Nonspecific interstitial pneumonia and idiopathic pulmonary fibrosis: changes in pattern and distribution of disease over time.
OBJECTIVE
To retrospectively assess the change in disease pattern of nonspecific interstitial pneumonia (NSIP) and idiopathic pulmonary fibrosis (IPF) findings seen at thin-section computed tomography (CT) at long-term follow-up and to compare the same with initial findings at CT.


METHODS
The study included 48 patients (28 men, 20 women; mean age, 57.5 years) with biopsy-proved NSIP (n = 23) or IPF (n = 25) who underwent CT at initial diagnosis and at follow-up 34-155 months later. The CT scans were randomized and reviewed by two independent thoracic radiologists for pattern and distribution of ground-glass opacity (GGO), reticulation, traction bronchiectasis and bronchiolectasis, and honeycombing. Statistical analysis was performed by using nonparametric methods and univariate logistic regression.


RESULTS
Follow-up CT in patients with NSIP showed marked decrease in the extent of GGO, increase in reticulation, and a greater likelihood of peripheral distribution (all P < .05). At presentation, the CT findings were interpreted as suggestive of NSIP in 18 of 23 patients with NSIP and indeterminate or suggestive of IPF in five. In five (28%) of 18 patients with initial findings suggestive of NSIP, the follow-up CT scans were interpreted as more suggestive of IPF. No CT features seen at presentation allowed distinction between patients with NSIP that maintained an NSIP pattern at follow-up and those that progressed to an IPF pattern.


CONCLUSIONS
At follow-up CT, 28% of patients with initial CT findings suggestive of NSIP progressed to findings suggestive of IPF. Similar initial CT findings for NSIP may have different imaging outcomes.
Silva
C Isabela S
CI
Department of Radiology, Vancouver General Hospital, University of British Columbia, 3350-950 W 10th Ave, Vancouver, BC, Canada V5Z 4E3. isabela.silva@vch.ca
Müller
Nestor L
NL
Hansell
David M
DM
Lee
Kyung S
KS
Nicholson
Andrew G
AG
Wells
Athol U
AU
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed