A novel physical standard for multi-modality perfusion imaging

The aim of this work package is to develop a physical standard (phantom) and calibration techniques that can be used across a range of imaging modalities for perfusion imaging. In the first phase, the project will improve and calibrate an existing phantom, which has been developed by one of the partners. The current set-up uses stationary flow with a more or less homogeneous distribution. Therefore, the influence of temporal and spatial resolution cannot be investigated within one or between different imaging modalities. In order to achieve this a redesign of the phantom is required using a pump with a physiological flow profile. The challenge will be the construction of the compartment with dimensions similar to the thickness of the human myocardium, while providing a controlled inhomogeneous flow distribution across the compartment. Reference techniques (flow meter and PIV) will be used to calibrate flow to reference values. The calibrated phantom (Phantom V2) will be used for a cross-modality comparison. The influence of different imaging protocols by varying the spatial and temporal resolution will be studied. Furthermore, the calibrated phantom allows for the comparison of different data analysis techniques (WP2) with respect to the known reference values. For this measurement data from WP1 will be required by WP2. Vice versa the uncertainty analysis in WP2 will also provide important input on the required temporal and spatial resolution in the protocol optimisation process. The optimised protocols in CT and PET perfusion imaging will be used in WP3 to study the effect on radiation dose. Therefore, there will be a strong interaction and dependency between the work packages.

In the second phase of the project, a novel approach will be investigated to create a two-compartment model representing the real pharmacokinetic behaviour of contrast agents. This is in particular important for contrast agents that rapidly leave vascular space and thus require quantification with pharmacokinetic modelling. New materials will be tested as filters to mimic the exchange between the vascular and interstitial space. The challenge will be the use of filters that work for the different multi-modality agents. The reliability of the filter for multi-injection of contrast agents will be studied. The two-compartment phantom (Phantom V3) will also be tested with different modalities and data analysis results will be compared to the phantoms from the first phase.

The tasks in this work package will be carried out by external partners with extensive experience in medical phantom design and multi-modality perfusion measurements, together with two NMIs with experience in calibration and uncertainty analysis of measurements.

A pulmonary volume for the phantom & CAD