Article
Vibrography during brain tumour surgery - a new intraoperative imaging method?
Vibrographie bei Hirntumoroperationen - eine neue intraoperative Bildgebung?
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Authors
Published: | May 4, 2005 |
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Outline
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Objective
Elastography is a new method in tumour diagnostics especially in prostate or breast cancer. After experimental work with swine brains we transferred this real time imaging technique to the human brain during open neurosurgery according to the requirements of the ethic commission of the Ruhr-University Bochum.
Methods
We used a conventional ultrasound system (Siemens Sonoline Omnia) with additional hard and software components for vibrography. Using this new approach the conventional static tissue compression was replaced by low frequency vibration operating in quasi static compression mode. The strain imaging system uses the fast phase root algorithm for strain estimation with ca. 40 Hz. Strain images are frame-to-frame filtered by an adaptive temporal filter which enables the use of an up to 50% smaller compression of the tissue achieving the same image quality as with the conventional frame-to-frame filters. Ultrasound rf-data was acquired using the system described above and a 6.5 MHz endocavity curved array. Two different holding devices were used and compared for ergonomic aspects: a very rigid tripod and a pneumatic holding device (Aesculap).
Results
The study demonstrated that with a total compression of only 0.3 mm, high quality strain images can be produced. Intracranial tumours with different histologies were detectable in 38 out of 40 tumours. Three major tumour groups of different strain (low, intermediate and high) in relation to normal brain tissue could be differentiated, The images were compared to conventional ultrasound and preoperative MRI. 2 very inhomogeneous tumours could not be allocated to one of theses groups. For detection of tumour remnants in the margin of resection cavities, the method has to be adapted because direct tissue contact is required for vibrography.
Conclusions
Elastography and its modification vibrography are new online imaging techniques which can be used in addition to conventional ultrasound in brain tumour surgery. Further studies are needed to improve image quality. In future investigations fusion with MRI-data for neuronavigation will be achieved. A project of the Ruhr Centre of Competence for Medical Engineering (KMR).
Supported by the Federal Ministry of Education and Research, No. 13N8079