Variability in the Cross-Sectional Area and Narrowing of the Internal Jugular Vein in Patients Without Multiple Sclerosis
Karen Buch1, Raymond Groller1, Rohini N. Nadgir1, Akifumi Fujita1, Muhammad M. Qureshi1,2 and Osamu Sakai1,2,3
Affiliations: 1Department of Radiology, Boston Medical Center, Boston University School of Medicine, 820 Harrison Ave, FGH Bldg, 3rd Fl, Boston, MA 02118.
2Department of Radiation Oncology, Boston Medical Center, Boston University School of Medicine, Boston, MA.
3Department of Otolaryngology–Head and Neck Surgery, Boston Medical Center, Boston University School of Medicine, Boston, MA.
Citation: American Journal of Roentgenology. 2016;206: 1082-1086. 10.2214/AJR.15.14689
OBJECTIVE. Chronic cerebrospinal vascular insufficiency is a proposed condition of intraluminal stenosis of the internal jugular vein (IJV) that impedes venous flow from the brain. Calculations of IJV stenosis are vague and described in veins with at least a 50% reduction in IJV caliber at a specific level. The purpose of this study was to assess normal changes in anatomic caliber of the course of the IJV in a generalized population.
MATERIALS AND METHODS. Images from 500 consecutive contrast-enhanced neck CT studies performed in January–July 2011 were reviewed. Cross-sectional areas of the IJV were calculated at the jugular foramen, C1–C7 levels, and jugular angles bilaterally. Patients were excluded if they had severely motion-limited studies; limited clinical data; a history of multiple sclerosis, neck mass, or neck dissection; or known IJV occlusion. Normalized IJV cross-sectional areas at each level were compared with an averaged normalized cross-sectional area from all patients at each level.
RESULTS. Greater than 50% narrowing compared with a normalized average was found in 133 of 363 patients (36.6%) and was seen at all IJV levels. In 36.1% of patients this narrowing occurred at the C1 level. Most of the areas of narrowing greater than 50% occurred above the C4 level.
CONCLUSION. The IJV has marked variability in its course in the neck. Areas of narrowing greater than 50% occur most commonly in the upper cervical and skull base regions. Given the normal anatomic variations in IJV caliber, caution should be used when making the diagnosis of and treating IJV stenosis.
This was interesting too -- if most areas of narrowing greater than 50% occurred about the C4 level, then it would actually be abnormal to have a jugular narrowing between C5-C7. Wouldn't the area of the valves be in the C5-C7 area? Doesn't this support the abnormality of such obstructions?
The supposed normal narrowings in the skull base area found in this study could be physiological narrowings, that would open with a deep breath. Whether or not they were physiological narrowings could be investigated, and have them disqualified if they were, so that only true obstructions are investigated. This was a retrospective study, but a prospective study could control for that variable, I think.