MR-imaging of the thoracic aorta: 3D-ECG- and respiratory-gated bSSFP imaging using the CLAWS algorithm versus contrast-enhanced 3D-MRA.
OBJECTIVE
To compare a contrast-enhanced 3D angiography (CE-3D-MRA) with the ECG- and respiratory gated 3D balanced steady state free precession (bSSFP) sequence using the CLAWS algorithm (3D-bSSFP-CLAWS) with respect to acquisition time, image quality, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).


METHODS
14 patients (4 women, mean age ± SD: 52 ± 18) with known or suspected thoracic aortic disease were imaged on a 1.5T scanner with both sequences. Two readers scored image quality of predefined levels of the thoracic aorta. Acquisition time, SNR and CNR were calculated for each examination.


RESULTS
Image quality achieved with the 3D-bSSFP-CLAWS was scored significantly better than with the CE-3D-MRA for the aortic annulus (P = 0.003), the sinuses of Valsalva (P = 0.001), the proximal coronary arteries (P = 0.001) and the sinotubular junction (P = 0.001). Effective acquisition time for the 3D-bSSFP-CLAWS and corrected acquisition time (corrected for imaging parameters) was significantly longer compared to the CE-3D-MRA (P = 0.004 and P = 0.028). SNR and CNR were significantly higher for the CE-3D-MRA (P = 0.007 and P = 0.001).


CONCLUSIONS
Providing the highest scan efficiency for a given breathing pattern, image quality for the proximal ascending aorta achieved with the 3D-bSSFP-CLAWS is significantly superior in contrast to the CE-3D-MRA.
Department of Radiology of the University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland. kaweln@cc.nih.gov
Nadine
N
Kawel
Permi
P
Jhooti
David
D
Dashti
Tanja
T
Haas
Leopold
L
Winter
Michael J
MJ
Zellweger
Peter T
PT
Buser
Jennifer
J
Keegan
Klaus
K
Scheffler
Jens
J
Bremerich
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001013:Aorta, Thoracic / Q000473:pathology*; D001018:Aortic Diseases / Q000473:pathology*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D055815:Young Adult