RESUMO
OBJECTIVES: The purpose of this study was to compare the diagnostic performance of the fat-to-lesion strain ratio (FLR) and gland-to-lesion strain ratio (GLR) for patients with indeterminate or suspicious breast lesions on ultrasound (US) imaging under a controlled precompression technique and to see whether the technique improves the reproducibility of FLR and GLR measurement. METHODS: Fifty-three lesions in 39 consecutive patients who had scheduled core biopsy or excision surgery based on US findings were examined by US elastography. Each lesion was acquired under controlled precompression by 2 sonographers independently. Both the FLR and GLR of the lesion were calculated. For diagnostic performance, the sensitivity, specificity, negative predictive value, positive predictive value, and accuracy were obtained. Interobserver reliability between different sonographers was assessed by the intraclass correlation coefficient (ICC). RESULTS: Forty lesions were benign, and 13 lesions were malignant. Both the FLR and GLR were significantly higher in malignant than benign lesions (P < .05). The FLR yielded higher accuracy and specificity compared to the GLR (accuracy, 79.2% versus 60.4%; and specificity, 87.5% versus 50.0%). With the controlled precompression applied at less than 25% during elastography, the interobserver agreement was excellent for FLR measurements (ICC, 0.853; 95% confidence interval, 0.738-0.920) and GLR measurements (ICC, 0.779; 95% confidence interval, 0.619-0.87). CONCLUSIONS: The FLR performed better than the GLR in the detection of breast malignancy; thus, fatty tissue was a better reference tissue for calculating the strain ratio on malignant breast tumor elastography. Keeping precompression to less than 25% will enable different operators to acquire similar elastograms with reproducible FLR and GLR readings.
