Preoperative 3D FSE T1-Weighted MR Plaque Imaging for Severely Stenotic Cervical ICA: Accuracy of Predicting Emboli during Carotid Endarterectomy

Comparison of Three-Dimensional T1-Weighted Magnetic Resonance and Contrast-Enhanced Ultrasound Plaque Images for Severe Stenosis of the Cervical Carotid Artery

BACKGROUND AND PURPOSE

Magnetic resonance (MR) and contrast-enhanced ultrasound assess characteristics and neovascularization, respectively, of the carotid plaque. The purpose of the present study was to clarify how findings of contrast-enhanced ultrasound plaque imaging are related to those of 3-dimensional (3D) fast spin echo (FSE) T1-weighted MR plaque imaging (WI) in severe stenosis (≥70%) of the cervical carotid artery.

METHODS

Fifty-three patients underwent 3D FSE T1-WI and contrast-enhanced ultrasound. For each patient, the averaged contrast ratio on MR (CR_MR) was calculated by dividing the averaged internal carotid artery plaque signal intensity by the sternocleidomastoid muscle signal intensity; maximally enhanced intensities on the intraplaque and lumen time-intensity curves were obtained from contrast-enhanced ultrasound data, and the ratio of the maximal intensity of the intraplaque curve to that of the lumen curve was calculated and defined as contrast effect (CE_US).

RESULTS

A linear correlation (r = .702; P <.0001) was observed between CR_MR and CE_US. Receiver operating characteristic curve analyses to evaluate the ability of the CE_US to differentiate each category of CR_MR from the other 2 categories showed that the sensitivity was significantly lower for category II (1.30 ≤ CR_MR ≤ 1.60) than for category I (CR_MR < 1.30) or III (1.60 < CR_MR). The CE_US was lower in plaques with higher CR_MR than in those with lower CR_MR in a subgroup of category III (P = .0196).

CONCLUSION

Findings of contrast-enhanced ultrasound plaque imaging are related to those of 3D FSE T1-WI MR plaque imaging according to the life history of arterial plaque and its neovascularization.