Compression of the left brachiocephalic vein: cause of high signal intensity of the left sigmoid sinus and internal jugular vein on MR images.
A Satoh and
+ Author Affiliations
Department of Neurosurgery, Yaizu Municipal General Hospital, Shizuoka, Japan.
To study the asymmetry in signal intensity of the sigmoid sinuses, internal jugular veins (IJVs), or both sets of structures on magnetic resonance (MR) images, the authors reviewed 226 serial sets of routine MR imaging studies. Cerebral digital subtraction angiography was performed in 20 patients with a markedly higher intensity and/or enhancement on the left; 15 of them also underwent venography. With every sequence, the left sigmoid sinus, IJV, or both were higher in signal intensity significantly more often than the right (range, P = .0001 to .0129). Angiography revealed hemostasis in the left IJV in 16 patients that disappeared during full inspiration in 14. In 13, venography revealed that the left brachiocephalic vein was compressed to occlusion between the aortic arch and the sternum during tidal volume ventilation. The occlusion disappeared at full inspiration, when the distance between the aortic arch and the sternum increased. This hemostasis could be the major cause of the frequent increased signal intensity of the left sigmoid sinus and IJV on MR images.
This was an interesting study in which the researchers looked for anomalies in the signal intensity on MR imaging of the sinus or IJV on one side only. They found 20 such patients in 226 serial sets of images. Then they had those patients get DSA done (cerebral digital subtraction angiography, where the arteries are subtracted out and you see only the veins). In sixteen of these patients, angiography revealed stasis in the left IJV. In 2 of those patients, the IJV remained in stasis (when the flow just sits there) but in 14 the stasis disappeared when they breathed fully in. Still with me? And in 13 of these patients, venography revealed a compression of the left brachiocephalic vein! This would be the innominate vein. When the patients breathed fully in, the compression was lifted and that is why the jugular flow resumed, in those patients, upon full inspiration.
Some thoughts: I like this research! The authors followed the path from high intensity one-sidedly seen in the jugulars or sinus, all the way to a compression of the innominate vein that would cause it. This connects an occlusion of the innominate vein with effects on flow in the jugulars and sinus.
Should it be treated? On one hand, if this is physiological and flow gets through every time the patient takes a deep breath, it might be something to leave alone. This was the case for 14 of the patients; in 2 of them, the flow did not get through when the patient took a deep breath, so perhaps only those 2 would warrant treating if symptoms were present.
On the other hand, if even a physiological brachiocephalic compression exists in a CCSVI in MS patient, it might be affecting cerebrospinal blood flow and warrant stenting.
Side note: during my second CCSVI procedure, in July, my left jugular's flow was as described here, in stasis, where the contrast just sat there and went up and down a bit. My left jugular is a scrawny little thing in comparison to my right jugular. But getting that jugular ballooned and the flow restored led to my best reduction in cogfog, and to the numbness that had returned six weeks after my first procedure going away again and, knock on wood, staying away. Other improvements too. From personal experience, I believe stasis even in one jugular is worth treating.
Dr. Sclafani's last case featured an innominate vein stenosis, which he suspected was due to compression by a tortuous innominate artery. Last spring at one of the conferences, there was a Polish doctor who performed a live case CCSVI procedure, which can be watched on youtube, and when jugular flow remained less than optimal after treatment of the valves, he performed a few balloonings of the innominate vein. I was surprised by this because there was nothing in the image to indicate innominate vein stenosis, but the lack of good flow in the jugular after treatment itself was considered a possible sign of obstruction in the innominate. Ballooning the innominate did not improve the jugular flow in that particular patient, but it was interesting to hear the doctor's thought process, and ballooning the innominate being the chosen course of action in such circumstances.