18F-FDG accumulation with PET for differentiation between benign and malignant lesions in the thorax.
Recent reports have indicated the value and limitations of (18)F-FDG PET and (201)Tl SPECT for determination of malignancy. We prospectively assessed and compared the usefulness of these scintigraphic examinations as well as (18)F-FDG PET delayed imaging for the evaluation of thoracic abnormalities.


METHODS
Eighty patients with thoracic nodular lesions seen on chest CT images were examined using early and delayed (18)F-FDG PET and (201)Tl-SPECT imaging within 1 wk of each study. The results of (18)F-FDG PET and (201)Tl SPECT were evaluated and compared with the histopathologic diagnosis.


RESULTS
Fifty of the lesions were histologically confirmed to be malignant, whereas 30 were benign. On (18)F-FDG PET, all malignant lesions showed higher standardized uptake value (SUV) levels at 3 than at 1 h, and benign lesions revealed the opposite results. Correlations were seen between (18)F-FDG PET imaging and the degree of cell differentiation in malignant tumors. No significant difference in accuracy was found between (18)F-FDG PET single-time-point imaging and (201)Tl SPECT for the differentiation of malignant and benign thoracic lesions. However, the retention index (RI) of (18)F-FDG PET (RI-SUV) significantly improved the accuracy of thoracic lesion diagnosis. Furthermore, (18)F-FDG PET delayed imaging measuring RI-SUV metastasis was useful for diagnosing nodal involvement and it improved the specificity of mediastinal staging.


CONCLUSIONS
No significant difference was found between (18)F-FDG PET single-time-point imaging and (201)Tl SPECT for the differentiation of malignant and benign thoracic lesions. The RI calculated by (18)F-FDG PET delayed imaging provided more accurate diagnoses of lung cancer.
Demura
Yoshiki
Y
Third Department of Internal Medicine, Fukui Medical University, 23 Matsuoka-cho, Fukui Pref 910-11, Japan. DEM2180@aol.com
Tsuchida
Tatsuro
T
Ishizaki
Takeshi
T
Mizuno
Shiro
S
Totani
Yoshitaka
Y
Ameshima
Shingo
S
Miyamori
Isamu
I
Sasaki
Masato
M
Yonekura
Yoshiharu
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification / Q000000981:diagnostic imaging; D008297:Male; D008477:Mediastinal Diseases / Q000145:classification / Q000000981:diagnostic imaging / Q000378:metabolism; D008479:Mediastinal Neoplasms / Q000145:classification / Q000000981:diagnostic imaging* / Q000378:metabolism; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013793:Thallium / Q000493:pharmacokinetics; D014055:Tomography, Emission-Computed / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C027549:thallium chloride; D013793:Thallium