Figure 2.

Hemodynamics, collagen turnover, and collagen maturity in ruptured or unruptured intracranial aneurysm (IA). A and B, Association between aneurysmal time-averaged wall shear stress (WSS; top) and corresponding collagen turnover rate (bottom) is illustrated in 2 ruptured IA samples: (A) an IA of the internal carotid artery with high WSS (10.4 Pa) and high collagen turnover (≥2000% per y) is shown; (B) an IA of the anterior cerebral artery with low WSS (1.4 Pa) and low collagen turnover (20% per y) is depicted. C and D, Movat pentachrome (small inset, with x50 magnification) for overview and corresponding Picrosirius Red staining for visualization of collagen I maturity in 2 representative unruptured IA samples: in each panel, 8-μm cryosections, stained in Picrosirius Red, are visualized by polarized microscopy (left: overview with x50 magnification; right: x200 magnification). C, Rather unstructured, immature collagen is illustrated in an unruptured IA patient with arterial hypertension and smoking, whereas D highlights rather structured, mature collagen in an unruptured IA patient without risk factors. ○ indicates F¹⁴C predicted value; ◊, F¹⁴C aneurysm sample; ×, F¹⁴C aneurysm excision date.