Work Package Leader: Caliean Clarkson (LGC)

The aim of this WP is to develop novel measurement (traceable to the SI where feasible) and manufacturing methods for qMRI phantoms focusing on materials in which qMRI measurands (e.g. relaxivities, fat fraction, iron content, intrinsic diffusivity) can be controlled during manufacturing and to verify by independent measurements the materials selected for phantoms used in the quantitative assessment of qMRI. To then use these materials and manufacturing methods and processes to design and produce novel qMRI phantoms which are well-characterised, traceable to primary standards and suitable for scanning in typical clinical MRI facilities.

The developed phantoms will be relevant to cardiac, liver, and brain disease models, and are to be used in the subsequent WPs. Focus will be on:

• The development of traceable reference methods/procedures appropriate to each measurand for the accurate determination of concentration agents such as iron and fat using ICP-MS/ICP-OES or qNMR, respectively, to support stability measurements for iron and fat concentrations and uncertainty estimations. These will then be used to determine the properties of candidate materials defined during the consultation stage for use in the construction of phantoms. These will be capable of providing SI traceability with well-defined uncertainties for the key qMRI measurands/parameters of mass fractions (as mass measurand/mass sample) of tissue iron and fat based on NMR- and ICP-measurements.

• The investigation of the feasibility of establishing SI traceable measurement methods for relevant MRI parameters including key relaxation parameters such as T1 and T2 (using NMR with a similar frequency to MRI, via a calibration based on a traceable oscilloscope), proton density and water diffusion coefficient using MR.

• The design and production of up to 6 phantoms using materials identified in Task 1.1 and the evaluation of these phantoms’ suitability for underpinning qMRI measurements

• The characterisation of the phantoms from Task 1.2 for tissue iron and fat mass fraction, relaxation parameters, water diffusion coefficient, stability, and measurement uncertainty.

The output of the work package will be six phantoms well characterised for iron and fat concentrations and relaxation and diffusion parameters using SI traceable methods, where feasible, to be used in the quantitative assessment of qMRI. The measurand stability in such phantoms will be monitored during the project duration.