Reliability of semiquantitative ultrasonic perfusion imaging of the brain.
OBJECTIVE
Contrast burst depletion imaging (CODIM) visualizes cerebral perfusion by destruction of microbubbles and observation of image intensity course. Because of its complexity, artifacts occur. Criteria of reliability to improve diagnostic significance were created and validated.


RESULTS
Eighteen healthy volunteers were examined with 2 echo contrast agents (ECAs) and 3 frame rates in 3 regions of interest (ROIs). Perfusion coefficient (PC), Tmin (time to decrease intensity to 10% of its max), and relative error (RE) (deviation of measured data from fitted model) were determined. PC differed significantly neither between CA nor between frame rates (overall mean = 1.60 +/- 0.21 x 10(-2) s-1). Tmin differed significantly between frame rate groups (P < .001, 33.4 +/- 11.2 s/0.5 Hz; 3.6 +/- 2.5 s/5 Hz) since it is related to destruction of microbubbles that occurs with each frame and to the perfusion rate. RE was higher in the Optison group and tended to decrease in ROIs closer to the probe.


CONCLUSIONS
PC was independent of frame rate and ECA. Tmin was shorter with higher frame rates. Due to a very rapid decay at 5 Hz, the ideal frame rate should be about 1 Hz, that is, because the number of frames acquired within Tmin and therefore signal-to-noise ratio is higher at 1 Hz. Since the algorithm is complex (high RE) and more artifacts should occur in patients (insufficient bone window, etc), a triggering of the insonations by, for example, heart rate could decrease artifacts and increase diagnostic power of CODIM.
Eyding
Jens
J
Department of Neurology, St. Josef University Hospital, Ruhr-University Bochum, Gudrunstr. 56, D-44791 Bochum, Germany. jeyding@web.de
Wilkening
Wilko
W
Reckhardt
Markus
M
Meves
Saskia
S
Postert
Thomas
T
D000328:Adult; D000418:Albumins / Q000493:pharmacokinetics; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000098:blood supply*; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003342:Corpus Striatum / Q000098:blood supply; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D005466:Fluorocarbons / Q000493:pharmacokinetics; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008297:Male; D008432:Mathematical Computing; D045423:Microbubbles; D008875:Middle Aged; D011134:Polysaccharides / Q000493:pharmacokinetics; D012016:Reference Values; D015203:Reproducibility of Results; D013788:Thalamus / Q000098:blood supply; D017585:Ultrasonography, Doppler, Transcranial / Q000295:instrumentation*
D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons; D011134:Polysaccharides; C059891:SHU 508