Vibrography during tumor neurosurgery.
OBJECTIVE
The aim of this study was to determine whether elastography, a sonographically based real-time strain imaging method for registering the elastic properties of tissue, can be used in brain tumor surgery.


METHODS
A modification of classic elastography called vibrography was applied in these measurements with static compression replaced by low-frequency axial vibration. Twenty patients were examined with this technique during brain tumor surgery. A conventional sonographic system with a custom-designed radio frequency (RF) interface was used. The RF data were digitized with a 50-MHz, 12-bit peripheral component interconnect analog/digital converter for real-time or offline processing. Sonographic RF data were acquired with a 6.5-MHz endocavity curved array. A special applicator equipped with a stepping motor moved the ultrasonic probe and produced a low-frequency mechanical vibration of approximately 5 to 10 Hz with a vibration amplitude of 0.3 mm.


RESULTS
Detection of tumors was possible in 18 of 20 cases. Brain tissue was normally color coded orange or red. Three major groups of tumors with different elastic properties relative to brain tissue could be differentiated. In 3 cases, the stiffness of the tumor was identical to that of brain tissue, but the tumors were surrounded by a thin yellow border. Six tumors displayed higher strain than brain, whereas 7 tumors exhibited lower strain than the surrounding cerebrum. Two patients could not be assigned clearly to either of these groups.


CONCLUSIONS
These findings indicate that vibrography is a feasible imaging method for brain tumor surgery and may have numerous potential applications in neurosurgery if further improvements are made.
Scholz
Martin
M
Department of Neurosurgery, Ruhr University Bochum, In der Schornau 23-25, 44892 Bochum, Germany. martin.scholz@ruhr-uni-bochum.de
Noack
Volker
V
Pechlivanis
Ioannis
I
Engelhardt
Martin
M
Fricke
Britta
B
Linstedt
Ulf
U
Brendel
Bernhard
B
Ing
Dipl
D
Schmieder
Kirsten
K
Ermert
Helmut
H
Harders
Albrecht
A
D000328:Adult; D000368:Aged; D000465:Algorithms; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery; D004453:Echoencephalography / Q000379:methods*; D004548:Elasticity; D005240:Feasibility Studies; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D038361:Neuronavigation / Q000379:methods; D019635:Neurosurgical Procedures / Q000295:instrumentation* / Q000379:methods; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods; D018084:Ultrasonography, Interventional / Q000379:methods; D014732:Vibration