From the Departments of Radiology (M.A., Z.A.K., T.H.)
Pathology (K.M., A.Y.).
AJNR Am J Neuroradiol. 2020 Feb;41(2):310-317. doi: 10.3174/ajnr.A6374. Epub 2019 Dec 26.
Intraplaque hemorrhage in the carotid artery is related to an increased risk of cerebrovascular ischemic events. We aimed to investigate whether quantitative susceptibility mapping can characterize carotid artery plaque components and quantify the severity of intraplaque hemorrhage.
For this ex vivo quantitative susceptibility mapping study, 9 carotid endarterectomy specimens were imaged on a 3T MR imaging scanner using a 3D multi-echo gradient-echo sequence and a microscopy coil. The samples were examined histologically using immunostains, including glycophorin A and Prussian blue. The areas of erythrocytes, iron deposits, calcification, and fibrous matrices observed on stained sections were compared with quantitative susceptibility mapping findings and their mean susceptibility values.
Intraplaque hemorrhage and iron deposits were observed only in areas hyperintense on quantitative susceptibility mapping; calcifications and fibrous matrices were prevalent in hypointense areas. The mean susceptibility values for necrotic cores with intraplaque hemorrhage but no iron deposits, cores with iron deposits but no intraplaque hemorrhage, cores without either intraplaque hemorrhage or iron deposits, and cores with calcification were 188 ± 51, 129 ± 49, -11 ± 17, and -158 ± 78 parts per billion, respectively. There was a significant difference in the mean susceptibility values among the 4 histologic components (< .01). The mean susceptibility values of the whole plaque positively correlated with the percentage area positive for glycophorin A ( = 0.65, < .001) and Prussian blue ( = 0.47, < .001).
Our findings suggest that quantitative susceptibility mapping can characterize the composition of carotid plaques and quantify the degree of intraplaque hemorrhage and iron deposits.
颈动脉斑块内出血与脑血管缺血性事件风险增加有关。本研究旨在探讨定量磁化率成像能否对颈动脉斑块成分进行特征描述并定量评估斑块内出血严重程度。
本离体研究采用 3T MR 成像扫描仪对 9 个颈动脉内膜切除术标本进行 3D 多回波梯度回波序列和显微镜线圈扫描。采用免疫组化染色（包括糖蛋白 A 和普鲁士蓝）对标本进行组织学检查。将染色切片上观察到的红细胞、铁沉积、钙化和纤维基质区域与定量磁化率成像结果及其平均磁化率值进行比较。
仅在定量磁化率成像上表现为高信号的区域中观察到斑块内出血和铁沉积；而在低信号区域中则常见钙化和纤维基质。伴有斑块内出血但无铁沉积、伴有铁沉积但无斑块内出血、既无斑块内出血也无铁沉积以及伴有钙化的坏死核心的平均磁化率值分别为 188 ± 51、129 ± 49、-11 ± 17 和-158 ± 78 皮摩尔/十亿。4 种组织学成分的平均磁化率值存在显著差异（< .01）。整个斑块的平均磁化率值与糖蛋白 A 阳性百分比（ = 0.65，< .001）和普鲁士蓝阳性百分比（ = 0.47，< .001）呈正相关。
本研究结果表明，定量磁化率成像可以对颈动脉斑块的成分进行特征描述，并定量评估斑块内出血和铁沉积的程度。
