A multicenter study to confirm further diagnostic value of strain ratio method giving to 5-point scoring by elastography for differentiation of breast lesions

Abstract

Objective To confirm whether strain ratio should be added after evaluation of lesions with 5-point elasticity scoring for differentiating breast lesions on ultrasonic elastography (UE). Methods Eight hundred and forty-six consecutive female patients with 1 071 breast lesions were recruited into a multicenter retrospective study, which involved 8 centers across China. All the patients underwent the UE procedure and the strain ratios were calculated. The sensitivity, specificity, accuracy, PPV and NPV were calculated for each of the two evaluation systems and the areas under the ROC curve were compared. Results The strain ratios of 559 benign lesions (2.7±1.4) and 512 malignant lesions (8.1±5.9) were significantly different (P<0.001). When the cutoff point was 3.03, strain ratio method had 81.6% sensitivity, 89.7% specificity, 81.7% accuracy, 80.2% PPV and 84.2% NPV. The areas under the ROC curve with the strain ratio method and 5-point scoring method were 0.865 and 0.862, respectively (P=0.622). For the lesions with elasticity score 3 and 4, the areas under the ROC curve of the two methods were 0.711 and 0.629, respectively(P=0.020). Conclusions Although the two UE methods have similar diagnostic performance, separate calculation of the strain ratios seems compulsory, especially for the lesions with elasticity score 3 and 4. Key words: Elasticity imaging techniques; Breast diseases; Strain ratio; Elasticity score