This study is aimed at evaluation of diagnostic value of Doppler sonography, MR venography and air-plethysmography for the assessment of abnormalities in the internal jugular veins, with catheter venography as the reference test.

1. Patients group

   Inclusion Criteria:

   • confirmed diagnosis of multiple sclerosis

   Exclusion Criteria:

   • coexisting another neurologic pathology (e.g. stroke, Parkinson disease)
   • significant stenosis of carotid or vertebral arteries
   • other significant abnormalities of blood vessels of the upper part of the body
   • tricuspid valve incompetence
   • allergy to iodine contrast dye
   • chronic renal failure
   • pregnancy
   • other severe comorbidities or significant abnormalities in standard lab tests

2. Healthy volunteers.

Inclusion Criteria:

• none

Exclusion Criteria:

• confirmed diagnosis of multiple sclerosis or related pathologies (CIS, NMO)
• coexisting another neurologic pathology (e.g. stroke, Parkinson disease)
• significant stenosis of carotid or vertebral arteries
• other significant abnormalities of blood vessels of the upper part of the body
• tricuspid valve incompetence