Abstract TP232: Symptomatic Plaque with Low-grade Stenosis Which Retains Hyperintensity After an Ischemic Event may Indicate a High Risk of a Subsequent Ipsilateral Ischemic Event

Abstract

Introduction: Intraplaque hemorrhage (IPH) has been reported to be a characteristic feature of a vulnerable plaque, indicated by an area of high signal intensity on carotid MRI. It has been reported that symptomatic low-grade stenosis with IPH is strongly associated with ischemic events, but there are limited data regarding the dynamics of the carotid plaque signal. The aim of this study was to assess the time-dependent change of carotid plaque in the symptomatic patient with low-grade stenosis. Methods: Thirty-eight symptomatic patients with carotid low-grade stenosis (0.31 between time points was considered significant. We then investigated changes in rSI and subsequent ipsilateral ischemic events. Result: Of the 38 patients, there were strong-positive and positive plaque at baseline in 22 and 12 patients, respectively. During a mean follow-up period of 42.5 months, 26 positive plaques (74%) at baseline kept an rSI of >1.25, and all of 4 negative plaques at baseline changed positive. Strong-positive plaques at baseline showed a lower tendency to be negative than positive plaque (p=0.08). Twenty-one of the 38 patients (55%) experienced a total of 26 recurrent ischemic events. In patients who experienced recurrent ischemic events, 19 plaques (73%) were strong-positive and 5 plaques (19%) were positive. Compared to the most recent carotid MRI, rSI at the event was stable in 18 patients (69%) and increased in 8 patients (31%). Conclusions: Most symptomatic plaque with low-grade stenosis retained its hyperintensity after ischemic events and had a high rate of subsequent ipsilateral ischemic events. A sustaining high signal intensity might be associated with an increased risk of subsequent ischemic events. Follow-up observation by carotid MRI has the potential to increase the accuracy of stroke risk stratification in the management of carotid low-grade stenosis.