RESUMEN
Background: The aim of this study was to evaluate the clinical usefulness of radiomics signature-derived 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) for the early prediction of neoadjuvant chemotherapy (NAC) outcomes in patients with (BC). Methods: A total of 124 patients with BC who underwent pretreatment PET-CT scanning and received NAC between December 2016 and August 2019 were studied. The dataset was randomly assigned in a 7:3 ratio to either the training or validation cohort. Primary tumor segmentation was performed, and radiomics signatures were extracted from each PET-derived volume of interest (VOI) and CT-derived VOI. Radiomics signatures associated with pathological treatment response were selected from within a training cohort (n = 85), which were then applied to generate different classifiers to predict the probability of pathological complete response (pCR). Different models were then independently tested in the validation cohort (n = 39) regarding their accuracy, sensitivity, specificity, and area under the curve (AUC). Results: Thirty-five patients (28.2%) had pCR to NAC. Twelve features consisting of five PET-derived signatures, four CT-derived signatures, and three clinicopathological variables were candidates for the model's development. The random forest (RF), k-nearest neighbors (KNN), and decision tree (DT) classifiers were established, which could be utilized to predict pCR to NAC with AUC ranging from 0.819 to 0.849 in the validation cohort. Conclusions: The PET/CT-based radiomics analysis might provide efficient predictors of pCR in patients with BC, which could potentially be applied in clinical practice for individualized treatment strategy formulation.
RESUMEN
The volumetric expansion of hydrogels driven by osmotic swelling stress has enabled hydrogel actuators for myriad applications. However, most existing studies disregard optimizing the osmotic swelling stress for powerful actuation and simply utilize the osmotic swelling stress to trigger certain modes of actuation. In this work, we probe the osmotic swelling stress of hydrogels using polyacrylamide as a model system. We design and perform constrained swelling experiments to measure the osmotic swelling stresses at different levels of constraint and compare the results to the theoretical predictions based on the Flory-Huggins model. We optimize the osmotic swelling properties by tuning the constituents and structures of the hydrogel and achieve an enhancement of the magnitude of actuation stress from â¼180 kPa to â¼400 kPa. As a proof of concept, we demonstrate a robust hydrogel jack that can lift a weight 2000 times its own weight by harnessing the high osmotic swelling stress. The feasibility and limits of harnessing the osmotic swelling stress of hydrogels for actuation are discussed.