Fibrotic idiopathic interstitial pneumonia: high-resolution computed tomography considerations

Area of Science:

• Pulmonary Medicine
• Radiology
• Pathology

Background:

• Idiopathic interstitial pneumonias (IIPs) encompass usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP).
• High-resolution computed tomography (HRCT) is crucial for diagnosing IIPs, with specific patterns aiding differentiation.
• Understanding the radiological features of IIPs is vital for prognosis and management.

Purpose of the Study:

• To delineate the characteristic HRCT findings of UIP and NSIP.
• To highlight the prognostic significance of CT findings in idiopathic pulmonary fibrosis (IPF).
• To discuss the role of imaging in identifying IPF complications and differentiating various IIPs.

Main Methods:

• Review of HRCT imaging features associated with UIP and NSIP.
• Correlation of imaging findings with clinical presentation and histopathology where available.
• Analysis of the prognostic value of CT-assessed fibrosis extent in IPF.

Main Results:

• UIP is characterized by reticular abnormality and honeycombing, predominantly in basal and peripheral lung regions; honeycombing is a strong UIP predictor.
• Ground-glass attenuation in IPF often progresses to fibrosis and honeycombing, and imaging can detect complications like accelerated progression or infection.
• NSIP typically shows extensive ground-glass abnormality and some reticular abnormality, also with basal and peripheral predominance, though CT findings can overlap with UIP, OP, and DIP, necessitating biopsy.

Conclusions:

• HRCT findings are key in characterizing UIP and NSIP, guiding diagnosis and prognosis in fibrotic interstitial lung diseases.
• Imaging plays a critical role in assessing IPF progression, complications, and differentiating between various interstitial pneumonia subtypes.
• While CT is highly informative, distinguishing between certain IIPs like NSIP and UIP may require histopathological confirmation.