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

ABSTRACT

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