Assessment of Semi-automated Computed Tomographic Measures of Segmental Perfusion Defects in a Swine Model (Sus scrofa) of Intermediate Coronary Lesions.

Computed tomographic myocardial perfusion (CTP) imaging is a tool that shows promise in emergent settings for defining the hemodynamic significance of coronary artery disease. In this study, we examined the accuracy with which the transmural perfusion ratio (TPR) derived through semiautomated CTP analysis reflected segmental perfusion defects associated with intermediate coronary artery lesions in swine. Lesions (diameter stenosis, 65% ± 11%) of the left anterior descending coronary artery (LAD) were created in 10 anesthetized female swine (weight, 47.5 ± 1.9 kg) by using a pneumatic occlusion device implanted on the LAD. Occluder inflation pressures were adjusted to maintain fractional flow reserve (FFR, 74.3 ± 1.7) during adenosine infusion (140ug/kg/min). Static CTP imaging using a stress-rest protocol and segmental TPR derived from semiautomated CT perfusion software was compared with microsphere-derived TPR (mTPR) by using a 16-segment model and polar mapping. Intermediate LAD stenosis was verified through multiplanar coronary CT angiography. Receiver operating characteristic analysis identified an optimal threshold for segmental perfusion defects for intermediate lesions (TPR threshold, ≤0.80); however, the area under the receiver operating characteristic curve was 0.58, and the overall accuracy was 63%. At this threshold, the sensitivity and specificity were 65% and 61%, and the positive and negative predictive values were 61% and 65%, respectively. Although CTP-TPR illustrated segmental perfusion defects with intermediate lesions, the disparity between CTP-TPR and mTPR measures of segmental perfusion suggests that further advances in analysis software may be necessary to improve the localization of segmental defects for intermediated lesions.

Comparison of Rectal and Infrared Thermometry Temperatures in Anesthetized Swine (Sus scrofa).

Infrared thermometry (IRTM) is a noncontact method to measure temperature. The purpose of this study was to compare rectal temperature and IRTM in healthy anesthetized swine, with the hypothesis that IRTM would be an accurate, noninvasive alternative for rectal temperature measurement. Two groups of female Yorkshire-cross swine (n = 14 and n = 12) were sedated with Tiletamine-zolazepam (0.5 mg/kg) for blood collection during a routine physical examination. While sedated, rectal temperatures were measured using a SureTemp Plus 690 (Welch Allyn) and IRTM measurements were taken using a FLIR E5 thermal imaging camera. The 2 anatomic sites used for thermography measurements were the area surrounding the eye and the neck at the base of the ear. The distance from the imaging camera and the animal during IRTM measurements was 24 to 32 inches, a distance that would allow camera access in a standard swine enclosure. The infrared imaging camera's surface temperature measurement exhibited a proportional bias when compared with the rectal temperature. All rectal temperature measurements were between 98.7 °F to 101.3 °F, with a mean temperature of 100.4 °F. IRTM tended to underestimate rectal temperatures at lower values, and overestimate rectal temperatures at higher values by approximately (+) or (-) 0.8 °F of rectal temperature. Infrared thermometry can provide a quick noninvasive assessment of the body surface temperature, without the need for animal handling or restraint, but should not be considered an accurate replacement for rectal temperature measurement.

Measurement of fecal corticosterone metabolites as a predictor of the habituation of rhesus macaques (Macaca mulatta) to jacketing.

Jacket use in NHP is a common practice and is often considered a form of refinement during experiments necessitating extended periods of catheterization. An important consideration when using jackets is the physiologic effects that jacketing has on NHP and its potential to confound research. Several studies have evaluated the stress response and habituation of NHP to various forms of restraint, but none have looked directly at the timeframe necessary for the habituation of rhesus macaques (Macaca mulatta) to jackets. We set out to determine whether 3 d was a sufficient timeframe for this species to become habituated to a jacket, with or without an undershirt, by evaluating 2 major physiologic parameters. After jacket placement, we measured food consumption and collected fecal samples to measure fecal corticosterone metabolites (FCM) daily for 2 wk. FCM measurements for NHP without undershirts were significantly increased for days 2 and 3 after jacketing before returning to baseline levels. FCM measurements for NHP with undershirts were significantly increased for only 1 d after jacketing, suggesting that the undershirt has a positive effect on jacket habituation. There were no measurable differences in food consumption during the jacket habituation period. Furthermore, no significant differences were noted between sexes. These findings suggest that FCM levels return to baseline 3 d after jacketing and could be a useful predictor of jacket habituation in rhesus macaques.