Fluorescence spectroscopy measurements in ultrasonic navigated resection of malignant brain tumors.
OBJECTIVE
Glioblastoma multiforme is a highly malignant primary brain tumor. It has no border but at best a marginal zone, however, invisible to the surgeon. An optical touch pointer (OTP) enabling differentiation of healthy and tumor tissue by means of fiber-optic fluorescence spectroscopy has been developed. In combination with an ultrasonic navigation system, the OTP may be used for demarcation of resectable tumor tissue. The aim of the study was to evaluate the clinical performance of OTP during surgery of malignant brain tumors.


METHODS
Nine patients were operated on with the standard surgical procedure, including white light microscopy and navigation. A total of 5 mg/kg bodyweight of 5-amino-levulin acid was orally administrated before surgery. The OTP was calibrated into the ultrasound-based navigation system and measurements were performed in tumor core and along the tumor border. The ratio between the protoporphyrin IX fluorescence at 635 nm and the autofluorescence was used for quantifications of data. Biopsies (n = 20), ultrasound images (n = 30), and visual inspection (n = 180) were compared to the fluorescence ratio.


CONCLUSIONS
Healthy and tumor tissue could be identified and differentiated with the OTP (P < 0.001). The fluorescence ratio in average was 0 outside the tumor and low in the gliotic edema zone around the tumor. It increased in the marginal zone and was highest in the solid tumor tissue. In the necrotic tissue, in the center of the tumor, the ratio in average was 0. The OTP can be used in combination with ultrasound-based navigation and may help to determine whether to resect otherwise not identifiable tissue.
Department of Biomedical Engineering, Linköping University, Linköping 58185, Sweden. johan.richter@lio.se
Johan C O
JC
Richter
Neda
N
Haj-Hosseini
Stefan
S
Andersson-Engel
Karin
K
Wårdell
D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013050:Spectrometry, Fluorescence; D018084:Ultrasonography, Interventional