TY - JOUR
T1 - Combined imaging with 18F-FDG-PET/CT and 111In-labeled octreotide SPECT for evaluation of thymic epithelial tumors
AU - De Luca, Serena
AU - Fonti, Rosa
AU - Palmieri, Giovannella
AU - Federico, Piera
AU - Del Prete, Giuseppina
AU - Pacelli, Roberto
AU - Pace, Leonardo
AU - De Placido, Sabino
AU - Salvatore, Marco
AU - Del Vecchio, Silvana
PY - 2013/5
Y1 - 2013/5
N2 - PURPOSE: This study aimed to test the role of combined imaging with F-FDG-PET/CT and In-octreotide SPECT in characterizing thymic epithelial tumors (TETs). METHODS: We evaluated 20 patients with newly diagnosed TETs who had undergone concomitant F-FDG-PET/CT and In-octreotide SPECT. Thymic epithelial tumors were classified by World Health Organization (WHO) as low-risk thymomas (5), high-risk thymomas (4), and thymic carcinomas (11, among which 6 neuroendocrine tumors). Patients were staged according to Masaoka system. F-FDG-PET/CT was performed and SUVmax of primary tumors was recorded. In-octreotide SPECT of the thorax was performed, and tumor-to-background ratio was determined on the 24-hour coronal sections. RESULTS: All patients showed increased F-FDG uptake in mediastinal lesions. SUVmax were significantly correlated with WHO classification (r = 0.66, P <0.01) and with Masaoka stage (r = 0.60, P <0.01). SUVmax of low-risk thymomas (mean [SD], 2.87 [0.83]) were significantly lower than those of high-risk thymomas (mean [SD], 7.21 [1.73], P <0.01) and of thymic carcinomas (mean [SD], 9.39 [5.80], P <0.05), whereas no significant difference was found between high-risk thymomas and thymic carcinomas. SUVmax of all high-risk thymomas and thymic carcinomas was 4.5 or greater. All primary tumors were detected by In-octreotide SPECT, and tumor-to-background ratios ranged between 1.67 and 10.10. No statistically significant correlation was found between tumor-to-background ratios and WHO classification (r = 0.24, P = 0.36) and Masaoka stages (r = 0.31, P = 0.23). However tumor-to-background ratios of thymic neuroendocrine tumors (mean [SD], 5.71 [3.09]) were significantly higher than those of all other TETs with SUVmax of 4.5 or greater (mean [SD], 2.41 [0.56]; P <0.05). CONCLUSIONS: F-FDG-PET/CT scan allows to differentiate high-risk epithelial tumors and thymic carcinomas from low-risk thymomas, whereas In-octreotide SPECT may identify neuroendocrine tumors among those showing high F-FDG uptake.
AB - PURPOSE: This study aimed to test the role of combined imaging with F-FDG-PET/CT and In-octreotide SPECT in characterizing thymic epithelial tumors (TETs). METHODS: We evaluated 20 patients with newly diagnosed TETs who had undergone concomitant F-FDG-PET/CT and In-octreotide SPECT. Thymic epithelial tumors were classified by World Health Organization (WHO) as low-risk thymomas (5), high-risk thymomas (4), and thymic carcinomas (11, among which 6 neuroendocrine tumors). Patients were staged according to Masaoka system. F-FDG-PET/CT was performed and SUVmax of primary tumors was recorded. In-octreotide SPECT of the thorax was performed, and tumor-to-background ratio was determined on the 24-hour coronal sections. RESULTS: All patients showed increased F-FDG uptake in mediastinal lesions. SUVmax were significantly correlated with WHO classification (r = 0.66, P <0.01) and with Masaoka stage (r = 0.60, P <0.01). SUVmax of low-risk thymomas (mean [SD], 2.87 [0.83]) were significantly lower than those of high-risk thymomas (mean [SD], 7.21 [1.73], P <0.01) and of thymic carcinomas (mean [SD], 9.39 [5.80], P <0.05), whereas no significant difference was found between high-risk thymomas and thymic carcinomas. SUVmax of all high-risk thymomas and thymic carcinomas was 4.5 or greater. All primary tumors were detected by In-octreotide SPECT, and tumor-to-background ratios ranged between 1.67 and 10.10. No statistically significant correlation was found between tumor-to-background ratios and WHO classification (r = 0.24, P = 0.36) and Masaoka stages (r = 0.31, P = 0.23). However tumor-to-background ratios of thymic neuroendocrine tumors (mean [SD], 5.71 [3.09]) were significantly higher than those of all other TETs with SUVmax of 4.5 or greater (mean [SD], 2.41 [0.56]; P <0.05). CONCLUSIONS: F-FDG-PET/CT scan allows to differentiate high-risk epithelial tumors and thymic carcinomas from low-risk thymomas, whereas In-octreotide SPECT may identify neuroendocrine tumors among those showing high F-FDG uptake.
KW - 111In-octreotide
KW - 18F-FDG-PET/CT
KW - functional imaging
KW - multimodality imaging
KW - thymic epithelial tumors
KW - thymic neuroendocrine tumors
UR - http://www.scopus.com/inward/record.url?scp=84876418788&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84876418788&partnerID=8YFLogxK
U2 - 10.1097/RLU.0b013e318286bd84
DO - 10.1097/RLU.0b013e318286bd84
M3 - Article
C2 - 23486323
AN - SCOPUS:84876418788
VL - 38
SP - 354
EP - 358
JO - Clinical Nuclear Medicine
JF - Clinical Nuclear Medicine
SN - 0363-9762
IS - 5
ER -