Reliable Parameters of Color Doppler Ultrasonography for Predicting Thyroid Function

To compare and determine color Doppler ultrasonography (CDU) parameters that is the most reliable parameter for predicting thyroid functional status between euthyroid and hyperthyroid states. We retrospectively reviewed data from a total of 256 patients (197 females and 59 males) who had undergone CDU from December 2003 to April 2008. Patients’ age ranged from 11-81 yr with average of 38.6 yr. The mean age of females was 37.0 ± 14.3 yr and that of males was 43.8 ± 14.2 yr. The parameters included the pulsatility index (PI), resist ive index (RI), peak systol ic velocity (PSV), blood volume flow (VF), inferior thyroid artery diameter (DIAM), end diastolic velocity (ED), time-averaged maximum velocity (TAmax), time-averaged mean velocity (TAmean), and acceleration (ACCE). We then evaluated the differences among these CDU parameters between the euthyroid group and the hyperthyroid groups. The Student’s t test was used to compare the means of the CDU parameters. The receiver operating characterist ic (ROC) curve was used to determine the optimal cutoff values of the CDU parameters to predict thyroid functional status between the groups. All CDU parameters, except for PI (p= 0.195) and RI (p= 0.544), showed significantly different results (p < 0.001) between these two groups, including VF, DIAM, PSV, ED, ACCE, TAmax, TA mean. Then, we selected the PSV, VF and TAmax, the most common parameters in clinical practice, to further determine which parameter is the most reliable parameter for predicting thyroid functional status. Area under the ROC curve for VF was 0.8061; for PSV, 0.8210; and for TAmax, 0.8024, without significant differences between these parameters for predicting thyroid functional status between the groups. According to the ROC analysis, the optimal cutoff values of the PSV, VF and TAmax were 25cm/sec, 8mL/min and 17cm/sec respectively. PSV, VF and TAmax are useful parameters in predicting thyroid function between euthyroid and hyperthyroid states according to the ROC analysis. The cutoff values of these parameters for differentiating thyroid functional status have powerful predictive accuracy and do not differ significantly. Because that VF measurement was easi ly affected by the DIAM, the main factor influenced by the physician’s procedure and individual vascular variation, we suggest that PSV or TAmax are the most reliable parameter for predicting thyroid functional status between euthyroid and hyperthyroid states.