Model-free phasor image analysis, well established in fluorescence lifetime imaging and only recently applied to qMRI T₂ data processing, is here adapted and validated for myocardial qMRI T₁ mapping. Contrarily to routine mono-exponential fitting procedures, phasor enables mapping the lifetime information from all image voxels to a single plot, without resorting to any regression fitting analysis, and describing multi-exponential qMRI decays without biases due to violated modelling assumptions. In this feasibility study, we test the performance of our recently developed full-harmonics phasor method for unravelling partial-volume effects, motion or pathological tissue alteration, respectively on a numerically-simulated dataset, a healthy subject scan, and two pilot patient datasets. Our results show that phasor analysis can be used, as alternative method to fitting analysis or other model-free approaches, to identify motion artifacts or partial-volume effects at the myocardium-blood interface as characteristic deviations, or delineations of scar and remote myocardial tissue in patient data.

Functionalized biomass waste sources of cellulose have drawn attention due to their high availability and sustainability properties. In this work we characterize the structural and flow properties of high-pressure homogenized citrus fiber cellulose dispersions, employing SAXS, rheology and rheo-MRI techniques. The high-pressure treatment disrupts the microfibrillar network within the citrus fibers, but leaves the individual microfibrils intact. Under moderate shear (0.1-100 s^-1) in a confined (<1 mm) geometry, these functionalized citrus fiber cellulose dispersions exhibit thixotropic shear-banding behavior accompanied by cooperative flow of microfibril flocs with correlation lengths ξ ~ 100 μm. The presented findings form a basis towards understanding and manipulating the structural and rheological properties of non-wood biomass cellulose microfibrils under industrially-relevant conditions.