Acoustic rhinometry in dog and cat compared with a fluid-displacement method and magnetic resonance imaging

Abstract

. Acoustic rhinometry in dog and cat compared with a fluid-displacement method and magnetic resonance imaging. J Appl Physiol 95: 635-642, 2003. First published April 18, 2003 10.1152/japplphysiol.01105. 2002.-An increasing number of studies have used acoustic rhinometry (AR) for study of pharmacological interventions on nasal cavity dimensions in dogs and cats, but there have been no attempts to validate AR in these species. This is done in the present study. We compared area-distance relationships of nasal cavities from five decapitated dogs (3.5-41 kg) and cats (3.8-6 kg). AR was compared with magnetic resonance (MR) imaging and a fluid-displacement method (FDM) using perfluorocarbon. AR measured 88% (98-79%) (mean and 95% confidence interval) of nasal cavity volume in dogs determined by FDM and 71% (83-59%) in cats. AR markedly underestimated nasal cavity dimensions when minimum areas were below 0.1 cm 2 in dogs and 0.05 cm 2 in cats. AR underestimation increased with the severity of the constriction and with distance. Cross-sectional areas in the deeper parts of the cavity measured 76% (99-54%) of FDM in dogs and 52% (66-39%) in cats. AR agreed well with MR, especially in the deeper part of the cavity. MR images showed that the nasal cavities had a very complex structure not expected to be reproduced by AR. MR could not be considered a "gold standard" because definition of the cross-sectional area of the lumen depended critically on subjective choices. FDM produced repeatable measurements and possibly offers the most adequate reference in future evaluation of AR. AR underestimated what we believed were the most correct cross-sectional areas determined by FDM, especially in the deeper part of the dog and cat nasal cavities. Despite these difficulties, AR has been shown to be useful to describe qualitative changes in cross-sectional area. nasal airway volume; nasal pharmacology; laboratory animals; rhinology

Noninvasive allergic sinus congestion and resolution assessments using microcomputed tomography imaging

“…Another noninvasive technique is magnetic resonance imaging (MRI) assessment, which has advantages similar to micro-CT of being repeatable and nonterminal. However, a study of MRI in comparison with the fluid displacement method in dogs and cats indicated that cross-sectional area of the sinus lumen was limited by the fact that its definition was dependent on subjective choices made by the image assessor, making MRI unsuitable as a gold standard of sinus measurement (45). Although we had obtained some interesting and congruent data with the 2-D linear cumulative-width measures of micro-CT images (Fig.…”

“…9 and 10, this would be particularly true for the distal sinus regions. Indeed, a series of studies comparing acoustic rhinometry with the fluid displacement method in dogs, cats, guinea pigs, and rats indicated that acoustic rhinometry underestimated sinus vol-ume by an average of approximately 15-30% across those species (44,45). Although noninvasive, for the reasons above, we judged the acoustic rhinometry method to be unacceptable as a gold standard for our purposes, against which to compare results from our noninvasive micro-CT methods.…”

Practical Use of Acoustic Rhinometry for Quantitative Assessment of Nasal Obstruction in an Allergic Model Using Macaque Monkeys

“…Acoustic rhinometry has been used in experimental guinea pigs [6], dogs, cats [7], and rats [8]. However, little information on its application in non-human primates (NHPs) has been accumulated to date.…”