Hyo Jeong Kang

Pseudoaneurysm forms as a sac from arterial wall damage due to percutaneous procedures and poses a high risk of rupture if untreated. Ultrasound-guided thrombin injection (UGTI) is the most common minimally invasive treatment, which specifically involves the interaction between injected thrombin and plasma fibrinogen. This study presents the development of a thrombin-induced thrombosis model within a computational fluid dynamics framework to simulate thrombus formation in plasma. The model was applied to pseudoaneurysms with complex geometries, including sac diameters greater than 20 mm, neck widths exceeding 10 mm, or neck lengths shorter than 5 mm. By varying injection parameters such as location, duration, and dosage, we evaluated procedural outcomes based on two clinical indicators: technical success and treatment success. The analysis revealed that injection times shorter than 5 s were associated with lower treatment success rates, indicating reduced procedural safety. In contrast, injection durations of 8 s or longer led to improved technical and treatment outcomes. Additionally, treatment success was more consistent when the thrombin dose approached 500 IU. However, in pseudoaneurysms with neck widths over 10 mm, increasing the thrombin dose caused excessive fibrin leakage outside the sac. To ensure both the safety and effectiveness of UGTI procedures, it is clinically recommended to maintain an injection time of at least 8 s, limit the thrombin dose to 500 IU or less, and target the center of the pseudoaneurysm sac for injection.

Several studies have investigated predictive factors such as morphological, physiological, and fluid dynamics perspectives for obstructive sleep apnea (OSA) using computed tomography imaging, computer simulations, and experiments. Computational fluid dynamics is used in this study to analyze airflow in the upper airway across different body mass index (BMI) groups to identify suitable factors for predicting OSA. A comparative analysis is conducted on three groups: normal BMI (22.8 ± 1.0), overweight BMI (31.8 ± 1.5), and OSA (28.6 ± 3.3), with nine participants in each group. Geometric parameters were analyzed in addition to fluid dynamics factors. A comparison of the geometric variables revealed that the OSA group had the shortest total airway length (1.5 × 10−1 m) and the smallest volume (5.4 × 10−5 m3). However, t-test results showed low statistical significance for these differences. For fluid dynamics variables, the OSA group experienced the highest pressure drop (−46.8 Pa) and the highest adjusted pressure coefficient (Cp = 0.88) compared to the other two groups. From the analysis of breathing diagrams, the OSA group exhibited the largest area under the breathing power curve (32.6 × 10−3 N m/s) followed by the normal weight (24.9 × 10−3 N m/s) and overweight (21.0 × 10−3 N m/s) groups in descending order. Analysis of fluid dynamics factors indicated that the OSA group exhibited significantly higher pressure drop and pressure coefficient values compared to other groups although the differences between the groups were less significant. Finally, one key finding from this research highlights a new computational approach that relies on the breathing diagram. This new approach could provide more accurate insights into predicting and managing OSA due to their distinctive shapes.