A novel high power vacuum diode with a focusing electrode for effective operation in a low guiding magnetic field.

A novel diode featuring an annular cathode and a ring-shaped focusing electrode and operating in a low guiding magnetic field (GMF) has been developed. It was found that the breakdown threshold for a focusing electrode made of titanium was 140 kV/cm higher than a stainless steel electrode for the same operating conditions. Comparison of the diode current measured by a Rogowski coil and the beam current measured by a Faraday cup at the collector indicated that an intense relativistic electron beam was transmitted effectively even in a GMF of as low as 0.

Standardized MRI assessment of high-grade glioma response: a review of the essential elements and pitfalls of the RANO criteria.

Accurately evaluating response in the treatment of high-grade gliomas presents considerable challenges. This review looks at the advancements made in response criteria while critically outlining remaining weaknesses, and directs our vision toward promising endpoints to come. The 2010 guidelines from the Response Assessment in Neuro-Oncology (RANO) working group have enhanced interpretation of clinical trials involving novel treatments for high-grade glioma.

Consensus recommendations for a standardized Brain Tumor Imaging Protocol in clinical trials.

A recent joint meeting was held on January 30, 2014, with the US Food and Drug Administration (FDA), National Cancer Institute (NCI), clinical scientists, imaging experts, pharmaceutical and biotech companies, clinical trials cooperative groups, and patient advocate groups to discuss imaging endpoints for clinical trials in glioblastoma. This workshop developed a set of priorities and action items including the creation of a standardized MRI protocol for multicenter studies. The current document outlines consensus recommendations for a standardized Brain Tumor Imaging Protocol (BTIP), along with the scientific and practical justifications for these recommendations, resulting from a series of discussions between various experts involved in aspects of neuro-oncology neuroimaging for clinical trials.

Volumetric MRI and MRS provide sensitive measures of Alzheimer's disease neuropathology in inducible Tau transgenic mice (rTg4510).

The purpose of this study was to determine if in vivo high resolution 3D MRI and localized (1)H MR spectroscopy (MRS) can detect brain findings resembling Alzheimer's disease in a transgenic mouse model of Tau pathology. Seven double transgenic rTg4510 female mice and 7 age-matched wild-type (wt) female mice were evaluated at 5 months of age. To confirm the usefulness and consistency of in vivo MRI/S, we also scanned the brains of 14 male mice (7 rTg4510 and 7 age-matched wt) at 8 months of age.

Characterizing the regional structural difference of the brain between tau transgenic (rTg4510) and wild-type mice using MRI.

rTg4510 transgenic mouse model demonstrates features resembling Alzheimer's disease including neurofibrillary degeneration and progressive neuronal loss. We investigated the volumetric differences of brain structures between transgenic and wild-type mice using MR images of fourteen 5.5 month old female mice.

Selective PPARdelta agonist treatment increases skeletal muscle lipid metabolism without altering mitochondrial energy coupling: an in vivo magnetic resonance spectroscopy study.

Peroxisome proliferator-activated receptor-delta (PPARdelta) activation results in upregulation of genes associated with skeletal muscle fatty acid oxidation and mitochondrial uncoupling. However, direct, noninvasive assessment of lipid metabolism and mitochondrial energy coupling in skeletal muscle following PPARdelta stimulation has not been examined. Therefore, in this study we examined the response of a selective PPARdelta agonist (GW610742X at 5 or 100 mg.

Normal and transplanted rat kidneys: diffusion MR imaging at 7 T.

Purpose: To investigate the feasibility of obtaining reproducible apparent diffusion coefficient (ADC) maps of normal rat kidneys by using respiratory-triggered spin-echo diffusion-weighted magnetic resonance (MR) imaging, to investigate the sensitivity of ADC maps in the evaluation of renal blood flow, and to use this technique to monitor acute graft rejection in transplanted rat kidneys.

Materials And Methods: Spin-echo diffusion-weighted MR imaging measurements were performed in 20 normal rats and nine rats that had undergone transplantation (six rats had received allografts; three had received isografts) at 7 T. To evaluate the effect of alteration in blood flow and water transport function, angiotensin II was infused in six normal rats and a series of spin-echo diffusion-weighted MR images was obtained at five time points.

Correlation of CT analysis and audiometry in Japanese otosclerosis.

Objective: To determine the extent of audiometric correlation with CT findings.

Methods: Forty-four patients (82 ears) with surgically confirmed otosclerosis underwent preoperative CT examination. Based on the computed tomography (CT) findings, the ears were classified into five groups as follows: Group A, the group with no pathological CT findings; Group B1, the group with demineralization localized in the region of the fissula antefenestram; Group B2, the group with demineralization extending towards the cochleariform process from the anterior region of the oval window; Group B3, the group with extensive demineralization surrounding the cochlea; and Group C, the group with thick anterior and posterior calcified plaques.

Improving spatiotemporal resolution of USPIO-enhanced dynamic imaging of rat kidneys.

This paper addresses the problem of enhancing spatiotemporal resolution of ultra-small superparamagnetic iron oxide (USPIO)-enhanced dynamic MRI of rat kidneys. To alleviate the limited resolution problem of conventional full-scan Fourier imaging methods, we use a generalized series-based imaging scheme to reduce coverage of kappa-space. Experimental results demonstrate that the generalized series imaging method with basis functions constructed using two references (pre- and post-contrast) can reduce the number of phase encodings measured during the dynamic contrast wash-in process by a factor of 4 with a negligible or minimal loss of image quality.

In vivo detection of acute rat renal allograft rejection by MRI with USPIO particles.

Background: Magnetic resonance imaging (MRI) for non-invasively detecting renal rejection was developed by monitoring the accumulation of macrophages labeled with dextran-coated ultrasmall superparamagnetic iron oxide (USPIO) particles at the rat renal allografts during acute rejection.

Methods: Five groups of male rats with DA-->BN renal allografts and one group with BN-->BN renal isografts were investigated by MRI before, immediately after, and 24 hr after intravenous infusion with different doses of USPIO particles. All infusions were done on post-operative day 4.