engleski

SONOGRAPHIC FEATURES OF VERTEBRAL ARTERY OCCLUSION (THE ROLE OF COLOR AND POWER DOPPLER IMAGING)

The visualisation of vertebral artery (VA) occlusion by means of ultrasound is sometimes difficult, what depends on the localisation and diameter of the VA. We studied patients with extra- and intracranial VA occlusion in order to compare the incidence of VA hypoplasia and advantages of visualisation by power Doppler imaging (PDI). We analyzed the Color Doppler flow imaging (CDFI) and PDI of carotid arteries and VA in 31 patients with VA occlusion. The criteria for extracranial VA occlusion were: visualisation of the VA lumen with absent color coded and PD flow. The criteria for intracranial occlusion were: visualisation of the VA lumen, present PDI flow, systolic velocities less than 40cm/s, unilateral absent diastolic flow. Diameter was measured in the V2 segment. The criteria for VA hypoplasia were: diameter < 2mm, systolic velocities <40cm/s, diastolic velocities <15cm/s. VA occlusion was found in 15 patients in extracranial, and in 16 patients in intracranial part. In the group of extracranial VA occlusion, 13 were males (mean age 56.1+ 13.1), and 2 females (mean age 77+ 3.5). Absence of CD flow was used for the presumed VA occlusion, and confirmed by absence of PD flow. CDFI allowed moderate of good collaterals visualization in 20% patients (3/15) versus PDI in 86.7% (13/15). PDI was superior in visualization of collateral flow (p<0.05). In the group of intracranial VA occlusion 12 were males (59.4+9.9) and 4 females (65.5+16). PDI was useful to distinguish extracranial from intracranial VA occlusion. Due to low BFV in intracranial VA occlusion, CD vessel filling was absent. The absence of PDI filling was used to confirm extracranial occlusion, and PDI presence in the whole lumen to exclude stenotic extracranial lesions. Coexistent carotid disease was equally present in both groups of patients (27% in extracranial and 25% in intracranial VA occlusion (p>0.05). The right VA was occluded more frequently extracranial (9/15 vrs. 5/16), although statistically not significant (p>0.05). The left VA was occluded more frequently intracranial (2/16 intracranial vrs. 6/15 extracranial) (p<0.05). The hypoplastic vertebral artery was occluded more frequently extracranial (33.3% vrs. 12.5%) (p<0.05). PDI was helpful in distinguishing extracranial from intracranial VA occlusion and in the differential diagnosis of hypoplasia, near-occlusion (pseudoocclusion, dissection) and assessment of collateral flow, whereas CDFI was applied first for vessel identification and diameter measurement.

ultrasonography;vertebral arteries;occlusion; color doppler; power doppler

nije evidentirano