Characterization of carotid atherosclerosis with black-blood carotid plaque imaging using variable flip-angle 3D turbo spin-echo: comparison with 2D turbo spin-echo sequences

Purpose

To compare the diagnostic performance of three-dimensional variable-flip-angle turbo spin-echo and two-dimensional turbo spin-echo sequences in carotid plaque imaging, with histological analysis as the standard of reference.

Materials and methods

Twenty-two patients scheduled for carotid endarterectomy underwent carotid plaque imaging including axial T1-weighted and T2-weighted two-dimensional turbo spin-echo, and coronal T1-weighted and T2-weighted three-dimensional variable-flip-angle turbo spin-echo sequences. The quality of images was visually graded using a three-point scale. The signal ratio of the arterial lumen to the plaque component, and that of the carotid plaque to the ipsilateral submandibular gland was calculated in each sequence. These ratios between two-dimensional and three-dimensional sequences were compared for each plaque component according to the histological category of the plaque.

Results

No significant difference was observed among the overall imaging quality scores of the two-dimensional and three-dimensional sequences, although three-dimensional sequences allowed visualization in arbitrary orientations, as well as depiction of small plaque components such as ulcerations and calcifications. The signal ratio of the plaque to the submandibular gland on T1-weighted three-dimensional sequence was significantly higher than that on two-dimensional sequence (p < 0.01), whereas no significant difference was found between two T2-weighted sequences.The signal ratios of the plaque to the submandibular gland of histology-defined soft plaque components were significantly higher on T1-weighted three-dimensional sequence than on two-dimensional sequence (p < 0.01), whereas no significant differences were observed between two T1-weighted sequences for hard components.

Conclusions

Three-dimensional variable-flip-angle turbo spin-echo is a promising tool for the diagnosis of carotid plaques.