Qualitative and semiquantitative evaluations of solid breast lesions by sonoelastography.

Objectives: Our purpose was to determine whether the combination of a qualitative elasticity scoring method and a semiquantitative strain index method by sonoelastography is useful for differentiating between benign and malignant breast masses.

Methods: Seventy-eight lesions in 71 consecutive patients with solid breast masses (62 benign and 16 malignant) were prospectively included in this study. For each lesion, B-mode sonographic and sonoelastographic images were obtained. After elasticity scores had been determined with a 5-point scoring method, strain indices of the lesions were calculated using a same-level and normal-appearing breast region as an internal reference by means of strain ratio measurement. The findings were compared with histopathologic findings. With the use of receiver operating characteristic curves, the diagnostic performances of the elasticity scoring and strain index methods were determined.

Results: The mean scores ± SD on sonoelastography were 2.69 ± 0.59 for benign lesions and 3.75 ± 0.68 for malignant lesions. The mean stiffness index values were 2.03 ± 2.67 for benign lesions and 5.97 ± 4.45 for malignant lesions. The areas under the curves were 0.864 for 5-point scoring and 0.840 for the strain index. Sensitivity and specificity were 80% and 95%, respectively, for 5-point scoring, 87.5% and 72.6% for B-mode sonography, and 80% and 93% for the strain index when a cutoff point of 3.52 was used. A semiquantitative evaluation using the strain index did not contribute to the qualitative scoring evaluation.

Conclusions: After 5-point scoring with sonoelastography, additional measurement with the strain index is not mandatory for differentiating between benign and malignant breast masses.