Soft continuum manipulators have shown great potential for applications in minimally invasive surgery (MIS) and endoscopy, due to the advantages they offer in terms of increased safety and high adaptability to unstructured environments. However, a compelling requirement yet to be fulfilled is the integration of a robust proprioceptive sensing system in the manipulaotr. In order to address this challenge, in this paper we present a promising method for shape sensing of soft continuum manipulators based on electrical impedance tomography (EIT). Saline is used as a conductive actuation fluid and the voltage differences detected by the electrodes are used to measure the deformations of the manipulator upon pressurization. The experiments show promising results, as the EIT system is sensitive to shape changes and can localize external forces.