Keywords:
Image registration, Screening, Observer performance, Ultrasound, Breast
Authors:
L. de Jong1, M. K. Welleweerd2, J. van Zelst1, F. J. Siepel2, S. Stramigioli2, J. J. Futterer1, R. M. Mann1, C. L. de Korte1; 1Nijmegen/NL, 2Enschede/NL
DOI:
10.1594/ecr2018/C-2956
Methods and materials
Marker production:
Markers were molded using a mold that was designed and 3D printed in a rubber-like material,
allowing for removal of the resulting markers. Spherical,
conical,
circular, and disk-shaped variants were molded in different sizes (Figure 1).
The material used for the marker is EcoFlex-Gel® (Macungie,
Pennsylvania USA), which is a commercially available Room Temperature Curing (RTC) silicon. This silicon proved suitable for US imaging and can also be used as phantom material [3].
After mixing the two components the silicon mixture is poured into the mold and is left to cure for two hours in a vacuum chamber for air removal. When the silicon is fully cured the markers can be removed from the mold for application.
Image acquisition:
3D ultrasound examinations were performed with the patient in supine position using a Siemens Acuson S2000 automated breast volume scanner (ABVS) system (Siemens,
Erlangen) (Figure 2). In 5 patients undergoing 3D ultrasound examinations for clinical reasons the same 3D volume was imaged twice,
once with and once without a marker in place.
Ultrasound acquisition parameters were the same as used in clinical practice and varied between patients based on cup size. Acquisition settings between the scans with and without a marker in place were identical in each patient.
Image assessment:
Markers were assessed by an experienced breast radiologist for ultrasound compatibility using qualitative parameters; detectability,
shadowing-,
enhancement-,
and displacement artifact.
Interpretability of the images with and without markers was compared.
Usability assessment:
For application in clinical practice parameters on usability were evaluated.
Application and removal of the marker,
adhesion to the skin during scanning and material safety were taken into account for evaluation.