Human heart: tagging with MR imaging--a method for noninvasive assessment of myocardial motion

Area of Science:

• Cardiovascular imaging
• Biomedical engineering
• Medical physics

Background:

• Myocardial motion analysis is crucial for understanding cardiac function.
• Accurate assessment of cardiac mechanics requires reliable motion-tracking techniques.

Purpose of the Study:

• To develop and validate a magnetic resonance imaging (MRI) technique for tagging myocardial regions.
• To visualize and quantify cardiac motion, including complex movements like twisting.

Main Methods:

• Utilized selective radio-frequency (RF) saturation to create thin tag planes in the myocardium during diastole.
• Employed conventional, orthogonal-plane imaging during systole to observe tag displacement.
• Implemented the technique on a 0.38-T MRI imager and tested on phantoms and human volunteers.

Main Results:

• Tagged myocardial regions were visible for 60-450 milliseconds, covering the entire cardiac cycle.
• Displacement patterns of the hypointense tag stripes accurately reflected cardiac motion, including translation, rotation, and twisting.
• Demonstrated the feasibility of tracking complex cardiac dynamics.

Conclusions:

• Myocardial tagging via RF saturation is an effective method for visualizing cardiac motion during the entire contractile phase.
• The technique allows for the assessment of both simple and complex cardiac deformations.
• Further investigation into factors affecting tag depiction, such as RF pulse angle and relaxation times, is warranted.