Toward rapid high resolution in vivo intravascular MRI: evaluation of vessel wall conspicuity in a porcine model using multiple imaging protocols.
OBJECTIVE
To assess magnetic resonance (MR) pulse sequences for high resolution intravascular imaging.


METHODS
Intravascular imaging of the abdominal aorta and iliac arteries was performed in vivo in a porcine model at 1.5 T using catheter-mounted micro-receive coils. Ten protocols, including spin-echo (SE)-echo planar imaging (SE-EPI), segmented EPI, half-Fourier single-shot turbo spin-echo (HASTE), fast imaging with steady-state free precession (TrueFISP), turbo spin-echo (TSE), and SE acquisition schemes were employed in 13 trials. Images were analyzed by six expert raters with respect to wall-conspicuity, wall-to-lumen/tissue contrast, visible layers of the arterial wall, anticipated clinical usefulness, and overall image quality. Mean differences between sequence-types were evaluated using analysis of variance (ANOVA) between groups with planned comparisons.


RESULTS
The vessel wall was delineated in almost all protocols. Motion artifacts from physiological and device motion were reduced in fast techniques. The best contrast between the wall and surrounding tissue was provided by a HASTE protocol. Anatomic layers of the vessel wall were best depicted on dark blood T2-weighted TSE. Overall, TrueFISP was ranked highest on the remaining measures.


CONCLUSIONS
Dedicated catheter-coils combined with fast sequences have potential for in vivo characterization of vessel walls. TrueFISP offered the best overall image quality and acquisition speed, but suffered from the inability to delineate the multiple layers of the wall, which seems associated with dark blood- and T2-weighted contrast. We believe future intra-arterial trials should proceed from this study in normal artery imaging and initially focus on fast T2-weighted dark blood techniques in trials with pathology.
Hillenbrand
Claudia M
CM
Department of Radiology, University Hospitals of Cleveland, Cleveland, Ohio 44106, USA.
Jesberger
John A
JA
Wong
Eddy Y
EY
Zhang
Shaoxiong
S
Chang
David T
DT
Wacker
Frank K
FK
Lewin
Jonathan S
JS
Duerk
Jeffrey L
JL
D000704:Analysis of Variance; D000818:Animals; D001012:Aorta, Abdominal / Q000033:anatomy & histology*; D002404:Catheterization; D017352:Echo-Planar Imaging / Q000379:methods*; D004730:Endothelium, Vascular / Q000033:anatomy & histology; D004867:Equipment Design; D005583:Fourier Analysis; D007083:Iliac Artery / Q000033:anatomy & histology*; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D023421:Models, Animal; D012680:Sensitivity and Specificity; D013552:Swine; D018084:Ultrasonography, Interventional