SOMATOSTATIN RECEPTOR SCINTIGRAPHY IN POSTSURGICAL FOLLOW-UP EXAMINATIONS OF MENINGIOMA

Surgery is the treatment of choice in patients with meningioma. Howeve r, the risk of postoperative, local recurrence is well-known since tot al resection is not always feasible. Moreover, in these patients MRI m ay fail to differentiate between tumor remnants, recurrent meningioma or nonspecific hyperperfusion, In this study, the value of functional imaging using somatostatin receptor scintigraphy (SRS) was evaluated i n postsurgical follow-up. Methods: Before and 2-3 mo after surgery, 27 patients with meningioma received MRI as well as SRS after intravenou s injection of 200 MBq In-111-octreotide. Planar whole-body images wer e obtained at 10 min, 1, 4 and 24 hr postinjection, and SPECT was perf ormed at 4 and 24 hr postinjection, The final diagnosis was proven his tologically in all patients. Results: Before surgery, MRI showed focal contrast enhancement in all patients, and SRS revealed focal accumula tion of In-111-octreotide. Thus, MRI and SRS yielded comparable result s in all 27 patients. After surgery, MRI showed diffuse contrast enhan cement in the area of the primary tumor site in all patients. Thus, MR I did not allow a differentiation between tumor and nonspecific hyperp erfusion, In contrast, SRS revealed focal accumulation of In-111-octre otide in 16 of 27 patients indicating remaining tumor tissue or relaps e of meningioma. This resulted either in an operative revision or in m ore frequent postsurgical follow-up examinations. In 11 of 27 patients , SRS was negative. Thus, total resection of meningioma was assumed, a nd no further interventions were performed. Conclusion: Functional ima ging using SRS is a highly specific imaging modality and has a signifi cant impact in postsurgical follow-up in patients with meningioma.