You Mie Han1, Young Chul Kim, Eun Kyung Park, Jae-Gol Choe. 1. Department of Radiology, Hallym University Hangang Sacred Heart Hospital, Yeongdeungpo-gu, Seoul, Republic of Korea. fran9704@hotmail.com <fran9704@hotmail.com>
Abstract
OBJECTIVE: The purpose of this article is to determine the diagnostic significance of thyroid density as determined by CT in patients with a diffuse hypermetabolic thyroid on PET/CT images. SUBJECTS AND METHODS: One hundred twelve patients were enrolled in this study, and all underwent PET/CT and a thyroid function test between August 2007 and December 2008. The 56 study patients enrolled had visible (18)F-FDG uptake in the thyroid, whereas the 56 control subjects had no visible FDG uptake. Maximum standardized uptake values (SUV(max)), Hounsfield units, thyroid-stimulating hormone levels, free thyroxine levels, and visual assessments of thyroid CT densities (grades 0-2) were evaluated. Analyses were performed to identify variables that differed between patients and control subjects and to examine relationships between Hounsfield unit and SUV(max) values, free thyroxine level, or thyroid-stimulating hormone level. RESULTS: Mean Hounsfield unit and SUV(max) values were significantly different between the two groups (p < 0.001), and SUV(max) values were found to be significantly different between grades. Free thyroxine and thyroid-stimulating hormone levels were also significantly different between thyroid density grades 0 and 2 (p < 0.001). A strongly negative relationship was found between Hounsfield units and SUV(max) values (r = 0.75), whereas Hounsfield units were found to be weakly correlated with free thyroxine level (r = 0.36) and thyroid-stimulating hormone level (r = -0.33). CONCLUSION: CT density is closely related to FDG uptake, and low CT density coupled with high FDG uptake suggests a change in thyroid tissue composition and is probably helpful for assessing the disease process and thyroid function of patients whose thyroid show diffuse FDG uptake on FDG PET/CT.
OBJECTIVE: The purpose of this article is to determine the diagnostic significance of thyroid density as determined by CT in patients with a diffuse hypermetabolic thyroid on PET/CT images. SUBJECTS AND METHODS: One hundred twelve patients were enrolled in this study, and all underwent PET/CT and a thyroid function test between August 2007 and December 2008. The 56 study patients enrolled had visible (18)F-FDG uptake in the thyroid, whereas the 56 control subjects had no visible FDG uptake. Maximum standardized uptake values (SUV(max)), Hounsfield units, thyroid-stimulating hormone levels, free thyroxine levels, and visual assessments of thyroid CT densities (grades 0-2) were evaluated. Analyses were performed to identify variables that differed between patients and control subjects and to examine relationships between Hounsfield unit and SUV(max) values, free thyroxine level, or thyroid-stimulating hormone level. RESULTS: Mean Hounsfield unit and SUV(max) values were significantly different between the two groups (p < 0.001), and SUV(max) values were found to be significantly different between grades. Free thyroxine and thyroid-stimulating hormone levels were also significantly different between thyroid density grades 0 and 2 (p < 0.001). A strongly negative relationship was found between Hounsfield units and SUV(max) values (r = 0.75), whereas Hounsfield units were found to be weakly correlated with free thyroxine level (r = 0.36) and thyroid-stimulating hormone level (r = -0.33). CONCLUSION: CT density is closely related to FDG uptake, and low CT density coupled with high FDG uptake suggests a change in thyroid tissue composition and is probably helpful for assessing the disease process and thyroid function of patients whose thyroid show diffuse FDG uptake on FDG PET/CT.
Authors: J M Debnam; N Guha-Thakurta; J Sun; W Wei; M E Zafereo; M E Cabanillas; N M Buisson; D Schellingerhout Journal: AJNR Am J Neuroradiol Date: 2020-04-23 Impact factor: 3.825