Can strain elastography be used in reclassification of indeterminate breast lesions in BIRADS lexicon?: A prospective study.

PURPOSE

To evaluate the role of strain elastography (SE) in reclassification of indeterminate breast lesions placed under BIRADS 3 and 4 categories by conventional ultrasound (US) parameters so as to recourse biopsy only for suspicious stiffer lesions.

METHODS

113 breast lesions in 100 women assigned as BIRADS category 3 and 4 on US parameters were prospectively evaluated by SE followed by histo-pathological examination. Strain ratio (SR) and Elastography Score (ES) were determined for each lesion. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated for each modality and diagnostic performance were compared. The best cut-off point was calculated for each of the elastography parameter using the receiver operator curve analysis (ROC).

RESULTS

Out of the 113 lesions, 40 were malignant (35.4%) and 73 were benign (64.6%). A statistically significant difference was observed in the AUC for ES and conventional US: 0.98 vs 0.90 (Difference = 0.08, = 0.02). Elastography parameters were more specific as compared to US (ES-94.5 & SR-93.2% vs 63%, < 0.05) with high NPV. SE performed better in BIRADS 4 category lesions. On the basis of elastography parameters, 85% of BIRADS 4 category lesions were correctly predicted as benign with overall sensitivity, specificity and diagnostic accuracy of elastography being 97%, 84.6% and 91.9%. Among BIRADS 3 category lesions, 97% were correctly predicted as benign and 50% lesions were correctly predicted as malignant with a sensitivity of 50%, specificity of 97.8% and diagnostic accuracy of 94%.

CONCLUSION

Strain elastography is a useful adjunct to conventional ultrasonography for the assessment of indeterminate breast lesions and may help in avoiding unnecessary follow ups and biopsies. Elastography score is a better parameter as compared to strain ratio.