Fig. 2

a–e Pathology procedure. First, by referring to MRI (a), the surgical specimen was oriented according to the in vivo geometry, and the colored edges indicate the direction of the specimen in the brain (b). Afterward, the fixed specimen was sectioned consecutively at approximately 3 mm intervals (c), which ensured that each specimen slice matched the MRI slice (d). Finally, the tissue specimen was selected for H&E (e). f Histologic features of areas surrounding the glioma: An atypical cell with a moderately irregular nucleus suspected of neoplasia (arrow) is shown. g H&E staining cross-Sect. (5 × magnification) shows a wide view of the specimen tissue section with the tumor outlined in white. Magnified H&E view (10 × magnification) shows invasive glioma cells (outlined in red) outside the boundary (B) of the tumor (T). The ME (Euclidean) distance from the edge of the tumor (*) to the microscopic tumor cells surrounding brain tissue was measured (yellow line)