Nonmammographic breast imaging techniques

Significant progress in early detection of malignancy has been achieved by the improvement of mammographic technique, the introduction of quality control, the demonstration of benefits from screening, and appropriate application of supplementary methods such as ultrasound, cytology, and stereotaxis. Certain problems in breast imaging, however, are still unsolved. These include early detection and exclusion of malignancy without microcalcifications in mammographically dense tissue (particularly in younger women), the still-limited accuracy of mammographic signs, and the management of diagnostic problems after surgery, radiation therapy, or silicone implants. Therefore, research is needed to further improve diagnostic capabilities. The research can be subdivided into different approaches: 1) further development of the mammographic technique (digital luminescence radiography); 2) evaluation of techniques that image other physical tissue properties (sonography, thermography, trans-illumination, CT, non-contrast-enhanced MR imaging, biomagnetism, biostereometry, and ductoscopy); 3) investigation of techniques that image metabolic changes (MR spectroscopy, positron-emission tomography) or metabolism-induced differences in perfusion or vascularity (Doppler ultrasound, contrast-enhanced MR imaging); and 4) development of techniques that attempt tissue diagnosis using monoclonal antibodies. Among these techniques, digital luminescence radiography and contrast-enhanced MR imaging are the most developed and the most promising. They are at the threshold of becoming clinically important. Doppler ultrasound could be useful for certain indications. Whereas MR spectroscopy, positron-emission tomography, the search for appropriate antibodies, and possibly transillumination, ductoscopy, and biomagnetism offer interesting new aspects for research, the value of CT, thermography, and biostereometry is not yet established.