Determination of the thyroid volume by ultrasonography - comparison with surgical facts

Aim: Objective of this prospective study was to find out, if especially the volume of large nodular goitres con be determined accurately by using ultr asonography and the ellipsoid model. Methods: 100 patients with different t hyroid disorders, who oil underwent a thyroid resection, were examined by a single experienced investigator. The preoperative thyroid volume was deter mined by ultrasonography and correlated to the sum of surgically removed an d postoperative thyroid volume determined by ultrasound. Results: Patients included had thyroid volumes between 12 and 450 ml (mean value 89 ml). With in the whole study group, coefficients of correlation and variation were r = 0.90 and CV = 0.29, respectively. The mean difference between the thyroid volume determined preoperatively by ultrasonography and the sum of surgica lly removed and postoperative thyroid volume was 3 +/- 27 ml or 13 +/- 38%. Excluding patients with retrosternal goitres or cysts with a diameter >2 c m, the correlation coefficient increased to r = 0.95 (CV = 0,21) and mean d ifferences decreased to 2 +/- 20 ml and 9 +/- 30%. Further subdivision acco rding to thyroid volume (less than or equal to 50 ml, less than or equal to 100 ml, >100 ml) revealed no significant influence of thyroid volume on th e accuracy of ultrasound volume determination. Subdividing the study collec tive according thyroid disorders, relevant deviations of preoperative sonog raphic thyroid volume from the sum of surgically removed and post-operative thyroid volume were observed in case of retrosternal goitre (19 +/- 62%), cystic degeneration (41 +/- 52%) and Graves' disease (23 +/- 29%). Conclusi on: These results show, that even large suprosternal goitres >100 mi con be sufficiently determined by ultrasound by an experienced examiner.