Probe-based confocal laser endomicroscopy of the respiratory tract: a data consistency analysis

Probe-based confocal laser endomicroscopy is a novel imaging tool in the field of respiratory medicine. It enables a real-time and bedside qualitative characterization at the level of small airways but due to a relatively small field of view the reliability of quantification remains uncertain.

Twenty-six lung transplant recipients were subjected to two consecutive alveoloscopic imaging procedures within a median time interval of 90 days to analyze test-retest reliability. Only patients in a stable clinical condition were analyzed. We studied alveolar duct diameter, elastic fiber thickness at the alveolar level, the number of autofluorescent cells at the level of the alveolar space, the diameter of autofluorescent alveolar cells and their autofluorescence intensity.

Intraclass correlation coefficients ranged from 0.56 for elastic fiber thickness, 0.62 for alveolar duct diameter, 0.29 for alveolar cell diameter, 0.74 for cellularity to 0.78 for alveolar cell autofluorescence.

Probe-based confocal laser endomicroscopy enables imaging and quantitative measurements at the level of small airways and alveolar ducts. Test-retest reliability is good for cellularity and autofluorescence quantification but only moderate for morphometric analysis of elastic fibers and alveolar ducts.