Objectives: We used whole-lung quantitative CT analysis
(QCT)—an objective method of evaluating emphysema severity and
distribution based on measurement of lung density—to determine whether
subjective selection criteria for lung volume reduction surgery are
applied consistently and to model the patient selection process, and
assessed the relationship of the model to postoperative outcome.
Design: Logistic regression analysis using QCT indexes of
emphysema and preoperative physiologic test results as the independent
variables, and the decision to operate as the dependent variable.
Setting: University hospital.
Seventy patients selected for bilateral lung volume reduction surgery
and 32 otherwise operable patients excluded from surgery based on
subjective assessment of emphysema morphology on chest radiography, CT,
and perfusion scintigraphy.
lung volume reduction surgery in the selected group.
Measurements and results: Emphysema in patients selected
for surgery was more severe overall and in the upper lungs by multiple
QCT indexes (p < 0.01, unpaired two-tailed t test).
Physiologic abnormalities were slightly more severe in selected
patients (p < 0.05, unpaired two-tailed t test). The
range of many QCT and physiologic values overlapped considerably
between the selected and excluded groups. The percent severe emphysema
(<− 960 Hounsfield units [HU]), upper/lower lung emphysema ratio
(− 900 HU threshold), and residual volume were the key variables in
the model predicting selection decisions (model
r2 = 0.48; p < 0.0001). The model
correctly predicted selection decisions in 87% of all cases, 91% of
the selected group, and 78% of the excluded group. Surgical patients
with a higher model-derived probability of selection had greater
postoperative improvement in FEV1 and 6-min walk
Conclusions: Radiologic selection
criteria are applied consistently to the majority of patients. QCT
features are strongly associated with selection decisions, are related
to outcome, and may help improve consistency and confidence in patient