Advanced techniques have been developed and are in development to extend the performance and functionality of breast imaging techniques. The use of contrast agents during acquisition of x-ray-based breast images can improve the detection and diagnostic task, and holds promise to obtain functional information to have an impact in the treatment realm. Of course, the use of nuclear medicine methods is an established technique to obtain functional images that also needs to be considered.
Contrast enhanced mammography combines mammographic imaging with an intravenous iodinated contrast to enable the depiction of cancers that would otherwise be occult on standard unenhanced mammography. As seen in other modalities, such as MRI, tumors preferentially take up the contrast agent, as compared to normal breast tissue. The technique uses dual energy subtraction to improve the visibility of the injected contrast in the breast. The examination can be obtained using standard mammography equipment with only small modifications, typically the addition of additional filtration options and software modification. Clinical studies on CEM date from 2003 and have shown it to be superior to unenhanced mammography and similar to MRI for tumor detection and characterization.
The addition of contrast enhancement to breast tomosynthesis imaging, combined with various image processing and correction techniques could result in more accurate functional information on tumor status than that obtained with contrast-enhanced mammography. However, to make contrast-enhanced tomosynthesis quantitative, various limitations of this limited angle tomographic technique need to be overcome. A review of current efforts in contrast enhanced tomosynthesis will be performed, and the development of quantitative images will be introduced.
Molecular breast imaging (MBI) is a nuclear medicine modality that uses dedicated gamma cameras to image the functional uptake of Tc-99m sestamibi in the breast. Single institution reports have shown supplemental MBI to reveal breast cancers missed over years of routine screening with anatomical techniques of mammography and digital tomosynthesis. Recent updates to allow low radiation dose MBI and direct biopsy may serve to enable wider adoption of this technology. Preliminary results from a current multicenter trial comparing MBI to tomosynthesis screening in dense breasts will be presented. Use of MBI and other functional modalities to probe the behavior of dense fibroglandular tissue and discover biomarkers of breast cancer risk will be discussed.
1. Learning objective 1: To describe the basics of contrast enhanced mammography and tomosynthesis imaging.
2. Learning objective 2: To list the uses of contrast enhanced mammography in the clinic.
3. Learning objective 3: To describe the limitations to be addressed to make quantitative contrast enhanced tomosynthesis possible.
4. Learning objective 4: To understand the technology behind MBI.
5. Learning objective 5: To describe the current possibilities for MBI in the clinical realm.