Phased‐Array Magnetic Resonance Imaging of the Carotid Artery Bifurcation: Preliminary Results in Healthy Volunteers and a Patient with Aherosclerotic Disease

Abstract

A high resolution MR imaging technique using a custom designed flexible phased-array surface coil was developed to examine the wall of the carotid artery bifurcation in vivo. The phased-array consisted of two overlapping coils which increased the image signal-to-noise ratio at the depth of the carotid artery by approximately 70%, relative to a similarly sized single loop coil. The imaging protocol included a 2D T1-weighted (T1W) spin-echo scan and cardiac gated T2-weighted and proton density-weighted (PDW) fast spin-echo (FSE) scans. Images were obtained of six healthy volunteers and of one patient with known atherosclerotic disease several days before carotid endarterectomy. On T1W and PDW images of the healthy volunteers, the carotid arterial wall appeared to be comprised of two concentric rings; a high signal inner ring and a lower signal outer ring. The MR images of the patient revealed a calcified carotid bifurcation plaque which was confirmed during surgery. The endarterectomy specimen was imaged in vitro with MR and then sectioned histologically for correlation with the patients in vivo images. Our preliminary findings indicate that a high resolution technique may provide a noninvasive technique to study atherosclerosis of the carotid bifurcation.

Noninvasive In Vivo Human Coronary Artery Lumen and Wall Imaging Using Black-Blood Magnetic Resonance Imaging

“…9,11,12,44,45 A misalignment of the imaging plane and the long axis of the vessel can lead to inaccurate cross-sectional images and lead to errors in wall thickness measurements and plaque imaging. Careful planning in this study minimized these errors.…”

Quadrature coil design for high‐resolution carotid artery imaging scores better than a dual phased‐array coil design with the same volume coverage

“…Previous studies demonstrated that phased-array coils provide better SNR than single-loop surface coils (6,11,12). The present study evaluates the performance of a quadrature-coil design in the depiction of the carotid bifurcation.…”

“…MRI HAS THE POTENTIAL to define atherosclerotic plaque components in vivo at the carotid artery (1)(2)(3)(4)(5)(6). Normally, the atherosclerotic plaque in the carotid artery has an averaged length of 2.0 -2.5 cm and the thickness in the axial plane is 5-10 mm.…”

“…In a previous study we compared a 3-inch single-loop coil with a phased-array coil and demonstrated that a more than 100% increase in SNR can be achieved at a depth of 3 cm at the center of the coil for the phased-array configuration (1)(2)(3)(4)(5)(6).…”

Mineral Volume and Morphology in Carotid Plaque Specimens Using High-Resolution MRI and CT

“…11 The potential role of MRI for noninvasive assessment of plaque morphology and lesion burden quantification has been addressed in several investigations ex vivo and in vivo. [12][13][14][15][16][17][18][19][20][21][22][23][24] The appearance of plaque calcification has been described as uniformly dark in signal intensity on all MRI sequences. 18,25,26 However, there are other components of atherosclerotic plaque that may show decreased signal intensity on some or all pulse sequences; for example, solid cholesterol hydrate may be present and plaque lipids may exhibit T2 shortening secondary to liquid crystal behavior, depending on the lipid composition and cholesterol content.…”