Wenyi Lian

Wenyi Lian, Joakim Lindblad, Christina Runow Stark et al.

Oral cancer is a global health challenge. It is treatable if detected early, but it is often fatal in late stages. There is a shift from the invasive and time-consuming tissue sampling and histological examination, toward non-invasive brush biopsies and cytological examination. Reliable computer-assisted methods are essential for cost-effective and accurate cytological analysis, but the lack of detailed cell-level annotations impairs model effectiveness. This study aims to improve AI-based oral cancer detection using multimodal imaging and deep fusion. We combine brightfield and fluorescence whole slide microscopy imaging to analyze Papanicolaou-stained liquid-based cytology slides of brush biopsies collected from both healthy and cancer patients. Due to limited cytological annotations, we utilize a weakly supervised deep learning approach using only patient-level labels. We evaluate various multimodal fusion strategies, including early, late, and three recent intermediate fusion methods. Our results show: (i) fluorescence imaging of Papanicolaou-stained samples provides substantial diagnostic information; (ii) multimodal fusion enhances classification and cancer detection accuracy over single-modality methods. Intermediate fusion is the leading method among the studied approaches. Specifically, the Co-Attention Fusion Network (CAFNet) model excels with an F1 score of 83.34% and accuracy of 91.79%, surpassing human performance on the task. Additional tests highlight the need for precise image registration to optimize multimodal analysis benefits. This study advances cytopathology by combining deep learning and multimodal imaging to enhance early, non-invasive detection of oral cancer, improving diagnostic accuracy and streamlining clinical workflows. The developed pipeline is also applicable in other cytological settings. Our codes and dataset are available online for further research.

Wenyi Lian, Patrick Micke, Joakim Lindblad et al.

Vision Transformers (ViTs) have achieved remarkable success in standard RGB image processing tasks. However, applying ViTs to multi-channel imaging (MCI) data, e.g., for medical and remote sensing applications, remains a challenge. In particular, MCI data often consist of layers acquired from different modalities. Directly training ViTs on such data can obscure complementary information and impair the performance. In this paper, we introduce a simple yet effective pretraining framework for large-scale MCI datasets. Our method, named Isolated Channel ViT (IC-ViT), patchifies image channels individually and thereby enables pretraining for multimodal multi-channel tasks. We show that this channel-wise patchifying is a key technique for MCI processing. More importantly, one can pretrain the IC-ViT on single channels and finetune it on downstream multi-channel datasets. This pretraining framework captures dependencies between patches as well as channels and produces robust feature representation. Experiments on various tasks and benchmarks, including JUMP-CP and CHAMMI for cell microscopy imaging, and So2Sat-LCZ42 for satellite imaging, show that the proposed IC-ViT delivers 4-14 percentage points of performance improvement over existing channel-adaptive approaches. Further, its efficient training makes it a suitable candidate for large-scale pretraining of foundation models on heterogeneous data. Our code is available at https://github.com/shermanlian/IC-ViT.