Chaotic phasic pattern as sole ultrasound evidence of extensive post-thrombotic change

We report three cases of extensive post-thrombotic change confirmed at ascending venography but which did not demonstrate the currently accepted duplex ultrasound criteria for post-thrombotic change. We also document a new ultrasound finding which we describe as a chaotic phasic pattern of deep venous flow which was the only duplex evidence of post-thrombotic change in two of the cases. We suggest that its routine inclusion in duplex ultrasound assessment of the deep veins should be considered.