Hyperspectral Imaging for Glioma Biopsy Analysis

We analyzed 240 biopsies obtained from a cohort of 26 patients undergoing surgery for lesions suspicious of HGG (Table 1) using two different imaging devices: the surgical microscope KINEVO 900 and a modified OPMI pico microscope (Fig. 2) for HI. We here evaluate the hyperspectral data using a sample cohort, of which primary data was published in part earlier³⁰ .Table 1

Overview of the patient cohort³⁰ . Patients and biopsies were classified according to 2016 World Health Organization (WHO) criteria^{43 (link)} (isocitrate dehydrogenase (IDH) mutant or wild type, O⁶-methylguanine-DNA-methyltransferase (MGMT) positive/methylated or negative/not-methylated) and according to the standardized performance score by the Eastern Cooperative Oncology Group (ECOG)^{44 (link)}.

		Patients	%	Biopsies	%
Number		26		240
Gender	Male	17	65	159	66
	Female	9	35	81	34
Age	Mean (SD), Range	60.8 ± 9.5, 37—75
Histology	Anaplastic astrocytoma IDH-mutant, MGMT positive	1	4	10	4
	Glioblastoma IDH-wild type, MGMT positive	13	50	124	52
	Glioblastoma IDH-wild type, MGMT negative	10	38	86	36
	Glioblastoma IDH-mutant, MGMT positive	2	8	20	8
ECOG score	1	16	62	144	60
	2	10	38	96	40
Primary tumor		16	62	150	63
Recurrent tumor		10	38	90	37

A standard dose of 20 mg/kg of 5-ALA (Gliolan®, medac, Wedel, Germany) was orally administered four hours before induction of anesthesia. Biopsies were collected from the non-contrast enhancing, FLAIR positive, infiltrative tumor margins during surgery. Nine biopsies were taken on average per patient (average: 9.2 ± 1.5; range: 5–10 biopsies per patient). The fluorescence quality in the surgical microscope was rated by an experienced neurosurgeon in the categories “none”, “weak”, and “strong” as described previously^{17 (link)}.
Methods were carried out in accordance with relevant guidelines and regulations. All experiments were approved by the local ethics committee of the University of Münster (2020-644-f-S) and informed consent was obtained from all patients.