Objective To investigate the visualization and quantitation of hemodynamic variables at carotid artery bifurcation in vivo by combining computational fluid dynamics(CFD)and vascular imaging. Methods A healthy volunteer underwent CT angiography of left carotid artery by SIEMENS multi-slice CT. Parameters of hemodynamics at this carotid bifurcation were calculated and visualized by combining vascular imaging post-processing and CFD.Results (1) The average range of flow velocity was 0.04～0.36 m/s. A region of high velocity was seen at medial wall of internal carotid artery (ICA) and medial wall of external carotid artery (ECA), respectively. The largest contiguous region of low velocity occurred at the carotid bulb. (2)The average range of absolute pressure, static pressure and dynamic pressure was 100 266.70～101 615.90 Pa, -1058.34～290.88 Pa, and 6.12～553.25 Pa, respectively. (3) The average range of wall shear stress (WSS) at the bifurcation was 0.59～5.35 Pa. There was a large region of low WSS at carotid bulb and posterior wall of ICA, with the lowest value of 0.25 Pa. Also there was a small region of low WSS at anterior and lateral wall of ECA.Conclusion CFD combined with vascular imaging can calculate and visualize the parameters of hemodynamics at carotid bifurcation in vivo individually. It is an interdisciplinary science of computer, radiology and hemodynamics and provides a new method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes.

Objective:To study the efficacy of endoscopic papillary balloon dilatation (EPBD) in the treatment of non-dilated small choledocholithiasis.Methods:Clinical data of 142 patients with non-dilated small choledocholithiasis admitted to Zhanjiang Central People's Hospital from April 2021 to March 2023 were retrospectively analyzed, including 63 males and 79 females, aged (55.1±15.4) years old. Patients were divided into the EPBD group ( n=63) and endoscopic sphincterotomy (EST) group ( n=79). Blood amylase, liver enzymology, liver metabolism, and blood routine were monitored before and 48 hours after treatment. The occurrences of intraoperative bleeding, perforation, post-ERCP pancreatitis (PEP), and cholangitis were compared between the groups. Patients were followed up and screened for stone recurrence by outpatient review 3 to 12 months from discharge. Results:Compared to preoperative data, the white blood cell count, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bili-rubin, and direct bilirubin decreased 48 hours after treatment (all P<0.05). The operation time in EPBD group was slightly longer than that in EST group [(43.1±5.9) min vs. (38.5±4.5) min, P=0.064] without statistical significance. There were no case of perforation in both groups. The incidences of intraopera-tive bleeding [3.17%(2/63) vs. 6.33%(5/79)], PEP [17.46%(11/63) vs. 10.53%(8/79)], and postoperative cholangitis [4.76%(3/63) vs. 1.27%(1/79)] were comparable between the groups (all P>0.05). Conclusion:EPBD could be feasible for non-dilated small choledocholithiasis, which does not increase the operation time and incidence of adverse events compared to EST.