Abstract
Resected lobes from patients having pre-operative pulmonary function tests
were fixed by inflation with formal saline and cut into 1cm parasagittal slices.
Randomly selected tissue, from the lateral two slices, was plastic embedded
and sections prepared for microscopic analysis.
A semi-automatic image analysis system was used to quantitate bronchiolar
calibre and shape and peribronchiolar attachment number, inter-alveolar
attachment distance and the amount of macroscopic emphysema. An
automatic image analyser (IBAS2) was used to measure alveolar surface area
per-unit volume (AWUV).
Measured bronchiolar calibre (minimum diameter and measured lumen area)
was not related to patient height, lung volume, pulmonary function or other
morphometric variables.
AWUV, mean inter-alveolar attachment distance, theoretical lumen area and
bronchiolar shape were independent of patient size and lung volume, but were
inter-related. A combination of low AWUV and loss of attachments profoundly
affected bronchiolar shape. However, AWUV and alveolar attachment loss were
not always in proportion and demonstrated different functional effects: AWUV
affects carbon monoxide transfer factor whereas attachments affect the slope
of phase III and forced expiratory volume with bronchiolar shape affecting
closing volume.
Macroscopic emphysema did not accurately reflect the extent of alveolar wall
loss as identified by AWUV and showed poor correlations with pulmonary function
tests.
Computerised axial tomography (CT scan) exhibited a strong correlation with
AWUV and can be used to assess lung density in life.
