engleski

POWER ENHANCEMENT DOPPLER SONOGRAPHY IN DIAGNOSING VERTEBRAL ARTERY OCCLUSION

The visualisation of vertebral artery (VA) occlusion by means of ultrasound is sometimes difficult, what depends on the localisation and diameter of the vertebral artery. We studied patients with extra- and intracranial VA occlusion in order to compare their mean diameters and possibility of better visualisation by power Doppler (PD) sonography. We analysed the Color Doppler flow imaging (CDFI) and PD of carotid 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 intracracranial occlusion were: visualisation of the lumen of VA, present PD flow, systolic velocities less than 40 cm/s, absent diastolic flow, when the diastolic flow was present in contralateral VA. Mean diameter was measured in the V2 segment between C6C5 segment. The criteria for hypoplasia of VA was the diameter <2mm. VA occlusion was found in 31 patients. In the group of extracranial VA occlusion, 13 were males, and 3 females. 6 had occlusion of the left and 10 of the right VA. Six patients had V0 occlusion of the hypoplastic VA (37%). In these patients, PD was helpful to distinguish hypoplasia of VA from collateral flow. In 10 patients with the suspected V0 occlusion, PD was used to confirm the absence of flow in VA and for the assessment of collateral flow. Five patients out of 16 had advanced carotid disease (31%). In the group of intracranial VA occlusion, 12 patients were males and 3 females. 4 had occlusion of the right and 11 of the left VA. Hypoplasia of VA was found in one patient (7%). Mean systolic blood flow velocity was 0.27+0.11 m/s in occluded artery, and 0.58+0.17m/s in the contralateral VA. PD was helpful for exclusion of extracranial VA pseudoocclusion. 6 patients had advanced carotid disease (40%). VA hypoplasia was more frequent in patients with V0 occlusion (p<0.05). Right VA was occluded more frequent extracranialy, and left VA intracranialy (p<0.01). Coexistent carotid disease was equally frequent in both groups of patients. Hypoplasia and right VA occlusion was more frequent in patients with V0 occlusion.. PD is helpful in distinguishing occlusion of extracranial and intracranial VA from hypoplasia, psudoocclusion and for the assessment of collateral flow.

power Doppler; vertebral artery; occlusion

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