2-D mammography also offers the possibility to visualise contrast media. Only recently, I published a first, large clinical evaluation of this procedure in the European Journal of Radiology. We used GE Healthcare’s Senograph 2000D with temporal subtraction. As far as I know most published studies on the use of iodinated contrast media in mammography were performed with this equipment, some even applying a sort of Spectral Imaging, meaning two images were acquired, one with low and one with high energy. Since two images need to be taken, motion artefacts are much more of an issue than in tomosynthesis with Spectral Imaging, where only one image is required, because the photon-counting detector separates the high and low energy spectrum. There are some promising studies on dual energy tomosynthesis using flat panel detectors.
‘Single Shot Spectral Imaging (SSSI) is based on tomosynthesis, a rather new 3-D mammography technique developed to overcome, at least partially, the overlapping of structures, one of the major limitations of mammography,’ explained Dr Diekmann, at the Charité Nuclear Medicine Clinic. ‘If, in addition, iodinated contrast media is applied, a further limitation of conventional mammography could be overcome: poor tumour contrast. This is where slit-scan tomosynthesis, using a photon-counting detector, comes in; it is particularly well suited for breast imaging since its spectrum splitting technology allows dual energy visualisation of the contrast media in a single scan – and with low dose – while generating a 3-D image of the breast. The long-term objective is to develop a financially viable procedure that offers the same image quality as breast MRI.’
Development of Low-Dose Photon-counting Contrast …
‘In the German mammography screening programme, several facilities perform 2-D mammography based on photon-counting detectors. The new method – slit-scan tomosynthesis with Spectral Imaging – can build upon the experiences gathered in these facilities and the existing detectors can be used. 3-D breast imaging and the application of iodinated contrast media are new features in mammography. 3-D procedures avoid overlapping of structures, which to date reduces the visualisation of tumours. The other major issue in conventional mammography -- low tumour contrast -- is addressed with the use of contrast media. In brief, the new approach promises to offer significantly increased detection of breast cancer.