A Category-Fragment Segmentation Framework for Pelvic Fracture Segmentation in X-ray Images
Daiqi Liu, Fuxin Fan, Andreas Maier
TL;DR
The paper tackles automatic segmentation of pelvic fracture fragments in 2D X-ray images, a challenging problem due to projection overlap. It introduces the Category-Fragment Segmentation (CFS) framework, comprising category segmentation via Swin UNETR, fragment segmentation via Mask R-CNN using category masks as inputs, and a post-processing step that multiplies category masks with fragment masks to refine outputs. Evaluated on a DeepDRR-generated MICCAI PengWin dataset (50,000 X-ray images from 100 CT volumes, 448×448 resolution), the approach achieves state-of-the-art-like performance with $IoU=0.914$ for category segmentation and $IoU=0.775$ for fragment segmentation using the best Swin UNETR +p model. The findings highlight the value of region-aware, multi-stage segmentation and post-processing for improving intraoperative pelvic fracture guidance, while also identifying challenges posed by overlapping anatomy and variability in fragment boundaries.
Abstract
Pelvic fractures, often caused by high-impact trauma, frequently require surgical intervention. Imaging techniques such as CT and 2D X-ray imaging are used to transfer the surgical plan to the operating room through image registration, enabling quick intraoperative adjustments. Specifically, segmenting pelvic fractures from 2D X-ray imaging can assist in accurately positioning bone fragments and guiding the placement of screws or metal plates. In this study, we propose a novel deep learning-based category and fragment segmentation (CFS) framework for the automatic segmentation of pelvic bone fragments in 2D X-ray images. The framework consists of three consecutive steps: category segmentation, fragment segmentation, and post-processing. Our best model achieves an IoU of 0.91 for anatomical structures and 0.78 for fracture segmentation. Results demonstrate that the CFS framework is effective and accurate.
