G. Kok, N. Pelevic, A. Chiribiri, X. Milidonis, M. Nazir, M. Capstick, S. Drost, C. Poelma, T. Schaeffter
A calibrated physical flow standard for medical perfusion imaging
In the medical sector, various imaging methodologies or modalities (e.g. MRI, PET, CT) are used to assess the health of various parts of the bodies of patients. One such investigation is the blood flow or perfusion of the heart muscle, expressed as the (blood) flow rate normalized by the mass of the volume of interest, with unit mL/min/g. Currently there is no physical flow standard for the assessment and validation of myocardial perfusion imaging methodologies, resulting in a large proportion of medical diagnoses being inaccurate and highly dependent on the scanner type, software used and the clinical operator. In the EMPIR 15HLT05 PerfusImaging project a phantom simulating myocardial perfusion has recently been developed with which imaging modalities can be tested. In this paper the construction and validation of the phantom is described which involved several iterations with design updates, computational fluid dynamics simulations, 3D printing of the phantom, ultrasound imaging velocimetry and magnetic resonance imaging (MRI). Dynamic contrastenhanced MRI was performed to image the passage of a tracer through the phantom and estimate perfusion. Two flow models and associated data analysis methods to relate the measurement data with the reference flow rates are presented and discussed.