A Comparative Study of MRI Diffusion-Related Parameters for the Early Detection of Radiation-Induced Tissue Changes in a Rodent Tumour Model

Frank Peeters¹, Dennis Rommel¹, Jorge Abarca-Quinones¹, Vincent Gregoire², Thierry Duprez¹

The diagnostic accuracy of diffusion MRI related parameters derived from different techniques should be empirically assessed. We have performed a comparative study for the assessment of early effects of radiation therapy in a rodent tumour model (rhabdomyosarcoma in rats). Parameters obtained from DTI (2-points ADC, mono- and bi-exponential fits) and q-space imaging (tensor analysis) were compared. Our study shows that diffusion coefficients were very sensitive to radiation-induced tissue changes. Q-space analysis yielded at least the most sensitive parameter: the excess kurtosis of the distribution. The mean value and anisotropy of the tensors detected different sub-areas within irradiated tissue.