Devices, systems, and methods for forward looking imaging are provided. A system for imaging a vessel of a patient comprises an elongated sheath having a proximal and a distal end. The sheath includes a flexible body with a first lumen in communication with a distal opening at the distal end. The system further comprises an imaging core disposed within the first lumen. The imaging core includes a transducer subassembly sized to extend within the first lumen. The transducer subassembly is adapted to transmit a beam, distally of the elongated sheath, through the distal opening.