Making acute ischemic stroke thrombi visible in MRI imaging

Area of Science:

• Biomedical Imaging
• Neuroscience
• Materials Science

Background:

• Current Magnetic Resonance Imaging (MRI) visualization of thrombi in acute ischemic stroke is suboptimal.
• MRI signal intensities are determined by tissue relaxation times (T1 and T2).
• Understanding clot composition's effect on relaxation times can enhance MRI sequences.

Purpose of the Study:

• To investigate the relationship between clot composition and MRI relaxation times (T1 and T2).
• To evaluate the imaging characteristics of various clot analogs using specific MRI sequences.
• To determine how clot components influence signal intensity for improved thrombus detection.

Main Methods:

• Studied relaxation times and MRI characteristics of diverse clot analogs.
• Analyzed three MRI sequences: T1w Turbo IR, T1w TSE SPIR, and T2w TSE DRIVE.
• Compared clot imaging behavior and intensity values with normal brain tissue.

Main Results:

• Histological composition strongly correlated with T1 relaxation times; iron content correlated with T2 relaxation times.
• Fibrin content was identified as a primary biomarker for increased T1 relaxation times, enabling clot subgroup classification.
• Clot signal intensity varied significantly with T1 and T2 relaxation times, with T2w DRIVE and T1w TSE sequences showing hyperintense thrombi.

Conclusions:

• Clot composition directly impacts MRI relaxation times and signal intensities.
• Specific MRI sequences (T2w DRIVE, T1w TSE) show promise for enhanced acute ischemic stroke thrombus visualization.
• Findings support optimizing MRI protocols for improved thrombus detection and characterization.