Przydatność fuzji SPECT/TK w weryfikacji zmian wykrytych w scyntygrafii receptorów somatostatynowych oraz w ocenie skuteczności terapii u pacjentów z guzami neuroendokrynnymi przewodu pokarmowego

Abstract

Background: Somatostatin receptor scintigraphy (SRS) is one of the most important studies in the diagnostics of patients with gastroenteropancreatic neuroendocrine tumors (GEP NET), but Single Photon Emission Computed Tomography (SPECT) study does not provide sufficient information about location of lesions. Computed Tomography (CT) combined with SPECT may solve this problem by adding morphological information to functional data. The aim of the study was to determine the usefulness of SPECT/CT fusion on GEP NET diagnostics and therapy. Material/Methods: 77 patients with GEP NET were analyzed using SPECT/CT software fusion: • in 12 patients the anatomical location of primary tumor was assessed; • in 14 patients clinically suspicious for NET, the presence of lesions was verified in CT, causing an increased accumulation of tracer found in SRS; • in 41 patients with proved NET, an increased local accumulation of the tracer, seen in SRS, was verified;• in 10 patients, the response to somatostatin analogue therapy was verified. SPECT was performed 3-4 h after injection of 740MBq 99mTc-EDDA/HYNIC-octreotate. CT was performed using multidetector CT scanner and standard protocols. SPECT/CT fusion was performed on SyngoMI (Siemens) workstation. Results: In the first subgroup of 12 patients, the primary tumor was localized in 11 cases (91.7%); • in the second subgroup of 14 patients, NET was confirmed in CT in 10 cases (71.4%), and not confirmed (a false positive scintigraphy) in 4 cases (28.6%), affecting therapy; • in the third subgroup of 41 patients, pathological accumulation of the tracer was confirmed in 10 cases (24.4%), in 23 (56.1%) the local accumulation of tracer was evaluated in fusion as the false positive scintigraphy (retention of tracer in intestines), and in 8 (19,5%) was verified as accumulation in normal adrenal glands; • in the fourth subgroup of 10 patients in all cases SPECT/CT fusion confirmed response to therapy, with SRS and CT compliance. Conclusions: SPECT/CT fusion, by combining assessment of morphological and functional imaging, may be a useful tool both in the initial diagnostics of GEP NET improving specificity of lesions detected by SRS alone and in the monitoring of therapy effects