Artikel
Advantages and pitfalls in the use of intraoperative ultrasound for the resection of brain tumours
Vorteile und Fallstricke in der Anwendung des intraoperativen Ultraschalls bei der Resektion von Hirntumoren
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Autoren
Veröffentlicht: | 23. April 2004 |
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Gliederung
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Objective
Intraoperative ultrasound (IOUS) is widely excepted as a fast and cost effective tool, enabling a save localization and good control of tumour removal, when applied in the context of brain tumour resection. Different from technically more sophisticated neuronavigation tools, the brain shift is not an issue due to the real-time modus of the technique. Whereas its general usefulness is undisputed, for the inexperienced user some findings can be easily misinterpreted.
Methods
Since 1997 in more than 2000 cases IOUS investigations have been performed where sonographic characteristics of primary and secondary brain tumours have been analysed and in particular technical pitfalls have been minimized over time. Accelerating the learning curve IOUS findings were frequently correlated to postoperative MR-images.
Results
Blood, microbubbles, artefacts and hypervascularization of the tumour resection zone frequently render difficulties in diagnosing residual tumour. Complete tumour resection will be only reached when careful IOUS investigations are performed prior to and repeated during the surgical procedures, tumour margins are related to the anatomic landmarks, adequate frequency probes are used and artefacts due to haemostatic agents, retractors, blood and air bubbles are avoided. However peritumoral oedema still remains as a diagnostic pitfall as it may not be easily differentiated from tumour infiltration zone. Postoperative MR-imaging helps to better interpret sonographic findings and should therefore be performed to enhance the diagnostic safety of IOUS.
Conclusions
Depending on the resolution of the ultrasound system sonographic characteristics of intracerebral and even spinal pathologies may be defined supplementing the diagnostic preoperative toolbox. With a reasonable amount of training in using IOUS (about 50-100 investigations) one may reliably localize and control the resection of brain tumours thereby increasing the safety of the surgical procedure, especially for trainees.