Application of Real-time Ultrasound Elastography for Discrimination of Low- and High-grade Serous Ovarian Carcinoma

Abstract

The purpose of this study was to evaluate real-time qualitative ultrasound elastography as an adjunct to conventional sonography for discrimination of low- and high-grade serous ovarian carcinoma. Eighty-six patients suspected of having serous ovarian cancer on the basis of clinical and biochemical evaluations underwent transvaginal and transabdominal sonography and then elastography and later underwent surgery. Histopathologic analysis revealed 64 serous ovarian carcinomas (74.4%): 39 (60.9%) high grade and 25 (39.1%) low grade. The mean elasticity score ± SD was statistically significantly higher for low-grade lesions (3.40 ± 0.76) than high-grade lesions (2.08 ± 0.58; P < .001). There was a trend for high-grade lesions to be less stiff than low-grade lesions due to rapidly developing necrosis; conversely, low-grade lesions developed relatively slowly so that their solid areas were stiffer and less elastic. The median elasticity score for low-grade lesions (based on a 4-point scale used to grade cervical lymph nodes) was 4 (stiffest), and the score for high-grade lesions was 2. When the score of 4 was used for diagnosis of low-grade carcinoma, elastography had 56.0% sensitivity, 100% specificity, a 100% positive predictive value, a 78.0% negative predictive value, and 82.8% accuracy. When the score of 2 was used for the diagnosis of high-grade carcinoma, elastography had 66.7% sensitivity, 84.0% specificity, an 86.7% positive predictive value, a 61.8% negative predictive value, and 73.4% accuracy. Our results suggest that ultrasound elastography could be helpful for discrimination of low- and high-grade serous ovarian carcinoma. Low-grade lesions are stiffer and not as elastic as high-grade lesions.