Limitations of thermodilution cardiac output measurements in the rat.

Heat loss from the vascular system could introduce an error in thermodilution cardiac output determinations. Cardiac output measured in the rat via the thermodilution technique following right atrial injection yielded different values (P less than 0.001), depending whether sampling was from the pulmonary artery (460 +/- 31 ml X min-1 X kg-1), right ventricle (311 +/- 19), or thoracic aorta (245 +/- 15).

Work in progress: hybrid temporal-energy subtraction in digital fluoroscopy.

Initial clinical results using a digital fluoroscopic implementation of the combined time-energy ("hybrid") subtraction technique are described, with emphasis on carotid and renal imaging. Where patient motion artifacts are due to soft-tissue motion alone, hybrid subtraction can remove them. Due to the need for a finite separation time between high- and low-energy pairs, however, the present implementation of the hybrid technique is not completely immune to soft-tissue motion.

A technique of scatter and glare correction for videodensitometric studies in digital subtraction videoangiography.

The logarithmic amplification of video signals and the availability of data in digital form make digital subtraction videoangiography a suitable tool for videodensitometric estimation of physiological quantities. A system for this purpose was implemented with a digital video image processor. However, it was found that the radiation scattering and veiling glare present in the image-intensified video must be removed to make meaningful quantitations.