Correlation between three-dimensional high-resolution magnetic resonance imaging enhancement characteristics of plaque and time of symptom onset of stroke in patients with intracranial atherosclerotic stenosis / 中华神经科杂志

ABSTRACT

Objective@#To assess the enhancement characteristics of plaques in patients with intracranial atherosclerotic stenosis using three-dimensional high-resolution magnetic resonance imaging (3D HR MRI), and to analyze the correlation between the enhancement characteristics of plaques and the time from onset of stroke symptoms to MRI examination.@*Methods@#The enhancement characteristics of plaques were retrospectively analyzed in 61 patients with cerebral infarction who were scanned in MRI room of the Affiliated Hospital of Yangzhou University from January 2014 to January 2016. According to the elapsed time between symptom onset and MR examination, 61 patients were classified into early stage group (<4 weeks, n=26), middle stage group (4-12 weeks, n=20) and late stage group (>12 weeks, n=15). All cases underwent three-dimensional sampling perfection with application optimized contrast using different angle evolutions (3D-SPACE) T1WI and enhanced 3D-SPACE T1WI sequence scans, as well as routine head MRI examinations. The signal intensities of plaques before and after enhancement scanning were compared on the 3D-SPACE T1WI sequence. The degrees of plaque enhancement were qualitatively analyzed, and the enhancement rates of plaques were quantitatively calculated. The correlation between the enhancement characteristics of plaques and time of symptom onset of stroke was analyzed.@*Results@#Sixty-one intracranial atherosclerotic plaques on the 3D HR MRI showed eccentric thickening or annular thickening of the vessel wall, and slightly higher signals on the T1WI. They showed different degrees of enhancement or no enhancement after enhancement scans. The characteristics of plaque enhancement in 61 patients with cerebral infarction were analyzed. The results showed that 26 plaques in the early stage group were obviously enhanced for 21 cases (80.8%), mildly enhanced for 4 cases (15.4%), no enhancement for 1 case (3.8%), and the enhancement rate was 80.49%±18.64%. Twenty plaques in the middle stage group were obviously enhanced for 2 cases (10.0%), mildly enhanced for 14 cases (70.0%), no enhancement for 4 cases (20.0%), and the enhancement rate was 52.09%±18.17%. Fifteen plaques in the late stage group were mildly enhanced for 2 cases (2/15), no enhancement for 13 cases (13/15), and the enhancement rate was 12.16%±10.44%. There were statistically significant differences in the degrees of plaque enhancement and plaque enhancement rates among the three groups (χ2=22.834, P<0.01; F=78.403, P<0.01). Further analysis showed that there was a statistically significant difference in the degree of enhancement and enhancement rate of plaques between the early stage group and the middle stage group (χ2=-4.177, P<0.01; t=5.179, P<0.01), and there was a statistically significant difference between the middle stage group and the late stage group (χ2=-2.484, P<0.05; t′=8.189, P<0.01), and the difference between the early stage group and the late stage group was also statistically significant (χ2=-3.796, P<0.01; t′=15.044, P<0.01). There was a significant negative correlation between the time from onset of stroke symptoms to MRI examination and the enhancement rate of plaques (r=-0.903, P<0.01).@*Conclusions@#Enhanced HR MRI scanning can clearly show the enhancement of intracranial atherosclerotic plaques. With the prolongation of the onset time interval, the enhancement of intracranial atherosclerotic plaques gradually weakens, which can assess the vulnerability of plaques and has important guiding significance for secondary prevention of ischemic stroke.