Background
Morphology-based methods for therapy monitoring, such as the response evaluation criteria in solid tumors (RECIST), have shortcomings in oncological therapy evaluation especially of new molecular therapies.
Objectives
Evaluation of the potential of modern functional imaging modalities, including volume perfusion computed tomography (CT), dual energy CT, dynamic contrast-enhanced magnetic resonance imaging (MRI), diffusion-weighted imaging and hybrid imaging, such as positron emission tomography (PET) CT and PET-MRI for therapy monitoring of oncological diseases.
Material and methods
The results of a selective Pubmed search and an evaluation of own analyses regarding the use of functional imaging in therapy evaluation of oncological diseases are presented.
Results
Early changes of tumor perfusion under antiangiogenetic therapy can be measured by volume perfusion CT and dynamic contrast-enhanced MRI. Different chemical tissue compositions and the maximum iodine uptake can be assessed by dual energy-CT. On the other hand, PET-CT is an established hybrid modality for therapy evaluation and provides information about morphology and tumor metabolism. Diffusion-weighted MRI enables the measurement of the higher cellularity in tumor lesions and the changes under therapy.
Conclusion
The new functional imaging modalities have a great potential to improve characterization of tumors and enable an earlier and more precise therapy evaluation of oncological diseases beyond morphological changes; however, validation in larger patient cohorts and standardization concerning examination techniques and interpretation criteria as well as postprocessing are still needed.