Contrast-enhanced spectral mammography in recalls from the Dutch breast cancer screening program: validation of results in a large multireader, multicase study

Abstract

Objectives: Contrast-enhanced spectral mammography (CESM) is a promising problem-solving tool in women referred from a breast cancer screening program. We aimed to study the validity of preliminary results of CESM using a larger panel of radiologists with different levels of CESM experience.

Methods: All women referred from the Dutch breast cancer screening program were eligible for CESM. 199 consecutive cases were viewed by ten radiologists. Four had extensive CESM experience, three had no CESM experience but were experienced breast radiologists, and three were residents. All readers provided a BI-RADS score for the low-energy CESM images first, after which the score could be adjusted when viewing the entire CESM exam. BI-RADS 1-3 were considered benign and BI-RADS 4-5 malignant. With this cutoff, we calculated sensitivity, specificity and area under the ROC curve.

Results: CESM increased diagnostic accuracy in all readers. The performance for all readers using CESM was: sensitivity 96.9 % (+3.9 %), specificity 69.7 % (+33.8 %) and area under the ROC curve 0.833 (+0.188).

Conclusion: CESM is superior to conventional mammography, with excellent problem-solving capabilities in women referred from the breast cancer screening program. Previous results were confirmed even in a larger panel of readers with varying CESM experience.

Key points: • CESM is consistently superior to conventional mammography • CESM increases diagnostic accuracy regardless of a reader's experience • CESM is an excellent problem-solving tool in recalls from screening programs.

Keywords: Breast cancer; CEDM; CESM; Contrast-enhanced dual energy mammography; Contrast-enhanced spectral mammography.

Fig. 1

Average ROC curves for all readers (a), experienced CESM readers (b), experienced FFDM readers (c) and resident readers (d). AUC values for FFDM and CESM given with confidence intervals in parenthesis. Differences in AUC between FFDM and CESM were significantly increased for all subgroup of reader panels, p-values given per subgroup of reader panel

Fig. 2

Overview of number of cases and diagnosis of false-positive findings. These cases were scored as false-positive cases by five or more readers

Fig. 3

Example of false negatives cases. Low-energy images at the top with corresponding re-combined images underneath. A: infiltrating grade 2 ductal carcinoma with grade 3 ductal carcinoma in situ (curved arrow), B: invasive grade 2 ductal carcinoma (arrow head) and C: grade 1 mucinous carcinoma (straight arrow)