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Updated: Jul 30, 2025
Quantifying Cognitive Decrements Caused by Cranial Radiotherapy
Published on: October 18, 2011
Relationship Between Microstructural Alterations and Cognitive Decline After Whole-Brain Radiation Therapy for Brain
Weiwen Zhou1, Xuyun Xie1, Jiamiao Hu1
1Department of Radiation Oncology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Background:
Cognitive impairment frequently occurs in patients with brain metastases (BM) after whole-brain radiotherapy (WBRT). It is crucial to explore the underlying mechanisms of cognitive impairment in BM patients receiving WBRT.
Purpose:
To detect brain microstructural alterations in patients after WBRT by neurite orientation dispersion and density imaging (NODDI), and evaluate the performance of microstructural alterations in predicting cognitive impairment.
Study Type:
Prospective.
Population:
Twenty-six patients (seven female; mean age, 60.9 years).
Field Strength/Sequence:
3-T, multi-shell diffusion-weighted single-shot echo-planar sequence. Three-dimensional magnetization-prepared rapid acquisition with gradient echo sequence.
Assessment:
Mini-mental state examination (MMSE) evaluations were conducted prior to, following, 1 and 3 months after WBRT. The diffusion data were collected twice, 1 week before and 1 week after WBRT. NODDI analysis was conducted to assess microstructural alterations in whole brain (orientation dispersion index, neurite density index, volume fraction of isotropic water molecules). Reliable change indices (RCI) of MMSE were used to measure cognitive decline. The performance of support vector machine models based on NODDI parameters and clinical features (prednisone usage, tumor volume, etc.) in predicting MMSE-RCI was evaluated.
Statistical Tests:
Paired t-test to assess alterations of NODDI measures and MMSE during follow-up. Statistical significance level of P-value <0.05.
Results:
Significantly decreased MMSE score was found at 3 months after WBRT. After WBRT, corpus callosum, medial prefrontal cortex, limbic lobe, occipital lobe, parietal lobe, putamen, globus pallidus lentiform, and thalamus demonstrated damage in NODDI parameters. The predicted MMSE-RCI based on NODDI features was significantly associated with the measured MMSE-RCI at 1 month (R = 0.573; P = 0.003) and 3 months (R = 0.687; P < 0.0001) after WBRT.
Data Conclusion:
Microstructural alterations in several brain regions including the middle prefrontal and limbic cortexes were observed in patients with BM following WBRT, which may contribute to subsequent cognitive decline.
Evidence Level:
2 TECHNICAL EFFICACY: Stage 2.
Insights
Whole-brain radiotherapy (WBRT) causes cognitive impairment in brain metastasis patients. Neurite orientation dispersion and density imaging (NODDI) detects microstructural brain changes linked to this decline.
Area of Science:
- Neuroimaging
- Radiotherapy Oncology
- Cognitive Neuroscience
Background:
- Cognitive impairment is a common complication for brain metastasis (BM) patients undergoing whole-brain radiotherapy (WBRT).
- Understanding the mechanisms behind WBRT-induced cognitive decline is crucial for patient management.
Purpose of the Study:
- To investigate brain microstructural alterations using neurite orientation dispersion and density imaging (NODDI) after WBRT.
- To assess the predictive capability of these microstructural changes for cognitive impairment in BM patients.
Main Methods:
- Prospective study involving 26 BM patients.
- Diffusion-weighted imaging (DWI) and NODDI analysis were performed before and after WBRT.
- Mini-mental state examination (MMSE) assessed cognitive function, with reliable change indices (RCI) calculated. Support vector machine models predicted MMSE-RCI using NODDI parameters and clinical data.
Main Results:
- MMSE scores significantly decreased at 3 months post-WBRT.
- NODDI revealed microstructural damage in the corpus callosum, prefrontal cortex, limbic lobe, and other brain regions.
- NODDI-based predictions of MMSE-RCI correlated significantly with measured cognitive decline at 1 and 3 months post-WBRT.
Conclusions:
- WBRT induces detectable microstructural brain alterations in BM patients.
- These microstructural changes, particularly in the prefrontal and limbic cortexes, are associated with cognitive impairment.
- NODDI shows promise in predicting cognitive decline following WBRT in BM patients.
