Current Trends for Improving Safety of Stereotactic Brain Biopsies: Advanced Optical Methods for Vessel Avoidance and Tumor Detection

Abstract

Stereotactic brain needle biopsies are indicated for deep-seated or multiple brain lesions and for patients with poor prognosis in whom the risks of resection outweigh the potential outcome benefits. The main goal of such procedures is not to improve the resection extent but to safely acquire viable tissue representative of the lesion for further comprehensive histological, immunohistochemical, and molecular analyses. Herein, we review advanced optical techniques for improvement of safety and efficacy of stereotactic needle biopsy procedures. These technologies are aimed at three main areas of improvement: (1) avoidance of vessel injury, (2) guidance for biopsy acquisition of the viable diagnostic tissue, and (3) methods for rapid intraoperative assessment of stereotactic biopsy specimens. The recent technological developments in stereotactic biopsy probe design include the incorporation of fluorescence imaging, spectroscopy, and label-free imaging techniques. The future advancements of stereotactic biopsy procedures in neuro-oncology include the incorporation of optical probes for real-time vessel detection along and around the biopsy needle trajectory and in vivo confirmation of the diagnostic tumor tissue prior to sample acquisition.

Keywords: 5-aminolevulinic acid; biopsy; fluorescein sodium; fluorescence; optical; spectroscopy; stereotactic.

Figure 1

Examples of the optical technologies for brain needle biopsies. (A) Images from the fluorescence optical needle endoscope described by Göbel et al. (22) for PpIX visualization in the tumor (left column) and vessel visualization using ICG (right column) in a mouse model. Adapted with permission from Göbel et al. (22)^© The Optical Society. (B) Illustration of PpIX spectroscopy method for tumor detection during stereotactic biopsy described by Haj-Hosseini et al. (28). The top two panels show the probe positioned in the stereotactic frame and the concept of measurements along the trajectory. The bottom panels show an MR image with calculated targets, spectral data of PpIX along the injection trajectory, and the histopathology slide of the target. Adapted with permission from Haj-Hosseini et al. (28)^© The Optical Society. (C) Stain-less reflectance imaging method from Ramakonar et al. (27). Left panel shows a photo of an imaging needle rolled over a vessel of 650 μm. The imaging window of the probe is not visible and is facing toward the tissue. The upper right panel displays OCT B-scan consisting of A-scans. The tissue surface corresponds to the top of the image. Depth increases going down the image. The bottom right panel displays a speckle decorrelation image calculated form the OCT scan with high decorrelation as white and low decorrelation as dark red. Adapted from Ramakonar et al. (27) under Creative Commons Attribution license. (D) Schematic summary of advanced optical methods and tool designs, for increasing safety of stereotactic brain biopsies. OCT, optical coherence tomography; PpIX, protoporphyrin IX; ICG, indocyanine green; SRH, Stimulated Raman Histology.