A Machine Learning Pipeline for Automated Bolus Segmentation and Area Measurement in Swallowing Videofluoroscopy...

Feeding efficiency and safety are often driven by bolus volume, which is one of the most common clinical measures of assessing swallow performance. However, manual measurement of bolus area is time-consuming and suffers from high levels of inter-rater variability. This study proposes a machine learning (ML) pipeline using ilastik, an accessible bioimage analysis tool, to automate the measurement of bolus area during swallowing. The pipeline was tested on 336 swallows from videofluoroscopic recordings of 8 infant pigs during bottle feeding. Eight trained raters manually measured bolus area in ImageJ and also used ilastik's autocontext pixel-level labeling and object classification tools to train ML models for automated bolus segmentation and area calculation. The ML pipeline trained in 1h42min and processed the dataset in 2 min 48s, a 97% time saving compared to manual methods. The model exhibited strong performance, achieving a high Dice Similarity Coefficient (0.84), Intersection over Union (0.76), and inter-rater reliability (intraclass correlation coefficient = 0.79). The bolus areas from the two methods were highly correlated (R² = 0.74 overall, 0.78 without bubbles, 0.67 with bubbles), with no significant difference in measured bolus area between the methods. Our ML pipeline, requiring no ML expertise, offers a reliable and efficient method for automatically measuring bolus area. While human confirmation remains valuable, this pipeline accelerates analysis and improves reproducibility compared to manual methods. Future refinements can further enhance precision and broaden its application in dysphagia research.