J Nucl Med 2001 Oct;42(10):1489-96
Comparison of [(18)F]FDG PET and (201)Tl SPECT in evaluation of pulmonary
nodules.
Higashi K, Ueda Y, Sakuma T, Seki H, Oguchi M, Taniguchi M, Taki S, Tonami H,
Katsuda S, Yamamoto I.
Recent reports have indicated the value of [(18)F]FDG PET and (201)Tl SPECT in
diagnosing lung cancer. In this study, we compared the diagnostic value of FDG
PET and (201)Tl SPECT in the evaluation of pulmonary nodules. METHODS:
Sixty-three patients with 66 pulmonary nodules suspected to be lung cancer on
the basis of chest CT were examined by FDG PET and (201)Tl SPECT (early and
delayed scans) within a week of each study. For semiquantitative analysis, the
standardized uptake value (SUV) or the tumor-to-nontumor activity ratio (T/N)
(or both) was calculated. All of these lesions were completely removed
thoracoscopically or by thoracotomy and were examined histologically. RESULTS:
Fifty-four nodules were histologically confirmed to be malignant tumors, and 12
were benign. Both techniques delineated focal lesions with an increase in tracer
accumulation in 41 of 54 lung cancers. (201)Tl SPECT on early or delayed scans
(or both) identified 4 additional lung cancers that FDG PET images did not
reveal: 3 bronchioloalveolar carcinomas and a well-differentiated adenocarcinoma.
FDG PET identified 3 additional lung cancers that (201)Tl SPECT images did not
reveal; 2 of these lung cancers were <2 cm in diameter. The mean FDG SUV and
T/N of bronchioloalveolar carcinomas (2.06 +/- 0.76 and 3.49 +/- 1.03,
respectively) were significantly lower than those of poorly differentiated
adenocarcinomas (5.55 +/- 2.01 [P = 0.026] and 8.23 +/- 2.16 [P = 0.01],
respectively). However, no significant difference was found in (201)Tl T/N on
early and delayed scans between bronchioloalveolar carcinomas (1.64 +/- 0.29 and
1.87 +/- 0.42, respectively) and poorly differentiated adenocarcinomas (1.58 +/-
0.32 and 2.76 +/- 1.36, respectively). Of the 12 benign nodules, FDG PET and
(201)Tl SPECT showed false-positive results for the same 7 benign nodules
(58.3%) (4 granulomas, 1 sarcoidosis, 1 inflammatory pseudotumor, and 1
aspergilloma). Negative FDG PET findings and positive (201)Tl SPECT findings
were obtained only for bronchioloalveolar carcinomas or a well-differentiated
adenocarcinoma but not for other histologic types of lung cancers or benign
pulmonary nodules. CONCLUSION: No significant difference was found between FDG
PET and (201)Tl SPECT in specificity for the differentiation of malignant and
benign pulmonary nodules. The degree of differentiation of lung adenocarcinoma
correlated with FDG uptake but not with (201)Tl uptake. Bronchioloalveolar
carcinoma (a well-differentiated, slow-growing tumor) findings typically were
positive with (201)Tl but were negative with FDG. The combination of FDG PET and
(201)Tl SPECT may provide additional information regarding the tissue
characterization of pulmonary nodules.
