INTRAOBSERVER VARIATION IN TRANSVAGINAL DOPPLER BLOOD-FLOW MEASUREMENTS IN BENIGN OVARIAN TUMORS

Intraobserver variation in transvaginal color Doppler ultrasound measu rements in ovarian tumors was evaluated in 20 women selected from a gr oup of patients undergoing surgical exploration for an ovarian lesion. Only those cases who were suspected of having a benign ovarian tumor other than a unilocular simple cyst were recruited. Pulsatility index (PI), resistance index (RI), peak systolic velocity (PSV) and time-ave raged maximum velocity (TAMXV) were measured from intratumoral arterie s in two repeat ultrasound sessions by the same observer. In each sess ion, only two vessels with optimum Doppler signals were investigated. The repeatability of the measurements was studied by calculation of th e within-subjects standard deviation (SD), the value below which the d ifference between the repeat measurements will lie with a probability of 0.95, the coefficient of variation (CV) and the intraclass correlat ion coefficient (intra-CC). The CV was 15% for the PI, 13% for the RI, 17% for the PSV and 23% for the TAMXV when the average value from two vessels was used. The corresponding intra-CC values were 0.86, 0.83, 0.96 and 0.90, respectively. In contrast, when a lowest (PI or RI) or a highest (PSV or TAMXV) value was preferred, the CV increased to 25% for the PI, to 18% for she RI, to 28% for the PSV and to 33% for the T AMXV. Similarly, the intra-CC values decreased. All in all, the averag ed PI and RI measurements in intratumoral arteries were considered to be reliable. Averaged PSV and TAMXV measurements had high CV figures, raising some doubt as to the consistency of these variables. Averaged index values were more consistent than the extreme (lowest or highest) values.