Correlation of the biopsy point on the MTRasym image and the ADC image with histology and semi-automatic cell counting.

A) Target point T of the biopsy trajectory on the intraoperative CE-T1 image of a 45-year-old male with glioblastoma (patient 15). It lies in the contrast-enhancing area. Marks of the stereotactic biopsy ring are visible frontally and occipitally. B) Target point T on the ADC image which was coregistered to the intraoperative CE-T1 image in MITK with an automatic multi modal rigid registration algorithm. The average ADC value of 3x3x3 voxels (= 27mm³) was read out to account for possible inaccuracies in coregistration and biopsy sampling. In the shown example, it yielded ADC = 659mm²/s. C) Target point T on the MTR_asym image which was coregistered to the intraoperative CE-T1 image in MITK with an automatic multi modal rigid registration algorithm. The average MTR_asym value of 3x3x3 voxels (= 27mm³) was read out to account for possible inaccuracies in coregistration and biopsy sampling. In the shown example, it yielded MTR_asym = -1,72% D) Corresponding slice of the 1 mm³ biopsy specimen (HE stain) in x20 magnification obtained at the target point T. E) Exemplary section to illustrate semi-automatic cell counting with the ImageJ plugin ITCN. Tumor cells that were recognized by the algorithm are marked red. Overall cell density of the shown biopsy specimen was 1684 cells/mm².