Patients with peripherally inserted central catheters (PICCs) are routinely discharged with the catheters in place. These patients experience complications due to undetected thrombosis or accidental dislodgement, with tracking through limited X-ray imaging. Developing catheters with the capability to be tracked without the need for X-ray imaging would greatly benefit these patients by decreasing patient stress, reducing time to diagnosis, and increasing nursing home capabilities. This study reports on the incorporation of echogenic microspheres into catheters to produce bulk echogenic effects for developments in the field of real-time ultrasound tracking of polymeric medical devices. The impact on elastic modulus, ultrasound contrast, and cytocompatibility of the polymer was analyzed when incorporating up to 10 wt % glass microspheres. Up to this loading level, the elastic modulus was found to remain constant. However, at 10 wt %, extrusion defects due to agglomeration, air bubbles, and shearing were numerous and deemed detrimental to ultrasound imaging. Successful, defect-free samples were produced with 5 wt % microsphere loading and when embedded in a soft tissue phantom revealed a significant increase in the signal-to-noise ratio as compared to the polymer alone. Preliminary results have shown a successful increase in polymer's echogenic properties, without undermining its mechanical and cytocompatibility properties.
Keywords: echogenic composites; glass microspheres; polyurethane; thin-walled medical devices.