While researchers have speculated that changes in brain blood flow due to vein abnormalities contribute to multiple sclerosis (MS) disease severity, a study published online Aug. 21 in Radiology has demonstrated this may not be the case as these abnormalities were shown not to be specific to MS.
Simone Marziali, MD, of the University of Rome Tor Vergata in Rome, and colleagues explained their results, gathered through the use of MR imaging, showed that chronic cerebrospinal venous insufficiency (CCSVI) is likely an accessory process occurring during the course of a disease, but plays little role in MS pathogenesis.
“The results also call into question whether CCSVI can really be considered a pathologic condition or if it simply represents an ‘epiphenomenon,’” wrote the authors. “This is important because, to date, studies about this association that have been assessed to try to estimate the prevalence of CCSVI in MS provided inconclusive results that varied widely, from none to 100 percent.”
CCSVI describes a condition characterized by compromised blood flow in veins draining the central nervous system. Recent studies have suggested a significant association between MS and CCSVI, leading to a hypothesis that MS could be treated with endovascular procedures like stent placement, but the relationship between blood flow and MS remains unclear.
To clarify the role of CCSVI in MS, Marziali and colleagues conducted dynamic susceptibility contrast-enhanced (DSC) MRI studies in 39 MS patients and 26 healthy control subjects. Color Doppler ultrasound was used to determine presence of CCSVI.
Results showed that 25 MS patients and 14 control subjects were positive for CCSVI. DSC MRI offered an accurate assessment of brain blood flow and showed that, while CCSVI-positive patients had decreased cerebral blood flow and volume compared to the CCSVI-negative cohort, there was no significant interaction between MS and CCSVI for any blood flow parameters. There was also no correlation between cerebral blood flow and volume in white matter regions and the severity of MS disability, according to the authors.
“This study clearly demonstrates the important role of MRI in defining and understanding the causes of MS,” Marziali said in a release. “In the future, it will be necessary to use powerful and advanced diagnostic tools to obtain a better understanding of this and other diseases still under study.”
The authors wrote that further studies featuring larger study groups in which patients are grouped by the form of MS they have need to be conducted in order to validate their findings.