M. Mijajlovic
Neurology Clinic, Clinical Center of Serbia and School of Medicine University of Belgrade – Belgrade, Serbia
The use of transcranial Doppler (TCD) is well established in the evaluation of many neurovascular conditions; however its use in cerebral vasculitis is less well documented.
Ultrasound has the highest resolution among the imaging techniques that are in use for the diagnosis of vasculitis. High-frequency probes provide an axial and a lateral resolution of 0.1 mm. Ultrasound depicts well the artery wall and provides information about blood flow characteristics.
Large-vessel vasculitis involves arteries that consist of intima, media and adventitia. Temporal- (TA) and Takayasu-arteritis (TYA) are well-recognized entities.
Ultrasonography is being used increasingly for the diagnosis of TA. Color Doppler ultrasound (CDU) shows hypoechoic (dark) oedematous wall swelling in acute TA that disappears with corticosteroid treatment. In addition, stenoses of short segments are typical for acute TA.
TCD is a valuable noninvasive bedside tool to monitor cerebral blood flow velocities and therapy response in patients with cerebral vasculitis, if large arteries are involved. A nonpulsatile cerebral (hypo) perfusion indicates severe hemodynamic impairment and is partially reversible by a surgical bypass graft. TCD/CDU seems to be useful to detect “high-risk” patients and to follow up in TYA.
CDU can be also used to discriminate different causes of sudden monocular blindness. Presence of the ‘‘spot sign’’ helps to discriminate embolic from vasculitic occlusion of the central retinal artery.
Observed association of microembolis signals (MES) with neurolupus may support the possible contribution of MES to the complex pathophysiology of this syndrome. More importantly, detection of MES on TCD monitoring might suggest a high risk of involvement of the central nervous system in neuropsychriatric lupus.
TCD/CDU has several advantages: it is noninvasive, relatively non-expensive, readily performed at the bedside, repeatable, and readily available. Safety and relative reproducibility make them attractive techniques for diagnosis and follow up of some forms of cerebral arteritis.
Key words: cerebral arteritis, diagnosis, treatment, ultrasonography.