*2.2. CESM Examination*

All CESM examinations were performed in our hospital. They were carried out with the use of a digital mammography device dedicated to performing dual-energy CESM acquisitions (SenoBright, GE Healthcare, 3000 N. Grandview Blvd., Waukesha, WI, USA). An intravenous injection of 1.5 mL/kg of body mass of non-ionic contrast agen<sup>t</sup> was performed using a power injector at a rate of 3 mL/s with a bolus chaser of 30 mL of saline. In CESM mode, the device automatically performed a pair of exposures (low- and high-energy) in each view. Specific image processing of low-energy and highenergy images was done. This processing aimed to obtain subtraction images to highlight contrast enhancement and suppress structured noise due to fibroglandular breast tissue. The morphological information obtained from low-energy images of CESM is similar to the morphological information given by standard mammography and the functional information obtained from subtraction images of CESM visualizes the vascularization of breast lesions [24,25,30]. For each view, the CESM technique made it possible to obtain two images: a low-energy acquisition at 26–30 kVp and a high-energy acquisition at 45– 49 kVp, with these values depending on breast density and thickness. Motion blur could be sometimes observed on subtraction images due to movements between the acquisition of low- and high-energy images. All of the images obtained were in the DICOM format [31]. The total examination time was usually 10 min. After examination, the patients were observed for approximately 30 min for any adverse reactions that may have occurred after administration of the contrast agent.
