Thanks to all who responded about the venography/phlebography question
I had posted on Friday. Thanks too to Dr. Conti for the trivia on
If anyone out there knows of any specific references which document
false positive venous duplex scans (especially proximally) or false
negative phlebograms, I'd still appreciate the info. For those who
wanted the rest of the story, the phlebogram was done approximately 20
hours after the initial positive duplex scan. As stated in my earlier
message, the phlebogram did not demonstrate the nonoccluding
iliofemoral DVT even though three planes were used for the phlebogram
images. The initial duplex showed a dilated vein, intraluminal
echoes, no spontaneous Doppler signals, and a non-compressible vein.
In fact, the adjacent artery was being deformed while the venous walls
remained unchanged. Approximately 24 hours after the phlebogram, a
repeat ultrasound by the chief of ultrasound showed a nonoccluding DVT
at the saphenofemoral junction. The repeat scan failed to determine
the cephalad extent of the thrombus. At that point (almost 48 hours
after the initial scan), a vena caval filter was placed based on the
final duplex that was performed. Incidentally, the interventional
radiologist who did not "believe" our initial duplex thought that the
DVT present on the final duplex scan was likely something new that was
a result of the phlebogram.
That's the rest of the story!