Development of a Dynamic Mouse Heart Phantom for Multimodal Imaging

We propose a novel cardiac phantom that mimics the left ventricle of a mouse heart. Motion in medical imaging procedures such as CT, MRI, PET or SPECT can impair the images and lead to blurring effects or artifacts. The phantom enables the validation of static and dynamic cardiac imaging of a beating left ventricular myocardium. The phantom is made of double-walled, elastic silicone. It comprises an outer myocardial volume of approximately $70 \mu \mathrm{l}$ and an inner residual blood volume of approximately $20 \mu \mathrm{l}$ with a variable ejection volume of 10-50 $\mu \mathrm{l}$. The heart was produced by casting with 3D printed molds. It allows the separate filling of myocardial and blood volumes with radioactive or/and contrast agent based fluids. A pneumatic piston system is developed that can simulate physiological heart rates of up to 400 bpm which is a typical rate for mice under anesthesia. As demonstrated in a preliminary study, the newly developed heart phantom is suitable for multimodal imaging for simulating different tracer uptake situations under variable cardiac motion. The mouse heart phantom can be operated in static and dynamic mode and thus has a wide range of potential applications in preclinical imaging studies.