Comparison of transcranial color-coded sonography and magnetic resonance angiography in acute ischemic stroke

Background and Purpose. This study was designed to assess the accuracy of t ranscranial color-coded sonography (TCCS) as compared to magnetic resonance angiography (MRA) for detecting intracranial arterial stenosis in patients with acute cerebral ischemia. Methods. The authors prospectively identifie d 120 consecutive patients admitted with acute ischemic stroke and performe d both TCCS and MRA with a mean interval of 1 day. TCCS data (sampling dept h, peak systolic and end diastolic angle-corrected velocity, mean angle-cor rected velocity, and pulsatility index) for middle cerebral arteries (MCAs) were compared to MRA data and classified into 4 grades: normal (grade 1): normal caliber and signal; mild stenosis (grade 2): irregular lumen with re duced signal; severe stenosis (grade 3): absent signal in the stenotic segm ent (flow gap) and reconstituted distal signal; and possible occlusion (gra de 4): absent signal. The cutoffs were chosen to maximize diagnostic accura cy. Results. Interobserver agreement for MRA grading resulted in a weighted -kappa value of 0.776. The rate of poor temporal window was 37% (89/240). D oppler signals were obtained in 135 vessels, and the angle-corrected veloci ties (peak systolic, end diastolic, mean) were significantly different (P = .001, P = .006, and P < .001) among the MRA grades: grade 1 (100, 47, 68 c m/s), grade 2 (171, 72, 110 cm/s), grade 3 (226, 79, 134 cm/s), grade 4 (61 , 26, 39 cm/s). Additionally, an angle-corrected MCA peak systolic velocity greater than or equal to 120 cm/s correlates with intracranial stenosis on MRA (grade 2 or worse) with high specificity (90.5%; 95% confidence interv al = 78.5%similar to 96.8%) and positive predictive value (93.9%) but relat ively low sensitivity (66.7%; 95% confidence interval = 61.2%similar to 69. 5%) and negative predictive value (55.1%). Conclusion. Elevated MCA velocit ies on TCCS correlate with intracranial stenosis detected on MRA. An angle- corrected peak systolic velocity greater than or equal to 120 cm/s is highl y specific for detecting intracranial stenosis as defined by significant MR A abnormality.