Ruptured abdominal aortic aneurysms: endovascular repair versus open surgery. A decision analytic approach

This thesis describes studies on the evaluation of endovascular repair versus open surgery in patients with ruptured abdominal aortic aneurysm (AAA). In chapter 1, the rationale for this research is presented. Since in the western world, the population is aging, it is expected that the incidence of abdominal aortic aneurysms will increase and consequently, ruptured AAAs. Ruptured AAA is a life threatening condition that requires immediate intervention. The condition can be treated with endovascular repair or open surgery. Therefore, the aim of this thesis was to investigate whether endovascular repair or open surgery would be the preferred treatment in this group of patients from a decision analytic approach, taking clinical effectiveness as well as costs into account. To enable comparison of the results of endovascular repair with open surgery in patients with a ruptured AAA from the literature, it is important to systemically evaluate the published studies and to adjust for differences in inclusion criteria among the studies. In chapter 2, we performed a systematic review of studies that compared endovascular repair with open surgery in the treatment of patients with a ruptured AAA. We found that, after adjustment for patients’ hemodynamic condition upon presentation, a benefit in 30-day mortality for endovascular repair compared with open surgery for patients with a ruptured AAA was observed but was not statistically significant. In chapter 3, we compared the clinical outcomes of treatment after endovascular repair and open surgery in patients with ruptured infrarenal AAAs including one-year follow-up. It turned out that in our study with a highly selective population, mortality and morbidity might be similar for patients with a ruptured infrarenal AAA treated with endovascular repair compared with open surgery, even after one- year follow-up. In addition to the aneurysm anatomy, other criteria may be needed for endovascular repair to improve clinical outcomes. The Glasgow Aneurysm Score (GAS) is a prediction rule to predict in- hospital mortality after open surgery for patients with ruptured and unruptured AAA. The GAS, however, was developed in patients treated with open surgery only, whereas nowadays, endovascular repair is the preferred treatment for repair of ruptured AAA in many European hospitals. In chapter 4, the GAS was validated in patients with ruptured AAA treated with endovascular repair or open surgery. In addition, our aim was to modify the GAS into an updated prediction rule that predicts 30-day mortality after endovascular repair or open surgery. We found that the GAS showed limited discriminative ability in our patient population. In addition, we showed that, considering the included risk factors, 30-day mortality was always lower if patients with ruptured AAA were treated with endovascular repair instead of with open surgery. To evaluate the incurred costs of both endovascular repair and open surgery, it is important to calculate both in-hospital costs and costs during follow-up after the procedure. Chapter 5 describes the retrospectively assessment of in-hospital costs and costs of one-year follow-up of endovascular repair and open surgery in patients with an acute infrarenal AAA, using the resource utilization approach. We found that total costs including in-hospital costs and one-year follow-up in patients with acute infrarenal AAA were lower for endovascular repair than for open surgery. From a health policy perspective, it should be questioned whether current available evidence justifies today’s policy to treat patients with ruptured AAA with endovascular repair if anatomically suitable. In addition, it is of interest whether additional information is required to inform the decision making process for patients with ruptured AAA in the future. Therefore, in chapter 6, we evaluated the cost-effectiveness of endovascular repair compared with open surgery in patients with ruptured AAA and investigated whether performing future research to obtain additional information is justified. We concluded that endovascular repair was more effective and less costly compared with open surgery in patients with ruptured AAA. Therefore, current available evidence does justify today’s policy to treat patients with ruptured AAA with endovascular repair if anatomically suitable. In addition, further research is justified and should concentrate on short-term costs and clinical! effectiveness of endovascular repair versus open surgery in patients with ruptured AAA. In chapter 7 the main findings were summarized of the preceding chapters and placed in a broader context. In addition, methodological considerations and future research were discussed

Automatic detection of actionable findings and communication mentions in radiology reports using natural language processing

__Objectives:__ To develop and validate classifiers for automatic detection of actionable findings and documentation of nonroutine communication in routinely delivered radiology reports. __Me

Assessment of actionable findings in radiology reports

Purpose: The American College of Radiology (ACR) Actionable Reporting Work Group defined three categories of imaging findings that require additional, nonroutine communication wit

Differential diagnosis and mutation stratification of desmoid-type fibromatosis on MRI using radiomics

Purpose: Diagnosing desmoid-type fibromatosis (DTF) requires an invasive tissue biopsy with β-catenin staining and CTNNB1 mutational analysis, and is challenging due to its rarity. The aim of this study was to evaluate radiomics for distinguishing DTF from soft tissue sarcomas (STS), and in DTF, for predicting the CTNNB1 mutation types. Methods: Patients with histologically confirmed extremity STS (non-DTF) or DTF and at least a pretreatment T1- weighted (T1w) MRI scan were retrospectively included. Tumors were semi-automatically annotated on the T1w scans, from which 411 features were extracted. Prediction models were created using a combination of various machine learning approaches. Evaluation was performed through a 100x random-split cross-validation. The model for DTF vs. non-DTF was compared to classification by two radiologists on a location matched subset. Results: The data included 203 patients (72 DTF, 131 STS). The T1w radiomics model showed a mean AUC of 0.79 on the full dataset. Addition of T2w or T1w post-contrast scans did not improve the performance. On the location matched cohort, the T1w model had a mean AUC of 0.88 while the radiologists had an AUC of 0.80 and 0.88, respectively. For the prediction of the CTNNB1 mutation types (S45 F, T41A and wild-type), the T1w model showed an AUC of 0.61, 0.56, and 0.74. Conclusions: Our radiomics model was able to distinguish DTF from STS with high accuracy similar to two radiologists, but was not able to predict the CTNNB1 mutation status

Radiomics approach to distinguish between well differentiated liposarcomas and lipomas on MRI

Background: Well differentiated liposarcoma (WDLPS) can be difficult to distinguish from lipoma. Currently, this distinction is made by testing for MDM2 amplification, which requires a biopsy. The aim of this study was to develop a noninvasive method to predict MDM2 amplification status using radiomics features derived from MRI. Methods: Patients with an MDM2-negative lipoma or MDM2-positive WDLPS and a pretreatment T1-weighted MRI scan who were referred to Erasmus MC between 2009 and 2018 were included. When available, other MRI sequences were included in the radiomics analysis. Features describing intensity, shape and texture were extracted from the tumour region. Classification was performed using various machine learning approaches. Evaluation was performed through a 100 times random-split cross-validation. The performance of the models wa