Differential diagnosis of benign and malignant breast calcification by quantitative measurement of gray value on contrast-enhanced spectral mammography / 中华放射学杂志

ABSTRACT

Objective:To investigate the value of gray value (GV) measurement of subtraction images in contrast-enhanced spectral mammography (CESM) in the differential diagnosis of breast benign and malignant calcification.Methods:This was a retrospective study. A total of 95 patients received CESM only with mammographic calcifications without any associated mass or distortions from March 2017 to July 2021 in Peking University Cancer Hospital were enrolled. The patients were all female with an average age of 34-76(48±7) years. The craniocaudal (CC) projection of bilateral breasts was obtained prior to the mediolateral-oblique (MLO) projection. Two radiologists were asked to independently review the images to diagnose the calcification as either benign or malignant based on the presence of enhancement on subtracted imaging. GV of the calcification and background parenchyma including breast parenchyma tissue, the pectoralis major muscle and subcutaneous fatty tissue were measured by another two radiologists. The difference of lesion to background parenchyma GV (D GV) and lesion to background parenchyma gray value ratio (DR GV) were calculated. The consistency of observers was compared using the Kappa statistic. The stability of GV was evaluated with coefficient of variation. Differences of GV, D GV and DR GV between benign and malignant calcification were compared using t test or Mann-Whitney U test. Receiver operating characteristic (ROC) curves were used to analyze the efficacy of GV in differentiating benign from malignant calcification. Comparisons between diagnostic efficacies were performed using χ 2 tests. Results:Totally 97 calcification (35 malignant and 62 benign) from 95 patients were enrolled. The consistency and stability of GV values on MLO and CC projections measured by two physicians were high. The GV, D GV and DR GV of malignant calcification were significantly higher than those of the benign lesions ( P<0.05). The area under the ROC curve for the differential diagnosis of benign and malignant calcification by GV in the MLO and CC positions was 0.799 and 0.843, respectively. Threshold of calcified area GV=2015.5 in CC position, its diagnostic accuracy was 76.8%, which was similar to the subjective diagnosis of radiologists (82.1%, 78/95, P>0.05). Conclusion:Quantitative GV on subtracted imaging of CESM can differentiate benign from malignant breast calcification, especially on craniocaudal projection.