The relationship between diurnal variation of TSH and thyroid blood flow with Doppler ultrasonography in healthy adults

Abstract

Aim. To determine the presence of a correlation between the Doppler parameters of thyroid blood flow and diurnal variation of TSH.

Method. Thirty healthy adults were included. FT3, FT4, and TSH measurements were made at 08.00, 16.00, and 24.00. Thyroid volumes were calculated followed by peak systolic velocity (PSV) and resistance index (RI) from the inferior thyroid artery by Doppler ultrasonography.

Results. The difference between diurnal measurements of TSH was found to be significant (1.29 ± 0.55 vs 3.09 ± 1.52; p < 0.001). PSV was detected to be higher at 24.00 compared to values measured at 08.00 and 16.00 (27.75 ± 9.54 vs 24.9 ± 8.51; p < 0.01 and 27.75 ± 9.54 vs 25.88 ± 9.82; p < 0.05). Mean RI values were lower at 24.00 compared to those at 08.00 and 16.00 (0.53 ± 0.07 vs 0.57 ± 0.07; p < 0.001 and 0.53 ± 0.08 vs 0.56 ± 0.05; p < 0.05).

Conclusion. Thyroid blood flow should be evaluated diurnally by Doppler ultrasonography in thyroid pathologies.

Keywords:

• Thyroid
• blood flow
• and Doppler ultrasonography