Molecular Imaging of Neuroendocrine Cancer by Fusion SPET/CT

摘要

Neuroendocrine (NE) cancers are usually suspected on clinical symptoms related to their metabolically active peptide secretion into the circulatory system. The most effective treatment is surgery and a preoperative accurate localization of these slow growing tumors is needed. Combined anatomical (CT) and molecular imaging modalities using single-photon emission computed tomography (SPET) with radiolabeled pentetreotide have been developed in routine, and we report here the potential of SPECT/CT image fusion for diagnosis, staging, and evaluation of treatment efficacy of NE cancers. Patients: Sixty-four consecutive patients were included: 2 patients with MEN 2b, thoracic lesions (n = 5), bowel lesions (n = 28), pancreatic lesions (n = 17), and unknown primary endocrine tumors in = 12). Age ranged from 31 to 64 years. Imaging Protocol: Hybrid images of functional SPET and anatomical CT data were acquired using a SPET/CT system combining a dual-detector gamma camera with a low-dose CT (Millennium VG & Hawkeye GE Healthcare), 24 hours after intravenous injection of 200 MBq ~(111)In-pentetreotide and compared with additional whole-body and planar conventional scintigraphies obtained, respectively, at 4 and 24 hours. All images were reviewed without knowledge of clinical data and the results correlated with the follow-up. Results: Thirty-four were true positives, twenty-one true negatives, and nine remained equivocal. Eighty-eight uptake sites in the neck, thorax, liver, abdomen, and skeleton were detected. Sensitivity and specificity raised, respectively, from 81 and 22 without fusion to 92 and 80% with fusion (p = 0.005). Equivocal foci decreased from 17% without CT to 5.7% with CT. Site-by-site interobserver performances were also improved from 60 to 88% when using CT fusion (p < 0.005). Conclusion: Molecular imaging of NE cancer by fusion SPECT/CT is an accurate modality to precise tumor site location and has a significant impact in the management of endocrine tumor patients.