Echo contrast-enhanced transcranial ultrasound: frequency of use, diagnostic benefit, and validity of results compared with MRA.

Abstract

The present study was undertaken to determine the frequency of use of the ultrasound contrast agent (UCA) Levovist in routine transcranial ultrasound (TU). Additionally, we evaluated the diagnostic validity of contrast-enhanced TU using 3-dimensional time of flight MR angiography. Indication for the UCA was an insufficient evaluation of the intracranial arteries after a combined approach with transcranial color-coded Duplex and transcranial Doppler examination. We prospectively analyzed every patient referred for TU over 6 months. Additionally, over a 3-month period, TU results were compared with 3-dimensional time-of-flight MR angiography. Indication for use of UCA was met in 61 of 687 patients (8.8%). After UCA application, a diagnostic result was achieved in 75% of cases during transtemporal and in 81% during transforaminal insonation. The sensitivity and specificity of TU in the diagnosis of intracranial stenosis were 83% and 82%, respectively. Use of UCA was necessary in 8.8% of the patients. A diagnostic benefit was achieved in 75% to 80% of cases. Contrast-enhanced TU demonstrated a high sensitivity and specificity in the diagnosis of intracranial stenosis.