Fluorescence-guided stereotactic biopsy: a proof-of-concept study

Area of Science:

• Neurosurgery
• Biomedical Engineering
• Optical Imaging

Background:

• Accurate histopathological diagnosis is crucial for neuro-oncology patient treatment.
• Stereotactic biopsy (STB) can fail to obtain diagnostic tissue from deep or eloquent brain regions, delaying treatment.
• Improved methods are needed to increase the diagnostic yield of STB.

Purpose of the Study:

• To determine if in vivo optical imaging coupled with STB can effectively identify diagnostic tissue during biopsy.
• To assess the feasibility of using a fiber optic fluorescence microendoscope with an STB system.

Main Methods:

• A fiber optic fluorescence microendoscope (0.65-mm diameter) was coupled to an STB system.
• Human U251 glioma cells expressing blue fluorescent protein (BFP) were used for in vitro and in vivo experiments.
• Transgenic athymic rats with U251-BFP tumors received fluorescein sodium (FNa) and underwent STB with integrated imaging.

Main Results:

• In vitro and in vivo fluorescence imaging confirmed BFP-expressing tumor cells.
• A strong correlation was found between tumor cells and FNa contrast (R2 = 0.91).
• In vivo FNa fluorescence intensity was significantly higher in tumor regions compared to normal brain (p < 0.001).

Conclusions:

• In vivo fluorescence imaging using a microendoscope integrated into an STB needle can visualize neoplastic tissue in a brain tumor model.
• This technique offers direct visualization prior to biopsy, confirmed by histological assessment.
• In vivo fluorescence guidance holds promise for improving the diagnostic yield of stereotactic biopsies.