CONTRAST-ENHANCED TRANSCRANIAL DOPPLER US WITH A NEW TRANSPULMONARY ECHO CONTRAST AGENT BASED ON SACCHARIDE MICROPARTICLES

The purpose of this first patient study (phase II) was to evaluate the clinical usefulness of a new echo contrast agent at transcranial Dopp ler ultrasonography (US). Twenty patients were selected from a group o f 242 patients undergoing conventional transcranial Doppler US who had low (n = 18) or absent (n = 2) Doppler signals from the middle cerebr al artery (MCA). The extent and duration of Doppler signal increase wa s measured in 30 MCAs and in 14 basilar arteries following the intrave nous injection of a transpulmonary galactose microparticle suspension (SH U 508 A) at three concentrations (200, 300, and 400 mg/mL). Dopple r waveform analysis became possible in 93% (28 of 30) of the MCAs foll owing injection. The maximal increase in average Doppler signal intens ity (11 dB at 200 mg/mL, 15 dB at 300 mg/mL, and 17 dB at 400 mg/mL) a nd the increase in average duration of the signal enhancement (163 sec onds at 200 mg/mL, 219 seconds at 300 mg/mL, and 240 seconds at 400 mg /mL) depended on contrast agent concentration. Doppler waveform analys is became possible in 79% (11 of 14) of the basilar arteries. The intr avenous injection of this new echo contrast agent markedly increases D oppler signal intensity in patients with nondiagnostic results at conv entional Doppler US.