Utility of FDG PET/CT in the Characterization of Sinonasal Neoplasms: Analysis of Standardized Uptake Value Parameters.

OBJECTIVE: We aimed to evaluate the contribution of different standardized uptake value (SUV) parameters generated from pretreatment 18 F-FDG PET/CT in the characterization of sinonasal neoplasms with histopathologic correlations.

MATERIALS AND METHODS: This retrospective study included 97 consecutive patients (58 men, 39 women; age range, 20-93 years; mean age, 62 years) with pathologically proven untreated sinonasal neoplasms who underwent FDG PET/CT from February 2010 to August 2017. Semiquantitative analysis of primary tumors were performed to evaluate the maximum standardized uptake value (SUVmax ), mean standardized uptake value (SUVmean ), and the ratio of the SUVmax of the primary tumor to the SUVmean of mediastinal blood pool, which we refer to here as " SUVratio ." Various sinonasal tumor histopathologic subgroups (n = 14) were analyzed. The Kruskal-Wallis test was used to compare the SUVmax , SUVmean , and SUVratio with the histopathologic diagnosis.

RESULTS: Mean values of SUVmax , SUVmean , and SUVratio for the sinonasal neoplasms were 16.6 ± 9.7 (SD), 8.6 ± 5.1, and 5.9 ± 3.7, respectively, and each parameter was significantly different between histopathologic types (p < 0.05). Mean values of SUVmax , SUVmean , and SUVratio were higher in sinonasal undifferentiated carcinoma (SNUC) than in olfactory neuroblastoma, metastasis, and adenoid cystic carcinoma (p < 0.05). Mean values of SUVmax and SUVmean were higher in squamous cell carcinoma (SCC) than in olfactory neuroblastoma and metastasis (p < 0.05). Also, mean SUVmax was higher in SCC and SNUC than in poorly differentiated carcinoma (p < 0.05). Mean SUVratio was higher in SCC than in small cell carcinoma, olfactory neuroblastoma, and adenoid cystic carcinoma (p < 0.05).

CONCLUSION: We conclude that different SUV parameters from FDG PET/CT can be used as so-called "metabolic biopsy" to categorize sinonasal neoplasms into different histopathologic subgroups because it can help in the characterization of some of the more common subgroups of sinonasal neoplasms. However, we found that there is overlap in FDG uptake values among some of the rare histologic subgroups; hence, surgical biopsy is still needed for differentiation of histologic subtypes of aggressive sinonasal masses.