P2A-3 Multimodal PET/Ultrasound Imaging for Cardiac Molecular Imaging

In cardiac diagnostics, multimodal images of morphological and functional properties could improve the early diagnosis of heart diseases. The well established 3D echocardiography provides morphological parameters, such as the size of the myocardium, blood volume or contractility, whereas PET offers complementary functional information, e.g. myocardial perfusion and viability. Therefore, a registration method based on a multimodal calibration phantom was developed and evaluated. The phantom consists of gelatine gel with 2% silica gel. It possesses three pairs of tubes, which are filled with water or a FDG solution depending on the imaging modality. Each pair intersects in one point. After acquiring an ultrasound and a PET volume of the phantom, the tubes were segmented in both datasets and the intersection points were estimated. A point based registration was performed. By using a dedicated heart phantom, which simulated the left ventricle, the accuracy was evaluated in a clinical situation. The average registration error, defined through the mean Euclidian distance between the intersection points, was smaller than 0.4 mm. The accuracy in a clinical situation lied below 1.6 mm, which is sufficiently accurate with respect to the PET image resolution.