SPECT IMPROVES ACCURACY OF SOMATOSTATIN RECEPTOR SCINTIGRAPHY IN ABDOMINAL CARCINOID-TUMORS

Abdominal carcinoid tumors are often small and difficult to localize. Somatostatin receptors have been detected in carcinoids, thus enabling their in vivo visualization by scintigraphy with In-111 pentetreotide , a radiolabeled somatostatin analog. The aim of this study was to det ermine the value of In-111-pentetreotide SPECT in the detection of abd ominal carcinoids and to compare these results with the outcomes from planar scans and conventional imaging techniques. Methods: Eighteen pa tients with a present, or previously operated, abdominal carcinoid wer e evaluated. Abdominal SPECT scans were acquired 4 hr postinjection of In-111-pentetreotide and multiple planar views were performed at 4, 2 4, and 48 hr. Results: No adverse reactions were observed after radiop harmaceutical injection. In 13 of 18 patients, abnormal sites of uptak e were found by SPECT, which localized 9 abdominal extrahepatic lesion s (in 7 patients) and 33 hepatic lesions (in 10 patients). No patholog ic accumulation was seen in the five patients considered in complete r emission after surgery. Planar scans visualized 5 abdominal extrahepat ic sites (in 4 patients) and 21 liver tumor sites (in 7 patients), whi le conventional procedures detected 3 abdominal extrahepatic lesions ( in 2 patients) and 30 hepatic lesions (in 7 patients). Conclusion: Ind ium-111-pentetreotide scintigraphy is a safe and practical procedure. SPECT appears to be more sensitive than planar scintigraphy and conven tional methods to detect abdominal carcinoids: it can increase the num ber of visualized tumor sites and that of patients with positive findi ngs and may therefore have a role not only in the mapping of tumor spr ead but also in therapeutic decisions.