High-Resolution Magnetic Resonance Imaging Study On Carotid Atherosclerotic Plaque With Various Clinical Symptoms

Part I:Differences of Signal Evolution of Intraplaque Hemorrhage and Associated Stenosis between Symptomatic and Asymptomatic Atherosclerotic Carotid ArteriesPurpose:To evaluate the differences of signal evolution of intraplaque hemorrhage (IPH) and associated stenosis between symptomatic and asymptomatic atherosclerotic carotid arteries.Methods: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 18 months. MR sequences included three-dimensional time-of-flight (3D-TOF), quadruple-inversion-recovery Tl-weighted imaging (QIR T1WI), proton density-weighted imaging (PDWI), and T2-weighted imaging (T2WI). Contrast-to-noise ratio (CNR) was used to monitor the signal strength of carotid IPH.Results: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). Conclusions: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. PartⅡ:Comparison of carotid arterial morphology and plaque composition between patients with acute coronary syndrome and stable coronary artery diseasePurpose:To evaluate the differences in carotid arterial morphology and plaque composition between patients with acute coronary syndrome (ACS) and patients with stable coronary artery disease (SCAD).Methods:Twenty-eight patients (12 ACS patients and 16 SCAD patients) underwent carotid high-resolution MRI examination using a 3.0-Tesla (3.0T) MRI scanner. The indicators of carotid arterial morphology included the maximum total vessel area (Max-TVA), mean TVA, minimum lumen area (Min-LA), mean LA, maximum wall area (Max-WA), mean WA, maximum wall thickness (Max-WT), mean WT, maximum normalized wall index (Max-NWI), mean NWI, and maximum stenosis (Max-stenosis). The indicators of plaque composition included the prevalence and mean area percentage (%) of lipid-rich necrotic core (LRNC), calcification (Ca), intraplaque hemorrhage (IPH), and fibrous cap rupture (FCR).Results:None of the indicators of carotid arterial morphology had significant differences (all P>0.05) between the ACS and SCAD patients. The prevalence and plaque composition area percentage of LRNC, Ca, and IPH did not exhibit significant differences between the two groups. However, carotid plaques in the ACS patients presented a higher prevalence of FCR than SCAD patients (P 0.05).Conclusions:This study revealed a similar carotid arterial morphology between ACS and SCAD patients. However, FCR is more common in carotid plaques with ACS than in those with SCAD. Ruptured carotid plaques may be a forewarning factor for those patients who are at high risk of ACS.