The effect of uterine volume on uterine artery Doppler velocimetry in the myomatous state.

This study aimed at testing the hypothesis that lower uterine arterial (UA) Doppler indices are caused by increased uterine volume rather than the presence of myoma. Uterine volumes were calculated and uterine and/or myomal arterial pulsatility index (PI) and resistance index (RI) were obtained by transvaginal color Doppler ultrasonography. The mean uterine volume in the myomatous group (276.2 cm3; range 65-928 cm3, n = 100) was significantly greater than that of the control group (101.4 cm3; range 36-171 cm3; n = 60; p = 0.00). The mean UA PI and RI values in the study group were significantly lower than their corresponding values in the control group (0.77 +/- 0.08 and 1.69 +/- 0.47 vs. 0.82 +/- 0.06 and 1.97 +/- 0.49, respectively, p = 0.01). When the myomatous uterine volumes of the study group were categorized into two subgroups (< 200 and > or = 200 cm2) the UA PI and RI values were lower in the latter group (p = 0.006 and p = 0.015, respectively). However, after analysis of receiver-operator-characteristic curves, none of the UA Doppler indices could differentiate the myomatous uterus from the normal uterus.