Multi-site Liver Tumour ADC Reproducibility at 1.5 T.

This work assesses the reproducibility of ADC measurement for data acquired across several clinical sites within IMI QuIC-ConCePT project. We present a model for expected ADC reproducibility which takes account of the initial ADC distribution within tumours and the volume of measurement. We show that the accuracies of ADC currently achieved are on average 7.5% but that better measurements are generally associated with increasing the measurement volume. Our analysis generates methods which are capable of predicting the reproducibility of individual tumours, and is therefore suitable for guiding the region of interest selection process. Overall performance of reproducibility for the ‘on scanner’ averaged acquisition (protocol A) is found to be currently insufficient for detection of change in individuals, but recent results regarding the expected improvement using ‘off scanner’ averaging (protocol B) would suggest the possibility of patient specific adjustment of therapy. Real tumour data for protocol B data is now required in order to confirm this expected benefit and such data is planned to be acquired as part of the upcoming BOS2 trial.