Differentiating dural metastases from meningioma: role of 68Ga DOTA-NOC PET/CT

To assess the ability of Ga DOTA-NOC PET/computed tomography (CT) to differentiate dural metastases from meningioma.

Patients who underwent a Ga DOTA-NOC PET/CT for differentiating meningiomas from dural metastases were included in the study. A visual score was assigned to the dural lesions (visual score - 1 to 3) in relation to the uptake in liver and spleen and variation in the visual score was evaluated. SUVmax of the dural lesions was also noted and difference in the values of the two pathologies were compared for statistical significance using nonparametric statistical tests. Final diagnosis was decided by histopathological confirmation whenever available.

Imaging, histopathology or follow-up data of 42 patients was available for analysis. Meningioma was the final diagnosis in 31 (73.8%) patients, whereas dural metastases were diagnosed in 9 (21.4%) patients. In two patients, histopathology revealed inflammatory pseudotumor and hemangioblastoma. Meningiomas showed intense tracer uptake in 30/31 patients (visual score 3). All metastatic lesions showed some degree of tracer uptake though the intensity was lesser compared to meningioma (visual score 1, 2). Meningiomas showed a significantly higher median SUV max value compared to metastases (12.7 vs. 6.0, P = 0.001).

Meningiomas can be differentiated from dural metastases by virtue of their higher uptake of Ga-labeled DOTA peptides reflecting higher SSTR expression. An asymptomatic meningeal based lesion with a high visual score (Visual score 3) has a very high probability to be a meningioma rather than dural metastasis.