Rationale

• A UIP pattern on CT has been considered the strongest prognostic indicator in interstitial lung disease
• Data emerging that UIP may be less prognostic than disease extent
• e-Lung is an AI powered CT tool which accurately quantifies the extent of fibrosis on CT
• The weighted reticulovascular score (WRVS) quantifies fibrosis in the peripheral lung 
• We evaluated the prognostic potential for WRVS compared with UIP and visual extent of disease in patients with non-IPF fibrotic ILD

Methods & Demographics

• 302 consecutive patients with non-IPF fibrotic ILD
• UIP status assessed by expert thoracic ILD radiologist (AD)
  • Definite and Probable UIP = UIP
  • Indeterminate and alternative diagnosis = non-UIP
• Visual disease extent scored by two experienced thoracic radiologists
• Evaluated relationships between WRVS, visual disease extent, UIP pattern on CT and outcomes
• Mean visual extent of fibrosis 21.6%
• Mean FVC 83%, Mean age 65, f=114 (44%)

Results

• WRVS more strongly associated with mortality and FVC decline than visual extent of disease or UIP

Conclusions

• In patients with non-IPF ILD, the e-Lung WRVS CT biomarker is associated with mortality independent of UIP status
• While both UIP and WRVS are associated with mortality, WRVS is a stronger prognostic factor 
• WRVS and not UIP is associated with future FVC decline regardless of imaging subtype
• In early disease where extent of disease is challenging to quantify visually, UIP status may be more important – e-Lung adds prognostic accuracy