Evaluation of carotid atherosclerotic plaque surface characteristics utilizing simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) technique

Abstract

Purpose To evaluate the feasibility of the Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) technique in identification of carotid plaque surface characteristics compared with the conventional multicontrast vessel wall imaging protocol. Materials and Methods Thirty symptomatic patients with carotid plaque were recruited and underwent carotid artery magnetic resonance imaging (MRI) (3.0T) using a conventional multicontrast protocol and SNAP sequence. As an intrinsic multicontrast sequence, SNAP could generate a gray blood reference (Ref) image set, a black blood corrected real (CR) image set, and a bright blood MR angiography (MRA) image set. A bright blood SNAP Ref2 image was implemented by combining Ref and MRA images for facilitating plaque surface characteristics evaluation. The presence/absence of calcification (CA), juxtaluminal calcification (JCA), and ulceration was assessed. The agreement between SNAP and multicontrast vessel wall protocol in identifying CA, JCA, and ulceration was analyzed using Cohen’s kappa analysis. The interreader and intrareader reproducibility of SNAP imaging in identifying plaque surface characteristics was also assessed. Results Good to excellent agreement was found between SNAP and conventional multicontrast protocol in identifying CA (κ = 0.74, 95% confidence interval [CI]: 0.54–0.93), JCA (κ = 0.81, 95% CI: 0.66–0.97), and ulceration (κ = 0.82, 95% CI: 0.65–0.99). In addition, excellent intrareader and interreader reproducibility was found for SNAP imaging in identification of CA, JCA, and ulceration. Conclusion SNAP imaging showed excellent agreement with multicontrast imaging and high reproducibility in identification of both JCA and ulceration, suggesting that SNAP imaging may be a time-efficient, alternative tool in identification of plaque surface characteristics in carotid arteries.

Evaluation of 3D multi-contrast carotid vessel wall MRI: a comparative study

“…CA can be detected by a hypointense signal in all contrast weightings and can be delineated more clearly using 3D multi-contrast imaging, as indicated in Figure 6. Recent studies showed that SNAP imaging, with high reproducibility, agreed well with conventional reference multi-contrast imaging in identification of CA (24), which was also illustrated in another representative case (Figure 6). As for LRNC detection, T1 and T2 imaging were mainly used.…”

Black‐Blood Contrast in Cardiovascular MRI

“…3D VFA‐FSE has also been proposed, exploiting the intrinsic flow sensitivity of this technique for black‐blood contrast 89, 90 . A recent technique permits 3D acquisition and simultaneous depiction of the vessel wall and the vascular lumen using a combined bright‐ and black‐blood imaging sequence 91 . Modern black‐blood MRI techniques of the carotid bifurcation are highly accurate for identifying carotid atherosclerosis, including intraplaque hemorrhage 92,93 and patients at increased risk for stroke 94–96 …”

CT and MR Imaging of Carotid Wall and Plaque

“…3) to characterize features of plaque vulnerability such as intra-plaque hemorrhage IPH, LRNC, and the status of the FC. 26 MR allows for the accurate distinction of plaque components 27 such as the LRNC, fibrous tissue, and IPH exploiting their different signal properties. While the identification of calcified components can be more challenging compared to CT, MR still offers usually good results.…”