American Journal of Neuroradiology 28:635-639, April 2007
© 2007 American Society of Neuroradiology
INTERVENTIONAL
Real-Time Cerebral Angiography: Sensitivity of a New Contrast-Specific Ultrasound Technique
a Department of Radiology, University of California San Diego, Calif
b Department of Neurology, University of California San Diego, Calif
c Department of Family & Preventive Medicine, University of California San Diego, Calif
d Department of Neurosciences, University of California San Diego, Calif
e Ruhr Center of Excellence for Medical Engineering, Bochum, Germany
Address correspondence to Thilo Hölscher, MD, Assistant Adjunct Professor, UCSD Medical Center, Department of Radiology, 200 West Arbor Dr, San Diego, CA 92103-8756; e-mail: thoelscher{at}ucsd.edu
BACKGROUND AND PURPOSE: To test a new contrast-specific sonography imaging method that offers visualization of the intracranial vasculature in a manner similar to that seen on angiography.
MATERIALS AND METHODS: Thirty patients (35 sonography studies total) were included in the study after they provided written informed consent. The patients were scanned through the temporal bone window from both sides after intravenous injection of an ultrasound contrast agent (UCA; perflexane lipid microspheres [Imagent]). The goal was to visualize the intracranial arteries, including the middle (M1–M3), anterior (A1 and A2), and posterior (P1–P3) cerebral arteries, using an axial scanning plane. The studies were performed using a contrast-specific imaging mode, based on a phase inversion technique (transcranial ultrasound angiography [tUSA]). For sensitivity, the results were compared with x-ray angiography as the "gold standard." For interobserver reliability, 24 of 35 sonography studies were evaluated by 2 physicians with little training in transcranial sonography and by a seasoned sonographer.
RESULTS: The sensitivity of tUSA ranged between 0.778 (95% confidence interval [CI] of 0.577–0.914) and 0.963 (95% CI of 0.810–0.999). The sensitivities were similar among physicians with little training in transcranial sonography and the seasoned sonographer, indicating high inter-rater reliability. Overall, tUSA provided high anatomic resolution and vascular delineation even of small vessels in the millimeter range. At peak intensity, no UCA-related artifacts were observed.
CONCLUSION: tUSA provides images of the intracranial arteries similar to those obtained at angiography with high anatomic resolution, reasonable sensitivity, and interobserver reliability.