[Precision and problems in interpretation of acoustic rhinometry in cases of nasal mass lesion]

Precision and problems in interpretation of results obtained by acoustic rhinometry (AR) in cases of mass lesion in the nasal cavity were evaluated with two models, a simple tubal model and a model based on the cast of a cadaver's nasal cavity (cadaver model), and with a human subject. A simple tubal model of 2 cm inside diameter was used. Spherical claies with volumes of 1, 2, 3, and 3.5 cm3, located at same point in the tube, were measured by AR, and a high correlation was found between the clay volume calculated by AR and the real volume of the clay (r = 0.996). But the peak of decrease on the acoustic curve caused by clay was seen a bit posterior to the point where it was actually located. In the entire segment posterior to the peak on the acoustic curve, the value of the area was shown to be smaller than the value of the control. And the large the volume of clay, the greater the degree of decrease in this segment. In the study using the cadaver model, a pill (0.3 cm3) was put at nine sites in the nasal cavity, and AR was performed in each case. The results were compared with the control curve. The decrease in the area on the acoustic curve corresponding to the site of pill placement was recognized, as in the simple tubal model study, and a decrease in the area in the posterior segment of the acoustic curve was also observed.(ABSTRACT TRUNCATED AT 250 WORDS)