The use of dual phase 201Tl SPECT for differentiating pulmonary malignancies from benign lesions.
BACKGROUND
This study examines the usefulness of thallium-201 single photon emission computed tomography ((201)Tl SPECT) in differentiating pulmonary malignancies from benign lesions by using dual phase (201)Tl scintigraphy.


METHODS
One hundred and six patients with thoracic lesions and confirmed diagnoses were assessed by (201)Tl chest SPECT examinations; of these 106 enrolled thoracic lesions, 59 were malignancies and 47 were benign lesions. Dual phase (201)Tl SPECT was performed with an early image acquired at 10-20 min and a delayed image at 2-3 h after intravenous injection of 2-3 mCi of (201)Tl. The results of (201)Tl SPECT images were classified as either malignant or benign lesions by visual interpretation: the lesion was interpreted as positive for malignancy if the uptake of (201)Tl in the lung lesion in the delayed phase was increased or persistent as compared with that in the early phase image; otherwise, it was considered as a benign lesion. Simultaneously, the traditional method of retention index (RI) was also calculated to help in the differential diagnosis of pulmonary lesions. Then, both methods of dual phase (201)Tl SPECT, visual reading and traditional RI, were compared to differentiate pulmonary malignancies from benign lesions.


RESULTS
Analyzing the image results, we found that dual phase (201)Tl SPECT could differentiate pulmonary malignancies from benign lesions with a sensitivity of 83%, a specificity of 91% and an accuracy of 87%. Moreover, by using the traditional RI method of (201)Tl SPECT, it could differentiate pulmonary malignancy from benign lesions with a sensitivity of 79.3%, a specificity of 80.8% and an accuracy of 80%.


CONCLUSIONS
We conclude that using dual phase (201)Tl SPECT with visual interpretation is a simpler and potentially more effective method for differentiating pulmonary malignancies from benign lesions, with results compatible with the traditional RI method of (201)Tl SPECT.
Yu
Yang-Hao
YH
Division of Pulmonary and Critical Care Medicine, Department of Medicine, China Medical University Hospital, Taichung, Taiwan.
Hsu
Wu-Huei
WH
Hsu
Nan-Yung
NY
Lin
Tze-Yi
TY
Hsia
Te-Chun
TC
Sun
Shung-Shung
SS
Kao
Chia-Hung
CH
D000230:Adenocarcinoma / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018288:Carcinoma, Small Cell / Q000000981:diagnostic imaging; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D004653:Empyema / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014397:Tuberculosis, Pulmonary / Q000000981:diagnostic imaging*
D013794:Thallium Radioisotopes