Investigating diffusion patterns of brain metastases pre- and post-stereotactic radiosurgery: a feasibility study

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Metastatic complications cause 90% of cancer mortality.
• Magnetic Resonance Imaging (MRI) can visualize brain microstructure.
• Diffusion Weighted Imaging (DWI) tracks water molecule kinetics.

Purpose of the Study:

• Characterize diffusion changes in brain metastases using DWI.
• Assess these changes pre- and post-stereotactic radiosurgery (SRS).
• Correlate diffusion patterns with metastasis occurrence and treatment response.

Main Methods:

• Retrospective analysis of 113 metastases from 13 patients.
• Used longitudinal apparent diffusion coefficient (ADC) maps registered to Gd-T1 and CT images.
• Calculated and compared ADC values pre- and post-SRS.

Main Results:

• ADC values in metastases were significantly higher than in healthy brain tissue.
• Three pre-SRS diffusion patterns showed significant changes post-SRS.
• Lung metastases showed decreased ADC, breast metastases showed increased ADC post-SRS.
• Progressing metastases exhibited elevated ADC values 6-9 months post-SRS.

Conclusions:

• DWI can characterize diffusion changes in brain metastases before they are visible on standard imaging.
• Identified diffusion patterns may improve early detection of brain metastases.
• Diffusion patterns show potential for predicting treatment response to SRS.