Mediastinal lymph node metastasis from lung cancer: evaluation with Tl-201 SPECT--comparison with CT.

Abstract

To assess the usefulness of thallium-201 single photon emission computed tomography (SPECT) in detection of mediastinal lymph node metastasis from lung cancer. Computed tomography (CT) and Tl-201 SPECT were performed in 113 patients with lung cancer. Surgical staging was performed in all patients, and the results of the two modalities were compared with the pathologic findings in 364 node stations. Cancerous nodes were found in 32.7% of the patients. The sensitivity of CT in detecting mediastinal node metastasis was 62%; specificity was 80%. These rates were higher for Tl-201 SPECT (76% and 92%, respectively). Furthermore, these rates were excellent in patients with enlarged mediastinal nodes at CT (87% and 93%, respectively). However, Tl-201 SPECT had more limited spatial resolution than did CT. Tl-201 SPECT is useful in evaluation of mediastinal node metastasis in lung cancer, especially for patients with enlarged nodes at CT.