TRANSCRANIAL DUPLEX ULTRASOUND - EXPERIENCE WITH CONTRAST ENHANCING AGENTS

Transcranial duplex real time sonography (TCCS) is a noninvasive imagi ng modality that allows repetitive examinations of central nervous sys tem vascular and parenchymal anatomy; a broad spectrum of cerebral pat hology may be disclosed: vascular changes include ischemic and hemorrh agic stroke, arteriosclerotic vascular degeneration, arteno-venous mal formations and aneurysms, as well as neoplastic and degenerative paren chymal disorders. Imaging was performed with a duplex ultrasound syste m, employing a 2.25 resp. 2.0 MHz phased-array transducer. imaging was achieved through the acoustic bone window of the temporal bone and th rough the foramen magnum. For three-dimensional image reconstruction a mechanical position sensor and online video grabbing was applied. To evaluate the potential of a transpulmonary stable ultrasound contrast enhancing agent we used galactose-based SH U 508 A (Levovist, Schering , Berlin) with 1 to 6 i.v. injections per patient in a phase 2/3 clini cal protocol. The signal to noise ratio is significantly improved; the Doppler signal intensity is increased by approx. 25 dB. Levovist was well tolerated and no adverse events occurred, approx. 30% of patients had a sensation of heat and slight pain at the injection site during and shortly after the injection. with the increase in signal intensity , the complete circle of Willis, the peripheral arterial branches, the vertebrobasilar system and the basal venous system may be depicted. I n addition, tumour parenchyma vascularisation may be detected, as well as improved delineation of arteriovenous malformations and aneurysms. Three dimensional image reconstruction may represent a novel option i n contrast enhanced transcranial duplex imaging including additional i nformation about 3D structure and continuity.