title: Somatostatin receptor scintigraphy in patients with pituitary adenoma.
abstract: Presence of high-affinity somatostatin (SST) receptors in most endocrine tumor cells allow in vivo scintigraphic visualization of these neoplasms after intravenous administration of a radionuclide-labeled somatostatin analog. 111In-octreotide is at present the most often used substance for imaging of the SST receptor expression in vivo. The aim of this study is to investigate the correlation between presence of in vivo scintigraphically detectable SST receptors in pituitary tumors and clinical parameters such as patients' age, tumor size, hormonal hypersecretion, and response to octreotide therapy. Forty-two-consecutive patients were enrolled in this trial. Twenty-five of them had nonsecreting pituitary tumors, 11 were acromegalic, and 6 had macro- or microprolactinoma. Scintigraphic images of the head were obtained at 10 min and 24 hours after injection of the radionuclide. In 23 patients, no specific binding of 111In-octreotide was found. Five patients showed a weak positive, 5 had a positive, and 9 a strong positive signal in the region of interest. Uptake of octreotide was significantly correlated with tumor size and age (p < 0.01). Small-size pituitary adenomas were most likely to be scintigraphically receptor-negative, while large suprasellar tumors tended to exhibit a rather strong receptor positivity. Statistical analysis of the data could not confirm the hypothesized correlation between endocrine activity of the pituitary tumors and the scintigraphically proven SST receptor expression in vivo. A positive Octreoscan was not predictive for the result of octreotide therapy.
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, Martin-Luther-University Halle-Wittenberg, Fed. Rep. of Germany.
authors.forename: A
authors.initials: A
authors.lastname: Rieger
authors.forename: N G
authors.initials: NG
authors.lastname: Rainov
authors.forename: C
authors.initials: C
authors.lastname: Elfrich
authors.forename: M
authors.initials: M
authors.lastname: Klaua
authors.forename: H
authors.initials: H
authors.lastname: Meyer
authors.forename: C
authors.initials: C
authors.lastname: Lautenschläger
authors.forename: W
authors.initials: W
authors.lastname: Burkert
authors.forename: T
authors.initials: T
authors.lastname: Mende
mesh_terms: D000172:Acromegaly / Q000000981:diagnostic imaging / Q000188:drug therapy; D000236:Adenoma / Q000000981:diagnostic imaging* / Q000188:drug therapy; D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000031:analogs & derivatives / Q000627:therapeutic use; D009384:Paraneoplastic Endocrine Syndromes / Q000000981:diagnostic imaging* / Q000188:drug therapy; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy; D015175:Prolactinoma / Q000000981:diagnostic imaging / Q000188:drug therapy; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000032:analysis* / Q000187:drug effects
chemical_list: D018931:Antineoplastic Agents, Hormonal; D017481:Receptors, Somatostatin; C094279:indium-111-octreotide; D019382:Human Growth Hormone; D015282:Octreotide