Study objectives: To determine whether
single-photon emission CT (SPECT) is useful in characterizing pulmonary
Design: Scans were prospectively acquired and
interpreted. Interpretations were performed with CT or chest radiograph
but interpreters were blinded to eventual diagnosis.
Setting: University hospital practice and affiliated
Veterans Administration medical center.
participants: Forty patients participated as part of an
institutional review board–approved research protocol, and informed
consent was obtained in all. Eight additional patient scans were
acquired as part of their clinical evaluation for pulmonary mass.
Measurements and results: There were 26 malignant lesions
(12 were 1 to 2 cm in size, the rest were larger) and 17 benign lesions
(3 were < 1 cm in size, 9 were 1 to 2 cm in size, and 5 were larger).
Averaged sensitivity, specificity, positive predictive value, and
negative predictive value were, respectively, 50% (12 of 24), 94% (17
of 18), 92% (12 of 13), and 59% (17 of 29) for lesions 1 to 2 cm in
size, 100% (28 of 28), 90% (9 of 10), 97% (28 of 29), and 100% (9
of 9) for lesions > 2 cm in size. There was good correlation between
readers (p < 0.0001).
Conclusion: FDG SPECT is
useful in characterizing pulmonary masses > 2 cm in size and appears
to be equivalent to positron emission tomography for these lesions.
Although currently clinically suboptimal for characterizing lesions≤
2 cm in size, FDG SPECT appears to be better than current anatomic
imaging methods. In addition, the positive predictive value of FDG
SPECT for small lesions is also high (92%), and this technique appears
potentially useful in the subset of patients in whom a positive result
would alter clinical diagnostic pathways or care.
Abbreviations: CXR = chest radiograph;
FDG = 2-[fluorine-18]fluoro-2-deoxy-d-glucose;
FWHM = full-width-half-maximum; PET = positron emission tomography;
SPECT = single-photon emission CT