A comparison between segmented k-space FLASH and interleaved spiral MR coronary angiography sequences.
A direct comparison of segmented fast low-angle short (FLASH) imaging and interleaved spiral magnetic resonance coronary angiography (MRCA) during free respiration using navigator echo has been performed. MRCA images were acquired in 30 normal subjects and 15 patients with coronary artery disease (CAD). Images of the right coronary artery were acquired during free respiration using navigator echo gating for both a segmented k-space FLASH sequence (8 views/segment, segment duration 105 msec) and an interleaved spiral sequence (20 interleaves, spiral read-out period 19 msec). Image quality was scored by three independent blinded observers, and coronary artery signal-to-noise ratio (SNR) and coronary artery/epicardial fat contrast-to-noise ratio (CNR) were measured. There was a significant improvement in image quality when coronary images were acquired with the interleaved spiral sequence (spiral 2. 3 vs. FLASH 1.8; P = 0.002). This was associated with an increase in the coronary artery SNR (16.6 +/- 6.9 vs. 11.8 +/- 5.0; P < 0.001), the coronary artery/epicardial fat CNR (12.5 +/- 6.1 vs. 7.4 +/- 4.0, P < 0.001), and the image resolution (256 x 256 vs. 256 x 128). However, there was a 12% increase in acquisition time for the interleaved spiral sequence. Image quality, SNR, CNR, and resolution can be improved using an interleaved spiral sequence. These improvements are secondary to the intrinsic characteristics of spiral imaging and the short acquisition period, which reduces the effects of both cardiac and respiratory motion.
Taylor
A M
AM
Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, SW3 6NP London, United Kingdom. and@doctors.org.uk
Keegan
J
J
Jhooti
P
P
Gatehouse
P D
PD
Firmin
D N
DN
Pennell
D J
DJ
D000328:Adult; D000368:Aged; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003331:Coronary Vessels / Q000033:anatomy & histology* / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values; D013997:Time Factors