Artikel
Contrast-enhanced harmonic imaging sonography: A method for intraoperative relative cerebral blood flow measurement
Kontrastmittelverstärkter Harmonic-imaging-Ultraschall: eine Methode zur Messung des relativen zerebralen Blutflusses
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Autoren
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Christine Lindner
- Neurochirurgische Klinik der Universität Würzburg, Würzburg
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J. Broscheit
- Anästhesiologische Klinik der Universität Würzburg, Würzburg
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M. Woydt
- Neurochirurgische Klinik der Universität Würzburg, Würzburg
| Veröffentlicht: | 23. April 2004 |
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Gliederung
Text
Objective
Different new ultrasound techniques are available to measure tissue perfusion. Ultrasound has the capability to be used intraoperatively and scanning a wide area of brain tissue. Therefore this study evaluates CE HI (=contrast-enhanced harmonic imaging) ultrasound to measure relative cerebral blood flow (=rCBF) intraoperatively in an animal model.
Methods
5 adult sheep were craniotomized , two Laser-Doppler-Flow (=LDF) probes and a linear 7.5MHz ultrasound probe were placed on the dura. During normoventilation 4 times 2ml of undiluted Sonovue® (Bracco) were infused as a bolus via a femoral venous catheter with and without occlusion of the carotid arteries. Additionally 4 sheep were hypoventilated. Relative cerebral blood flow was calculated in different regions-of-interest by using time-intensity-curves. Due to the low ultrasound energy in this method, no CE destruction occurred. The area-under-the-curve (=AUC) intensity gives the relative cerebral blood volume (=rCBV) which was divided by the time gap between the 50% maximum intensity during in- and outflow giving the mean transit time (=MTT) [rCBF=rCBV / MTT]. Inter- and intraobserver varibility, changes of rCBF during carotid occlusion, reperfusion and hypoventilation were calculated and correlated to LDF for both hemispheres.
Results
During carotid occlusion, a significant reduction of rCBF was found for the left hemisphere (p<0,05) and significant increase in rCBF (p<0,05) for reperfusion for both sides in the paired t-test. During hypoventilation we found a significant increasing of rCBF (p<0,05) for both hemispheres. Good correlation to flow measurements in LDF was found.
Conclusions
Perfusion measurement with contrast-enhanced HI ultrasound proved to be a method for calculation of rCBF during different perfusion stages, which can be used during operation.
