A catheter assembly for an ultrasound system , the catheter assembly comprising: a distal section comprising a distal sheath; a proximal extension comprising a proximal sheath; a telescoping pullback section between the distal section and the proximal extension , the telescoping pullback section comprising a first telescope , a second telescope , a distal grip coupling the first telescope to the distal sheath of the distal section , and a proximal grip coupled to the second telescope , wherein the first telescope is configured to slide into the second telescope ; a sensor disposed along the telescoping pullback section to determine a position of the first telescope as the first telescope is moved relative to the sensor ; an elongated, rotatable driveshaft having a proximal end and a distal end and extending along the distal section , proximal extension , and telescoping pullback section , wherein the proximal end is configured and arranged for coupling to a motordrive for rotating the driveshaft ; a sheath comprising the distal sheath and the proximal sheath, the sheath defining a lumen extending along the sheath; an imaging core disposed in the lumen , the imaging core including an imaging device situated at a distal tip of the imaging core , the imaging device being coupled to the distal end of the driveshaft with rotation of the driveshaft causing a corresponding rotation of the imaging device , the imaging device comprising at least one transducer configured and arranged for transforming applied electrical signals to acoustic signals and also for transforming received echo signals to electrical signals, wherein the imaging device is moved in a proximal direction by gripping the distal and proximal grips and manually moving the distal and proximal grips away from each other; and at least one conductor extending along the distal section , proximal extension , and telescoping pullback section and coupled to the imaging device for carrying the electrical signals. a distal section comprising a distal sheath; a proximal extension comprising a proximal sheath; a telescoping pullback section between the distal section and the proximal extension , the telescoping pullback section comprising a first telescope , a second telescope , a distal grip coupling the first telescope to the distal sheath of the distal section , and a proximal grip coupled to the second telescope , wherein the first telescope is configured to slide into the second telescope ; a sensor disposed along the telescoping pullback section to determine a position of the first telescope as the first telescope is moved relative to the sensor ; an elongated, rotatable driveshaft having a proximal end and a distal end and extending along the distal section , proximal extension , and telescoping pullback section , wherein the proximal end is configured and arranged for coupling to a motordrive for rotating the driveshaft ; a sheath comprising the distal sheath and the proximal sheath, the sheath defining a lumen extending along the sheath; an imaging core disposed in the lumen , the imaging core including an imaging device situated at a distal tip of the imaging core , the imaging device being coupled to the distal end of the driveshaft with rotation of the driveshaft causing a corresponding rotation of the imaging device , the imaging device comprising at least one transducer configured and arranged for transforming applied electrical signals to acoustic signals and also for transforming received echo signals to electrical signals, wherein the imaging device is moved in a proximal direction by gripping the distal and proximal grips and manually moving the distal and proximal grips away from each other; and at least one conductor extending along the distal section , proximal extension , and telescoping pullback section and coupled to the imaging device for carrying the electrical signals. <EOS>