Role of 131I-metaiodobenzylguanidine in the localization of suspected phaeochromocytomas.
Iodine-131-metaiodobenzylguanidine is a recently-developed radiopharmaceutical agent for adrenal medullary scintigraphy. Twenty-one scans with 131I-metaiodobenzylguanidine were performed in 20 adults with suspected phaeochromocytomas over a four-year period. All patients previously had undergone computed tomographic scans of the abdomen and pelvis. The computed-tomographic scans were abnormal in 14 patients (16 tumours), eight (nine tumours) of whose 131I-metaiodobenzylguanidine scans gave positive results. Both types of scan gave negative results in the remaining six patients. Among 12 patients who underwent surgery or postmortem examination, the 131I-metaiodobenzylguanidine scan correctly showed eight phaeochromocytomas; six tumours that were found on computed-tomographic scans but not on 131I-metaiodobenzylguanidine scans proved not to be phaeochromocytoma. The 131I-metaiodobenzylguanidine scan probably gave a true-positive result in an additional case (surgical confirmation was not available). None of the remaining seven patients in whom the 131I-metaiodobenzylguanidine scan gave negative results has been shown to harbour a phaeochromocytoma on extended follow-up (2.5 to four years). Iodine-131-metaiodobenzylguanidine is a highly sensitive and specific agent for the localization of phaeochromocytomas. In patients with suspected phaeochromocytomas and abnormal computed-tomographic findings, 131I-metaiodobenzylguanidine permits a non-invasive, functional evaluation of the morphological abnormalities to be made. The importance of making a biochemical diagnosis of a phaeochromocytoma before attempting localization studies is emphasized.
Khafagi
F A
FA
Royal Brisbane Hospital, Herston, QLD.
Mortimer
R H
RH
Egerton-Vernon
J M
JM
Perry-Keene
D A
DA
D019797:3-Iodobenzylguanidine; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D014057:Tomography, X-Ray Computed
D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D019797:3-Iodobenzylguanidine