Ectopic thyroids have lower computed tomography attenuation values than orthotopic thyroids

Purpose To determine whether ectopic thyroid had the same computed tomography (CT) value as orthotopic thyroid. Methods Twenty-one patients with 23 ectopic thyroids and 23 controls with orthotopic thyroids underwent CT scans and were included in this retrospective study. The CT images were reviewed in a blinded fashion by two radiologists. Independent-Samples T- test was used for comparison of CT attenuation values between two groups. Results Ectopic thyroids had significantly lower non-enhanced attenuation (91.04 ± 5.97 Hounsfield Units vs. 106.56 ± 4.06 Hounsfield Units, P = 0.038) and contrast-enhanced attenuation (141.32 ± 6.42 Hounsfield Units vs. 169.82 ± 4.30 Hounsfield Units, P = 0.001) values than orthotopic thyroids. Conclusions Ectopic thyroids have lower CT attenuation values than orthotopic thyroids probably due to the structural or functional abnormalities. The dysgenesis and pathological changes of the ectopic thyroids may contribute to functional deficiency which finally leads to decrease of the CT attenuation values.