There is growing evidence that imaging biomarkers derived from multi-detector computed tomography (MDCT) and diffusion-weighted magnetic resonance imaging (DW-MRI) can be of great help in the diagnosis， monitoring of response to treatment and prognosis of gastric cancer.

 

MDCT allows the quantification of physical and biological properties of the microenvironment attenuating the X-ray beam. This aspect is of paramount importance when it comes to the application of texture analysis to this technique. Through texture analysis it is possible to extrapolate many textural features and parameters that are related， as an example， to the grey-level distribution of the pixels and voxels of digital images.

 

Likewise， DW-MRI provides information about the cellularity of tumours， apoptosis or necrosis through the quantification of the apparent diffusion coefficient (ADC). This parameter measures the degree of free diffusion of water molecules within tissues (mainly influenced by cell organisation and density). As a consequence of the higher cellularity and decreased extracellular space (e.g. in tumours)， water diffusion is restricted and ADC values will be lower than the normal tissue. At the same time， cell death corresponds to a loss of cell membrane integrity (e.g. necrosis after neoadjuvant therapy)， resulting in higher water diffusivity and， consequently， increasing ADC values.

 

Therefore， imaging biomarkers are invaluable in providing information for diagnostic purposes and clinical decision-making at different time-points in the treatment pathway of gastric cancer.

 

This talk represents an update of the current status of the application of imaging biomarkers (with a particular focus on texture analysis and ADC) in gastric cancer. 

 

Starting from a brief description of each technique， we will discuss the use of these biomarkers in terms of validation and clinical applications in gastric cancer. Finally， a discussion of the current limitations and future perspectives will be carried out.