Weekly hippocampal diffusion changes during partial-brain radiotherapy for high-grade glioma: links to radiation dose and early memory outcomes

By
Ory Haisraely
Bikash Panthi
Kyle Richard Noll
Eleni Konstantinopoulou
Andrew Elliott
Sara Thrower
Holly Langshaw
Wasif Talpur
Catherine Sullaway
Todd Swanson
Chenyang Wang
Martin C. Tom
Thomas Beckham
Wen Jiang
Debra Nana Yeboa
Mary Frances McAleer
Amol Ghia
Susan Lynne McGovern
Jing Li
Jeffrey Scott Wefel
Caroline Chung
October 13, 2026

Journal Of Neuro-Oncology

Overview

This prospective, single-arm observational analysis evaluated weekly hippocampal diffusion MRI during six weeks of partial-brain radiotherapy in 45 adults with high-grade glioma. The supplied article material describes the study rationale, cohort, imaging, and cognitive methods, but does not provide its results; therefore, no diffusion trajectories, dose associations, or memory-outcome findings can be reported.

Background

Radiotherapy is a cornerstone of high-grade glioma management, while irradiation of normal brain tissue may contribute to neurocognitive morbidity. The hippocampus is of interest because of its role in learning and memory and the radiosensitivity of the dentate-gyrus neurogenic niche. Prior work cited in the article has associated hippocampal dose with long-term associative-memory decline and regional brain dose with neurocognitive outcomes. ADC and FA are nonspecific diffusion measures responsive to multiple tissue processes, rather than direct or validated indicators of irreversible radiation injury.

Data Highlights

Study feature	Details reported
Analytic cohort	45 adults with histologically confirmed high-grade glioma and evaluable serial diffusion imaging
Radiotherapy	60 Gy in 30 fractions over 6 weeks using IMRT or VMAT, with concurrent and subsequent adjuvant temozolomide
Imaging schedule	Multiparametric MRI before radiotherapy and weekly during treatment
Diffusion acquisition	1.5-T MRI; DTI with 64 diffusion-encoding directions at b = 1000 s/mm² and b = 0 acquisitions
Cognitive assessment	Cogstate C3 learning and memory testing at baseline and Week 6; composite based on BPTX Lure Discrimination Index, FNMT, and OCL z scores
Results available in supplied material	Outcome estimates and statistical results are not included

Key Findings

The analysis was designed to characterize weekly hippocampal ADC and FA trajectories during partial-brain radiotherapy and assess their association with planned hippocampal dose.
A secondary objective was to explore associations between baseline-to-Week 6 diffusion changes and early memory change.
The analytic cohort included 45 adults with high-grade glioma receiving 60 Gy in 30 fractions over six weeks with concurrent temozolomide.
Diffusion MRI was acquired weekly on a 1.5-T scanner; the protocol included 64 diffusion-encoding directions at b = 1000 s/mm².
Learning and memory were assessed at baseline and Week 6 using the examiner-administered Cogstate C3 battery; the supplied materials do not report cognitive or imaging outcome results.
Related evidence in the supplied context describes hippocampal-avoidance whole-brain radiotherapy for brain metastases as preserving neurocognitive function, but this is a different clinical setting from partial-brain radiotherapy for high-grade glioma.

Clinical Implications

The supplied material supports describing the study design and its planned imaging and memory assessments, but not drawing conclusions about dose-related diffusion changes or early memory outcomes. The article characterizes ADC and FA as nonspecific imaging phenotypes, so they should not be presented as direct measures of irreversible radiation injury.

Conclusion

This study was designed to examine weekly hippocampal diffusion changes during partial-brain radiotherapy for high-grade glioma and their relationships to dose and early memory change. The provided source text does not include the results needed to state whether these associations were observed.