Parallel and nonparallel simultaneous multislice black-blood double inversion recovery techniques for vessel wall imaging.
OBJECTIVE
To reduce long examination times of black-blood vessel wall imaging by acquiring multiple slices simultaneously and by using parallel acquisition techniques.


METHODS
DIR-rapid acquisition with relaxation enhancement (RARE) techniques imaging up to 10 simultaneous slices per acquisition with single and multiple 180 degrees -reinversion pulses were developed. A slab-selective reinversion multislice DIR-RARE sequence incorporating generalized autocalibrating partially parallel acquisitions (GRAPPA) imaging was implemented. Four-channel and eight-channel carotid coils were built to test these sequences. A total of 11 subjects were studied. Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) efficiency factor (SEF, SNR/unit time/slice) were measured from aortic images of three healthy subjects to determine optimal MR parameters. The DIR-RARE-GRAPPA sequence was run on aortas and carotid arteries of the five remaining healthy subjects and three atherosclerotic patients with optimal parameters (acquisition times 12-21 seconds).


RESULTS
SEFs of slab-selective protocols were significantly higher than those of slice-selective protocols, and SEFs of DIR-RARE-GRAPPA protocols were significantly higher than corresponding non-GRAPPA protocols (P < 0.05). CNR was not significantly different for all imaging protocols. The DIR-RARE-GRAPPA multislice sequence showed 8.35-fold time improvement vs. single-slice DIR-2RARE sequence.


CONCLUSIONS
Future MRI atherosclerotic plaque studies can be performed in substantially shorter times using these methods.
Itskovich
Vitalii V
VV
Imaging Science Laboratories, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
Mani
Venkatesh
V
Mizsei
Gabor
G
Aguinaldo
Juan Gilberto S
JG
Samber
Daniel D
DD
Macaluso
Frank
F
Wisdom
Paul
P
Fayad
Zahi A
ZA
D000328:Adult; D000368:Aged; D001011:Aorta / Q000033:anatomy & histology / Q000473:pathology; D001018:Aortic Diseases / Q000175:diagnosis*; D001161:Arteriosclerosis / Q000175:diagnosis*; D002339:Carotid Arteries / Q000033:anatomy & histology / Q000473:pathology; D002340:Carotid Artery Diseases / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted