Fully automatic segmentation of the mitral leaflets in 3D transesophageal echocardiographic images using multi-atlas joint label fusion and deformable medial modeling.

Comprehensive visual and quantitative analysis of in vivo human mitral valve morphology is central to the diagnosis and surgical treatment of mitral valve disease. Real-time 3D transesophageal echocardiography (3D TEE) is a practical, highly informative imaging modality for examining the mitral valve in a clinical setting. To facilitate visual and quantitative 3D TEE image analysis, we describe a fully automated method for segmenting the mitral leaflets in 3D TEE image data. The algorithm integrates complementary probabilistic segmentation and shape modeling techniques (multi-atlas joint label fusion and deformable modeling with continuous medial representation) to automatically generate 3D geometric models of the mitral leaflets from 3D TEE image data. These models are unique in that they establish a shape-based coordinate system on the valves of different subjects and represent the leaflets volumetrically, as structures with locally varying thickness. In this work, expert image analysis is the gold standard for evaluating automatic segmentation. Without any user interaction, we demonstrate that the automatic segmentation method accurately captures patient-specific leaflet geometry at both systole and diastole in 3D TEE data acquired from a mixed population of subjects with normal valve morphology and mitral valve disease.

Application of an exclusively binarized correlation-calculation method to wind velocity measurement by use of stellar scintillation patterns.

An exclusively binarized method for the correlation calculation of image processing is presented with application to velocity measurements. The exclusively binarized correlation-calculation method is capable of determining the peak position of the correlation even with a small number of random-pattern images. Because the velocity is deduced from the movement of the correlation-peak position within a time interval, the method is suitable for the velocity measurement of random patterns. The method is applied to the measurement of the upper-atmospheric wind velocity by use of stellar scintillation patterns.

Nondiffracting narrow light beam with small atmospheric turbulence-influenced propagation.

A narrow light beam that propagates in the atmosphere with less disturbance than conventional light beams is introduced. The operating method and features of the newly proposed long-range nondiffracting beam (LRNB) are briefly demonstrated. Some experimental results of the atmospheric propagation of this beam at a distance of 500 m are shown in comparison with a conventional collimated beam and a focused beam. The results and related analyses show that the LRNB is much less influenced by atmospheric turbulence than other beams and suggest that the LRNB can apply to many fields.

Laser-ranging scanning system to observe topographical deformations of volcanoes.

We have developed a laser-ranging system to observe the topographical structure of volcanoes. This system can be used to measure the distance to a target by a laser and shows the three-dimensional topographical structure of a volcano with an accuracy of 30 cm. This accuracy is greater than that of a typical laser-ranging system that uses a corner-cube reflector as a target because the reflected light jitters as a result of inclination and unevenness of the target ground surface. However, this laser-ranging system is useful for detecting deformations of topographical features in which placement of a reflector is difficult, such as in volcanic regions.

Thiamin depletion after ethanol and acetaldehyde administration to rabbits.

The role of thiamin in the catabolism of ethanol and acetaldehyde has been investigated. When thiamin and subsequently ethanol were administered orally to rabbits, the thiamin concentration in blood increased slightly during the first 3 h and then decreased gradually. After 12 h, it became lower than the value before thiamin administration. Finally, it reached the lowest value after 24 h and then increased slowly to revert to normal in 72 h. It is suggested that thiamin participates in the catabolic pathway of ethanol. An oral administration of pyrazole, an inhibitor of alcohol dehydrogenase, followed by ethanol to rabbits caused a delay in ethanol elimination from blood. When acetaldehyde was injected intravenously to rabbits, thiamin concentration and the transketolase activity in blood decreased gradually and after 12 h the thiamin level reached its lowest value, then increased slowly and normalized in 72 h. Thus, it could be postulated that the decrease in thiamin after an acute ethanol ingestion linked greatly to the acetaldehyde catabolism.

Participation of thiamin in hepatic microsomal ethanol oxidizing system.

In order to assess the role of thiamin on ethanol metabolism, changes in the activity of hepatic microsomal ethanol oxidizing system (MEOS) were measured in rats fed thiamin deficient diet for 4-6 weeks. In thiamin deficient rats, the activity of hepatic MEOS was significantly decreased as compared with control rats. In vitro addition of thiamin or thiamin pyrophosphate (TPP) caused the restoration of the decreased MEOS activity, and this effect was dependent on the concentration of thiamin in rat liver microsomal fraction. Thus, thiamin partly involves in the oxidation of ethanol, and chronic thiamin deficiency predisposes to impair the ethanol oxidation, and consequently to increase the toxicity due to ethanol.

An experimental study of thiamine metabolism in acute ethanol intoxication.

A dose of 3.9 g/kg b.wt of ethanol was administered to rabbits, and ethanol and thiamine concentrations, transketolase activity and thiamine pyrophosphate (TPP) effect in blood samples were determined. It was established that ethanol ingestion produced a rapid decrease in blood thiamine levels and transketolase activity in erythrocytes and an increase in TPP effect in erythrocytes. These values reverted to normal within 2 or 3 days after the ingestion of alcohol.