Frequency scouting for cardiac imaging with SSFP at 3 Tesla

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Medical Physics
• Pediatric Cardiology

Background:

• Steady-state free precession (SSFP) cine MRI is widely used for cardiac imaging.
• Off-resonance artifacts are a significant limitation of SSFP, particularly at 3 Tesla.
• These artifacts can compromise the accurate assessment of cardiac structures, including the left ventricle.

Purpose of the Study:

• To review the types and prevalence of off-resonance artifacts in the left ventricle using SSFP cine MRI at 3 Tesla.
• To describe and evaluate a technique for mitigating these artifacts.
• To assess the impact of artifacts on myocardial boundary detection.

Main Methods:

• SSFP cine imaging was performed on 16 healthy children at 3 Tesla.
• Synthesizer frequency was optimized by acquiring a series of SSFP images with varying frequency shifts.
• 136 short-axis slices were analyzed for the presence and severity of off-resonance artifacts.

Main Results:

• Off-resonance artifacts, including dark bands and flow artifacts, were prevalent in the apex region.
• Despite artifact presence, only 3.6% of slices showed artifacts detrimental to myocardial boundary detection.
• The frequency adjustment technique successfully suppressed artifacts in most cases.

Conclusions:

• Off-resonance artifacts are common in pediatric SSFP cine MRI at 3 Tesla, particularly in the apex.
• The implemented frequency adjustment technique is effective in mitigating these artifacts.
• This method provides a fast and simple solution to improve image quality and diagnostic accuracy in SSFP imaging at 3 Tesla.