Table 2.

Fulfillment of the five ‘Zamboni criteria’ in 20 MS patients and 20 healthy controls

Criterion	Definition according to ‘Zamboni protocol’*	No of MS patients	No of controls	p Value†
1	Reflux >0.88 s in the IJVs and/or VVs in sitting or supine position	0	0	/
2	Reflux >0.5 s in the deep cerebral veins	0	0	/
3	High resolution B-mode evidence of IJV stenoses defined as VCSA of ≤0.3 cm†‡	13	16	0.48
4	Flow not Doppler-detectable in at least one IJV or VV§ in the supine and upright position	0	1§	1.0
5	Atypical main cerebral venous outflow measured in IJV defined as ΔVCSAupright–supine>0¶	0	0	/
At least two criteria fulfilled		0	1	1.0

^*Zamboni et al.⁵

^†Fisher exact test.

^‡Criterion 3 was not defined consistently by Zamboni et al. We used the definition in Zamboni et al,⁵ where a venous cross-sectional area (VCSA) of ≤0.3 cm² is given as a cut-off value. Doepp et al²¹ obtained different results in assessing criterion 3, but referred to a deviating definition of ‘stenosis’ given in Zamboni et al,^25a J Neurol Sci 2009;282:21–7, where a local VCSA reduction of ≥50% is considered ‘stenotic.’

^§Criterion 4 is not specified clearly by Zamboni et al. Here, we defined criterion 4 as ‘no flow detectable in at least one internal jugular vein (IJV) or vertebral vein (VV) in the supine and the upright position.’

^¶This Zamboni criterion was modified. Given that negative values for ΔVCSA in the IJV represent not a pathological but a physiological state, this criterion was substituted by ‘atypical flow,’ /, indicates p value could not be calculated. indicating a positive value of ΔVCSA.