Diffuse reflectance spectroscopy sensor to differentiate between glial tumor and healthy brain tissue: a proof-of-concept study

Abstract

Glial tumors grow diffusely in the brain. Survival is correlated to the extent of tumor removal, but tumor borders are often invisible. Resection beyond the borders as defined by conventional methods may further improve prognosis. In this proof-of-concept study, we evaluate diffuse reflectance spectroscopy (DRS) for discrimination between glial tumors and normal brain ex vivo. DRS spectra and histology were acquired from 22 tumor samples and nine brain tissue samples retrieved from 30 patients. The content of biological chromophores and scattering features were estimated by fitting a model derived from diffusion theory to the DRS spectra. DRS parameters differed significantly between tumor and normal brain tissue. Classification using random forest yielded a sensitivity and specificity for the detection of low-grade gliomas of 82.0% and 82.7%, respectively, and the area under curve (AUC) was 0.91. Applied in a hand-held probe or biopsy needle, DRS has the potential to provide intra-operative tissue analysis.

In situ detection of human glioma based on tissue optical properties using diffuse reflectance spectroscopy

“…The GBDT classifier could achieve a sensitivity of 93% and specificity of 95% for discriminating HGG from NW. Nonetheless, this model did not perform as well for discriminating LGG from NG (sensitivity = 71%, specificity = 75%, accuracy = 73%), which is also in line with the previous studies [26, 28].…”

“…The results could not be directly comparable with ours because these studies combined the DRS with fluorescence and(or) Raman spectroscopy [20–27]. One recent study evaluated DRS alone for detection of LGG with a sensitivity and specificity of 82% and 82.7%, respectively [28]. However, in their study, the included patients with glioma received the preoperative administration of 5‐ALA, which may produce fluorescent agent PpIX in the brain tissue, possibly affecting the DRS spectra acquired [28].…”

“…One recent study evaluated DRS alone for detection of LGG with a sensitivity and specificity of 82% and 82.7%, respectively [28]. However, in their study, the included patients with glioma received the preoperative administration of 5‐ALA, which may produce fluorescent agent PpIX in the brain tissue, possibly affecting the DRS spectra acquired [28]. Additionally, normal brain and tumor samples were collected from different individuals [28].…”

“…However, in their study, the included patients with glioma received the preoperative administration of 5‐ALA, which may produce fluorescent agent PpIX in the brain tissue, possibly affecting the DRS spectra acquired [28]. Additionally, normal brain and tumor samples were collected from different individuals [28]. Unlike their study, in our study, both normal and brain cancer tissues were collected from the same individuals, eliminating inter‐individual variation.…”

“…Previous research has demonstrated that a DRS instrument can conduct label-free detection for diagnostics of cancer, including breast cancer [13,14], colorectal cancer [18], pancreatic cancers [19], and so forth. Several studies have attempted to use DRS integrated with a fiberoptic probe to differentiate between brain cancer and noncancer tissues, demonstrating the great potential of DRS for brain surgery guidance [20][21][22][23][24][25][26][27][28]. DRS has also been shown to monitor cerebral BVF and StO 2 in freely moving mice with glioma models [29].…”