Advanced Magnetic Resonance Imaging Techniques for Assessing Brain Metastases Response Following Stereotactic...

Area of Science:

• Neuroradiology
• Oncology
• Medical Imaging

Background:

• Enlargement of brain metastases after stereotactic radiosurgery (SRS) causes diagnostic challenges.
• Differentiating tumor progression from radiation-induced changes is crucial for timely intervention.

Purpose of the Study:

• To evaluate the combined diagnostic role of delayed contrast-enhanced MRI (treatment response assessment maps, TRAM) and multiparametric MRI (diffusion, perfusion, spectroscopy).
• To distinguish tumor progression from radiation-induced changes in post-SRS brain metastases.

Main Methods:

• Retrospective analysis of 23 patients with 24 enlarging lesions post-SRS.
• Utilized advanced MRI including TRAM, perfusion (rCBV), and MR spectroscopy (Cho/Cr ratio).
• Diagnostic performance assessed against 12-month radiological follow-up.

Main Results:

• MR spectroscopy (Cho/Cr ≥ 1.8) achieved 90% accuracy, 88% sensitivity, and 92% specificity.
• Integrated neuroradiologist interpretation of all modalities yielded 95% diagnostic accuracy, 100% sensitivity, and 92% specificity.
• TRAM alone had 100% sensitivity but only 38% specificity.

Conclusions:

• Advanced multiparametric MRI, especially MR spectroscopy, significantly improves diagnostic accuracy for post-SRS brain metastases.
• This multimodal approach aids in accurate lesion characterization, guiding timely treatment decisions.
• Integrated interpretation enhances diagnostic confidence and patient management.