A system comprising dynamic contrast enhanced MRI data and dynamic susceptibility contrast MRI data for a volume of the patient's body including a rectal tumor along with data processing apparatus for processing the MRI data for analysis of rectal tumors, wherein the data processing apparatus comprises: an MRI data receiving module for receiving the dynamic contrast enhanced MRI data and dynamic susceptibility contrast MRI data; a volume of interest identification module for generating and/or receiving data identifying a volume of interest enclosing the rectal tumor; data storage; and an MRI data processing module for processing the MRI data for the volume of interest and being arranged to: identify one or more parameters relating to the transverse relaxation rate and/or to dynamic changes in the transverse relaxation rate, wherein the one or more parameters relating to the transverse relaxation rate and/or to dynamic changes in the transverse relaxation rate include one or more of: the peak change in tumor R 2 *, the dynamic peak change in tumor R 2 *, a maximum of the peak change or the dynamic peak change, and/or an integral for dynamic peak change in tumor R 2 * over a time period, compare the one or more parameters to previously obtained similar parameters for multiple other patients having similar rectal tumors that are either known to exhibit lymph node metastasis or are known not to exhibit lymph node metastasis, wherein the previously obtained similar parameters for rectal tumors are stored on the data storage and accessed therefrom by the MRI data processing module, and thereby determine if the MRI data indicates that the rectal tumor is at a greater risk of exhibiting lymph node metastasis or at a lesser risk of exhibiting lymph node metastasis. an MRI data receiving module for receiving the dynamic contrast enhanced MRI data and dynamic susceptibility contrast MRI data; a volume of interest identification module for generating and/or receiving data identifying a volume of interest enclosing the rectal tumor; data storage; and an MRI data processing module for processing the MRI data for the volume of interest and being arranged to: identify one or more parameters relating to the transverse relaxation rate and/or to dynamic changes in the transverse relaxation rate, wherein the one or more parameters relating to the transverse relaxation rate and/or to dynamic changes in the transverse relaxation rate include one or more of: the peak change in tumor R 2 *, the dynamic peak change in tumor R 2 *, a maximum of the peak change or the dynamic peak change, and/or an integral for dynamic peak change in tumor R 2 * over a time period, compare the one or more parameters to previously obtained similar parameters for multiple other patients having similar rectal tumors that are either known to exhibit lymph node metastasis or are known not to exhibit lymph node metastasis, wherein the previously obtained similar parameters for rectal tumors are stored on the data storage and accessed therefrom by the MRI data processing module, and thereby determine if the MRI data indicates that the rectal tumor is at a greater risk of exhibiting lymph node metastasis or at a lesser risk of exhibiting lymph node metastasis. identify one or more parameters relating to the transverse relaxation rate and/or to dynamic changes in the transverse relaxation rate, wherein the one or more parameters relating to the transverse relaxation rate and/or to dynamic changes in the transverse relaxation rate include one or more of: the peak change in tumor R 2 *, the dynamic peak change in tumor R 2 *, a maximum of the peak change or the dynamic peak change, and/or an integral for dynamic peak change in tumor R 2 * over a time period, compare the one or more parameters to previously obtained similar parameters for multiple other patients having similar rectal tumors that are either known to exhibit lymph node metastasis or are known not to exhibit lymph node metastasis, wherein the previously obtained similar parameters for rectal tumors are stored on the data storage and accessed therefrom by the MRI data processing module, and thereby determine if the MRI data indicates that the rectal tumor is at a greater risk of exhibiting lymph node metastasis or at a lesser risk of exhibiting lymph node metastasis.