Simultaneous acquisition of velocity and fat using MRI.

Phase-contrast MRI (PC-MRI) is a non-invasive technique that accurately measures blood flow and calculates hemodynamic parameters by inducing a velocity-dependent phase shift in the MR signal. Multi-point Dixon methods, used for separating water and fat signals, achieve fat suppression and quantification by encoding differences in resonance frequency in the MR signal's phase. PC-MRI and Dixon techniques share the characteristic that the difference in frequency between water and fat, and the velocity, are encoded in the phase of the MR signal. This can result in challenges in PC-based measurements in regions with significant fat content. Therefore, it would be ideal to obtain both sets of images simultaneously. Such an acquisition will improve efficiency by obtaining both types of images in the same scan, providing co-registered images of water-fat components and velocity images, and offering artifact-free PC-MRI flow measurements. These simultaneous measurements will be beneficial for diagnosing diseases such as Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD), diabetes, and cardiac steatosis, where fat and flow quantification is sometimes required. Nevertheless, the simultaneous acquisition of Dixon and PC-MRI data is challenging. We have recently developed a novel method that simultaneously acquires water-fat components and velocity images by integrating PC-MRI with 3p-Dixon. This method involves straightforward algebraic post-processing to separate water-fat and estimate velocity. A pilot study is planned to demonstrate the method’s applicability in the carotid artery of a few volunteers. The goal of this project is to extend this technique to simultaneous acquisition of 4D flow and fat imaging, and to apply it to more challenging body areas, such as the heart and liver. The project will involve programming the acquisition on a Siemens scanner and developing post-processing steps to separate water, fat, and velocity components.