Cardiac T₂ * mapping: Techniques and clinical applications.

Area of Science:

• Cardiovascular MRI
• Magnetic Resonance Imaging
• Medical Imaging

Background:

• Cardiac T₂ * mapping is a noninvasive MRI method to assess myocardial iron accumulation in diseases like hemochromatosis, sickle cell disease, and β-thalassemia major.
• The technique has evolved with improvements in MR acquisition, artifact reduction, and T₂ * quantification, including blood pool signal suppression and scanner/software consistency.

Purpose of the Study:

• To review and compare different methods for quantifying cardiac T₂ * and generating T₂ * maps.
• To recommend optimal MR acquisition and quantification techniques for reliable myocardial iron overload measurement and follow-up.
• To discuss the clinical applications and future prospects of cardiac T₂ * mapping, including integration with other MRI techniques like T₁ mapping.

Main Methods:

• Review of existing literature on cardiac T₂ * mapping techniques.
• Analysis of factors influencing T₂ * measurement reproducibility and accuracy, including curve-fitting methods and region of interest selection.
• Comparison of region of interest-based versus pixelwise quantification for spatial iron loading information.

Main Results:

• Current data processing varies between centers, leading to outcome discrepancies.
• Pixelwise quantification offers superior spatial iron loading information compared to region of interest-based methods.
• Proposed improvements include free-breathing acquisition, fast mapping, noise reduction, and automated contour delineation.

Conclusions:

• Standardization of data processing is crucial for consistent T₂ * measurement outcomes.
• Optimized MR acquisition and quantification methods are essential for reliable assessment of myocardial iron overload.
• Cardiac T₂ * mapping is vital for early detection, monitoring, and guiding treatment of iron overload conditions.