Distinguishing clinical and radiographical features of idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia
| Idiopathic pulmonary fibrosis | Nonspecific interstitial pneumonia | |
| Duration of illness | Chronic (>12 months) | Subacute to chronic |
| Frequency of diagnosis | 47–64% | 14–36% |
| Treatment | Poor response to any treatment | Corticosteroid responsiveness |
| Prognosis | 50–70% mortality within 5 yrs | <15% mortality in 5 yrs |
| Chest radiograph | Bilateral reticular opacities in lower zones; volume loss plus honeycombing | Bilateral hazy and reticular opacity |
| HRCT | Peripheral, subpleural, basal predominance; reticular opacities; honeycombing; traction bronchiectasis; architectural distortion | Peripheral, basal, symmetrical; ground-glass attenuation; consolidation; traction bronchiectasis; lower lobe volume loss |
| Key histological features | UIP pattern | NSIP pattern: cellular, fibrotic |
HRCT: high-resolution computed tomography; UIP: usual interstitial pneumonia; NSIP: nonspecific interstitial pneumonia.