Effectiveness of use of CT and SPECT with 99mTc-MAA and Ga-67 citrate in assessing the expansion of lung cancer in the determination of surgical intervention tactics

Abstract

Introduction. Algorithms of the early detection of lung cancer remain a topic of discussion and the problem of timely assessment of the expansion of lung cancer remains unresolved.Objective – to determine if the combined use of contrast­enhanced MDCT and 99mTc­MAA SPECT and Gallium‐67 citrate SPECT is effective in assessing the expansion of lung cancer in the determination in the intervention tactics.Material and methods. In the study, radiologic examination was performed to 81 patients with lung cancer. Combined examinations included bolus contrast­enhanced computed tomography (n = 81 patients), 99mTc­MAA SPECT (n = 62 patients) and Gallium‐67 citrate SPECT (n = 9 patients).Results.According to MDCT data in most cases (n = 65 patients; 80 %) this method was able to diagnose the T­stage of the tumor; in some cases, the stage of malignancy was overestimated (n = 8 patients, 10 %), or underestimated (n = 8 patients, 10 %). According to the results of 99mТc­МАА SPECT, it was possible to reliably determine the microcirculation disorders that were observed in the whole group of patients, while in 12 cases the impaired blood flow was recorded only according to the results of 99mTc­MAA SPECT and in 50 cases the severity of changes in blood flow was more signifcant than according to MDCT. When analyzing Ga­67 citrate SPECT data, in all 9 cases whole­body Ga­67 citrate SPECT showed intense hot areas at the tumor region. It was also possible to show several mildly increased foci in the hilar lymph nodes in 6 cases, but in 3 cases the result was false positive.Conclusions. Bolus contrast­enhanced computed tomography in most cases allows to correctly determine the T­stage of lung cancer and show tumor invasion into the surrounding tissues and vessels. At the same time, an additional 99mTc­MAA SPECT study allows to clarify the degree of disturbance of the microvasculature in more detail. It is possible to supplement the assessment of regional metastasis by Gallium‐67 citrate SPECT, however, it is necessary to take into account the inflammatory nature of lymph node changes as a cause of false­positive data.