Context Focal pulmonary lesions are commonly encountered in clinical practice,
and positron emission tomography (PET) with the glucose analog 18-fluorodeoxyglucose
(FDG) may be an accurate test for identifying malignant lesions.
Objective To estimate the diagnostic accuracy of FDG-PET for malignant focal pulmonary
Data Sources Studies published between January 1966 and September 2000 in the MEDLINE
and CANCERLIT databases; reference lists of identified studies; abstracts
from recent conference proceedings; and direct contact with investigators.
Study Selection Studies that examined FDG-PET or FDG with a modified gamma camera in
coincidence mode for diagnosis of focal pulmonary lesions; enrolled at least
10 participants with pulmonary nodules or masses, including at least 5 participants
with malignant lesions; and presented sufficient data to permit calculation
of sensitivity and specificity were included in the anaylsis.
Data Extraction Two reviewers independently assessed study quality and abstracted data
regarding prevalence of malignancy and sensitivity and specificity of the
imaging test. Disagreements were resolved by discussion.
Data Synthesis We used a meta-analytic method to construct summary receiver operating
characteristic curves. Forty studies met inclusion criteria. Study methodological
quality was fair. Sample sizes were small and blinding was often incomplete.
For 1474 focal pulmonary lesions of any size, the maximum joint sensitivity
and specificity (the upper left point on the receiver operating characteristic
curve at which sensitivity and specificity are equal) of FDG-PET was 91.2%
(95% confidence interval, 89.1%-92.9%). In current practice, FDG-PET operates
at a point on the summary receiver operating characteristic curve that corresponds
approximately to a sensitivity and specificity of 96.8% and 77.8%, respectively.
There was no difference in diagnostic accuracy for pulmonary nodules compared
with lesions of any size (P = .43), for semiquantitative
methods of image interpretation compared with qualitative methods (P = .52), or for FDG-PET compared with FDG imaging with a modified
gamma camera in coincidence mode (P = .19).
Conclusions Positron emission tomography with 18-fluorodeoxyglucose is an accurate
noninvasive imaging test for diagnosis of pulmonary nodules and larger mass
lesions, although few data exist for nodules smaller than 1 cm in diameter.
In current practice, FDG-PET has high sensitivity and intermediate specificity