Quantification of Diffusion and Permeability of MRI in the Head and Neck Region - Abstract
Diffusion Weighted Image (DWI) has various roles such as tissue characterization, the prediction and monitoring of the response to treatment and differentiation of recurrent tumors from post-therapeutic changes. The malignant tumors have a lower ADC compared to benign lesions. Follow-up of early
response to cancer treatment is reflected in an ADC increase in the primary tumor and nodal metastases; whereas nonresponding lesions tend to reveal only a slight increase or even a decrease in ADC during follow-up. However, there are many limitations regarding the performance of DWI in the head and neck
region, therefore, many attempts has been performed to overcome the flaws of the diffusion-weighted single-shot-echo planar imaging.
The pharmacokinetic analyses of dynamic contrast enhanced MRI (DCE-MRI) can provide physiological condition of the tissue, and Tofts and Kermode Model has been applied to the head and neck region. Some researchers have used it for the prediction and monitoring of the tumor response to cancer therapy. The general consensus is that the early changes of these parameters during the early phase after the treatment are useful for the interpretation of the response to the treatment. However, the parameters reported in the literature vary considerably; therefore, it is difficult to compare the values of the parameters among research groups.
Both DWI and the pharmacokinetic analysis of the DCE-MRI have shown a wide range of potential benefits in this region, but more comparative studies with established scan techniques and the quantification of the data are required.