Anaesthesia. 1998 Jul;53(7):627-33.
Anatomical variation of cerebral venous drainage: the theoretical effect on jugular bulb blood samples.
Beards SC, Yule S, Kassner A, Jackson A.
SourceIntensive Care Unit, Withington Hospital, South Manchester University Hospitals Trust, UK.
Recent studies have demonstrated significant variation in bilateral jugular venous oxygen saturation measurements which may be of clinical significance. We have therefore measured variations in normal dural sinus venous drainage to assess the possible effects of normal anatomical variations on measured jugular venous oxygen saturation. Normal volunteers (n = 25) were imaged using magnetic resonance venography to demonstrate variations in venous anatomy. Flow was measured in the superior sagittal sinus and bilaterally in the transverse sinus, sigmoid sinus proximal to the jugular bulb and proximal jugular vein using phase difference magnetic resonance imaging. Examination of magnetic resonance venogram images showed considerable variability in the symmetry of transverse sinus flow. Complete absence of one transverse sinus was seen in four cases and significant asymmetry in the size of the transverse sinuses was present in 13. Quantitative flow studies demonstrated that the ratio of superior sagittal sinus to combined jugular bulb flow showed remarkably little variation (0.46 +/- 0.06). Measurements of transverse sinus flow showed significant asymmetry (< 40% of superior sagittal sinus flow in one transverse sinus) in 21 of 25 volunteers. The effect of the observed asymmetry on jugular venous oxygen saturation was modelled based on the assumption of either a supratentorial or infratentorial lesion. This model predicted significant asymmetry in jugular venous oxygen saturation measurements (> 10%) in 65% of cases with a supratentorial lesion which is in close agreement with clinical observations. This study suggests that normal variations in venous drainage may account for observed asymmetry in jugular venous oxygen saturation measurements.
I am being dragged away from CCSVI to watch Paranormal Activity 2. Which might be scary. But I am starting this thread for research into any effects of jugular vein asymmetry. The jugular veins vary in size, with the left more commonly but not always being the smaller one.
This article was looking at the effects of 'normal' anatomical variants in the dural sinuses to see how it affected the oxygen saturation in the jugular bulb, which is right where the sinus connects to the jugular.