Impact of acquisition parameters on diffusion magnetic resonance imaging quality

Abstract

Acquisition parameters play a crucial role in Diffusion Tensor Imaging (DTI), having such an impact on white matter (WM) scalar measures values such as Fractional Anisotropy (FA), Signal to Noise Ratio (SNR) or even when it comes to whole brain tractography studies. Among those acquisitions parameters we find the b-values (e.g. b-value is a factor that reflects the strength and timing of those gradients used to generate Diffusion-Weighted Images; the higher the b-value, the stronger the diffusion effects), voxel size (the smaller the voxel size the higher the quality) and diffusion directions (as the number of directions increases the acquisition time increases as well). This project, places all of them of the focus of several clinical MRI studies performed on healthy subjects in the IDIBAPS’ MRI core facility. Those studies have been grouped into 5 datasets according to different acquisition protocols; in addition, 8 new acquisition proposal are first undergone and analysed. Results show that as expected those parameters play a crucial role in image quality; however, each one of them has a different weight over those quality measurements. This will be discussed by splitting the results into datasets. Furthermore, the analysis performed on the protocol proposals confirm that they have reached what was their goal, to demonstrate that depending on the purpose of the scanner (emergency MRI, clinical MRI and research MRI) a specifical acquisition sequence can be used.