ESTRO 2024 - Abstract Book

S3909

Physics - Image acquisition and processing

ESTRO 2024

For all but one patient the CC was segmented in three sagittal mid-plane images. CC was chosen since it is one of the major parts of white matter, not affected by surgery. The area/number of voxels in the segmentation was extracted as well as the quantitative myelin concentration in each voxel. Histograms of the myelin concentration were calculated as a mean for three different groups including; (i) healthy volunteers, (ii) non-irradiated brain tumor patients and (iii) irradiated brain tumor patients. The mean value of myelin concentration was also calculated.

Results:

The total volume of myelin calculated by SyMRI, was lower in the brain tumor group compared with healthy volunteers. The volumes are shown in Table 1.

The CC received in general the prescribed dose of either 23.4 Gy or 24.0 Gy. For two patients, part of the CC received up to 50 Gy, depending on the boost volume location.

Fewer pixels were segmented for the CC for the irradiated patients than for the non-irradiated, and both were significantly (p-value <0.05) smaller than in the healthy controls. The mean value of myelin concentration was lower in the patient group, although not significantly, shown in Table 1. In Figure 1 the distribution of myelin is shown, normalized to the size of the segmented volume.

Non irradiated brain tumors

Irradiated brain tumors

Healthy controls

p-value

p-value

Myelin volume in whole brain [ml]

166

159

0.3

145

0.08

Number voxels segmented, corpus callosum of

1320

1134

0.03

988

<0.01

Mean value of myelin concentration in corpus callosum [%]

31.4

30.6

0.27

30.3

0.19