FDG SPECT in patients with lung masses

Study objectives: To determine whether 2-[fluorine-18]fluoro-2-deoxy-D-gluc ose (FDG) single-photon emission CT (SPECT) is useful in characterizing pul monary masses. 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 Administratio n medical center. Patients ol participants: Forty patients participated as part of an institu tional review board-approved research protocol, and informed consent was ob tained in all. Eight additional patient scans were acquired as part of thei r clinical evaluation for pulmonary mass, Measurements and results: There were 26 malignant lesions (12 were 1 to 2 c m in size, the rest were larger) and 17 benign lesions (3 were < 1 cm in si ze, 9 were 1 to 2 cm in size, and 5 were larger). Averaged sensitivity, spe cificity, positive predictive value, and negative predictive value were, re spectively, 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 correl ation between readers (p < 0.0001), Conclusion: FDG SPECT is useful in characterizing pulmonary masses > 2 cm i n size and appears to be equivalent to positron emission tomography for the se lesions. Although currently clinically suboptimal for characterizing les ions less than or equal to 2 cm in size, FDG SPECT appears to be better tha n current anatomic imaging methods. In addition, the positive predictive va lue of FDG SPECT for small lesions is also high (92%), and this technique a ppears potentially useful in the subset of patients in whom a positive resu lt would alter clinical diagnostic pathways or care.