Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact.

For the protection of the human head by energy absorption structures, a soft mechanical response upon contact with the head is required to mitigate the effect of impact, while a hard mechanical response for highly efficient energy absorption is required to stop the movement of the head. This study realized the opposite mechanical properties during head protection by transitioning the deformation mode from bending to auxetic compression. First, non-linear finite element (FE) models were constructed to numerically reproduce the bending behavior.

Does cerebrospinal fluid pulsation affect diffusion-weighted imaging thermometry? A study in healthy volunteers.

Diffusion-weighted imaging (DWI)-based thermometry offers potential as a noninvasive method for measuring temperatures deep inside the human brain. However, DWI might be influenced by the pulsatile flow of cerebrospinal fluid (CSF). This study aimed to investigate the influence of such pulsations on DWI thermometry in healthy individuals.

Effects of different fat-suppression methods on T1 values in dynamic contrast-enhanced magnetic resonance imaging: a phantom study.

Dynamic contrast-enhanced MRI may yield variable longitudinal-relaxation time (T1) values depending on the precision of the fat-suppression (FS) technique. This study aimed to investigate the influences of FS methods on T1 value measurements on phantoms containing test tubes filled with mixtures of five volumes of fat, six amounts of contrast agent, and water. Volumetric interpolated images were obtained using several FS methods and flip angles.

[Usefulness of the Principle of Selective Excitation Technique Non-electrocardiogramgated 3D-TOF Method in Lower-extremity MRA Using a Whole-body Coil].

Purpose: Generally, non-contrast, lower-extremity, magnetic resonance angiography (MRA) uses electrocardiography; thus, examination is difficult in patients who exhibit arrhythmia. However, the use of electrocardiography can be avoided by using the selective excitation technique in non-electrocardiogram-gated three-dimensional time-of-flight (TOF) (pNon-Gate) MRA. Therefore, patients who exhibit arrhythmia can be examined with pNon-Gate MRA.

Can we shorten the q-space imaging to make it clinically feasible?

Purpose: Q-space imaging (QSI) is a novel magnetic resonance imaging (MRI) technique that enables assessment of micro-structural changes of white matter. The acquisition time, however, is comparatively long to use for routine clinical assessment. Therefore, the present study investigated the clinically feasible b value combinations to measure the water molecular displacement probability density function (PDF) in healthy subjects.

Stereoscopic analysis of optic nerve head parameters in primary open angle glaucoma: the glaucoma stereo analysis study.

Purpose: The Glaucoma Stereo Analysis Study (GSAS), a cross sectional multicenter collaborative study, used a stereo fundus camera to assess various morphological parameters of the optic nerve head (ONH) in glaucoma patients and investigated the relationships between these parameters and patient characteristics.

Subjects And Methods: The study included 187 eyes of 187 subjects with primary open angle glaucoma or normal tension glaucoma (male: female  = 100: 87, age  = 61±9 years). Stereo pairs of ONH photographs were made with a stereo fundus camera (nonmyd WX).

Intraobserver and interobserver agreement of computer software-assisted optic nerve head photoplanimetry.

Purpose: To report the reproducibility profile of optic nerve head parameters obtained by computer software-assisted fundus photoplanimetry.

Methods: Fundus photographs obtained during a population-based health survey (Sakurae Study) were planimetrically analyzed using newly developed computer software, CDSketch. The parameters assessed included vertical and horizontal cup-to-disc (C/D) ratios, superior and inferior rim-to-disc (R/D) ratios, disc and cup vertical-to-horizontal (V/H) ratios, and disc-macular distance-to-disc diameter (DM/DD) ratio.

[Fundus photoplanimetry of the optic nerve head in the Sakurae Study].

Purpose: To explore the fundus photoplanimetric distribution of the optic nerve head in a population-based health survey conducted in Sakurae area, in Shimane, Japan(the Sakurae Study).

Methods: After the exclusion of poor quality images from the 1660 right eye-fundus photos obtained from the Sakurae Study in 1991, 1583 photos were digitized, and then were planimetrically analyzed using a newly developed computer software, CDSketch. The parameters calculated included vertical and horizontal cup-to-disc (C/D) ratios, superior and inferior rim-to-disc (R/D) ratios, disc and cup vertical-to-horizontal (V/H) ratios, and disc-macular distance-to-disc diameter (DM/DD) ratio.

Automated determination of cup-to-disc ratio for classification of glaucomatous and normal eyes on stereo retinal fundus images.

Early diagnosis of glaucoma, which is the second leading cause of blindness in the world, can halt or slow the progression of the disease. We propose an automated method for analyzing the optic disc and measuring the cup-to-disc ratio (CDR) on stereo retinal fundus images to improve ophthalmologists' diagnostic efficiency and potentially reduce the variation on the CDR measurement. The method was developed using 80 retinal fundus image pairs, including 25 glaucomatous, and 55 nonglaucomatous eyes, obtained at our institution.

Automated segmentation of optic disc region on retinal fundus photographs: Comparison of contour modeling and pixel classification methods.

The automatic determination of the optic disc area in retinal fundus images can be useful for calculation of the cup-to-disc (CD) ratio in the glaucoma screening. We compared three different methods that employed active contour model (ACM), fuzzy c-mean (FCM) clustering, and artificial neural network (ANN) for the segmentation of the optic disc regions. The results of these methods were evaluated using new databases that included the images captured by different camera systems.

Improvement of automated detection method of hemorrhages in fundus images.

This paper describes an improved method for detecting hemorrhages in fundus images. The detection of hemorrhages is one of the important factors in the early diagnosis of diabetic retinopathy. So, we had suggested several methods for detecting abnormalities in fundus images, but our methods had some problems.

Quantitative depth analysis of optic nerve head using stereo retinal fundus image pair.

Depth analysis of the optic nerve head (ONH) in the retinal fundus is important for the early detection of glaucoma. In this study, we investigate an automatic reconstruction method for the quantitative depth measurement of the ONH from a stereo retinal fundus image pair. We propose a technique to obtain the depth value from the stereo retinal fundus image pair, which mainly consists of five steps: 1.

Radial-searching contour extraction method based on a modified active contour model for mammographic masses.

In this study, we developed an automatic extraction scheme for the precise recognition of the contours of masses on digital mammograms in order to improve a computer-aided diagnosis (CAD) system. We propose a radial-searching contour extraction method based on a modified active contour model (ACM). In this technique, after determining the central point of a mass by searching for the direction of the density gradient, we arranged an initial contour at the central point, and the movement of a control point was limited to directions radiating from the central point.

Computer-aided diagnosis: the emerging of three CAD systems induced by Japanese health care needs.

The aim of this paper is to describe three emerging computer-aided diagnosis (CAD) systems induced by Japanese health care needs. CAD has been developing fast in the last two decades. The idea of using a computer to help in medical image diagnosis is not new.

Three-dimensional reconstruction of optic nerve head from stereo fundus images and its quantitative estimation.

It is important for diagnosis of glaucoma to grasp 3-D structure of an optic nerve head (ONH). The quantitative 3-D reconstruction of the ONH is required for the diagnosis. We propose a technique to obtain the depth value from stereo image pair of a retinal fundus for the 3-D reconstruction of the ONH.

Automated detection algorithm for arteriolar narrowing on fundus images.

We have developed a computer-aided diagnosis system (CAD) to detect abnormalities in fundus images. In Japan, ophthalmologists usually detect hypertensive changes by identifying arteriolar narrowing and focal arteriolar narrowing. The purpose of this study is to develop an automated method for detecting arteriolar narrowing and focal arteriolar narrowing on fundus images.

Lower prevalence of circulating natural killer T cells in patients with angina: a potential novel marker for coronary artery disease.

Objective: Atherosclerosis is an inflammatory disease. Natural killer T cells are a unique lymphocyte subset that can recognize lipid antigens presented by CD1d and secrete copious amounts of pro-atherogenic cytokines such as interferon-gamma. We have previously shown that natural killer T cells accelerate atherosclerosis in mice and macrophages incubated with oxidized low-density lipoproteins induce natural killer T cells to produce interferon-gamma.

[Follow-up studies of Hokkaido residents with Kawasaki disease].

Objectives: Sixteen national surveys of Kawasaki disease in Japan from 1970 to 2000 have identified a total of 169,117 patients with Kawasaki disease. Based on that figure, 8,460 residents of Hokkaido probably have a history of Kawasaki disease. It is also estimated that almost 270 Hokkaido residents would have Kawasaki disease-related coronary artery disease.