Quantitative Relaxometry Metrics for Brain Metastases Compared to Normal Tissues: A Pilot MR Fingerprinting Study

Area of Science:

• Radiology and Imaging Science
• Neuroscience
• Biomedical Engineering

Background:

• Brain metastases (BM) present a significant challenge in oncology.
• Accurate characterization of BM and normal brain tissue is crucial for diagnosis and treatment planning.
• Quantitative MRI techniques offer potential for improved tissue characterization.

Purpose of the Study:

• To evaluate a novel, rapid Magnetic Resonance Fingerprinting (MRF) technique for simultaneous T1 and T2 mapping.
• To assess the capability of MRF-derived metrics in characterizing brain metastases (BM) and normal-appearing brain tissues.
• To compare quantitative T1 and T2 values between BM and different normal brain tissue types.

Main Methods:

• A prototype MRF sequence was implemented on a 3T MRI scanner.
• 14 patients with BM underwent MR imaging.
• Quantitative T1 and T2 values were derived from solid BM (n=42) and normal brain tissues including gray matter, white matter, and cerebrospinal fluid (n=66).

Main Results:

• Significant differences in mean T1 and T2 values were observed between BM and normal-appearing white matter (p < 0.05).
• Mean T1 values for untreated and treated BM were 2035 ms and 2163 ms, respectively.
• Mean T2 values for untreated and treated BM were 168 ms and 141 ms, respectively, showing distinct values from normal brain tissues.

Conclusions:

• The rapid MRF technique is a promising quantitative tool for characterizing brain metastases.
• MRF-derived T1 and T2 values can help differentiate BM from normal brain tissue.
• This technique has potential for assessing free water content and tumor morphology in BMs.