Cardiac cine MR-imaging at 3T: FLASH vs SSFP

Area of Science:

• Magnetic Resonance Imaging
• Cardiovascular Imaging
• Medical Physics

Background:

• Functional cardiac examinations are crucial for diagnosing heart conditions.
• Magnetic Resonance Imaging (MRI) field strength impacts image quality and diagnostic capabilities.
• Optimizing MRI sequences for higher field strengths is essential for clinical translation.

Purpose of the Study:

• To investigate the implications of increasing MRI field strength from 1.5 T to 3 T for functional cardiac imaging.
• To compare the performance of Steady-State Free Precession (SSFP) and Fast Low Angle Shot (FLASH) cine sequences at 1.5 T and 3 T.
• To determine the optimal sequence for routine 3 T cardiac functional examinations.

Main Methods:

• Flip angle optimization for SSFP and FLASH cine sequences at 1.5 T and 3 T.
• Application of optimized sequences in ten healthy volunteers for cardiac function assessment.
• Quantitative analysis of Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR) in myocardium and blood pool.
• Qualitative assessment of image quality and artifact levels.

Main Results:

• Both SSFP and FLASH sequences demonstrated increased SNR at 3 T compared to 1.5 T.
• SSFP sequence showed higher SNR increases (48% myocardium, 30% blood) than FLASH (19% myocardium, 13% blood).
• SSFP exhibited a significant CNR increase (22%) and superior image quality over FLASH at both field strengths.
• While SSFP had more artifacts at 3 T, they were deemed clinically acceptable.

Conclusions:

• Cardiac functional examinations benefit significantly from the increased field strength of 3 T MRI.
• The SSFP sequence is recommended for routine functional cardiac examinations at 3 T due to superior performance.
• Optimized SSFP sequences provide diagnostically valuable cardiac imaging at 3 T despite minor artifact increases.