Factors contributing to the accuracy in diagnosing ovarian malignancy by color Doppler ultrasound.

Abstract

To determine whether resistance index values obtained by color Doppler ultrasound contribute to the accuracy in diagnosing ovarian malignancies. Four hundred ten patients with ovarian neoplasms referred for color Doppler ultrasound evaluation were enrolled, excluding patients examined during the luteal phase. Resistance index of the intra-tumor arteries was measured by color Doppler ultrasound. The corresponding clinical and histopathologic information was recorded. For statistical determinations, we used the Yates corrected chi 2 analysis, Fisher exact test, Student t test, and linear regression analysis. Satisfactory intra-tumor artery waveforms were obtained in 96.1% (99 of 103) of ovarian malignancies. Resistance index values varied at 0.23-0.82. Regression analysis of resistance index values on tumor size and amount of ascites demonstrated a linear association (R = 0.498 and 0.362, respectively; P < .01 in both). If we regard a resistance index of 0.4 as a cutoff value, the overall sensitivity and specificity in detecting malignancy were 68.0 and 97.4%, respectively. Primary ovarian malignancies exhibited significantly more false negatives (30 of 79) than malignancies metastasized to the ovary (three of 24) (P = .018). Malignancies containing mainly cystic components exhibited more false negatives (20 of 41) than did tumors with primarily solid components (13 of 62) (P < .01). Significantly more false negatives were encountered in malignancies with larger diameters (greater than 10 cm) compared to smaller ones (27 of 63 versus six of 40; P < .01), and in malignancies accompanied by considerable ascites (greater than 1000 mL) (13 of 25 versus 20 of 78; P < .05). Tumor origin, size, component nature, and amount of ascites contributed to the accuracy in diagnosing ovarian malignancies using resistance index values obtained by color Doppler ultrasound.