7T dynamic contrast-enhanced MRI for the detection of subtle blood-brain barrier leakage

Area of Science:

• Neuroimaging
• Radiology
• Biophysics

Background:

• Assessing blood-brain barrier (BBB) integrity is crucial for diagnosing neurological disorders.
• Detecting subtle BBB leakage at lower magnetic field strengths (≤3T) is challenging due to signal noise.
• Higher field strengths offer improved signal-to-noise ratio for enhanced imaging.

Purpose of the Study:

• To explore the application of 7 Tesla (7T) Dynamic Contrast-Enhanced MRI (DCE-MRI) for sensitive detection of BBB leakage.
• To evaluate a dual-time resolution DCE-MRI protocol optimized for 7T imaging.
• To assess the capability of 7T DCE-MRI in quantifying BBB permeability parameters.

Main Methods:

• Implemented a dual-time resolution DCE-MRI protocol at 7T.
• Utilized a slow contrast agent injection rate (0.3 ml/s) and low dose (3 mmol) to minimize T2* degradation.
• Employed the Patlak graphical approach to calculate leakage rate (Ki) and blood plasma volume fraction (vp).
• Evaluated the method in 10 controls, an ischemic stroke patient, and a transient ischemic attack patient.

Main Results:

• Significantly higher Ki and vp values were observed in gray matter compared to white matter across all participants.
• Both patient groups exhibited higher Ki values than the control subjects.
• The ischemic stroke lesion showed elevated leakage values compared to normal-appearing tissue.

Conclusions:

• A 7T DCE-MRI protocol with dual-time resolution and reduced contrast agent dose can effectively detect subtle BBB leakage.
• This tailored 7T DCE-MRI method demonstrates high sensitivity for assessing BBB integrity over a range of Ki values.
• The findings highlight the potential of 7T DCE-MRI as a superior tool for evaluating BBB status in neurological conditions.