Contrast-enhanced spectral mammography: comparison with conventional mammography and histopathology in 152 women

Abstract

Objective: The goal of the study was to compare conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) in preoperative women.

Materials and methods: The study was approved by the local Ethics Committee and all participants provided informed consent. The study included 152 consecutive patients with 173 breast lesions diagnosed on MG or CESM. All MG examinations and consults were conducted in one oncology centre. Non-ionic contrast agent, at a total dose of 1.5 mL/kg body weight, was injected intravenous. Subsequently, CESM exams were performed with a mammography device, allowing dual-energy acquisitions. The entire procedure was done within the oncology centre. Images from low and high energy exposures were processed together and the combination provided an "iodine" image which outlined contrast up-take in the breast.

Results: MG detected 157 lesions in 150 patients, including 92 infiltrating cancers, 12 non-infiltrating cancers, and 53 benign lesions. CESM detected 149 lesions in 128 patients, including 101 infiltrating cancers, 13 non-infiltrating cancers, and 35 benign lesions. CESM sensitivity was 100% (vs. 91% for MG), specificity was 41% (vs. 15% for MG), area under the receiver operating characteristic curve was 0.86 (vs. 0.67 for MG), and accuracy was 80% (vs. 65% for MG) for the diagnosis of breast cancer. Both MG and CESM overestimated lesion sizes compared to histopathology (p < 0.001).

Conclusion: CESM may provide higher sensitivity for breast cancer detection and greater diagnostic accuracy than conventional mammography.

Keywords: Breast cancer; Contrast enhanced spectral mammography; Mammography.

Fig. 1

Contrast-enhanced spectral mammography examination scheme (example where left breast is most suspicious) (Courtesy of GE Healthcare). LCC = left craniocaudal, LMLO = left mediolateral oblique, RCC = right craniocaudal, RMLO = right mediolateral oblique

Fig. 2

Infiltrating ductal carcinoma (arrows) of right breast in 63-year-old woman with dense fibroglandular breast tissue. A. Digital conventional mammography (MG) with mediolateral oblique (MLO) view of right breast reveals oval, well demarcated shadow 15 mm in diameter. This mass is not visible in MG craniocaudal (CC) projection. B. Contrast-enhanced spectral mammography in same patient shows poorly demarcated focus of enhancement 15 mm in diameter visible in both MLO and CC projections. Additionally, in right breast, small enhancing foci are visible in upper and lower outer quadrants. C. In histopathological examination, infiltrating carcinoma (of no special type) grade 2 was found within main focus of enhancement. Ductal carcinoma in situ (DCIS) component was noticed in unaltered areas macroscopically. Hematoxylin and eosin staining. Objective magnification 10 × (invasive component, left) and 20 × (DCIS, right).

Fig. 3

Comparison of correct and incorrect assessments on conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) based on Breast Imaging Reporting and Data System (BI-RADS) scores (BI-RADS scores on MG and CESM were consistent and correct in 91% of proven malignant lesions). Diagnosis was correct if lesion scored as BI-RADS < 4 was benign or scored ≥ 4 was malignant. Left picture presents agreement between MG and CESM diagnoses with pathological results in 59 benign lesions, right picture-in 114 malignant lesions.

Fig. 4

Receiver operating characteristic curves from Breast Imaging Reporting and Data System (BI-RADS) conventional mammography (MG) and contrast-enhanced spectral mammography (CESM) assessments.