Matthew David Blackledge1, Christina Messiou1,2, Jessica M Winfield1,2, Dow Mu Koh1,2, David J Collins1,2, and Martin O Leach1,2
1CRUK Cancer Imaging Center, Division of Radiotherapy and Imaging, Institute of Cancer Research, London, United Kingdom, 2MRI, Royal Marsden Hospital, London, United Kingdom
We compare two enhancement fraction parameters that may be used for quantification of two-point contrast-enhanced MRI studies: The relative enhancement and the fractional enhancement. Using computer simulations we show that fractional enhancement is better behaved in the presence of imaging noise, resulting in better SNR for this parameter over a range of intrinsic longitudinal tissue relaxivities and contrast medium concentrations. Further, in a cohort of 25 patients with retroperitoneal sarcoma, fractional enhancement significantly outperformed the relative enhancement in terms of visual assessment of contrast-to-noise, signal-to-noise, tumour detection, imaging artefacts and within tumour contrast.