Differences of signal evolution of intraplaque hemorrhage and associated stenosis between symptomatic and asymptomatic atherosclerotic carotid arteries: an in vivo high-resolution magnetic resonance imaging follow-up study

Abstract

To evaluate the differences of signal evolution of intraplaque hemorrhage (IPH) and associated stenosis between symptomatic and asymptomatic atherosclerotic carotid arteries. Thirty-three carotid arteries (15 symptomatic and 18 asymptomatic plaques) with recent carotid IPH underwent serial high-resolution MRI examinations on a 3.0-Tesla (3.0T) MRI scanner over a period of 18months. MR sequences included three-dimensional time-of-flight (3D-TOF), quadruple-inversion-recovery T1-weighted imaging (QIR T1WI), proton density-weighted imaging (PDWI), and T2-weighted imaging (T2WI). The contrast-to-noise ratios (CNRs) of subsequent IPH during the follow-up period between symptomatic and asymptomatic carotid IPH showed a significant difference on 3D-TOF (P=0.029), T1WI (P=0.005), and PDWI (P=0.028), except for that on T2WI (P=0.362). Compared with no significant signal intensity change of symptomatic IPH, CNRs of asymptomatic IPH exhibited a gradually descending trend on all contrast weighted images (P<0.05). Compared with asymptomatic arteries, the degree of diameter stenosis associated with IPH increased significantly in the symptomatic atherosclerotic carotid arteries between baseline and the 18th month (10.53±12.29% vs. 1.65±7.74%, P=0.017). Symptomatic and asymptomatic carotid IPH demonstrated different MRI signal evolution and associated carotid stenosis. Repeated carotid IPH may be more common in symptomatic plaques than in asymptomatic plaques and might produce a stronger stimulus for progression of atherosclerosis than one-time carotid IPH.