and the development, occurrence, and intractableness of West syndrome in patients with tuberous sclerosis complex (TSC), using visual analysis.

Methods: We collected data for 44 patients with TSC who had undergone brain MRI and developmental evaluation after the ages of 2 and 3 years, respectively. Fluid-attenuated inversion recovery (FLAIR) and T1-weighted images were used to analyze the number of cyst-like tubers, the number of cyst-like subcortical lesions, and the presence of diffuse lesions involving the cortices and white matter.

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Background: Magnetic resonance imaging (MRI) artifacts of adjustable shunt devices are thought to be similar to metal clip artifacts, in that they are larger with higher field strength scanners. We have published several reports about the artifacts of new MRI-resistant adjustable shunt devices, and we found a case in which a 3.0-T scanner showed smaller artifacts than the 1.

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Tuberous sclerosis complex (TSC) is an autosomal dominant inherited disease characterized by lesions that involve multiple organs. Interdisciplinary management at individual facilities needs to be coordinated to treat multiple organ systems. We hypothesized that the number of patients, opportunities for patients to undergo examinations, and opportunities for patients to be treated would increase after establishment of a TSC board (TB) in our hospital.

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Objective:: Mesenchymal chondrosarcoma (MCS) of the orbit is a rare and aggressive form of chondrosarcoma. The purpose of this study was to retrospectively identify the imaging features of mesenchymal chondrosarcoma of the orbit.

Methods:: This study included five patients with histologically confirmed MCS of the orbit who had undergone either CT, MRI, or both.

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Background: When the results of electroencephalography (EEG), magnetic resonance imaging (MRI), and seizure semiology are discordant or no structural lesion is evident on MRI, single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are important examinations for lateralization or localization of epileptic regions. We hypothesized that the concordance between interictal 2-[F]fluoro-2-deoxy-D-glucose (FDG)-PET and iomazenil (IMZ)-SPECT could suggest the epileptogenic lobe in patients with non-lesional findings on MRI.

Method: Fifty-nine patients (31 females, 28 males; mean age, 29 years; median age, 27 years; range, 7-56 years) underwent subdural electrode implantation followed by focus resection.

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Objective: Adjustable shunt valves that have been developed for the management of hydrocephalus all rely on intrinsically magnetic components, and artifacts with these valves on MRI are thus inevitable. The authors have previously reported that the shapes of shunt artifacts differ under different valve pressures with the proGAV 2.0 valve.

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Mesenchymal chondrosarcoma of the orbit is an extremely rare and aggressive tumor. We report image findings of F-fluorodeoxyglucose (FDG) positron emission/computed tomography (PET/CT) in 2 cases, one primary case and one recurrent case. The F-FDG PET/CT images revealed high uptake with an SUVmax of 6.

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Magnetic resonance angiography (MRA) is capable of imaging arteries in the half to whole body by a single acquisition without a nephrotoxic contrast medium, and acquired images can be reconstructed into a specific cross-sectional view in an arbitrary directions. MRA is applicable for vessels non-reachable by a catheter approach, and collateral vessels can be fully visualized. Since MRA is minimally-invasive with no exposure to ionized radiation, it can be repeatedly applied for follow-up.

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Purpose: To compare the abilities of T2-weighted (T2W) imaging using respiratory-triggered fast spin-echo (RT-FSE), breathhold fast-recovery FSE (BH-FRFSE), and BH single-shot FSE (BH-SSFSE) sequences without an endorectal coil to detect rectosigmoid carcinomas.

Materials And Methods: Forty patients (stage: pT0, 1; pTis-2, 15; pT3-4, 24) were included in the study. All examinations were performed on a 1.

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Purpose: The aim of this study was to compare magnetic resonance cholangiopancreatography (MRCP) using respiratory-triggered (resp) three-dimensional Fourier transformation (3D) fast-recovery fast spin echo (FR-FSE) sequence with array spatial sensitivity technique (ASSET) for visualization of the pancreatobiliary system with breath-hold single thick-section and multiple thin-section MRCP using 2D single shot FSE (SSFSE) sequences.

Materials And Methods: Forty patients underwent MRCP for evaluation of pancreatobiliary abnormalities in a 1.5-T magnet.

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Objectives: To evaluate the incidence of acute adverse reactions and degrees of heat sensation and local pain after intravenous injection of high and medium concentrations of iodinated contrast medium for computed tomography (CT).

Methods: A prospective study was performed involving 729 patients who underwent contrast CT scans. High-concentration (370 mgI/mL) and medium-concentration (300 mgI/mL) iodinated contrast medium was assigned to 342 patients (group H, aged 20-90 years, mean = 59.

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Pancreatic lymphoma is rare and is usually found as a large pancreatic mass. We report the case of a small 2-cm pancreatic lymphoma in a 54-year-old woman that had its histological origin in the pancreatic parenchyma. The mass showed homogeneously high signal-intensity on T2-weighted images and low signal-intensity on T1-weighted images.

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Hepatic hemangioma is a common benign tumor, but its exophytic and expansile forms may be atypical. We report a case of exophytic hemangioma of the liver with a growing tendency, demonstrated using magnetic resonance imaging (MRI) and computed tomography (CT) combined with angiography.

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Purpose: To evaluate whether multiphase-multisection T2-weighted magnetic resonance (MR) images help exclude pseudolesions mimicking leiomyoma and adenomyosis on static T2-weighted fast spin-echo (FSE) MR images and to characterize temporal changes in uterine signal intensity related to uterine contraction.

Materials And Methods: T2-weighted FSE and multiphase-multisection single-shot FSE (SSFSE) MR imaging were performed in 43 patients who underwent hysterectomy. Each imaging set was evaluated separately by two independent readers, and receiver operating characteristic analysis was performed.

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Purpose: Our goal was to test the hypothesis, as previously reported in other studies, that apparent diffusion coefficients (ADCs) provide specific information to diagnose ovarian tumors, especially to discriminate between benign and malignant lesions.

Method: T1-and T2-weighted spin echo imaging and diffusion-weighted echo planar imaging were performed in 31 women with 61 cystic components of ovarian tumors.

Results: The lesions that showed typical watery intensity, hypointensity in T1-weighted imaging, and hyperintensity in T2-weighted imaging had similar ADCs, ranging from 1.

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