Objective:

To investigate the application value of Youngs modulus of mass (

E

) and surrounding Youngs modulus of 2 mm shell (

S

) in sound touch elastography (STE) for breast BI-RADS 4 masses by retrospective study.

Methods:

A total of 210 Breast Imaging Reporting and Data System (BI-RADS) 4 breast masses treated in The Third Affiliated Hospital of Soochow University from January 2018 to December 2020 were selected as the training group and 68 BI-RADS 4 masses as the verification group. The hardness of the lesion area (

E

max

E

mean

E

min

E

sd

) and the glandular tissue around the lesion (

S

max

S

mean

S

min

S

sd

) were quantitatively evaluated. Taking the pathological results as the gold standard

the elastic parameters with the highest diagnostic performance in STE of BI-RADS 4 masses in the training group were selected

and their cutoff values were used to evaluate the performance of 68 BI-RADS 4 masses as the verification group

and then the performance of BI-RADS 4A

4B and 4C masses in this study group were evaluated respectively.

Results:

The diagnostic efficiency of the

S

max

modulus of 2 mm around the mass was the highest in STE imaging. The best cut-off value of

S

max

(91.73 kPa) was used to evaluate the performance of 68 cases of BI-RADS 4 masses. The area under curve (AUC) was 0.774

AUC 0.822 and Youden index 0.64 in BI-RADS 4A group; AUC 0.703 and Youden index 0.41 in BI-RADS 4B group

AUC 0.50 and Youden index 0.002 in BI-RADS 4C group

respectively.

Conclusion:

The value of

S

max

modulus in STE is an important auxiliary parameter in the differential diagnosis of benign and malignant breast lesions

and it is more valuable in distinguishing BI-RADS 4A breast masses

which can

reduce the unnecessary biopsy of BI-RADS 4A masses.