Intravascular Ultrasound in the diagnosis and treatment of chronic cerebrospinal venous insufficiency

Performing the examination

I perform diagnosis and treatment of CCSVI using fluoroscopy, venography, intravascular ultrasound and external ultrasound access guidance. The procedure is performed under local anesthesia and with micropuncture access. Vascular entry is obtained under external ultrasound guidance through a left inguinal approach, to enter the saphenous vein at the saphenofemoral junction. A 10 French sheath is introduced and positioned above the right atrium in the superior vena cava. The sheath is positioned and all instrumentation is moved through the sheath, as an essential protection because the very small wire required to track the IVUS buckles into the heart and mat cause arrhythmias.

Once the sheath is in place, all, or at least most, of the catheterizations are performed over the 0.014 inch guidewire needed for the IVUS. I perform venography followed by IVUS for each of the three major cerebrospinal outflow veins, namely the right and left IJV and the azygous vein. I perform venography alone in the majority of transverse sinuses, in the left renal vein, in the left common and external iliac vein and in the left ascending lumbar vein. I do not recommend routine IVUS of the left renal vein or the left iliac vein because these veins are rarely associated with immobile valves. However when stenoses or prominent collaterals are identified, IVUS is used. When compression of the renal or iliac veins is seen, the diagnosis of Nutcracker or May Thurner syndrome can be made. IVUS is then critical to accurate sizing of these veins to reduce risk of migration.

With the guidewire in the transverse sinus and using a rapid exchange system, the IVUS is positioned in the jugular bulb and then withdrawn manually at deliberate speed down into the innominate vein. I do not use the automated pull-back device because such devices were developed for coronary use and the pull back moves too slowly to be practical for the long length of the jugular vein. Critical areas to evaluate include the upper internal jugular vein at the C-2 level, the mid jugular vein where venous compression by the carotid artery or the strap muscles occurs and, most importantly in the lower jugular vein at the confluens with the subclavian vein where most of the pathology is located. (Figure 1)

After azygous venography IVUS is performed throughout the azygous vein, extending as far down the azygous and hemiazygous as possible. Transient narrowings are common in the azygous. Inspection of narrowings throughout the ascending azygous should include inspiration and expiration views as this area common dilates during inspiration. I do not treat transient narrowings. The area of the junction of the ascending azygous and its arch is inspected in great detail. Subtle immobile valves in the azygous vein are often unrecognizable on venography and are often visualized only by IVUS. (Figure 2)

B-mode imaging in both the cross sectional and longitudinal views are important. The cross-section image looks at the circumference of the vein, and reflective tissue such as webs, membranes, septums and valves. The longitudinal view gives a good view of collateral entries, longitudinal views of stenoses and a different view of intraluminal pathology. I have not relied upon ChromaFlo or Virtual Histology at this time.