Optical Brain Biopsy with a Fluorescence and Vessel Tracing Probe

Abstract

BACKGROUND Accurate stereotactic biopsies of brain tumors are imperative for diagnosis and tailoring of the therapy. Repetitive needle insertions enhance risks of brain lesioning, hemorrhage, and complications due to prolonged procedure. OBJECTIVE To investigate clinical benefits of a combined 5-aminolaevulinic acid (5-ALA) fluorescence and laser Doppler flowmetry system for the detection of malignant brain tumor and blood vessels in stereotactic biopsies. METHODS Planning of targets and trajectories was followed by optical measurements in 20 patients, using the Leksell Stereotactic System and a manual insertion device. Fluorescence spectra, microvascular blood flow, and tissue grayness were recorded each millimeter along the paths. Biopsies were taken at preplanned positions. The diagnoses were compared with the fluorescence signals. The recordings were plotted against measurement positions and compared. Sites indicating a risk of hemorrhage were counted as well as the time for the procedures. RESULTS Signals were recorded along 28 trajectories, and 78 biopsies were collected. The final diagnosis showed 17 glioblastomas, 2 lymphomas, and 1 astrocytoma grade III. Fluorescence was seen along 23 of the paths with 4 having the peak of 5-ALA fluorescence 3 mm or more from the precalculated target. There was increased microcirculation in 40 of 905 measured positions. The measurement time for each trajectory was 5 to 10 min. CONCLUSION The probe provided direct feedback of increased blood flow along the trajectory and of malignant tissue in the vicinity of the target. The method can increase the precision and the safety of the biopsy procedure and reduce time.

5-ALA fluorescence in randomly selected pediatric brain tumors assessed by spectroscopy and surgical microscope

“…Observation of fluorescence in the surgical microscope is a subjective finding depending on the experience of the surgeon. Measurements with the spectroscopic system in vivo and on multiple tissue samples provide an objective and, in our view, accurate assessment of true fluorescence [16,18,33,34] as the fluorescence intensity can be quantified. Furthermore, fluorescence in the skin was observed only in the three oldest patients in contrast to our previous findings in adults where approximately 95% had PpIX fluorescence on the forearm after receiving 5-ALA 20 mg/kg [17].…”

“…Observation of fluorescence in the surgical microscope is a subjective finding depending on the experience of the surgeon. Measurements with the spectroscopic system in vivo and on multiple tissue samples provide an objective and, in our view, accurate assessment of true fluorescence [ 16 , 18 , 33 , 34 ] as the fluorescence intensity can be quantified.…”

Deep Brain Stimulation: Emerging Tools for Simulation, Data Analysis, and Visualization

“…In addition, more than five times higher blood flow was found in 2.2% of the anatomical spots, a number closely related to documented hemorrhage incidents when using MER ( Tonge et al, 2015 ). LDF alone ( Zsigmond et al, 2017 ) or in combination with MER and stimulation features in one probe ( Wårdell et al, 2019 ) has a potential to identify high-risk regions (“vessel alarm”) during DBS implantations in a similar manner as fluorescence and LDF measurements during stereotactic brain tumor biopsies ( Richter et al, 2021 ).…”

Advances, technological innovations, and future prospects in stereotactic brain biopsies

“…Similarly, in a study published in 2021, Richter et al used a forward-looking probe to get direct feedback on PpIX fluorescence and blood flow detection on 20 stereotactic biopsies [ 54 ]. With this tool, they expect to shorten the time for the procedure, improve the diagnostic yield, and reduce the risk of bleeding complications.…”