[Imaging the smallest tumor vessels using color Doppler ultrasound in an experiment].
OBJECTIVE
We present an experimental, statistical approach to estimate the size required for small vessels to become detectable with color Doppler sonography.


METHODS
A murine experimental tumor was examined with color Doppler sonography after injection of 1.5 ml of the contrast medium Levovist. Histologically, we measured vessel diameters inside the tumor as well as other, clearly identifiable locations.


RESULTS
With color Doppler at a transmit frequency of 7 MHz, vessels were only detected in the tumor's environment, but not inside. From the 95% quantiles of the vessel diameter distribution found histologically, we estimate that vessels 80-140 microns in diameter or above may be detectable with color Doppler sonography, while vessels 40 microns in diameter or smaller are indetectable.


CONCLUSIONS
Although a direct sonographic--histologic correlation is impossible for small vessels, a systematic assessment of the size distribution in clearly identifiable regions permits to estimate the sensitivity of color Doppler to detect blood flow in small vessels. According to our results, capillary blood flow is indetectable, and precapillary vessels may be detected only under optimal conditions.
Deutsches Krebsforschungszentrum (DKFZ), Forschungsschwerpunkt Radiologische Diagnostik und Therapie, Heidelberg. s.delorme@dkfz-heidelberg.de
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Delorme
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Peschke
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Zuna
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van Kaick
D000818:Animals; D003287:Contrast Media; D007091:Image Processing, Computer-Assisted; D008297:Male; D008833:Microcirculation / Q000000981:diagnostic imaging*; D009368:Neoplasm Transplantation; D011134:Polysaccharides; D011471:Prostatic Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging; D051381:Rats; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color / Q000379:methods*
D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508