A comparison between segmented k-space FLASH and interleaved spiral MR coronary angiography sequences

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Radiology

Background:

• Magnetic Resonance Coronary Angiography (MRCA) is crucial for diagnosing coronary artery disease (CAD).
• Respiratory motion during free-breathing acquisitions poses a significant challenge to image quality.

Purpose of the Study:

• To directly compare the efficacy of segmented fast low-angle short (FLASH) imaging and interleaved spiral MRCA techniques.
• To evaluate image quality, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) during free respiration using navigator echo gating.

Main Methods:

• Acquisition of MRCA images in 30 healthy subjects and 15 CAD patients using both segmented FLASH and interleaved spiral sequences.
• Navigator echo gating was employed during free respiration for both sequences.
• Image quality scoring by blinded observers and quantitative measurement of SNR and CNR.

Main Results:

• The interleaved spiral sequence demonstrated significantly improved image quality (2.3 vs. 1.8, P = 0.002).
• Coronary artery SNR (16.6 vs. 11.8, P < 0.001) and CNR (12.5 vs. 7.4, P < 0.001) were significantly higher with the spiral technique.
• Image resolution was also enhanced (256x256 vs. 256x128) with the spiral sequence, though acquisition time increased by 12%.

Conclusions:

• Interleaved spiral MRCA offers superior image quality, SNR, CNR, and resolution compared to segmented FLASH MRCA.
• These improvements are attributed to the inherent properties of spiral imaging and reduced motion artifacts.
• The interleaved spiral technique represents a promising advancement for non-invasive coronary angiography.