General Characteristics of the Patients and Aneurysms
The baseline characteristics of the patients and UIAs are summarized in Table 1. In accordance with the inclusion and exclusion criteria set for this study, a total of 68 cases of unruptured intracranial aneurysms were included. Among these cases, there were 30 males and 38 females, with an average age of 52.22 ± 9.22 years and a range of 35 to 78 years. Among the patients, 32 had a history of hypertension (47.1%), 6 had a history of diabetes (8.8%), 9 had a history of smoking (13.2%), 3 had a history of spontaneous subarachnoid hemorrhage (4.4%), and 10 patients had multiple aneurysms (14.7%).
Patients with multiple aneurysms were selected based on higher scores according to an aneurysm morphological assessment. The sizes of the aneurysms ranged from 2.5mm to 11.5mm, with an average size of 6.36 ± 2.44mm. Among them, 24 aneurysms (33.8%) were in the size range of 0-5.0mm, 33 aneurysms (50.0%) were in the size range of 5.0-10.0mm, and 11 aneurysms (16.2%) were larger than 10.0mm. Of these aneurysms, 26 (38.2%) were located in the internal carotid artery, 11 (16.2%) in the middle cerebral artery, 7 (10.3%) in the posterior circulation, 20 (29.4%) in the posterior communicating artery, and a total of 4 (5.9%) in the anterior cerebral artery and anterior communicating artery.Among the included aneurysms, 27 (39.7%) exhibited an irregular morphology.
Morphological and Hemodynamic Characteristics Related to Serum MBL Concentration
In accordance with the detected serum MBL concentrations, the included 68 cases were divided into three groups:low concentration (30 cases, 44.1%), moderate concentration (25 cases, 36.8%), and high concentration (13 cases, 19.1%). Univariate analysis results demonstrated that there were no statistically significant differences in general characteristics, including age, gender, history of hypertension, history of diabetes, smoking history, history of spontaneous subarachnoid hemorrhage, aneurysm multiplicity, and aneurysm location among the different concentration groups. The distribution of unruptured intracranial aneurysm sizes among the concentration groups was as follows: low concentration group with a median size of 4.35 (2.50, 9.43) mm, moderate concentration group with a median size of 6.50 (3.92, 11.20) mm, and high concentration group with a median size of 8.20 (6.80, 11.00) mm. The differences in aneurysm sizes among the groups were statistically significant (P < 0.001) (Table 2). As aneurysm size increased, serum MBL concentration gradually elevated. The proportions of aneurysms within different size ranges were as follows: for sizes in the range of 0.0-5.0mm, proportions were 83.3% (20/24), 16.7% (4/24), and 0.0% (0/24) for low, moderate, and high concentration groups, respectively; for sizes in the range of 5.0-10.0mm, proportions were 27.3% (9/33), 51.5% (17/33), and 21.2% (7/33); for sizes greater than 10.0mm, proportions were 9.1% (1/11), 36.4% (4/11), and 54.5% (6/11) (as shown in Fig. 1).
Morphological and hemodynamic parameters among the different groups are presented in Table 2. Parameters including Size, SR, AR, and VNR exhibited statistically significant differences, showing an increasing trend with higher serum MBL concentration. The proportion of irregularly shaped aneurysms also increased with higher serum MBL concentration. Other parameters such as HW, aneurysm angle θA, and inlet angle IA did not exhibit statistically significant differences. Hemodynamic parameter results among the groups demonstrated that WSS, velocity, LSA, and RRT exhibited statistically significant differences and demonstrated trends corresponding to serum MBL concentration. However, parameters such as OSI and pressure did not exhibit statistically significant differences (as shown in Fig. 2).
To further analyze the independent risk factors for elevated serum MBL concentration in unruptured intracranial aneurysms, a multiple linear regression analysis was conducted including factors that exhibited statistical significance in univariate analysis. The results indicated that SR, WSS, velocity, LSA, and RRT were independent risk factors for elevated serum MBL concentration (Table 3). Consequently, it can be inferred that these parameters contribute to the exacerbation of inflammation in the walls of unruptured intracranial aneurysms (Fig. 3).
Morphological, Hemodynamic, and MBL Patterns of High Rupture Risk
To assess the rupture risk, we calculated the PHASES score for each case, and after statistical analysis, we observed a significant difference in PHASES scores among the different concentration groups (P < 0.001) (Fig. 4). According to the PHASES study, scores of 5 and 8 correspond to 1% and 3% 5-year rupture probabilities, respectively7. Therefore, we divided the overall scores into three intervals: 0–4, 5–7, and ≥ 8. In the 0–4 interval, there were 33 cases (48.5%), in the 5–7 interval, 25 cases (36.8%), and in the ≥ 8 interval, 10 cases (14.7%). The distribution of serum MBL concentration and aneurysmal hemodynamic parameters across different score intervals is presented in Table 4. The results indicated the following: a、Differences in serum MBL concentration among different score interval groups were statistically significant (P < 0.001) (Fig. 4). With an increase in PHASES score, serum MBL concentration also gradually increased. Within the 0–4 score interval, the proportions of low, moderate, and high concentration groups were 84.8% (28/33), 15.2% (5/33), and 0.0% (0/33). Within the 5–7 score interval, the proportions were 8.0% (2/25), 72.0% (18/25), and 20.0% (5/25). Within the ≥ 8 score interval, the proportions were 0.0% (0/8), 30.0% (3/10), and 70.0% (7/10) (Fig. 1).b、Among the different score intervals, morphological parameters including Size, SR, AR, VNR, and irregular morphology exhibited statistically significant differences. These parameters showed a trend of increasing values with higher PHASES rupture risk scores. Parameters such as HW (P = 0.768), aneurysm angle θA (P = 0.884), and inlet angle IA (P = 0.578) did not exhibit statistically significant differences among the groups. Among the hemodynamic parameters, WSS, velocity, LSA, and RRT exhibited statistically significant differences, consistently reflecting lower and more variable wall shear stress, slower blood flow velocity within the aneurysm, and relatively longer residence time of blood within the aneurysm. Differences in OSI and pressure among the groups were not statistically significant (Fig. 5).