arXiv Machine Learning

Flow Matching Meets 3D Curvilinear Structure Segmentation in Medical Imaging

arXiv:2608. 19965v1 Announce Type: cross Abstract: Segmentation of curvilinear anatomical structures in 3D medical images remains challenging due to complex topology, severe class imbalance, weak contrast, and large variations in structure morphology.

arXiv AI
Jul 7

From Raw Segmentations to Simulation-Ready Cardiac Meshes: An Automated Framework for Anatomical Reconstruction and Virtual Cohort Generation

arXiv:2607. 02564v1 Announce Type: cross Abstract: Computational models of the human heart are widely used to study electromechanical and fluid-dynamical cardiac function and to support applications such as in silico clinical trials.

By Francesco Fabbri, Martino Andrea Scarpolini, Paolo Ciancarella, Francesco Tudisco, Roberto Verzicco, Alessandro Ricci, Francesco Viola
arXiv AI
Sep 28

ReG-SAM: Reference Graph-Driven SAM for 2D Foundational Vessel Segmentation

ReG-SAM is a SAM-based framework designed for 2D vessel segmentation in medical images. It introduces reference graph prompt embeddings (GPEs) and vascular prototype embeddings (VPEs) to capture global spatial and fine-grained modality-specific vessel features, respectively. By building a modality-wise vascular database and learning these embeddings from reference masks, ReG-SAM consistently outperforms existing baselines across 19 datasets, especially on thin vessels.

By Donghang Lyu, Zichen Zhang, Oleh Dzyubachyk, Marius Staring
arXiv Computer Vision
Aug 27

Steer the Sampling, Not the Kernel Grid: Geometry-Guided Sampling Operator for Volumetric Segmentation

The paper introduces a geometry‑guided sampling operator that directs feature sampling rather than altering convolution kernels in 3D encoder‑decoder networks. By predicting local orientations and bounded step sizes, the operator samples symmetrically around each voxel, generating compact geometric and boundary cues that improve fine‑structure segmentation. Replacing stride‑1 and stride‑2 operations in a 3D U‑Net yields consistent gains on BraTS, MSD Hepatic Vessel, and TDSC‑ABUS datasets, with better boundary metrics and fewer parameters, and the operator can be integrated into other backbones without architectural changes.

By Sizhe Wang, Himashi Peiris, Zhaolin Chen
arXiv Computer Vision
Oct 9

VesselSDF: Distance Field Priors for Vascular Network Reconstruction

VesselSDF introduces a new framework that transforms vessel segmentation into a signed distance field (SDF) regression task, enabling continuous representation of vascular geometry. By employing an adaptive Gaussian regularizer, the method suppresses common SDF artifacts such as floating segments while maintaining precise vessel boundaries. Experimental results show that VesselSDF outperforms existing approaches, preserving vessel geometry and connectivity for more reliable clinical vascular analysis.

By Salvatore Esposito, Daniel Rebain, Arno Onken, Changjian Li, Oisin Mac Aodha
arXiv AI
Oct 7

Local2Mesh: Spatially Localized Contour-to-Mesh for Left Ventricular Reconstruction from Sparse 2D Cardiac MRI

Local2Mesh is a spatially localized contour‑to‑mesh framework that reconstructs 3‑D left ventricular geometry from sparse 2‑D cardiac MRI contours without requiring 3‑D mesh annotations. It corrects inter‑slice misalignment through geometry‑aware alignment and routes contour features to template vertices via a plane‑aware Local Router, then jointly uses local and global features to deform a template mesh. Experiments on M&Ms‑2 and ACDC datasets show superior geometric reconstruction, functional estimation, and disease classification compared to existing methods, with strong cross‑dataset generalization.

By Haoyu Wu, Ling Lin, Pascal Lef\`evre, Ruizhe Li, Xiaowu Sun
arXiv Computer Vision
Aug 28

Unsupervised Adaptation of 3D CT Foundation Models for 3D CBCT Segmentation

The paper introduces an unsupervised domain adaptation framework that aligns redundancy-reducing features to enable accurate 3D segmentation of cone-beam CT (CBCT) without target-domain annotations or inference-time adaptation. The method is architecture-agnostic, working with both CNN-based and ViT-based foundation models, and is evaluated on two liver segmentation benchmarks for interventional vascular procedures and radiation therapy. Results show that even large pretrained segmentation networks need explicit feature-space bridging to generalize across diagnostic CT and CBCT, and the proposed approach consistently outperforms existing pretrained foundation models and UDA strategies.

By Gauthier Miralles, Loic Le Folgoc, Vincent Jugnon, Pietro Gori