Scanner Quality Assurance using the IMI QuIC - ConCePT Ice - Water Phantom ( draft # 2 )

The aim of this document is to define the quality assurance (QA) methods for scanners using the ice-water phantom and the corresponding software developed within the IMI QuIC-ConCePT project, for the upcoming ‘BOS2’ trials. The outlined methods are what we consider to constitute the best use of currently available data following our recent papers [1] [2] in which we studied ADC (apparent diffusion coefficient) measurements corresponding to five phantom tubes obtained from four scanners located at four different sites. Scanners are required to gain approval based on their phantom data quality in order to proceed to the clinical trial. The idea is to obtain one phantom data-set from each site before site activation and one week prior to clinical scans. Scanners used in our recent study resulted in about 6% average measurement variability in healthy liver data. These results and those from phantom studies, have been used here to set criteria for QA pass/fail. To approve the quality of each new scanner, several metrics of image quality will be automatically extracted from phantom data-sets. A simple statistical analysis then provides a three step procedure for the pass or fail decision. The full process is described below with example data. For the current QA we concentrate on signal to noise and absolute quantitation, ignoring issues of fat suppression and inhomogeneity which will need to be addressed separately (where possible).