Value of ¹³¹I SPECT/CT on the re-staging and recurrence risk stratification and its impact on subsequent treatment strategy in post-surgical patients with differentiated thyroid carcinoma

Objective: To evaluate the role of ¹³¹I SPECT/CT in post-surgical re-staging and recurrence risk stratification in patients with DTC and its impact on subsequent treatment strategy. Methods: ¹³¹I-WBS and ¹³¹I SPECT/CT were performed at the same time 5 to 7 d after ¹³¹I treatment in 118 patients (33 males, 85 females, average age 45 years) with DTC. Difference in the localization and qualitative diagnosis of ¹³¹I uptake lesions between ¹³¹I-WBS and ¹³¹I SPECT/CT were compared. Value of ¹³¹I SPECT/CT in the diagnosis of TNM staging, risk stratification and impact on the treatment strategy was evaluated. Paired χ² test was used for data analysis. Results: A total of 509 foci with ¹³¹I uptake were detected. ¹³¹I-WBS found 449 foci with ¹³¹I uptake, 354 of which (78.84%) were correctly diagnosed. ¹³¹I SPECT/CT found 509 foci with ¹³¹I uptake, and 504(99.02%) were correctly diagnosed. The difference was statistically significant (χ² = 21.51, P < 0.01). ¹³¹I-WBS changed the clinical staging in 13 cases with diagnostic accuracy of 5/13. ¹³¹I SPECT/CT changed the clinical staging in 19 cases and with diagnostic accuracy of 19/19 (χ² = 74.41, P < 0.01). ¹³¹I-WBS changed the risk stratification of 13 patients after operation and the accuracy was 5/13, the corresponding data were 22 and 100%(22/22) for ¹³¹I SPECT/CT (χ² = 74.41, P < 0.01). The treatment strategy was changed in 50 patients with ¹³¹I SPECT/CT. Conclusions: Compared with ¹³¹I-WBS, ¹³¹I SPECT/CT could provide more accurate positioning and qualitative information for ¹³¹I treatment and is more accurate in re-staging and risk stratification. (authors)