Table 2 Doppler parameters that detect five anomalous venous hemodynamic criteria affecting cerebrospinal venous return ^a

(1)

 Reflux-bidirectional flow constantly present in the IJV and/or vertebral vein with the patient in both examination positions (sitting and supine posture) in at least one of the three landmarks (J1, J2, J3)

(2)

 Reflux-bidirectional flow in the intracranial veins: The presence of intracranial venous reflux is diagnosed when there is reflux on the Rosenthal’s vein and/or transverse sinus and/or cavernous sinus and/or superior or inferior petrosus sinus

(3)

 B-mode and M-mode demonstration of intraluminal defects (septa, valvular malformations, double-channel) and/or cross-sectional area <0.3 cm²

(4)

 Absent flow in internal jugular veins and/or vertebral veins after repeated deep inhalations with the patient in both examination positions (sitting and supine) in at least one of the three landmarks (J1, J2, J3). The finding of absence of flow in only one body position becomes a useful criterion even if reflux-bidirectional flow is found in the other position.

(5)

 Cross-sectional area of the IJV at J2 point greater in sitting that in supine posture