An interface for intravascular pressure sensing devices, comprising: a distal input configured to receive a distal pressure signal from a distal pressure sensing device; a proximal input configured to receive a proximal pressure signal from a proximal pressure sensing device; a pullback device configured to interface with a proximal portion of the distal pressure sensing device to cause translation of the distal pressure sensing device relative to the proximal pressure sensing device; a processor in communication with the distal input, proximal input, and the pullback device, the processor configured to calculate a pressure differential between the distal pressure and the proximal pressure based on the received distal pressure signal and the received proximal pressure signal obtained as the pullback device translates the distal pressure sensing device relative to the proximal pressure sensing device; and a display in communication with the processor and configured to display the pressure differential calculated by the processor including a relative position of the distal pressure sensing device to the proximal pressure sensing device associated with the calculated pressure differential, characterised in that the processor is further configured to identify a diagnostic window for calculating the pressure differential, the diagnostic window consisting of a portion of a heartbeat cycle of a patient, wherein the portion of the heartbeat cycle of the patient is selected at least partially based on one or more characteristics of the proximal pressure signal, and wherein the portion of the heartbeat cycle of the patient is selected at least partially based on one or more characteristics of the distal pressure signal. a distal input configured to receive a distal pressure signal from a distal pressure sensing device; a proximal input configured to receive a proximal pressure signal from a proximal pressure sensing device; a pullback device configured to interface with a proximal portion of the distal pressure sensing device to cause translation of the distal pressure sensing device relative to the proximal pressure sensing device; a processor in communication with the distal input, proximal input, and the pullback device, the processor configured to calculate a pressure differential between the distal pressure and the proximal pressure based on the received distal pressure signal and the received proximal pressure signal obtained as the pullback device translates the distal pressure sensing device relative to the proximal pressure sensing device; and a display in communication with the processor and configured to display the pressure differential calculated by the processor including a relative position of the distal pressure sensing device to the proximal pressure sensing device associated with the calculated pressure differential, characterised in that the processor is further configured to identify a diagnostic window for calculating the pressure differential, the diagnostic window consisting of a portion of a heartbeat cycle of a patient, wherein the portion of the heartbeat cycle of the patient is selected at least partially based on one or more characteristics of the proximal pressure signal, and wherein the portion of the heartbeat cycle of the patient is selected at least partially based on one or more characteristics of the distal pressure signal.