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Unlabelled: We assessed the performance of a new serum chromogranin A (CgA) assay in combination with the results of (131)I-metaiodobenzylguanidine (MIBG) scintigraphy for diagnosis and follow-up in 89 patients with clinical findings suggestive of pheochromocytoma., Methods: The study population consisted of 41 patients with proven pheochromocytoma and 48 patients with refuted pheochromocytoma. Eighty-seven scintigraphy examinations were performed, 52 in patients with proven pheochromocytoma (39 before surgery and 13 after surgery) and 35 in patients with refuted pheochromocytoma., Results: The sensitivity of the CgA level was 90.2%, and the specificity was 99.0% and 92.3% in the control and refuted pheochromocytoma groups, respectively. A significant relationship was seen between serum levels of CgA and tumor mass (r = 0.70; P < 10(-5)). The postoperative CgA level was an early and accurate predictor of curative surgery or relapse. The concordance between CgA levels and scintigraphic data was 90.8%., Conclusion: Serum CgA level is an effective marker of pheochromocytoma. Increased levels strongly correlate with tumor mass; therefore, small tumors may go undetected. The concordance between CgA level and the results of (131)I-MIBG scintigraphy is high. A CgA level in the reference range is highly predictive of normal scintigraphy findings.

Unlabelled: The aim of this article was to study the physiopathology of tumoral uptake of 111In-pentetreotide using factorial analysis of dynamic series (FADS) and to assess the usefulness of this analysis in somatostatin receptor scintigraphy., Methods: Forty-one patients were included, 24 women and 17 men. After intravenous injection of 111 MBq 111In-pentetreotide, dynamic image acquisition (68 images of 30 s) began in front of the suspected tumoral site: thoracic in 10 patients with medullary carcinoma of the thyroid and 2 patients with bronchogenic carcinoid, and abdominal in 12 cases of midgut carcinoid and 17 cases of other gastroenteropancreatic neuroendocrine tumors. FADS was performed with FAMIS software. Static images were obtained 4 h and 24 h later. For every patient, surgery and/or clinical follow-up (4 y) was used to classify results as true (T) or false (F) positive (P) or negative (N) and to evaluate both the sensitivity of static images and the usefulness of FADS., Results: Of the 14 cases of carcinoid tumor, 5 patients were TN; 9 patients were TP with static images but only 8 were TP with FADS (a bronchogenic carcinoid of 6 mm was missed). Of the 17 cases of gastroenteropancreatic neuroendocrine tumor, static images were TP in 9 patients, and FADS were TP in 5 of these patients (and 4 FN). Static images and FADS were FN in 4 patients and TN in 3 patients, and in the 2 last patients static images were FP, but FADS were TN. Of the 10 cases of medullary carcinoma of the thyroid, static images and FADS were TN in 1 patient, static images were TP in 3 patients and FADS were TP in 2 of these patients (and 1 FN). In the six last cases, static images were FN, but FADS were FN in 3 patients and TP in 3 patients, showing an infiltrate., Conclusion: FADS demonstrates that tumoral kinetics are similar to those of the spleen. FADS can show a diffuse tumoral uptake corresponding to tumoral infiltrate in medullary carcinoma of the thyroid or in hepatic miliaria, whereas static images were normal or doubtful.

Unlabelled: Pretargeting labeled bivalent hapten with bispecific antibodies has proven feasible in the clinic, and our earlier results have suggested the technique may be very sensitive for detecting small recurrences and metastases. Medullary thyroid carcinoma (MTC) is an example where this technique may be the most useful since local recurrences and isolated metastases are removed surgically when detected, and thyrocalcitonin provides a specific and sensitive tumor marker. In our current study, we evaluated pretargeted immunoscintigraphy in a larger number of MTC patients., Methods: Anti-carcinoembryonic antigen (CEA) x anti-diethylenetriaminepentaacetic acid (DTPA) indium bispecific antibody and 111In-labeled bivalent DTPA hapten were administered sequentially (4-5 days apart) to 44 patients with elevated circulating calcitonin after resection of primary MTC. Immunoscintigraphy was performed 2, 5 and 24 hr after hapten injection and, when necessary, at longer time intervals. When available, a handheld gamma probe was used during surgery., Results: Fifteen patients had known tumor sites before immunoscintigraphy. Tumors were imaged in 12 (80%) of these patients, including 3 with liver metastases. Five unknown tumor sites were detected. For the 29 patients with occult disease, immunoscintigraphy detected high-activity uptake sites in 21 patients (72%), including 5 in the liver. Twelve were confirmed by surgery, 1 by guided morphologic imaging and 1 by venous catheterization. There were 2 false-positive patients. The other 5 patients have not yet been confirmed. All detected liver metastases were high-activity uptake areas. Radioimmunoguided surgery was used in 14 patients. It was considered helpful by the surgeon in 12 patients, including 4 patients where it determined the resection of small, not palpable nor visible, tumor-involved lymph nodes. Surgical resection resulted in a significant decrease (8 patients) or normalization (1 patient) of circulating calcitonin and CEA., Conclusion: This technique affords high sensitivity and specificity for detecting small tumor lesions including liver metastases. Its use for immunoscintigraphy and guided surgery should improve the therapeutic management of recurrent MTC.

Unlabelled: Uptake of 123I-Tyr-3-octreotide (TOCT) by hormone-secreting abdominal tumors was studied to compare scintigraphic observations with the reduction in hormone levels brought about by a brief therapeutic test., Methods: A prospective study was conducted on 17 patients, totalizing 46 proven lesions, with endocrine tumors of the pancreas (10 patients, 20 lesions) and/or carcinoid metastases (8 patients, 26 lesions). Tumor hormonal hypersecretion was inhibited by octreotide., Results: There was good agreement between the results of these examinations., Conclusions: The detection of abdominal tumors using this radiotracer is strongly related to its functional characteristics. Variations in the scintigraphic and test results according to different tumor types were in agreement with published data on the density of somatostatin receptors measured by in vitro studies or scintigraphy and by the therapeutic effects of octreotide.