Comparison of apparent diffusion coefficient (ADC) values obtained by echo planar imaging diffusion-weighted imaging (DWI) and radial acquisition regime DWI in low field MRI systems: A phantom study.

Introduction: Diffusion-weighted imaging (DWI) with radial acquisition regime (RADAR; RADAR-DWI) is a fast spin echo (FSE)-based DWI imaging technique that is known to be robust to magnetic susceptibility artifacts and distortions as compared with echo planar imaging DWI (EPI-DWI). Several reports have suggested that the apparent diffusion coefficient (ADC) values obtained with FSE-based DWI are different from those obtained with EPI-DWI. The purpose of this study was to create phantoms that mimic the T and ADC values of various tissues and to demonstrate the ADC values obtained with RADAR-DWI and EPI-DWI in low-field magnetic resonance imaging (MRI) systems.

Technical Note: Novel imaging method to obtain gray matter-attenuated inversion recovery image using low-field magnetic resonance imaging systems.

Introduction: The double inversion recovery (DIR) technique suppresses two types of tissue signals with different T1 values by applying two inversion recovery (IR) pulses with different inversion times (TI). In contrast, the double tissue suppression with multi-echo acquisition and single TI combining HIRE (DOMUST-HIRE) method, is a technique enabling the white-matter-attenuated inversion recovery (WAIR) images by setting one inversion time (TI) in a sequence based on the multi-echo method and subtracting the second echo image from the first echo image. Here, we propose a new sequence that can provide the gray-matter-attenuated inversion recovery image based on the DOMUST-HIRE method.

A New Magnetic Resonance Imaging Method for 2 Tissue Suppression: Double Tissue Suppression With Multiecho Acquisition and Single Inversion Time Combining High-Intensity Reduction (DOMUST-HIRE).

Introduction: The fluid-attenuated inversion recovery (FLAIR) method is one of the most important magnetic resonance imaging techniques for the brain, and the high-intensity reduction (HIRE) method is an imaging technique to obtain cerebrospinal fluid suppression images by subtracting long echo time images from short echo time images. In contrast, the double inversion recovery technique suppresses 2 types of tissue signals with different T1 values by applying 2 inversion recovery pulses with different inversion times. However, the double inversion recovery method requires the setting of 2 inversion times in a sequence; thus, its use is limited to relatively high-specification equipment.

Feasibility of salt pads to improve fat suppression in low-field MRI systems.

Introduction: Fat-suppressed images are essential in clinical practice but are often affected by magnetic field inhomogeneity, resulting in poor image quality. We hypothesized that salt (99% sodium chloride [NaCl]) could be used as a magnetic field uniformity assist pad and verified whether salt pads improve magnetic field uniformity and the fat suppression effect in low-field magnetic resonance imaging (MRI) systems.

Methods: We conducted a small clinical study where coronal 2D fast spin-echo T2-weighted MRI with fat suppression was performed.

Radiation exposure dose outside the irradiation field due to differences in pediatric head computed tomography scanning methods.

The use of pediatric computed tomography (CT), a valuable imaging tool, has been increasing rapidly. The present study examined radiation exposure in non-irradiated fields of CT scans in pediatric patients using a 7-year-old child phantom. Radio-photoluminescence glass dosimeters were placed in the insertion ports of the phantom corresponding to the organs.

COMPARISON OF THE PERIPHERAL DOSES FROM DIFFERENT IMRT TECHNIQUES FOR PEDIATRIC HEAD AND NECK RADIATION THERAPY.

Intensity-modulated radiation therapy (IMRT) can deliver high and homogeneous doses to the target area while limiting doses to organs at risk. We used a pediatric phantom to simulate the treatment of a head and neck tumor in a child. The peripheral doses were examined for three different IMRT techniques [dynamic multileaf collimator (DMLC), segmental multileaf collimator (SMLC) and volumetric modulated arc therapy (VMAT)].

[Development of an automated patient recognition method for chest CT images using a template-matching technique].

If patient information, such as identification number or patient name, has been entered incorrectly in a picture archiving and communication system (PACS) environment, the image may be stored in the wrong place. To prevent such cases of misfiling, we have developed an automated patient recognition system for chest CT images. The image database consisted of 100 cases with present and previous chest CT images.

[Diagnostic detection performance of a simulated nodule in chest computed tomography images and gray and color nuclear medicine images: comparison between a medical liquid crystal display monitor and an ordinary liquid crystal display monitor].

The purpose of this study was to evaluate the detection performance of simulated nodules in chest computed tomography (CT) images and nuclear medicine images with an ordinary liquid crystal display (LCD) and a medical LCD (grayscale standard display function: GSDF) and gamma 2.2. We collected 72 chest CT image slices obtained from an LSCT phantom with simulated signals composed of various sizes and CT values and 78 slices of monochrome and color nuclear medicine images obtained from a digital phantom with a simulated signal composed of various sizes and radiation levels.

Effectiveness of temporal and dynamic subtraction images of the liver for detection of small HCC on abdominal CT images: comparison of 3D nonlinear image-warping and 3D global-matching techniques.

Misregistration errors occur at the periphery of the hepatic region due to respiratory- and interval-related changes in hepatic shape. To reduce these misregistration errors, we developed a temporal and dynamic subtraction technique to enhance small hepatocellular carcinoma (HCC) by using a 3D nonlinear image-warping technique. The study population consisted of 21 patients with HCC.

[Image examination of malignant tumors in lungs observed on the basis of cost analysis using diagnosis procedure combination data].

Recently, the environment of medical treatment in our country has become more strict. The purpose of this study is to find changes in the implementation of diagnostic imaging from the point of view of cost analysis, through the use of diagnosis procedure combination (DPC) data. The patient data has been extracted from the DPC data.