Transcranial duplex ultrasound: experience with contrast enhancing agents

Area of Science:

• Neurology
• Medical Imaging
• Ultrasound Technology

Background:

• Transcranial duplex real time sonography (TCCS) is a non-invasive method for examining central nervous system vascular and parenchymal anatomy.
• It can reveal a wide range of cerebral pathologies, including stroke, vascular degeneration, malformations, aneurysms, and neoplastic disorders.

Purpose of the Study:

• To evaluate the efficacy of a transpulmonary stable ultrasound contrast agent, galactose-based SH U 508 A (Levovist), in enhancing TCCS imaging.
• To assess improvements in signal-to-noise ratio and Doppler signal intensity for better depiction of cerebral structures.

Main Methods:

• Utilized a duplex ultrasound system with phased-array transducers (2.25/2.0 MHz) for TCCS.
• Administered Levovist via 1 to 6 intravenous injections per patient in a phase 2/3 clinical protocol.
• Employed a mechanical position sensor and online video grabbing for three-dimensional (3D) image reconstruction.

Main Results:

• Levovist significantly improved the signal-to-noise ratio and increased Doppler signal intensity by approximately 25 dB.
• The contrast agent was well-tolerated, with minor side effects like heat sensation or injection site pain in about 30% of patients.
• Enhanced imaging allowed for improved visualization of the circle of Willis, peripheral arteries, vertebro-basilar system, basal veins, tumor vascularization, and delineation of AVMs and aneurysms.

Conclusions:

• Contrast-enhanced TCCS with Levovist offers improved diagnostic capabilities for cerebrovascular and parenchymal diseases.
• The enhanced signal intensity facilitates detailed visualization of complex vascular structures and pathologies.
• 3D image reconstruction in contrast-enhanced TCCS presents a novel option for assessing 3D structure and continuity.