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.
