Fig 1.
Calculation of the biopsy point S that is located in the enhancing tumor area (CE).
Combination of an axial and a coronal slide of intraoperative cT1 MRI in a 60-year-old patient with glioblastoma. Cranial view. The biopsy point S is marked within the NE-area of the tumor. The trajectory (red line, length: 50.4mm) and the biopsy point S (170/113/37) were calculated via vector analysis in MATLAB from the coordinates of the known entry point E (192/121/54) and the target point T (161/152/30). The distance between S and T was 15.0 mm.
Fig 2.
Correlation of cT1 MRI and histology.
A) Target point T with its coordinates in an axial slide of the intraoperative cT1 MRI of the patient from Fig 1a. It lies in the CE area. B) Corresponding slice of the 1mm3 biopsy specimen (HE stain) in x20 magnification which was classified as “necrosis with cellular component”. This type of histology occurred in 31% of all biopsies originating from CE. C) Calculated biopsy point C with its coordinates in an axial slide of the intraoperative cT1 MRI of an 82-year-old patient with glioblastoma. It lies in the CE area. D) Corresponding slice of the 1mm3 biopsy specimen (HE stain) in x20 magnification which was classified as “viable tumor tissue”. This type of histology occurred in 60% of all biopsies originating from CE. E) Different biopsy point D with its coordinates along the trajectory in the same patient. It lies in the NEC area. F) Corresponding slice of the 1mm3 biopsy specimen (HE stain) in x20 magnification which was classified as “pure necrosis”. This type of histology occurred in 4% of all biopsies originating from NEC.
Fig 3.
Correlation of biopsy point S with histology and semi-automatic cell counting.
A) Biopsy point S is located in the NE area on an axial slide of the intraoperative cT1 MRI. B) Corresponding slice of the 1mm3 biopsy specimen (HE stain) in x20 magnification which was classified as “viable tumor tissue”. This type of histology occurred in 89% of all biopsies originating from NE. C) Example of semi-automatic cell counting with the ImageJ plugin ITCN. Correctly recognized tumor cells are marked red. Yellow dots are falsely detected areas of apoptotic cells or intercellular space.
Table 1.
Biopsy counts by histologic and MRI-based classification.
Fig 4.
Histological composition of the different MRI classifications.
For all 561 biopsy samples, the relative frequency of the different histologic classifications within each MRI classification is displayed. NE = non-enhancing part on cT1; CE = contrast enhancement on cT1; NEC = Necrosis on cT1.
Fig 5.
Boxplots of the cell densities in each MRI compartment.
A) Cell densities for all biopsies (“viable tumor cells”, “necrosis with cellular component”, “pure necrosis”, “blood cells”). B) Cell densities in biopsies with “viable tumor cells” only. NE = non-enhancing part on cT1; CE = contrast enhancement on cT1; NEC = Necrosis on cT1.
Table 2.
Cell densities within MRI classifications.