[Imaging Parameter Optimization of Non-contrast Three-dimensional Time-of-flight Magnetic Resonance Angiography for Patients with Intracranial Stents Using a 1.5 T Magnetic Resonance Imaging System].

The imaging parameters of non-contrast three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA) were optimized to improve the image quality for patients treated using stent-assisted coiling. A simulated blood flow phantom with three types of stents (Enterprise 2, Neuroform Atlas, and LVIS) was imaged by changing echo time (TE), band width (BW), flip angle (FA), and matrix (phase, frequency). The difference between the signal intensity in the simulated vessel and the background was measured at each imaging condition.

Note: Utilization of polymer gel as a bolus compensator and a dosimeter in the near-surface buildup region for breast-conserving therapy.

Tangential beam radiotherapy is routinely used for radiation therapy after breast conserving surgery. A tissue-equivalent bolus placed on the irradiated area shifts the depth of the dose distribution; this bolus provides uniform dose distribution to the breast. The gel bolus made by the BANG-Pro(®) polymer gel and in an oxygen non-transmission pack was applicable as a dosimeter to measure dose distribution in near-surface buildup region.

Cerebral relaxation times from postmortem MR imaging of adults.

Purpose: We measured T1 and T2 values of cerebral postmortem magnetic resonance (PMMR) imaging and compared the data of cadavers with that of living human subjects.

Materials And Methods: We performed PMMR imaging of the brains of 30 adults (22 men, 8 women; mean age, 58.2 years) whose deaths were for reasons other than brain injury or disease at a mean of 29.

Optimization of inversion time for postmortem short-tau inversion recovery (STIR) MR imaging.

Purpose: Signal intensity and image contrast differ between postmortem magnetic resonance (PMMR) images and images acquired from the living body. We sought to achieve sufficient fat suppression with short-tau inversion recovery (STIR) PMMR imaging by optimizing inversion time (TI).

Material And Methods: We subjected 37 deceased adult patients to PMMR imaging at 1.

[Investigation of polymer gel dosimetry for small circular irradiated fields].

Polymer gels can be used as tissue equivalent dosimeters, and polymer gel dosimetry can be employed without perturbation of the radiation field. In this study, polymer gel dosimetry was used for small circular irradiation fields 10-30 mm in diameter using a radiation planning system. The irradiated gels were compared with planned data for a 50% dose width of 6 Gy dose maximum, and for the dose difference between gels and planned data over an 80% dose maximum area.

[Comparison of diffusion tensor imaging-derived fractional anisotropy in multiple centers for identical human subjects].

The fractional anisotropy (FA) is calculated by using diffusion tensor imaging (DTI) with multiple motion probing gradients (MPG). While FA has become a widely used tool to detect moderate changes in water diffusion in brain tissue, the measured value is sensitive to scan parameters (e.g.

Postmortem magnetic resonance imaging dealing with low temperature objects.

In Japan, the medical examiner system is not widespread, the rate of autopsy is low, and many medical institutions therefore perform postmortem imaging using clinical equipment. Postmortem imaging is performed to clarify cause of death, select candidates for autopsy, make a guide map for autopsy, or provide additional information for autopsy. Findings are classified into 3 categories: cause of death and associated changes, changes induced by cardiopulmonary resuscitation, and postmortem changes.

Characteristic signal intensity changes on postmortem magnetic resonance imaging of the brain.

Purpose: We investigated and identified postmortem changes on magnetic resonance imaging (MRI) of the brain to provide accurate diagnostic guidelines.

Materials And Methods: Our subjects were 16 deceased patients (mean age 57 years) who underwent postmortem computed tomography (CT), MRI, and autopsy, the latter of which showed no abnormalities in the brain. The subjects underwent CT and MRI 6-73 h after confirmation of death (mean 26 h), after being kept in cold storage at 4 degrees C.