Role of 99mTc-hexakis-2-methoxyisobutylisonitrile in the diagnosis and staging of lung cancer

Background: Preliminary studies have shown that ^99mTc-hexakis-2-methoxyisobutylisonitrile (MIBI) is an interesting tracer for various tumors. The aim of this study was to determine the feasibility of using ^99mTc-MIBI as a diagnostic and staging procedure for lung cancer. Methods: We prospectively compared the results of biopsy with ^99mTc-MIBI imaging in patients with potentially resectable lung lesions (stages IIIA or lower). In the patients with radiopharmaceutical uptake, the staging provided by CT was compared with that obtained with ^99mTc-MIBI. Results: Ninety-nine of the 116 patients examined had lung cancer. For the diagnosis of malignancy, the specificity of ^99mTc-MIBI was 100%, sensitivity was 89.8%, positive predictive value was 100%, negative predictive value was 62.9%, and accuracy was 91.4%. In the 87 patients with radiopharmaceutical uptake in their lung cancer, the values for the specificity and sensitivity of ^99mTc-MIBI in the detection of mediastinal lymph node metastases were 100% and 54.5%, respectively. The corresponding values for CT in the same patients were 87.6% and 63.3%, respectively. The difference in specificity is statistically significant (p = 0.011). Conclusions: This study demonstrates that ^99mTc-MIBI provides significant diagnostic and staging information in patients with lung lesions. The high specificity and positive predictive value of ^99mTc-MIBI suggest that this radiopharmaceutical could be a very useful tool for the diagnosis of lung cancer, especially in consideration of its low costs and wide availability.