Procedure-related risk factors for bleeding after percutaneous transhepatic biliary drainage: A systematic review and meta-analysis.

BACKGROUND/PURPOSE: Bleeding is the most dreaded complication after percutaneous transhepatic biliary drainage (PTBD). Clarifying the risk factors of bleeding can reduce the morbidity and mortality rates of PTBD. However, the procedure-related risk factors for bleeding after PTBD are still controversial. Therefore, this systematic review and meta-analysis were performed to identify procedure-related risk factors of bleeding after PTBD. METHODS: PubMed, Cochrane database, and Google Scholar were searched for published studies until 1st May 2021. Inclusion criteria were: studies associated with bleeding complications after PTBD and with sufficient data to compare different procedure-related factors for bleeding. Sources of bias were assessed using the Newcastle-Ottawa Scale and Cochrane risk-of-bias tool for randomised trials. Probable procedure-related risk factors were evaluated and outcomes were expressed in the case of dichotomous variables, as an odds ratio (OR) (with a 95% confidence interval, (CI)). RESULTS: Eleven studies were included in the meta-analysis. There was no significant difference in bleeding rates with respect to the side of PTBD (left/right, OR = 1.10, 95% CI: 0.68-1.76), the insertion level of bile duct (central/peripheral, OR = 1.39, 95% CI: 0.82-2.35), and the usage of ultrasound guidance (OR: 1.25, 95% CI: 0.60-2.60). A subgroup analysis revealed a left-sided approach that resulted in more hepatic arterial injuries than the right-sided approach (left/right, OR = 1.93, 95% CI: 1.32-2.83). CONCLUSION: Left-sided approach is a risk factor for hepatic arterial injuries after PTBD.

Graph theory applications in congenital heart disease.

Graph theory can be used to address problems with complex network structures. Congenital heart diseases (CHDs) involve complex abnormal connections between chambers, vessels, and organs. We proposed a new method to represent CHDs based on graph theory, wherein vertices were defined as the spaces through which blood flows and edges were defined by the blood flow between the spaces and direction of the blood flow. The CHDs of tetralogy of Fallot (TOF) and transposition of the great arteries (TGA) were selected as examples for constructing directed graphs and binary adjacency matrices. Patients with totally repaired TOF, surgically corrected d-TGA, and Fontan circulation undergoing four-dimensional (4D) flow magnetic resonance imaging (MRI) were included as examples for constructing the weighted adjacency matrices. The directed graphs and binary adjacency matrices of the normal heart, extreme TOF undergoing a right modified Blalock-Taussig shunt, and d-TGA with a ventricular septal defect were constructed. The weighted adjacency matrix of totally repaired TOF was constructed using the peak velocities obtained from 4D flow MRI. The developed method is promising for representing CHDs and may be helpful in developing artificial intelligence and conducting future research on CHD.

Small-Field Measurements of 3D Polymer Gel Dosimeters through Optical Computed Tomography.

With advances in therapeutic instruments and techniques, three-dimensional dose delivery has been widely used in radiotherapy. The verification of dose distribution in a small field becomes critical because of the obvious dose gradient within the field. The study investigates the dose distributions of various field sizes by using NIPAM polymer gel dosimeter. The dosimeter consists of 5% gelatin, 5% monomers, 3% cross linkers, and 5 mM THPC. After irradiation, a 24 to 96 hour delay was applied, and the gel dosimeters were read by a cone beam optical computed tomography (optical CT) scanner. The dose distributions measured by the NIPAM gel dosimeter were compared to the outputs of the treatment planning system using gamma evaluation. For the criteria of 3%/3 mm, the pass rates for 5 × 5, 3 × 3, 2 × 2, 1 × 1, and 0.5 × 0.5 cm2 were as high as 91.7%, 90.7%, 88.2%, 74.8%, and 37.3%, respectively. For the criteria of 5%/5 mm, the gamma pass rates of the 5 × 5, 3 × 3, and 2 × 2 cm2 fields were over 99%. The NIPAM gel dosimeter provides high chemical stability. With cone-beam optical CT readouts, the NIPAM polymer gel dosimeter has potential for clinical dose verification of small-field irradiation.