ESTRO 2024 - Abstract Book

S3908

Physics - Image acquisition and processing

ESTRO 2024

Keywords: Generative AI, Diffusion model, CT reconstruction

2274

Digital Poster

Demyelination in white matter after pediatric brain tumor treatment, assessed with quantitative MRI

Anna Ljusberg 1,2 , Per Nyman 1,2,3 , Ida Blystad 2,4 , Emelie Adolfsson 1 , Peter Lundberg 1,2 , Anders Tisell 1,2

1 Department of Medical Radiation Physics, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden. 2 Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden. 3 Crown Princess Victoria's Child and Youth Hospital, and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden. 4 Department of Radiology in Linköping, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden

Purpose/Objective:

Magnetic Resonance Imaging (MRI) is used for diagnosis and follow-up of brain tumors. There are many different kinds of MR-sequences, some focus on qualitative structural properties for visual assessment such as T1- and T2 weighted images, while others are quantitative and are used for calculations and statistical testing. 3DQALAS is a novel relaxometry quantitative MRI (qMRI) method that allows 1.2 mm isotropic resolution with a scan time of 6 min where simultaneous measurements of R1 (1/T1), R2 (1/T2) and proton density are performed (1, 2). Moreover, from the qMRI parameters tissue content such as myelin concentration can be assessed in the brain (3). Radiation therapy is known to affect the surrounding healthy brain tissue and MRI is used to assess these effects. It is known that there is a dose dependent decrease in volume of the corpus callosum (CC) and by using diffusion weighted images (DWI) a decrease has also been observed in fractional anisotropy (FA). The FA measured in white matter, such as the CC, can be correlated to the extent of myelination (4).

The aim of this work is to explore treatment related changes in white matter by using qMRI in children treated for brain tumors.

Material/Methods:

The cohort includes two groups of adolescents at the age of 18. One group consists of healthy volunteers (n=9) and the other of patients that sometime during their childhood have been treated for a brain tumor (n=11). Four patients had radiation therapy, given as 24 Gy in 15 fractions, to a PTV including the ventricles with margins (n=2) or with craniospinal radiotherapy with 23.4 Gy in 13 fractions, with a boost up to 50.6 Gy (n=2). All participants underwent MR-examinations, using the 3DQALAS sequence on a 3 T Prisma MR-scanner (Siemens Healthineers, Germany). Using SyMRI (SynthethicAB, Sweden), synthetic T1W-images were created and myelin concentration maps were calculated.