To study the geometry of the nasal cavity we applied an acoustic method (J. Appl. Physiol. 43: 523-536, 1977) providing an estimate of cross-sectional area as a function of distance. Acoustic areas in a model constructed from a human nasal cast, in the nasal cavity of a cadaver and in 10 normal subjects and two patients with well-defined afflictions of the nasal cavity, were compared with similar areas obtained by computerized tomography (CT) scans, a specially developed water displacement method, and anterior rhinomanometry. We found a coefficient of variation of the areas of less than 2% by the acoustic method compared with 15% for the rhinomanometric measurements. Acoustic areas correlated highly to similar areas obtained by CT scanning (r = 0.94) and by water displacement (r = 0.96). In two patients the acoustic method accurately outlined, respectively, a tumor in the nose and a septum deviation. It is concluded that this method provides an accurate method for measuring the geometry of the nasal cavity. It is easy to perform and is potentially useful for investigation of physiological and pathological changes in the nose.

ILD is a serious complication in RA, with a significantly increased mortality compared with a large matched cohort of RA comparisons without ILD.

A decade after its introduction acoustic rhinometry is a well-established method for evaluation of nasal patency, but further improvement can be obtained by continued validation and adjustments of the technique.

ILD and IPF incidence was 4.1 and 1.3 per 100,000 inhabitants/year. The diagnostic re-evaluation raised the number of IPF diagnoses, but a diagnostic "grey zone" was still evident in patients with UIP features not qualifying the patients to be diagnosed with IPF. The GAP index was valuable as a measure of IPF severity in this cohort.

These findings emphasize the need of careful diagnosis and treatment of comorbidities and their risk factors in patients with IPF. In the absence of efficient treatment options for the majority of patients diagnosed with IPF, this may play a role in the effort to optimize the survival of IPF patients. Further studies are needed to fully clarify the impact of comorbidities on prognosis in patients diagnosed with IPF.