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Tensor-Valued Diffusion MRI for Microstructural Assessment During Stereotactic Radiotherapy of Brain Metastases : A Feasibility Study

Lerner, Minna LU ; Brynolfsson, Patrik LU orcid ; Szczepankiewicz, Filip LU orcid ; Medin, Joakim LU ; Sundgren, Pia C LU orcid ; Olsson, Lars E LU orcid and Alkner, Sara LU (2026) In Tomography 12(5).
Abstract

OBJECTIVES: Early identification of treatment response in brain metastases remains clinically challenging. This study explores tensor-valued diffusion MRI (dMRI), specifically q-space trajectory imaging (QTI), as a novel source of early imaging biomarkers during stereotactic radiotherapy (SRT).

METHODS: Twenty-six patients with brain metastases were enrolled; thirteen met quality and completeness criteria for QTI analysis (10 responders, three non-responders). MRI was acquired at four time points: before SRT, before final SRT fraction, and at 3 and 6 months post-SRT. QTI-derived metrics included mean diffusivity (MD), fractional anisotropy (FA), microscopic FA (µFA), and isotropic (MKI) and anisotropic (MKA) diffusional variance.... (More)

OBJECTIVES: Early identification of treatment response in brain metastases remains clinically challenging. This study explores tensor-valued diffusion MRI (dMRI), specifically q-space trajectory imaging (QTI), as a novel source of early imaging biomarkers during stereotactic radiotherapy (SRT).

METHODS: Twenty-six patients with brain metastases were enrolled; thirteen met quality and completeness criteria for QTI analysis (10 responders, three non-responders). MRI was acquired at four time points: before SRT, before final SRT fraction, and at 3 and 6 months post-SRT. QTI-derived metrics included mean diffusivity (MD), fractional anisotropy (FA), microscopic FA (µFA), and isotropic (MKI) and anisotropic (MKA) diffusional variance. Parameter values within the tumour volume were compared pre- and during SRT and correlated with treatment response from standard MRI follow-up. Overall survival was assessed using Kaplan-Meier analysis.

RESULTS: Median survival was 12 months. QTI analysis was feasible with visible changes in the tumour tissue parameter maps over time. Statistically significant differences (p < 0.05) were found between responders and non-responders in FA before treatment. MKI in responders was significantly lower (p < 0.05) during SRT than before.

CONCLUSIONS: This study presents a first exploration of QTI-derived parameters in a cohort of patients with brain metastases. We demonstrate feasibility and a scalable workflow, supporting further investigation in larger cohorts and in patients with larger or more stable lesions.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Humans, Brain Neoplasms/secondary, Feasibility Studies, Radiosurgery/methods, Female, Male, Aged, Middle Aged, Diffusion Magnetic Resonance Imaging/methods, Treatment Outcome, Aged, 80 and over, Diffusion Tensor Imaging/methods, Adult, Brain/diagnostic imaging
in
Tomography
volume
12
issue
5
article number
71
publisher
MDPI AG
external identifiers
  • scopus:105039988556
  • pmid:42188712
ISSN
2379-1381
DOI
10.3390/tomography12050071
language
English
LU publication?
yes
id
b65f9a93-205f-4867-902c-78c96241975d
date added to LUP
2026-06-10 10:31:21
date last changed
2026-07-24 13:26:15
@article{b65f9a93-205f-4867-902c-78c96241975d,
  abstract     = {{<p>OBJECTIVES: Early identification of treatment response in brain metastases remains clinically challenging. This study explores tensor-valued diffusion MRI (dMRI), specifically q-space trajectory imaging (QTI), as a novel source of early imaging biomarkers during stereotactic radiotherapy (SRT).</p><p>METHODS: Twenty-six patients with brain metastases were enrolled; thirteen met quality and completeness criteria for QTI analysis (10 responders, three non-responders). MRI was acquired at four time points: before SRT, before final SRT fraction, and at 3 and 6 months post-SRT. QTI-derived metrics included mean diffusivity (MD), fractional anisotropy (FA), microscopic FA (µFA), and isotropic (MKI) and anisotropic (MKA) diffusional variance. Parameter values within the tumour volume were compared pre- and during SRT and correlated with treatment response from standard MRI follow-up. Overall survival was assessed using Kaplan-Meier analysis.</p><p>RESULTS: Median survival was 12 months. QTI analysis was feasible with visible changes in the tumour tissue parameter maps over time. Statistically significant differences (p &lt; 0.05) were found between responders and non-responders in FA before treatment. MKI in responders was significantly lower (p &lt; 0.05) during SRT than before.</p><p>CONCLUSIONS: This study presents a first exploration of QTI-derived parameters in a cohort of patients with brain metastases. We demonstrate feasibility and a scalable workflow, supporting further investigation in larger cohorts and in patients with larger or more stable lesions.</p>}},
  author       = {{Lerner, Minna and Brynolfsson, Patrik and Szczepankiewicz, Filip and Medin, Joakim and Sundgren, Pia C and Olsson, Lars E and Alkner, Sara}},
  issn         = {{2379-1381}},
  keywords     = {{Humans; Brain Neoplasms/secondary; Feasibility Studies; Radiosurgery/methods; Female; Male; Aged; Middle Aged; Diffusion Magnetic Resonance Imaging/methods; Treatment Outcome; Aged, 80 and over; Diffusion Tensor Imaging/methods; Adult; Brain/diagnostic imaging}},
  language     = {{eng}},
  month        = {{05}},
  number       = {{5}},
  publisher    = {{MDPI AG}},
  series       = {{Tomography}},
  title        = {{Tensor-Valued Diffusion MRI for Microstructural Assessment During Stereotactic Radiotherapy of Brain Metastases : A Feasibility Study}},
  url          = {{http://dx.doi.org/10.3390/tomography12050071}},
  doi          = {{10.3390/tomography12050071}},
  volume       = {{12}},
  year         = {{2026}},
}