Little et al used to a number of parameters to characterize bronchial changes in a patient with asthma as seen on high resolution computed tomography (HRCT). Asthma tends to be associated with thickening of the bronchial wall with a decrease in the area available for air flow. The authors are from the University of Glasgow and Western Infirmary at Glasgow.


Measurements from the HRCT:

(1) outside diameter (OD) of the bronchial wall in mm

(2) inside diameter (ID, luminal diameter) of the bronchial wall in mm


thickness of the bronchial wall in mm =

= ((OD) - (ID))/ 2


ratio of wall thickness to outside diameter =

= (thickness of wall) / (OD)


area occupied by the bronchus =

= PI() * (((OD) / 2)^2)


area occupied by the lumen =

= PI() * (((ID) / 2)^2)


wall area as percent of total bronchial area as a percent =

= ((area occupied by bronchus) - (area occupied by lumen)) / (area occupied by the bronchus) * 100%


These parameters showed a positive correlation with asthma severity an inverse association with the gas transfer coefficient.


To read more or access our algorithms and calculators, please log in or register.