Research: SWI venography

EpubBeggs et al. Sensitivity and specificity of SWI venography for detection of cerebral venous alterations in multiple sclerosis.Neurol Res. 2012 Jun 16.

OBJECTIVES: To determine the sensitivity and specificity of decreased venous vasculature visibility (VVV) on susceptibility-weighted imaging (SWI) venography in MSers versus controls, and to compare this with assessment of whole brain atrophy.

METHODS: Forty MSers and 22 controls without known central nervous system (CNS) disease who had non-specific white-matter (WM) lesions were imaged on a 3T GE scanner using SWI venography. Apparent total venous volume (ATVV) and increased average distance from vein (DFV) were calculated for various vein mean diameter categories: <0.3, 0.3-0.6, 0.6-0.9, and >0.9 mm. Data was analysed using quite complex statistical techniques.

RESULTS: Analysis identified 0.3-0.6 mm venous relative fraction (VRF) and 
distance from vein as useful metrics. ROC analysis results in initial sample of 40 MS patients and 22 controls were (sensitivity, specificity): 0.3-0.6 mm VRF (95.0%, 100.0%); DFV (100.0%, 100.0%); and NBV (82.5%, 68.2%). The results in validation sample were: 0.3-0.6 mm VRF (92.9%, 75.0%); DFV (100.0%, 100.0%); and NBV (78.6%, 75.0%).

DISCUSSION: Altered VVV indices on SWI venography showed high sensitivity and specificity for MS. The value of SWI venography for diagnosis of MS has to be further tested at early disease stages and against patients with other neurologic diseases.

“This study suggests that detecting decreased venous vasculature visibility (smaller veins) can distinguish MSers from healthy controls. It is interesting that MSers have a reduced venous volume; if there was an obstruction to flow, as proposed with the CSSVI hypothesis, you would expect an increased volume due to distension of the veins.”

“Blood volume and flow is proportional to the tissue requirements of oxygen and glucose; i.e. reduced brain volume less blood flow hence reduced venous volume. As MS is associated with brain atrophy, from nerve cell and axonal loss, you would expect MSers to have reduced blood flow and venous volumes. Therefore the correct comparator for this study would be another disease control group, of a similar age, that has a similar degree of brain atrophy. Normal controls are a poor comparator group. Finally, this is a small study and hence will need to be reproduced.”

2 thoughts on “Research: SWI venography”

  1. "if there was an obstruction to flow, as proposed with the CSSVI hypothesis, you would expect an increased volume due to distension of the veins"The proposed obstructions of flow are extracranial, therefore one would expect to see those extracranial veins distended, not the intracranial veins, right above the point of occlussion. No better example for this than the Baracchini internal jugular vein.Inside the skull there are three interconnecting fluid systems, the arterial blood, the venous blood and the csf. Venous blood has the least pressure of all, therefore intracranial veins would get distended only if the venous pressure got significantly higher than the csf pressure and the pressure of the surrounding tissue, since the volume inside the skull is fixed and only fluids can move inside-out.

  2. Thank you vv for your clarity again, I always enjoy your intuitive and reasoned arguments.

Leave a Reply

%d bloggers like this: