LIMITATIONS OF ACOUSTIC RHINOMETRY DETERMINED BY A SIMPLE-MODEL

To determine the accuracy of a commercially available transient signal acoustic rhinometer we constructed simple models from tubing of known dimensions. A series of models was constructed in which the main cyli nder was constant whilst the aperture of an included constricted area was varied from 0.07 cm(2)-0.95 cm(2). The area reconstruction for eac h model was then compared with the true area. Two parameters based on those used in clinical practice of acoustic rhinometry were employed t o evaluate the error. The results demonstrate that the measurement of both the volume beyond a constriction and the area of the constriction may be associated with systematic errors. The reconstructed profile o f each model is similarly erroneous. As the nose presents a proximal c onstriction, these findings are of considerable relevance to the clini cal use of acoustic rhinometry.