The invention concerns a method for obtaining diagnostic images of a human or animal body organ, region, fluid or tissue by using combined X-ray and/or Magnetization Transfer (MT) based MRI techniques and iodinated radiographic compounds as contrast agents, as well as improved Chemical Exchange dependent Saturation Transfer (CESDT or CEST) based MRI procedures in which a iodinated contrast agents is used for in vivo determining a physiological parameter of diagnostic interest.