CD163 and aneurysm: Hasan also obtained the same result by immunohistochemistry, and they found that RIA from patients possess increased M1 (HLA-DR+) cells opposed to M2 (CD163+) cells.[51] In addition, based on the research of macrophages, many institutions apply macrophage imaging technology to more detailed classification of aneurysms, which has important guiding significance for clinical practice.[52]