The use of a thrombus-specific ultrasound contrast agent to detect thrombus in arteriovenous fistulae

RATIONALE AND OBJECTIVE. To evaluate the use of a new thrombus-specific ultrasound contrast agent, MRX-408, in the ultrasonic detection of thrombus in arteriovenous (AV) fistulae, METHODS. Six purpose-bred mongrels with two AV fistulae each mere imaged with gray-scale ultrasound 7 weeks after graft implantation before and after the intravenous bolus injection of MRX-408 (a GPIIb receptor-targeted ultrasound contrast agent). Pre- and postcontrast videotaped segments were randomized and reviewed by four radiologists blinded to the presence of thrombus in the grafts, RESULTS. After the use of MRX-408, there was improved visualization of thrombus within the grafts (P < 0.0001), This was due to the enhancement of the thrombus (P < 0.0001), The improved visualization and contrast enhancement were more marked in the grafts that contained thrombus nonhyperechoic to surrounding soft tissues. CONCLUSIONS. MRX-408 demonstrated better visualization of thrombus within AV fistulae, This was shown in both patent and occluded grafts, These results are encouraging and suggest that this contrast agent merits further development.