title: Somatostatin receptor imaging in CNS tumours using 111In-octreotide.
abstract: This study evaluates the in vivo visualization of somatostatin (SS) receptors in central nervous system (CNS) tumours using 111In-octreotide imaging and discusses the clinical implications. Ninety-five patients with histologically confirmed diagnosis of CNS tumours were imaged 2-4 and 24 h after the intravenous injection of 111-185 MBq of 111In-octreotide. An uptake index was computed using tumour/non-tumour ratios evaluated using a standard region-of-interest method. Semi-quantitative immunohistochemical studies of SS binding sites were performed on frozen tumour sections. All meningiomas, most pituitary adenomas and many glial tumours showed a positive scan, whereas all neurinomas, craniopharingiomas and ependymomas had negative receptor scans. Radio-octreotide uptake varied among the SS receptor positive CNS tumours: very intense in meningioma, intermediate in pituitary adenoma and of a low grade in glioma. The results of immunohistochemical studies confirmed the scintigraphic findings in all cases. We believe 111In-octreotide is a suitable radiopharmaceutical for characterizing CNS tumours in vivo as SS receptor positive or negative. This new neuronuclear imaging technique may be useful for differential diagnosis in selected cases, for post-surgical follow-up and in the assessment of differentiation in glial tumours.
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging; D001254:Astrocytoma / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000000981:diagnostic imaging; D016543:Central Nervous System Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D003397:Craniopharyngioma / Q000000981:diagnostic imaging; D004806:Ependymoma / Q000000981:diagnostic imaging; D005909:Glioblastoma / Q000000981:diagnostic imaging; D005910:Glioma / Q000000981:diagnostic imaging; D006801:Humans; D007150:Immunohistochemistry; D007205:Indium Radioisotopes; D008279:Magnetic Resonance Imaging; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging; D008579:Meningioma / Q000000981:diagnostic imaging; D009442:Neurilemmoma / Q000000981:diagnostic imaging; D015282:Octreotide / Q000031:analogs & derivatives*; D009837:Oligodendroglioma / Q000000981:diagnostic imaging; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging; D017481:Receptors, Somatostatin / Q000032:analysis*; D013120:Spinal Cord Neoplasms / Q000000981:diagnostic imaging; D014055:Tomography, Emission-Computed / Q000379:methods
chemical_list: D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; C094279:indium-111-octreotide; D015282:Octreotide