Impaired response of perforating arteries to hypercapnia in chronic hyperglycemia.

Diabetes mellitus increases the risk of cerebrovascular disease, the effects of hypercapnia on CBF (cerebral blood flow) and cerebrovascular reactivity during diabetes are still inconsistent. Here, we have established a new microangiographic technique using synchrotron radiation (SPring-8, Japan), which enabled us to visualize rat cerebral vessels with high spatial resolution in real time. The goal of the study presented here was to identify the effects of chronic hyperglycemia on hypercapnia-induced vascular responses (endothelium-dependent vasodilatation) and nitric oxide (NO) donor- induced vascular responses (endothelium-independent) of perforating arteries and of the deeply located large cerebral arteries.

Ray tracing analysis of overlapping objects in refraction contrast imaging.

We simulated refraction contrast imaging in overlapping objects using the ray tracing method. The easiest case, in which two columnar objects (blood vessels) with a density of 1.0 [g/cm3], run at right angles in air, was calculated.

Estimation of contrast of refraction contrast imaging compared with absorption imaging-basic approach.

Purpose: We discuss the usefulness of the refraction contrast method using highly parallel X-rays as a new approach to minute lung cancer detection. The advantages of refraction contrast images are discussed in terms of contrast, and a comparison is made with absorption images.

Materials And Methods: We simulated refraction contrast imaging using globules with the density of water in air as models for minute lung cancer detection.

Imaging of fine structure of bone sample with high coherent X-ray beam and high spatial resolution detector.

In this study, we observed bone specimens of the mouse using a very high coherence beam and high spatial resolution detector (zooming tube: approximately 0.7 micron resolution) and successfully obtained images of the Haversian canal, osteocytes, and osteoclasts.

Measurement of blood vessel diameter for angiography using refraction contrast imaging.

We developed micro blood vessel diameter measurement algorithm for angiography using refraction contrast by monochromatic X-ray of the 3rd generation synchrotron radiation with the high degree parallel beam. The accuracy is evaluated using the actually obtained image.

Intrabody three-dimensional position sensor for an ultrasound endoscope.

To avoid or reduce the X-ray exposure in endoscopic examinations and therapy, as an alternative to the conventional two-dimensional X-ray fluoroscopy we are developing an intrabody navigation system that can directly measure and visualize the three-dimensional (3-D) position of the tip and the trace of an ultrasound endoscope. The proposed system can identify the 3-D location and direction of the endoscope probe inserted into the body to furnish endoscopic images. A marker transducer(s) placed on the surface of the body transmits ultrasound pulses, which are visualized as a marker synchronized to the scanning of the endoscope.