Improvement of diffusion weighted MRI by practical B0 homogenization for head & neck cancer patients undergoing radiation therapy.
Phys Med
; 97: 59-65, 2022 May.
Article
em En
| MEDLINE
| ID: mdl-35413606
ABSTRACT
BACKGROUND:
MRI is a frequently used tool in radiation therapy planning. For MR-based tumor segmentation, diffusion weighted imaging plays a major role, which can fail due to excessive image artifacts for head and neck cancer imaging. Here, an easy-to-use setup is presented for imaging of head and neck cancer patients in a radiotherapy thermoplastic fixation mask.METHODS:
In a prospective head and neck cancer study, MRI data of 29 patients has been acquired at 3 different time points during radiation treatment. The data was analyzed with respect to Nyquist ghosting artifacts in the diffusion images in conventional single shot and readout segmented EPI sequences. For 9 patients, an improved setup with water bags for B0 homogenization was used, and the impact on artifact frequency was analyzed. Additionally, volunteer measurements with B0 fieldmaps are presented.RESULTS:
The placement of water bags to the sides of the head during MRI measurements significantly reduces artefacts in diffusion MRI. The number of artifact-free images in readout segmented EPI increased from 74% to 95% of the cases. Volunteer measurements showed a significant increase in B0 homogeneity across slices (head foot direction) as well as within each slice.CONCLUSIONS:
The placement of water bags for B0 homogenization is easy to implement, cost-efficient and does not impact patient comfort. Therefore, if very sophisticated soft- or hardware solutions are not present at a given site, or cannot be implemented due to restrictions from the thermoplastic mask, this is an excellent alternative to reduce artifacts in diffusion weighted imaging.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Imagem Ecoplanar
/
Neoplasias de Cabeça e Pescoço
Tipo de estudo:
Clinical_trials
/
Observational_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article