Article
Ultrasonic radio-frequency spectrum analysis of the brain: a possible tool for intraoperative tissue characterization
Spektralanalyse der Hochfrequenzechodaten von Hirngewebe zur intraoperativen Gewebetypisierung
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Authors
Published: | May 4, 2005 |
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Outline
Text
Objective
Commercially available scanners are modifying the ultrasound signals in order to create uniformly bright pictures using the envelope of the radio-frequency signals only. We present a method and first results of quantitative analysis of the echogenic properties of brain tissue that may lead to intraoperative tissue characterization.
Methods
A commercially available ultrasound scanner (Hitachi CS 9600) was modified in order to obtain the pure radio-frequency signals without any preprocessing. Data were stored on a standard PC. Diffraction correction was done using tissue mimicking reference phantoms and implemented in the spectral analysis. Analytic emphasis was put on frequency dependent attenuation and relative backscatter coefficient using a self-developed routine.
Results
Quantitative data could be obtained from normal parenchyma (n=18), edematous tissue (n=8) and meningiomas (n=12). There was a quantifiable loss of attenuation in meningioma tissue (2.268 dB/cm) compared to edematous tissue (3,065 dB/cm, p=0,014) and normal brain parenchyma (3.971 dB/cm, p=0,0002). Values of relative backscatter coefficient did not show significant differences, possibly due to the attenuation of the overlying tissue.
Conclusions
A method is presented for system independent ultrasonic radio-frequency spectrum analysis of brain tissue. Quantitative determination of the echogenic properties shows significant differences between meningioma and brain tissue and thus may lead to intraoperative tissue characterization, a goal that is not yet reached mainly due to inhomogeneities and sample volume.