Computed tomography perfusion imaging for therapeutic assessment: has it come of age as a biomarker in oncology?

With the emergence of novel targeted therapies, imaging techniques that assess tumor vascular support have gained credence for response assessment alongside standard response criteria. Computed tomography (CT) perfusion techniques that quantify regional tumor blood flow, blood volume, flow-extraction product, and permeability-surface area product through standard kinetic models are attractive, but the level of evidence for CT perfusion to be a truly mature biomarker remains insufficient. Studies to date have not been powered to assess this. Future studies that include good quality prospective validation correlating perfusion CT to outcome end points in the trial setting are needed to take CT perfusion forward as a biomarker in oncology.