Objective To examine the incidence and distribution of extravascular compression of the extracranial venous pathway (the jugular and/or  azygous veins) in multiple sclerosis patients with chronic cerebrospinal venous insufficiency evaluated by mulitislice computer tomographic angiography.                     

Methods and results Study group consisted of 51 consecutive patients with multiple sclerosis in whom chronic cerebrospinal venous insufficiency was diagnosed by color Doppler sonography (CDS). Mulitislice computer tomographic angiography was performed in all patients,  and it revealed significant extravascular compression (>70%) of extracranial venous pathway in 26 patients (51%), while in                25 patients (49%) no significant extravascular compression was seen. Extracranial compression due to transverse processus of cervical vertebrae was seen in 23 patients, carotid bulb compression was seen in two patients, and in one case, compression presented as a thoracic outlet syndrome.                     

Conclusion Our data indicate that extravascular compression of the extracranial venous pathway is frequent in multiple sclerosis patients  with chronic cerebrospinal venous insufficiency, and that it is mainly due to compression caused by transverse processes of cervical vertebrae. Further studies are needed to evaluate potential clinical implications of this phenomenon.