Objective:To investigate the CD163 expression characteristics in intracranial aneurysm (IA) tissue and blood of patients with IA and its feasibility as an early clinical screening indicator for IA.Methods:A total of 28 patients with IA admitted to Department of Neurosurgery, First Affiliated Hospital of Xinjiang Medical University from January 2021 to November 2023 were selected as IA group, and 28 healthy subjects from Health Management Center, First Affiliated Hospital of Xinjiang Medical University at the same time period were selected as control group. Eight saccular IA tissues and 12 superficial temporal artery tissues were collected from patients from IA group accepted IA clipping, and real-time fluorescent quantitative PCR (RT-qPCR) was used to detect the CD163 mRNA expression in these tissues. RT-qPCR was also used to detect the CD163 mRNA expression in the blood of the 2 groups. Seven patients with IA and 7 control subjects from the above 2 groups were randomly selected, respectively; and plasma CD163 protein content was detected by enzyme-linked immunosorbent assay (ELISA). Multivariate Logistic regression was used to analyze the influencing factors for IA. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic values of blood CD163 mRNA expression and plasma CD163 protein content in IA. Results:CD163 mRNA expression in IA tissues was significantly higher than that in superficial temporal artery tissues (41.870±20.355 vs. 6.080±5.444, P<0.05). CD163 mRNA expression in the blood of IA patients was significantly higher than that in the controls (1.969[1.124, 2.318] vs. 1.124[0.933, 1.379], P<0.05). CD163 mRNA expression in the blood of ruptured IA group, unruptured IA group, and control group was gradually decreased, with significant differences ( P<0.05). CD163 mRNA expression in the blood of female IA patients was not statistically different compared with that in male IA patients ( P>0.05). ELISA showed that the CD163 protein content in plasma of the IA group was significantly higher than that in the control group [10.537±1.879] ng/L vs. [8.598±0.885] ng/L, P<0.05). Multivariate Logistic regression analysis showed that age and CD163 mRNA expression in the blood were independent influencing factors for IA occurrence ( OR=0.844, 95% CI: 0.750-0.951, P=0.005; OR=0.111, 95% CI: 0.024-0.506, P=0.004). ROC curve showed that the area under the curve (AUC) of CD163 mRNA expression in blood in diagnosing IA was 0.759 (95% CI: 0.618-0.890, P=0.002), and that of CD163 protein content in plasma in diagnosing IA was 0.864 (95% CI: 0.610-1.000, P=0.035). Conclusion:CD163 mRNA expressions in blood and IA tissues and CD163 protein content in plasma are high in patients with IA; CD163 mRNA expression in blood is an independent risk factor for IA; CD163 protein in plasma can be used as a molecular marker for screening IA.