Carotid ultrasound criteria for detecting intracranial carotid stenosis

Background/Aims: This study attempted to establish carotid ultrasound criteria for identifying stenosis of the intracranial internal carotid artery (ICA) and middle cerebral artery (MCA). Methods: Two hundred and fifty-five patients were enrolled. Ultrasound measurements for common carotid artery (CCA) and ICA were as follows: flow volume (FV), peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI) and resistance index (RI). The sensitivity and specificity of the ultrasound criteria for determining intracranial ICA or MCA >= 50% stenosis were calculated. Results: The criteria identified for detecting intracranial ICA >= 50% stenosis were ICA FV < 159 ml/min, ICA PSV < 33 cm/s and CCA PSV < 42 cm/s. When ICA PSV < 33 cm/s was combined with CCA PSV < 42 cm/s, sensitivity increased to 82%, with 91% specificity. The criteria identified for detecting MCA >= 50% stenosis were CCA FV < 285 ml/min, ICA FV < 179 ml/min, ICA PSV < 33 cm/s, > 35% reduction in FV in the CCA, > 40% reduction in FV in ICA, and > 35% reduction in PSV in ICA. When these criteria were combined, sensitivity increased to 69%, with 85% specificity. Conclusion: This study demonstrated that ultrasound criteria are sensitive and specific for detecting intracranial ICA and MCA significant obstruction. Copyright (c) 2007 S. Karger AG, Basel.