Reconstruction of time-varying 3-D left-ventricular shape from multiview X-ray cineangiocardiograms

This paper reports on the clinical application of a system for recovering the time-varying three-dimensional (3-D) left-ventricular (LV) shape from multiview X-ray cineangiocardiograms. Considering that X-ray cineangiocardiography is still commonly employed in clinical cardiology and computational costs for 3-D recovery and visualization are rapidly decreasing, it is meaningful to develop a clinically applicable system for 3-D LV shape recovery from X-ray cineangiocardiograms. The system is based on a previously reported closed-surface method of shape recovery from two-dimensional occluding contours with multiple views. To apply the method to "real" LV cineangiocardiograms, user-interactive systems were implemented for preprocessing, including detection of LV contours, calibration of the imaging geometry, and setting of the LV model coordinate system. The results for three real LV angiographic image sequences are presented, two with fixed multiple views (using supplementary angiography) and one with rotating views. 3-D reconstructions utilizing different numbers of views were compared and evaluated in terms of contours manually traced by an experienced radiologist. The performance of the preprocesses was also evaluated, and the effects of variations in user-specified parameters on the final 3-D reconstruction results were shown to be sufficiently small. These experimental results demonstrate the potential usefulness of combining multiple views for 3-D recovery from "real" LV cineangiocardiograms.

A viewpoint determination system for stenosis diagnosis and quantification in coronary angiographic image acquisition

This paper describes the usefulness of computer assistance in the acquisition of "good" images for stenosis diagnosis and quantification in coronary angiography. The system recommends the optimal viewpoints from which stenotic lesions can be observed clearly based on images obtained from initial viewpoints. First, the viewpoint dependency of the apparent severity of a stenotic lesion is experimentally analyzed using software phantoms in order to show the seriousness of the problem. The implementation of the viewpoint determination system is then described. The system provides good user-interactive tools for the semiautomated estimation of the orientation and diameter of stenotic segments and the three-dimensional (3-D) reconstruction of vessel structures. Using these tools, viewpoints that will not give rise to foreshortening and vessel overlap can be efficiently determined. Experiments using real coronary angiograms show the system to be capable of the reliable diagnosis and quantification of stenosis.

Experimental infection with avian infectious bronchitis virus (Kagoshima-34 strain) in chicks at different ages

Chicks at 2, 4 or 6 weeks of age were experimentally infected individually with a nephrosis/nephritis-causing avian infectious bronchitis virus (IBV) strain Kagoshima-34. The susceptibility of chicks in each group to the infection was compared, based on the clinical signs, excretion of virus in the faeces and antibody titres in the serum. The results showed that although all chicks appeared to be susceptible to IBV infection, the most severe clinical response was observed following infection at 2-week-old. Likewise, whilst the virus was also recovered from the faeces of all the chicks infected, the duration of viral excretion was longest in the 2-week-old chicks. A high antibody titre was detected at 4 weeks post infection (PI) and was maintained for at least another 16 weeks in the 4- and 6-week-old chicks. In contrast, a low antibody titre was detected only between 8 to 12 weeks PI in the 2-week-old chicks. Thereafter, no antibody was detected despite the presence of clinical signs.