An extension cable is adapted for use in an intravascular ultrasound system. It has a first connector, for connecting to a catheter and a second connector for connecting to a patient interface module.A cable arrangement provides power transmission, data transmission and data signal processing (amplification or regeneration) between the first and second connectors. The extension cable enables sterility to be maintained in a workflow in a time efficient and easy manner as the catheter to extension cable connection may remain in a sterile environment.