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 ult rasound 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 wi th gray-scale ultrasound 7 weeks after graft implantation before and after the intravenous bolus injection of MRX-408 (a GPIIb receptor-targeted ultra sound contrast agent). Pre- and postcontrast videotaped segments were rando mized 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 thro mbus 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 s urrounding soft tissues. CONCLUSIONS. MRX-408 demonstrated better visualization of thrombus within A V fistulae, This was shown in both patent and occluded grafts, These result s are encouraging and suggest that this contrast agent merits further devel opment.