The most common roles of longitudinal high-resolution computed tomography (HRCT) data in the evaluation of patients with diffuse lung disease (DLD)

HRCT roleNotes
Initial diagnosisPattern may become more diagnostic over time
Resolved or improved findings suggest an inflammatory or infiltrative component (e.g. not IPF)
PrognosisWorsening abnormalities or rapid progression suggest a worse prognosis
Routine follow-upParticularly helpful when PFTs may be inaccurate: patient unable to cooperate with PFTs; multifactorial restrictive disease (e.g. both fibrosis and pleural disease); mixed interstitial and airways disease; or early disease (below threshold of PFTs)
Distinguish inflammation/infiltration from fibrosis on baseline HRCT
Detection of disease progressionParticularly helpful in patients with worsening symptoms and/or PFTs
HRCT may be used as endpoint in clinical drug trials
Quantitative analysis may provide a more objective analysis of findings and extent of lung involved
Evaluation of patients with acute lung symptomsDistinguish progression of DLD versus a superimposed process (e.g. infection)
Detection of acute exacerbation
Detection of complicationsDetection of lung cancer, pulmonary hypertension and other abnormalities associated with DLD

IPF: idiopathic pulmonary fibrosis; PFT: pulmonary function test.