MR spectroscopy in the breast clinic is improving

Early studies suggested that in vivo proton MR spectroscopy could be added as an adjunct to dynamic contrast-enhanced MRI of the breast and increase the specificity [1]. Today there have been a wide range of results ranging from excellent to bad. It becomes obvious that these outcomes are dependent on the local clinical culture, hardware manufacturer and experience of the local MR team. Even when all aspects are covered the results are currently only acceptable for tumors 1 cm and above. The discrepancy between the US and Australian sites was the assertion that the diagnosis of breast cancer could be undertaken based on one dimensional (1D) MRS in vivo if the total choline resonance is resolved into components at 3.23 and 3.28 ppm [2]. However, many sites could not achieve this resonance separation and report the “total” choline using the resonance intensity to deduce the pathology [3]; and monitor response to chemotherapy [4]. However it transpired that they were recruiting patients from tertiary referral centre who had undergone core biopsy. This was also the case with our Boston based Centre. An important difference was that the Australian surgeons had recruited patients where neither core biopsies nor clips were placed prior to the MR scan. Two technical issues also need attention. The first is the need for a highly trained operator due to the need to shim the magnet to acceptable levels of field homogeneity prior to data acquisition. The second is dependent on the first for success that is the capability to make a diagnosis on small tumors i.e. 0.3 to 1 cm in size which often have a low cellularity. Resultant FID needs monitoring to ensure adequate signal to noise to allow a diagnosis to be made. The ability to continue collecting data whilst accumulating averages would be of great assistance.