Digital mammography using iodine-based contrast media: initial clinical experience with dynamic contrast medium enhancement.

PURPOSE: We sought to evaluate the potential of dynamic contrast enhancement after the intravenous administration of an iodine-based contrast medium in full-field digital mammography. MATERIAL AND METHODS: A protocol for image acquisition was established for contrast-enhanced mammography and the mammography unit (Senographe 2000D, GE Healthcare, Buc, France) changed as required. The effect of the protocol parameters on imaging was investigated. Subsequently, 21 patients with 25 suspicious lesions of the breast (10 benign, 1 borderline, and 14 malignant) underwent mammography with administration of an iodine-based contrast medium (Ultravist 370, Schering AG, Berlin, Germany), after approval of ethical committee as well as permission of German federal office for Radiation protection, and informed consent from each patient was obtained. Three sequential digital mammographic images of the respective breast were acquired after administration of the contrast medium at a dose of 1 mL/kg body weight and a flow of 4 mL/s. The postcontrast images were acquired 60, 120, and 180 seconds after administration. Subsequently, the precontrast image was logarithmically subtracted from the postcontrast images. Enhancement of the lesions was measured in absolute terms as well as relative to the enhancement of the glandular tissue. The subtracted images were evaluated for lesion depiction and dynamic contrast enhancement. Lesion-enhancement kinetics were compared with the histologic findings. RESULTS: All malignant lesions were identified on the contrast-enhanced images of digital mammography. Three of the tumors (2 malignant, 1 benign) were detected only by contrast-enhanced mammography and not by standard mammography. Dynamic enhancement curves of benign and malignant tumors in contrast-enhanced mammography look similar to the curves known from gadolinium-enhanced magnetic resonance imaging. Nevertheless differentiation between malignant and benign tumors based on the enhancement patterns cannot be directly taken over from magnetic resonance imaging, as suggested by our initial results. The results are somewhat better when tumor enhancement relative to surrounding glandular tissue is used instead of absolute enhancement. CONCLUSION: The results of this preliminary study suggest that contrast-enhanced digital mammography is a potentially useful tool for the detection and the differentiation of benign and malignant breast lesions.

Development of contrast digital mammography.

Development of breast tumors is often accompanied by angiogenesis--the formation of new blood vessels. It is possible to image the effects of this process by tracking the uptake and washout of contrast agents in the vicinity of a lesion. In this article, a method for carrying out contrast subtraction mammography on a full-field digital mammography unit is described. Spectral measurements and modeling were performed to optimize the choice of x-ray target, kilovoltage and x-ray beam filtration for contrast digital mammography (CDM) on an available digital mammography system. Phantom studies were carried out to determine the sensitivity of CDM to iodine. Detection of iodine area densities of 0.3 mg/cm2 is possible for a circular object with a radius of 1.3 mm, which allows detection of uptake levels in the breast typically seen with cancer and some benign breast conditions. It was found that with a molybdenum anode x-ray tube, copper filtration could be used to effectively shape the x-ray spectrum to maximize the proportion of x rays with energies above the k edge of iodine. Simple logarithmic subtraction was found to be adequate in suppressing background signals dependent on the x-ray beam intensity and background thickness of the breast. The total x-ray dose from the procedure ranges between 1 and 3 mGy, similar to that from a conventional single view film mammogram. A clinical pilot study is currently being carried out to evaluate this technique.