Fat fraction (FF) and apparent diffusion coefficient (ADC) values estimated by Dixon MRI and diffusion weighted MRI (DWI) techniques respectively, are relatively new quantitative imaging parameters and increasingly accepted as imaging biomakers for all sorts of purposes. The aim
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Fat fraction (FF) and apparent diffusion coefficient (ADC) values estimated by Dixon MRI and diffusion weighted MRI (DWI) techniques respectively, are relatively new quantitative imaging parameters and increasingly accepted as imaging biomakers for all sorts of purposes. The aim of the BOCASEcA study is to research whether these techniques can be used as biomarkers for patient-reported xerostomia and dysphagia post-radiotherapy. In this project, steps have been taken to validate the use of certain fat quantification and ADC mapping protocols in the BOCASEcA study. mDIXON Quant is a Philips product designed for MR fat quantification. We performed phantom studies and a healthy volunteer study to evaluate the accuracy and repeatability of a standard mDIXON Quant protocol with default parameters and an mDIXON Quant protocol that is used in LUMC on muscles throughout the whole body. Another phantom study was done to evaluate the (geometrical) accuracy of DWI-SPLICE, a technique that can be used for ADC mapping. This DWI technique is known to have less susceptibility issues than conventional EPI-DWI. We tested both the accuracy and deforming artifacts for an EPI sequence and a clinically used DWI-SPLICE protocol from LUMC. Adequate accuracy and robustness were observed for the standard Philips mDIXON Quant protocol. The LUMC muscle protocol, however, yielded incorrect measurements that were underestimations of the real FF values. The DWI-SPLICE protocol showed better geometrical accuracy than the EPI protocol. Accuracy of the ADC measurements was sufficient for ADC values higher than 0.6 x 10−3 mm2/s which is a clinically relevant range. Since the accuracy of both the standard Philips mDIXON Quant protocol and DWI-SPLICE protocol was validated, it is recommended that they are used and further optimized for the BOCASEcA study.