Imaging the vessel wall in major peripheral arteries using susceptibility-weighted imaging

To demonstrate a novel contrast mechanism for imaging the vessel wall and vessel wall calcification using susceptibility-weighted imaging (SWI).

Eighteen subjects were imaged with multidetector computed tomography (MDCT) and high-resolution SWI at 3T. The SWI imaging parameters were optimized to allow for the best visualization of the femoral artery lumen and the arterial wall in magnitude and phase images, respectively. SWI-filtered phase data were used to evaluate the diamagnetic susceptibility of vessel wall and of putative vessel wall calcification. Imaging was performed using TE = 15.6 msec (in-phase for fat); TR = 25 msec, flip angle (FA) = 10 degrees , bandwidth (BW) = 80 Hz/pixel, resolution = 0.5 x 0.5 mm in-plane and 1.0 mm through-plane, an acquisition matrix of 512 x 384 x 64 (for read, phase, and slice-select directions), and a total scan time of 8 minutes.

Nineteen calcifications were identified in CT and SWI and they correlated well in both size and position. The contrast-to-noise ratio between the blood signal in the lumen of the artery and arterial wall was 11.7:1 and 7.4:1 in magnitude and in phase images, respectively.

SWI provides a novel means to visualize vessel wall and recognize the presence of calcification.