Advancing the health and well-being of animals and people

Principal Investigator: Peter Scrivani
Co-Principal Investigator: Manuel Martin Flores

Department of Clinical Sciences
Contact Information: Email: - Phone: 607-253-3160
Sponsor: Bernice Barbour Foundation
Grant Number: 0174.12011
Title: Dynamic CT Evaluation of Blood Flow in the Maxillary Artery of Cats with the Mouth Closed and Maximally Opened
Annual Direct Cost: $9,358
Project Period: 01/01/2012-12/31/2012

DESCRIPTION (provided by applicant): The broad objective of this study is to eliminate blindness and deafness in cats that undergo general anesthesia for dental procedures. Previously, these infrequent but devastating outcomes were attributed to anesthesia-associated low blood pressure and/or hypoxemia. We posit that mechanical obstruction of blood flow in the maxillary arteries is a heretofore unrecognized part of the pathogenesis that may make these outcomes avoidable. In cats the maxillary arteries (via the rete branches) are the primary arterial blood supply to the eyes, inner ears, and brain. Blood flow through the maxillary arteries may be at risk for occlusion in cats when the mouth is maximally opened because the maxillary arteries course around the mandibles. This anatomic relationship is important because movement of the mandibles is such that it could compress the maxillary arteries. During general anesthesia the mouth may be maximally opened for a prolonged period when a spring-loaded mouth gag is used, which could lead to substantial reduced blood flow to the eyes, inner ears, and brain. Our specific aim is to provide evidence that blood flow in the maxillary arteries is reduced when the mouth is maximally opened versus closed. Both subjective and objective assessments will be made in 6 cats. Subjective assessments include visual inspection of computed tomography (CT) and magnetic resonance imaging (MRI) angiograms when the mouth is opened and closed. Quantitative assessment will be made by performing dynamic CT of a maxillary artery following intravenous injection of contrast material: once with the mouth closed and once with the mouth opened maximally. A region of interest (ROI) will be drawn around one of the maxillary arteries to measure the change in Hounsfield units (HU), which is a measure of tissue density, over time. Using these data, time-density curves will be produced. Our hypothesis is that there is at least a reduce peak HU and shorter duration to peak in cats with the mouth closed versus opened.