3D velocity quantification in the heart: improvements by 3D PC-SSFP.
OBJECTIVE
To test whether a 3D imaging sequence with phase contrast (PC) velocity encoding based on steady-state free precession (SSFP) improves 3D velocity quantification in the heart compared to the currently available gradient echo (GE) approach.


METHODS
The 3D PC-SSFP sequence with 1D velocity encoding was compared at the mitral valve in 12 healthy subjects with 3D PC-GE at 1.5T. Velocity measurements, velocity-to-noise-ratio efficiency (VNR(eff)), intra- and interobserver variability of area and velocity measurements, contrast-to-noise-ratio (CNR), and artifact sensitivity were evaluated in both long- and short-axis orientation.


RESULTS
Descending aorta mean and peak velocities correlated well (r(2) = 0.79 and 0.93) between 3D PC-SSFP and 3D PC-GE. At the mitral valve, mean velocity correlation was moderate (r(2) = 0.70 short axis, 0.56 long axis) and peak velocity showed good correlation (r(2) = 0.94 short axis, 0.81 long axis). In some cases VNR(eff) was higher, in others lesser, depending on slab orientation and cardiac phase. Intra- and interobserver variability was generally better for 3D PC-SSFP. CNR improved significantly, especially at end systole. Artifact levels did not increase.


CONCLUSIONS
3D SSFP velocity quantification was successfully tested in the heart. Blood-myocardium contrast improved significantly, resulting in more reproducible velocity measurements for 3D PC-SSFP at 1.5T.
Department of Physics and Medical Technology, ICaR-VU, VU University Medical Center, Amsterdam, the Netherlands. mp.rolf@vumc.nl
Marijn P
MP
Rolf
Mark B M
MB
Hofman
Joost P A
JP
Kuijer
Albert C
AC
van Rossum
Rob M
RM
Heethaar
D000328:Adult; D001011:Aorta / Q000033:anatomy & histology / Q000473:pathology; D016477:Artifacts; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008943:Mitral Valve / Q000033:anatomy & histology / Q000502:physiology; D015233:Models, Statistical; D009206:Myocardium / Q000473:pathology; D019047:Phantoms, Imaging
D003287:Contrast Media