Fig. 1

Representative examples of the subjective thoracic duct tortuosity grading scale used for this project. Arrowheads indicate the thoracic duct. The following guidance was used when assigning tortuosity: no turns/deviations from course for no tortuosity, one turn or multiple very subtle turns for mild tortuosity, more than one large turn or multiple small turns for moderate tortuosity, and turns along the entire or nearly entire course for severe tortuosity. The images for moderate and severe grading are a composite of two reformatted images to best show the course of the thoracic duct