Table 3 Classification for the extracranial venous abnormalities determined by composite criteria or use of multimodal imaging with relative compensatory mechanisms

Venous abnormalities determined by composite criteria and multimodal imaging modalities:

CCSVI:

• A cutoff for CCSVI diagnosis classification consists of two or more abnormal DS VH criteria.

VHISS:

• VHISS is based on the sum of extracranial venous abnormality VH criteria based parameters measured for each of the five CCSVI criteria examined and is ranging from 0 to 16.

Multimodal imaging application for detection of extracranial venous abnormalities

• Use of multimodal imaging criteria on DS, MRV, CV and IVUS to determine a significant narrowing of extracranial venous system with hemodynamic consequences for the intracranial venous drainage.

Compensatory mechanisms for venous abnormalities:

Collateral veins:

• The presence of two or more extracranial collateral veins and of epidural collateral veins may serve as an indirect sign of impaired venous outflow.