Dr. Vasia Papoutsaki PhD is an MRI Physicist, senior research fellow at the Center for Medical Imaging, University College London. Her research primarily involves quality assurance for quantitative imaging biomarkers. She has previously developed a variety of test objects (phantoms) for T1/T2 weighted imaging and diffusion weighted imaging, and also been involved in the preparation for imaging with Hyperpolarized 13C imaging.
“One of my main research areas is developing and validating novel imaging biomarkers, and I am working with Professor Shonit Punwani on this topic. Our current focus is on the validation of the apparent diffusion coefficient (ADC) in diffusion weighted MRI (DW-MRI) for use in the detection of prostate cancer. To do this we have started a clinical trial, where we are attempting to mimic the anatomy and ADC values of prostate cancer using test objects, or phantoms. Since the phantoms that we are using show temperature-dependent values of their diffusion characteristics, we absolutely need to control for the environmental parameters, and in particular we need to maintain the temperature of the liquid surrounding the test objects stable or controlled over the time of the examination. This trial is expected to last three years in the UK and US across multiple MRI scanner vendors.
“Diffusion weighted MRI is based on the Brownian motion of water and is the only MRI technique able to reflect tissue cellularity. Currently, the Prostate-Specific Antigen test (PSA) is the first step in prostate cancer screening. However, this is inaccurate, resulting in high rates of false positives and false negatives, which leads to excessive numbers of follow up biopsies to establish diagnosis, which are painful and time-consuming. Recently, the National Institute for Healthcare and Excellence (NICE) in the UK included the use of multi-parametric MRI as an intermediate step in an attempt to reduce the number of biopsies recommended by changing the diagnostic pathway, and we are now working to further increase the accuracy and specificity of MRI.”
I have previous experience in producing phantoms, however we lacked specialist equipment, which is why we decided to work with a manufacturer. The Gold Standard Phantoms team (led by Dr. Aaron Oliver-Taylor, GSP CTO) understood all the requirements we needed for this trial and was able to suggest ideas I was not aware of. In total, the collaboration process lasted six months, which also involved double validation of our diffusion solution in the US. This was something Gold Standard Phantoms were willing to accommodate, while other companies weren’t, and this, along with their excellent knowledge of MRI and phantoms, is why we decided to work with them. The end product became the MultiSample190, I have been using it for six months and the results have been very good.”
“The outcome of this trial, undertaken in collaboration with the Quantitative Imaging Biomarkers Alliance (QIBA®), is to validate the ADC values in prostate cancer by establishing the influence changing the MRI sequence parameters has on the apparent diffusion coefficient and how this impacts the translatability of the value across protocols and scanners in terms of diagnosis and cut off values for patients. Its results will be used as part of the guidance provided by QIBA® for the use of ADC in prostate cancer.“
“Overall, we have been very happy working with Gold Standard Phantoms and I would definitely recommend them to other clinicians and researchers that need a test object.”