Navigator echo-based respiratory gating for three-dimensional MR coronary angiography: reduction of scan time using a slice interpolation technique.
OBJECTIVE
The aim of the study was to compare a conventional respiratory-gated 3D MR coronary angiographic technique (conventional MRCA) with a respiratory-gated 3D MR coronary angiographic technique that includes a slice interpolation technique (slice interpolation MRCA). Both MRCA techniques were compared based on the quality of visualization of the coronary arteries and the diagnostic accuracy in identifying hemodynamically significant coronary artery stenoses.


METHODS
Forty patients with known proximal coronary artery stenosis after conventional CA were examined on a 1.5 T scanner, that is, 20 patients with each sequence. A 6 point grading system (0 = worst quality, 5 = best quality) was used to evaluate and compare the image quality. The length and proximal diameter of the depicted coronary arteries were measured. Detection of coronary artery stenoses was compared with that obtained by conventional CA by two blinded readers.


RESULTS
With the slice interpolation technique, the average scan time of the entire heart was reduced by approximately 40%. With use of conventional MRCA, 69% of all proximal and middle coronary artery segments were visualized with a sufficient image quality; with the slice interpolation technique, 79% of these segments were depicted adequately. For the assessment of stenoses, sensitivity was 71% and specificity was 53% for conventional MRCA and 72 and 60% for slice interpolation MRCA, respectively. These differences in sensitivity and specificity were statistically not significant.


CONCLUSIONS
The application of a slice interpolation technique reduces the scan time, maintains a comparable sensitivity and specificity for the assessment of coronary artery stenoses, and increases the number of completely identified coronary artery segments compared with the conventional technique.
Nikolaou
K
K
Department of Clinical Radiology, Klinikum Grobetahadern, Ludwig Maximilians University Munich, Germany. Konstantin.Nikolaou@ikra.med.uni-muenchen.de
Huber
A
A
Knez
A
A
Scheidler
J
J
Petsch
R
R
Reiser
M
M
D000368:Aged; D003327:Coronary Disease / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D012680:Sensitivity and Specificity