Abstract: A shaft is shown having inner and outer members in interfering contact along their length, at least one of which comprises a wire, at least a portion of which is superelastic, to achieve substantial mechanical fidelity and resistance to damage. An ultrasound imaging catheter has a hollow catheter shaft, an ultrasound transducer in the shaft, and a drive shaft that rotates the transducer. The shaft comprises at least one metal coil having characteristic elastic deformation under stress in the range of about 3% to 9%, while a restraint means prevents torsional deflection of the coil. A drive shaft having a coil surrounded by a tube, a coil bonded to an inner coaxial cable, and an inner and outer coil that interfere with one another are shown. A superelastic coil is formed by continuously winding a wire about a mandrel, heating a region of the wire to render it superelastic, and after cooling, removing it from the mandrel.

Abstract: A multi-function intraluminal ultrasound catheter assembly includes an axially disposed lumen having at least a first portion with a flat inner wall forming a "D-shaped" cross-section. An acoustic imaging window having a circular cross-section is connected to a distal end of the catheter assembly, wherein the cross-sectional dimension of the D-shaped portion of the lumen that extends from the flat inner wall is less that the available inner diameter of the imaging window. A flexible drive-shaft extends through the lumen and is connected to a transducer housing disposed in the acoustic imaging window area, the transducer housing having a substantially "D-shaped" outer perimeter, wherein the drive-shaft and connected transducer housing may thereby be retracted from the catheter assembly by first rotating the transducer housing until its D-shaped outer perimeter is substantially oriented with the D-shaped cross-section of the lumen.

Abstract: An ultrasound imaging device has a stationary, elongated flexible tubular body, a rotatable drive shaft extending through the body, and a nose member located distally of the tubular body. The nose member is mounted on the distal end of the drive shaft to rotate therewith, and an acoustic imaging instrument is incorporated in the nose member for producing acoustic images of adjacent tissue as the drive shaft turns. The nose member is covered with a bio-compatible, acoustically transparent, lubricous coating of hydrophilic material sufficient to shield and space the nose member from the adjacent tissue. The lubricous coating of hydrophilic material covers an area of the surface of the ultrasound imaging device through which the acoustic imaging instrument causes acoustic signals to pass. The coating has sufficient thickness to avoid puncturing of a wall of a blood vessel by the nose member while the nose member rotates within the blood vessel sufficiently close to the wall for puncturing otherwise to occur.

Abstract: A shaft is shown having inner and outer members in interfering contact along their length, at least one of which comprises a wire, at least a portion of which is superelastic, to achieve substantial mechanical fidelity and resistance to damage. An ultrasound imaging catheter has a hollow catheter shaft, an ultrasound transducer in the shaft, and a drive shaft that rotates the transducer. The shaft comprises at least one metal coil having characteristic elastic deformation under stress in the range of about 3% to 9%, while a restraint means prevents torsional deflection of the coil. A drive shaft having a coil surrounded by a tube, a coil bonded to an inner coaxial cable, and an inner and outer coil that interfere with one another are shown. A superelastic coil is formed by continuously winding a wire about a mandrel, heating a region of the wire to render it superelastic, and after cooling, removing it from the mandrel.