Biomechanical assessment predicts aneurysm-related events in patients with abdominal aortic aneurysm

Objective To test whether aneurysm biomechanical ratio (ABR; a dimensionless ratio of wall stress and wall strength) can predict aneurysm related events. Methods In a prospective multicentre clinical study of 295 patients with an abdominal aortic aneurysm (AAA; diameter ≥ 40 mm), three dimensional reconstruction and computational biomechanical analyses were used to compute ABR at baseline. Participants were followed for at least two years and the primary end point was the composite of aneurysm rupture or repair. Results The majority were male (87%), current or former smokers (86%), most (72%) had hypertension (mean ± standard deviation [SD] systolic blood pressure 140 ± 22 mmHg), and mean ± SD baseline diameter was 49.0 ± 6.9 mm. Mean ± SD ABR was 0.49 ± 0.27. Participants were followed up for a mean ± SD of 848 ± 379 days and rupture (n = 13) or repair (n = 102) occurred in 115 (39%) cases. The number of repairs increased across tertiles of ABR: low (n = 24), medium (n = 34), and high ABR (n = 44) (p = .010). Rupture or repair occurred more frequently in those with higher ABR (log rank p = .009) and ABR was independently predictive of this outcome after adjusting for diameter and other clinical risk factors, including sex and smoking (hazard ratio 1.41; 95% confidence interval 1.09–1.83 [p = .010]). Conclusion It has been shown that biomechanical ABR is a strong independent predictor of AAA rupture or repair in a model incorporating known risk factors, including diameter. Determining ABR at baseline could help guide the management of patients with AAA

Towards Personalized Management of Ovarian Cancer

Despite advances in surgery and chemotherapy, the overall outcomes for patients with advanced ovarian cancer remain poor. Although initial response rates to platinum-based chemotherapy is about 60–80%, most patients will have recurrence and succumb to the disease. However, a DNA repair–directed precision medicine strategy has recently generated real hope in improving survival. The clinical development of PARP inhibitors has transformed lives for many patients with BRCA germline-deficient and/or platinum-sensitive epithelial ovarian cancers. Antiangiogenic agents and intraperitoneal chemotherapy approaches may also improve outcomes in patients. Moreover, evolving immunotherapeutic opportunities could also positively impact patient outcomes. Here we review the current clinical state of PARP inhibitors and other clinically viable targeted approaches in ovarian cancer

Medical students’ preparedness for professional activities in early clerkships

Background Sufficient preparedness is important for transitions to workplace participation and learning in clinical settings. This study aims to analyse medical students’ preparedness for early clerkships using a three-dimensional, socio-cognitive, theory-based model of preparedness anchored in specific professional activities and their supervision level. Methods Medical students from a competency-based undergraduate curriculum were surveyed about preparedness for 21 professional activities and level of perceived supervision during their early clerkships via an online questionnaire. Preparedness was operationalized by the three dimensions of confidence to carry out clerkship activities, being prepared through university teaching and coping with failure by seeking support. Factors influencing preparedness and perceived stress as outcomes were analysed through step-wise regression. Results Professional activities carried out by the students (n = 147; 19.0%) and their supervision levels varied. While most students reported high confidence to perform the tasks, the activity-specific analysis revealed important gaps in preparation through university teaching. Students regularly searched for support in case of difficulty. One quarter of the variance of each preparedness dimension was explained by self-efficacy, supervision quality, amount of prior clerkship experience and nature of professional activities. Preparedness contributed to predicting perceived stress. Conclusions The applied three-dimensional concept of preparedness and the task-specific approach provided a detailed and meaningful view on medical students’ workplace participation and experiences in early clerkships

Simulation of Vehicle-Pedestrian Interaction

The literature on vehicle crash reconstruction provides a number of empirical or classical theoretical models for the distance pedestrians are thrown in impacts with various types of vehicles and impact speeds. The aim of this research was to compare the predictions offered by computer simulation to those obtained using the empirical and classical theoretical models traditionally utilised in vehicle-pedestrian accident reconstruction. Particular attention was paid to the pedestrian throw distance versus vehicle impact speed relationship and the determination of pedestrian injury patterns and associated severity. It was discovered that computer simulation offered improved pedestrian kinematic prediction in comparison to traditional vehicle-pedestrian accident reconstruction techniques. The superior kinematic prediction was found to result in a more reliable pedestrian throw distance versus vehicle impact speed relationship, particularly in regard to varying vehicle and pedestrian parameters such as shape, size and orientation. The pedestrian injury prediction capability of computer simulation was found to be very good for head and lower extremity injury determination. Such injury prediction capabilities were noted to be useful in providing additional correlation of vehicle impact speed predictions, whether these predictions were made using computer simulation, traditional vehicle-pedestrian accident reconstruction methods or a combination of both. A generalised approach to the use of computer simulation for the reconstruction of vehicle-pedestrian accidents was also offered. It is hoped that this approach is developed and improved by other researchers so that over time guidelines for a standardised approach to the simulation of vehicle-pedestrian accidents might evolve. Thoracic injury prediction, particularly for frontal impacts, was found to be less than ideal. It is suspected that the relatively poor thoracic biofidelity stems from the development of pedestrian mathematical models from occupant mathematical models, which were in turn developed from cadaver and dummy tests. It is hoped that future research will result in improved thoracic biofidelity in human mathematical models

Iterative reconstruction incorporating background correction improves quantification of [18F]-NaF PET/CT images of patients with abdominal aortic aneurysm

Background A confounding issue in [18F]-NaF PET/CT imaging of abdominal aortic aneurysms (AAA) is the spill in contamination from the bone into the aneurysm. This study investigates and corrects for this spill in contamination using the background correction (BC) technique without the need to manually exclude the part of the AAA region close to the bone. Methods Seventy-two (72) datasets of patients with AAA were reconstructed with the standard ordered subset expectation maximization (OSEM) algorithm incorporating point spread function (PSF) modelling. The spill in effect in the aneurysm was investigated using two target regions of interest (ROIs): one covering the entire aneurysm (AAA), and the other covering the aneurysm but excluding the part close to the bone (AAAexc). ROI analysis was performed by comparing the maximum SUV in the target ROI (SUVmax(T)), the corrected cSUVmax (SUVmax(T) − SUVmean(B)) and the target-to-blood ratio (TBR = SUVmax(T)/SUVmean(B)) with respect to the mean SUV in the right atrium region. Results There is a statistically significant higher [18F]-NaF uptake in the aneurysm than normal aorta and this is not correlated with the aneurysm size. There is also a significant difference in aneurysm uptake for OSEM and OSEM + PSF (but not OSEM + PSF + BC) when quantifying with AAA and AAAexc due to the spill in from the bone. This spill in effect depends on proximity of the aneurysms to the bone as close aneurysms suffer more from spill in than farther ones. Conclusion The background correction (OSEM + PSF + BC) technique provided more robust AAA quantitative assessments regardless of the AAA ROI delineation method, and thus it can be considered as an effective spill in correction method for [18F]-NaF AAA studies