Dark blood late enhancement imaging.

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Medical Imaging Techniques
• Cardiac Pathology

Background:

• Late gadolinium enhancement (LGE) imaging excels at differentiating infarcted from normal myocardium.
• Suboptimal contrast between myocardial infarction (MI) and the blood pool often hinders detection of sub-endocardial MIs.
• Sub-endocardial MIs, common in coronary artery disease, are frequently difficult to delineate due to poor contrast with the blood pool.

Purpose of the Study:

• To develop and evaluate a free-breathing, dark blood phase sensitive inversion recovery (PSIR) LGE technique.
• To improve the visualization and delineation of sub-endocardial myocardial infarctions (MIs).
• To overcome the limitations of bright blood LGE in cases with poor contrast between MI and the blood pool.

Main Methods:

• Combined inversion recovery (IR) T2 preparation with single-shot steady-state free precession imaging and respiratory motion-corrected averaging.
• Implemented phase-sensitive inversion recovery (PSIR) reconstruction to achieve dark blood imaging.
• Utilized a T1-map scout with a Modified Look-Locker Inversion recovery (MOLLI) protocol for automatic parameter calculation, simplifying the user interface.
• Conducted free-breathing imaging to enhance patient comfort and clinical workflow.

Main Results:

• Dark blood (DB) PSIR LGE significantly improved the conspicuity and delineation of sub-endocardial fibrosis and MI.
• The contrast between MI and the blood pool was positive in all DB cases, unlike 63% of bright blood cases where it was negative.
• While the contrast-to-noise ratio (CNR) between MI and remote myocardium showed a 13% loss compared to bright blood, the improved MI-to-blood pool contrast was clinically advantageous.
• Enhanced visualization of thin-walled structures like atrial walls, valves, and papillary muscles was also observed.

Conclusions:

• Free-breathing dark blood PSIR LGE imaging effectively enhances the visualization of sub-endocardial MI and fibrosis, particularly in cases with low contrast to the adjacent blood pool.
• The technique offers improved delineation of myocardial scar and thin-walled cardiac structures.
• This method represents a valuable advancement in cardiac MRI for diagnosing and characterizing myocardial pathologies.