Here's a nice slideshow presenting Dr. Ferral's study and results:http://www.slideshare.net/cdyte/ccsvi-h ... -enero2012
Under materials & methods, he says the intravascular ultrasound is an 8 French Volcano system, that he advances the catheter to the mid-neck level, that he does a slow withdrawal looking for stenotic areas or tight valves, and that vein measurements are obtained.
Indications for angioplasty are:
severe stenosis or reflux seen on venogram
severe stenosis seen on IVUS
thick rigid valve seen on IVUS
It's interesting to note that if IVUS were not used, two out of those three indications for angioplasty would be gone.
It's also of interest that he only advances the catheter to the mid-neck level. I wonder why he does not advance it to the top of the jugular?