Diagnosis of Usual Interstitial Pneumonitis in the Absence of Honeycombing: Evaluation of Specific CT Criteria With Clinical Follow-Up in 38 Patients

OBJECTIVE. We sought to evaluate specific CT criteria for the diagnosis of usual interstitial pneumonitis (UIP) in the absence of honeycombing. These criteria included peripheral reticulation and lobular distortion; some upper lobe involvement, but a lower zone predominance; a heterogeneous appearance with areas of normal lung, minimal reticulation, and substantial distortion alternating throughout the study and often on an individual image; a nonsegmental distribution; and traction bronchiectasis. MATERIALS AND METHODS. We searched reports of CT studies performed between January 1, 2009, and January 1, 2012, to identify patients for whom UIP was a likely or probable diagnosis and reviewed the CT study for each case (n = 106). There were 38 patients who met all CT criteria and who also had a clinical diagnosis of idiopathic UIP (also known as idiopathic pulmonary fibrosis [IPF]) and follow-up of at least 6 months, as determined from the electronic medical record. We reviewed prior and subsequent CT examinations in this cohort. RESULTS. The median age of our patients was 80 years, and the duration of clinical follow-up was 6-104 months (mean, 38 months; median, 37 months). For all patients, a pulmonary medicine physician made a working diagnosis of IPF. Fifteen patients died from pulmonary complications, and 16 of the surviving patients had clinical or functional progression of disease. There were no instances in which the initial diagnosis was revised or reversed. CONCLUSION. Strict application of specific CT criteria may allow a specific diagnosis of UIP in the proper clinical setting in the absence of honeycombing.