Quantitative T₁ and T₂* carotid atherosclerotic plaque imaging using a three-dimensional multi-echo phase-sensitive...

Area of Science:

• Medical Imaging
• Cardiovascular Research
• Radiology

Background:

• Magnetic resonance imaging (MRI) is crucial for detecting carotid atherosclerotic plaques.
• Evaluating vulnerable plaques, including those with lipids and intra-plaque hemorrhages (IPHs), is vital but challenging due to variable T1-weighted image contrast.
• Differentiating thrombus from hemorrhage requires assessing iron content using both T1-weighted and T2*-weighted imaging, necessitating quantitative plaque component evaluation.

Purpose of the Study:

• To assess if the multi-echo phase-sensitive inversion recovery (mPSIR) sequence enhances T1 contrast.
• To determine if mPSIR can simultaneously provide accurate T1 and T2* values for intra-plaque hemorrhages (IPHs).

Main Methods:

• Comparison of T1 and T2* values measured by mPSIR against conventional methods in both phantom and in vivo studies.
• Evaluation of T1 contrast between IPH phantoms and surrounding tissues (sternocleidomastoid muscle) in vivo.
• Correlation analysis of T1 and T2* values obtained with mPSIR for blood vessel walls and muscles against conventional measurements and prior literature.

Main Results:

• Phantom studies showed a linear correlation between T1 and T2* values estimated by mPSIR and conventional methods.
• In vivo studies demonstrated superior T1 contrast with mPSIR between IPH phantoms and sternocleidomastoid muscle compared to conventional methods.
• mPSIR-derived T1 and T2* values for neck tissues correlated well with conventional measurements and previously reported values.

Conclusions:

• The mPSIR sequence effectively enhances T1 contrast in the neck region.
• mPSIR provides accurate simultaneous T1 and T2* measurements, crucial for evaluating carotid plaque components.
• While further clinical validation is needed, mPSIR shows promise for improved carotid plaque detection and detailed component analysis.