A Combined Power M-mode and Single Gate Transcranial Doppler Ultrasound Microemboli Signal Criteria for Improving Emboli Detection and Reliability

BACKGROUND AND PURPOSE Single gate transcranial Doppler spectrogram (sgTCD) has a high variability in the detection of microembolic signals (MES), Adding Power M-mode Doppler (PMD) information may improve MES detection. Our study's aim is to derive combined PMD/sgTCD microemboli criteria to overcome this limitation. METHODS Patients with symptomatic carotid disease were prospectively enrolled within 24 h of symptom onset underwent 1 hour TCD emboli monitoring. We reviewed disparity between PMD MES criteria and sgTCD MES criteria. We compared combined PMD/sgTCD criteria to sgTCD alone criteria by measuring the intraclass correlation coefficient (ICC). RESULTS Of 92 patients, 28 patients had evidence of MES on sgTCD or PMD. Total MES count was 269 based on sgTCD criteria, and 326 based on combined PMD/sgTCD criteria (P= 0.005). Combined PMD/sgTCD criteria revealed 17 MESs (4.8%) based on sgTCD criteria to represent artifacts and 57 MESs (17.5%) not to be detected by sgTCD criteria. Overall ICC based on sgTCD criteria was 0.67 [95% confidence interval (CI): 0.58–0.74]; however, introducing combined PMD/sgTCD criteria resulted in a significant increase in the ICC, 0.91 (95% CI: 0.88–0.93). CONCLUSION Our combined PMD/sgTCD criteria for MES appeared to improve the yield of MES detection. Reliability in MES detection interpretation was improved when combined PMD/sgTCD criteria was applied.