Background and purpose: The "venous hypothesis" of multiple sclerosis (MS) postulates that intracranial venous congestion disintegrates the blood-brain barrier, resulting in iron accumulation in brain parenchyma triggering the inflammatory process of MS. Transcranial sonography (TCS) reveals brain parenchyma hyperechogenic alterations (BPHA) that are thought to reflect iron accumulation. We sought to investigate potential association of BPHA with chronic cerebrospinal venous insufficiency (CCSVI) in MS.
Methods: MS patients were evaluated according to established TCS protocol for extrapyramidal disorders examining the presence of hyperechogenicities in different basal ganglia regions. Cerebral and cervical venous system was assessed according to proposed ultrasound protocol for CCSVI detection.
Results: In a total of 32 MS patients (age = 40 ± 14 years; male = 41%; EDSS-score = 3.1 ± 2.2) brain parenchyma hyperechogenic alterations were detected in twelve (38%) patients. The two sonographers agreed independently in 28 (87.5%) of the 32 examinations, resulting in a substantial to almost perfect agreement (Cohen's weighted kappa: substantia nigra = 0.904, Lentiform nucleus = 0.871, Thalamus = 0.784, caudate nucleus = 0.651). Two (6%) patients fulfilled the neurosonology criteria of CCSVI, while in 7 patients (22%) one positive criterion was detected. No BPHA were observed in any MS patient fulfilling CCSVI criteria. The prevalence of one positive CCSVI feature did not differ (P = .999) among patients with present (25%) or absent (20%) BPHA.
Conclusion: There was no association of BPHA with CCSVI findings. Our findings do not support the "venous hypothesis" resulting in iron accumulation even in the few MS patients fulfilling CCSVI-criteria.
Keywords: Chronic cerebro-spinal venous insufficiency; blood-brain barrier; iron accumulation; transcranial sonography; ultrasound.
Copyright © 2015 by the American Society of Neuroimaging.