The invention relates to an elongated medical device (1), such as a catheter, for insertion into a cavity of a patient body to characterize material arranged in a vicinity of a distal end section of the device (1). The device (1) comprises an actuator formed of a responsive material (34) and disposed at the distal end section of the device (1), which is configured to deform in response to an actuation signal applied to the responsive material (34) to thereby apply a pressure to the material in the vicinity of the distal end region of the device (1). Further, the device (1) comprises a sensor configured to react to a deformation of the actuator and to provide a measurement signal indicative of a resistance of the material against the applied pressure.
