Hemodynamic testing of vertebral artery occlusion assessed by vascular ultrasound

Abstract

Objective To investigate the combination of color Doppler flow imaging （CDFI） and transcranial Doppler （TCD） in the assessment of the hemodynamic changes of vertebral artery occlusion disease and their clinical value. Methods A total of 101 patients with vertebral artery occlusion detected by the combination of CDFI and TCD and confirmed by DSA were enrolled from January 2005 to January 2009. Taking the result of digital subtraction angiography （DSA） as a golden standard, The differences between the different types of the side of vertebral artery occlusion and contralateral vertebral artery on the extra- and intracranial segments were compared and analyzed in peak systolic velocity （PSV）, end diastolic velocity （EDV）, resistive indices （RI）, pulsatility index （PI）, spectrum morphology, and hemodynamics. Results No blood flow signals were detected by CDFI and TCD in patients of complete occlusion of the vertebral artery; the weak blood flow signals were detected by CDFI in patients of the occlusion in the intracranial segment of the vertebral artery. The blood flow signals after the establishment of collateral circulation in patients of the segmental occlusion were detected in the extracranial segment or intracranial segment of the vertebral artery. The PSV on the occluded sides of the extracranial segments were decreased more significantly than that on the unoccluded sides （27.39 ± 12.44 cm/s vs. 62.61 ± 13.22 cm/s, P = 0. 000）; RI was significantly higher than the unoccluded sides （0.99 ± 0.21 vs. 0.62 ± 0.07, P = 0. 000）. When a vertebral artery had the segmental occlusion and the collateral circulation was established, the PSV, EDV, and PI of the intracranial segment of the vertebral artery on the occluded sides were decreased more significantly than those on the unoccluded sides, PSV were 37.81 ± 12.28 crn/s and 73.17 ±30.99 crn/s, respectively （P =0.000）, EDV were 17.58 ± 7.10 crn/s and 29.31 ± 12.94 cm/s, respectively （P = 0. 000）, PI were 0.84 ± 0.22 and 1.01 ±0.18, respectively （P =0. 000）. The compared DSA showed that the sites of vertebral artery occlusion were different. There was significant difference in the Doppler flow velocity spectrum between the CDFI and TCD. Conclusions PSV, EDV, RI, and PI are the hemodynamic parameters of accurately assessing vertebral artery occlusion, and the combination of CDFI and TCD has significant value for the hemodynamic changes of different types of vertebral artery occlusion and the clinical comprehensive assessment. Key words: vertebral artery; arterial occlusive diseases; blood flow velocity; ultrasonography, Doppler, color; ultrasonography, Doppler transcranial; hemodynamics