Am. J. Respir. Crit. Care Med.,
Volume 160, Number 3, September 1999, 913-918
Noninvasive Diagnosis of Emphysema
Aerosol Morphometry and Aerosol Bolus Dispersion
in Comparison to HRCT
MARTIN
KOHLHÄUFL,
PETER
BRAND,
CLEMENS
ROCK,
THORSTEN
RADONS,
GERHARD
SCHEUCH,
THOMAS
MEYER,
HOLGER
SCHULZ,
KLAUS J.
PFEIFER,
KARL
HÄUSSINGER,
and
JOACHIM
HEYDER
Clinical Research Group "Aerosols in Medicine" of the GSF, Institute for Inhalation Biology and Center for Respiratory Medicine,
Munich-Gauting; and Department of Radiology, Klinikum Innenstadt, University of Munich, Munich, Germany
Aerosol-derived airway morphometry (ADAM) and aerosol bolus dispersion (ABD) test are altered in
patients with emphysema. We examined the diagnostic power of these aerosol methods in comparison with the noninvasive "gold-standard" HRCT in 50 consecutive patients with various lung diseases. The severity of airflow limitation was mild to moderate in the group of patients without emphysema and moderate to severe in the group of patients with HRCT-confirmed emphysema (FEV1,
78 ± 23% pred versus 53 ± 33% pred; p < 0.001). Among all lung function parameters under consideration ADAM showed the highest sensitivity and specificity for separating patients with emphysema
from those without emphysema (area under the operating characteristics curve: pROC, 0.92), followed
by ABD (pROC, 0.90), a marker for ventilation inhomogeneities. In patients with HRCT-confirmed macroscopic emphysema, peripheral air-space dimensions (EAD) at a relative volumetric lung depth Vpr
of 0.20 measured by ADAM were 155% larger, and bolus dispersion (ABD) at a lung depth of Vp 600 ml was 53% larger than those observed in patients with other lung diseases (EAD = 0.84 ± 0.53 mm
versus 0.33 ± 0.10 mm, p < 0.0001; ABD = 706 ± 154 cm3 versus 462 ± 109 cm3; p < 0.0001). EAD
showed a significant correlation with the HRCT visual score (r = 0.78, p = 0.01). ABD showed weak
significant correlations with all HRCT parameters under consideration (visual score, pixel density,
mean lung density) (r = 0.45 to 0.66; p < 0.05). ADAM and ABD are powerful tools for the noninvasive diagnosis of macroscopic emphysema.