Diagnosis of solid breast lesions by elastography 5-point score and strain ratio method

Purpose

To compare the diagnostic performance of 5-point scoring system and strain ratio by sonoelastography in the assessment of solid breast lesions.

Material and methods

One hundred and eighty-seven solid masses in 155 patients were scanned by two-dimensional ultrasonography and sonoelastography. Elasticity scores were determined with a 5-point scoring method, and the strain ratio was based on the comparison of the average strain measured in the lesion with the adjacent breast tissue in the same depth. Pathological results were taken as gold standards to compare the diagnostic efficacy of two methods with clinical diagnostic test and receiver operating characteristic (ROC) curves.

Results

Among 187 lesions, 130 were benign and 57 were malignant. The mean scores (1.62 ± 0.69 vs 4.07 ± 0.26, P < 0.05) and strain ratios (2.06 ± 1.27 vs 6.66 ± 4.62, P < 0.05) were significantly higher of malignant than benign lesions. The area under the curve for the 5-point scoring system and for strain ratio-based elastographic analysis was 0.892 and 0.909, respectively (P > 0.05). For 5-point scoring, sonoelastography had 84.2% sensitivity, 84.6% specificity, 84.5% accuracy, 70.6% positive predictive value and 92.4% negative predictive value. When a cutoff point of 3.06 was used, sensitivity, specificity, accuracy, positive and negative predictive values were 87.7%, 88.5%, 88.2%, 76.9% and 94.3%, respectively for the strain ratio (P > 0.05).

Conclusions

The 5-point scoring system and strain ratio has similar diagnostic performance, and the strain ratio could be more objective to differentiate the masses when those masses were difficult to be judged by using 5-point scoring system in sonoelastographic images.