Assessment of the Cerebral Vasomotor Reactivity in Internal Carotid Artery Occlusion Using a Transcranial Doppler Sonography and Functional MRI

Abstract

Several methods are being used to assess cerebral vasomotor reactivity (CVR), including transcranial Doppler (TCD) sonography and blood oxygenation level-dependent functional magnetic resonance imaging (fMRI). The aim was to assess the correlation of TCD and fMRI in the CVR assessment. Study group consisted of 28 patients (24 males, 4 females; aged 30-82, mean 63.1 +/- 10.0 years), presenting with 29 occluded internal carotid arteries. The TCD examination, including breath-holding/hyperventilation test (BH/HV) and breath-holding index (BHI), and fMRI examination were used for the assessment of CVR. fMRI employed a bimanual motor task within both a block paradigm and an event-related paradigm. Cohen's kappa was applied when statistically assessing correlation of the methods. The following correlations were found--between BH/HV and BHI 58.6%, kappa= .205; BH/HV and fMRI 65.5%, kappa= .322; BHI and fMRI 58.6%, kappa= .151; TCD (consistent result of both BH/HV and BHI test) and fMRI 70.6%, kappa= .414. In the evaluation of CVR, there is only a minimal correlation between the particular TCD tests (both BH/HV and BHI), and fMRI examination. However, there is a moderate correlation between TCD and fMRI in the case of congruity of both TCD tests.