THE QUANTITATION OF TURBINATE ATROPHY IN PIGS TO MEASURE THE SEVERITYOF INDUCED ATROPHIC RHINITIS

The two-fold purpose of this study was to establish a useful image ana lysis technique for quantitation of turbinate atrophy and to determine an optimum bacterial dose for inducing atrophic rhinitis (AR). Two mo rphometric analysis methods were compared to determine a turbinate are a ratio (TAR) and a turbinate perimeter ratio (TPR); the ratios of tur binate area to total nostril area and of turbinate perimeter to total nostril perimeter, respectively. Our first image analysis method diffe red from Collins et al (1) in that we used direct image capture (digit alization) via a video camera and a Macintosh microcomputer, rather th an photographs and a digitizer tablet. The tracing techniques were the same as those used by Collins et al The second morphometric method wa s modified from the first by exclusion of dorsal turbinate when tracin g the nostril area and directly tracing only the ventral turbinate to get a turbinate measurement without subtracting. Area and perimeter ra tios, for both methods, were compared to conventional visual snout sco res, ventral measurements, and to each other. The results of the two i mage analysis methods correlated well, both with each other and with t he visual scores. Doses of Pasteurella multocida (Pm) at a constant le vel, and Bordetella bronchiseptica (Bb) at various concentrations, wer e administered to 36 Hampshire-Duroc F1 SPF pigs to determine the best dose and frequency for inducing AR. Although the dose selection may h ave been somewhat affected by the pre-existing presence of Bb, the opt imal dose per naris in this study was 2 mL Bb at 10(7) cfu/mL combined with 2 mt Pm at 10(9) cfu/mL inoculum. The frequency of administratio n (1x or 2x) did not greatly affect results. Turbinate area ratio was the best tool for quantitating gross morphological turbinate changes a ssociated with atrophic rhinitis in this study. Our simplified modific ation of Collins et al image analysis method (exclusion of dorsal turb inates and direct measurement of ventral turbinates) correlated well w ith visual scores, and, when compared to Collins et al method, require d less data manipulation and labour.