arXiv AI

EUReCA: End-to-End Unified CBCT Reconstruction Across Clinical Acquisitions

EUReCA is a geometry‑aware, feed‑forward model that reconstructs cone‑beam CT images from 8–100 projections without needing view‑specific retraining. It encodes each projection with a shared multiscale backbone, back‑projects features into 3‑D grids, aggregates variable views at fixed cost, and refines the volume using a global transformer and decoder. On simulated and real patient data, EUReCA outperforms existing feed‑forward and iterative methods, achieving high PSNR and superior performance across all tested view counts.

arXiv AI
3d ago

EPC-RawDC: Equivariant Physics Constrained 3D Diffusion with Raw Data Consistency for CBCT to CT Image Synthesis

EPC‑RawDC is a 3‑D latent diffusion model that synthesises CT images from CBCT scans by enforcing two physics‑based constraints: a geometry‑equivariant projection loss and raw data consistency using scan‑specific CBCT projections. Trained on two clinical cohorts with different scanner geometries, the method achieved SSIM of 0.97 and improved PSNR and MAE over a baseline DDPM, reducing projection and equivariant errors by 55 % and 41 % respectively.

By Alzahra Altalib, Chunhui Li, Alessandro Perelli
arXiv Machine Learning
Aug 5

Dual-domain U-Nets with embedded back projection operators for motion-resolved 4D CBCT reconstruction

arXiv:2608. 03430v1 Announce Type: cross Abstract: Four-dimensional cone beam CT (4D CBCT) is important for image-guided radiation therapy of thoracic cancers, but its use is limited by long scan times, causing high patient dose and motion/sparse-sampling artifacts.

By Ivo Herzig, Pascal Paysan, Daniel Barco, Marc Andr\'e Stadelmann, Frank-Peter Schilling, Igor Peterlik, Michal Walczak, Lijin Aryananda, Woo Sang Ahn, Rudolf Marcel F\"uchslin, Lukas Lichtensteiger
arXiv AI
Aug 19

Learning Where and What to Lift for Bi-planar X-ray-to-CT Reconstruction

The paper introduces LiftXR, a geometry‑guided framework that first reconstructs a 3D anatomical layout from bi‑planar X‑ray images and then uses this layout to guide CT volume reconstruction. An anatomical parser refines the layout by analyzing the reconstructed CT, enabling region‑specific intensity calibration. Experiments on two public datasets show LiftXR surpasses recent X‑ray‑to‑CT methods and improves downstream segmentation performance.

By Yifei Wu, Yicheng Wu, Qiang Ma, Qi Chen, Renyang Gu, Xinyu Liu, Yongsheng Pan, Yong Xia
arXiv AI
Aug 11

Resolution Meets Reduction: Efficient Visual Context for 3D Radiology Report Generation

arXiv:2608. 08713v1 Announce Type: cross Abstract: Vision-language models offer a promising path toward automating radiology report generation, but applying them to full 3D CT volumes poses substantial computational challenges.

By Jonathan Suprijadi, Raphael Stock, Moritz Langenberg, David Zimmerer, Kim-Celine Kahl, Stefan Denner, Yannick Kirchhoff, Karol Gotkowski, Maximilian Rokuss, Jeremias Traub, Tassilo Wald, Constantin Ulrich, Klaus Maier-Hein
arXiv AI
Sep 24

Field-of-View Extension in Dental Cone-Beam CT via Implicit Neural Representations and Diffusion Model-Based Refinement

The paper presents a three‑stage framework to extend the field of view in dental cone‑beam CT scans that are limited by truncated detector configurations. First, an implicit neural representation estimates missing projection data; second, an iterative reconstruction generates a secondary volumetric image with better anatomical consistency; third, a fast diffusion model refines the image for enhanced quality. Experiments show reduced truncation artifacts and improved reconstruction of structures beyond the original field of view.

By Susanne Schaub, Florentin Bieder, Matheus L. Oliveira, Yulan Wang, Buyanbileg Sodnom-ish, Dorothea Dagassan-Berndt, Michael M. Bornstein, Philippe C. Cattin
arXiv AI
3d ago

SparseTokenGS: Gaussian-based Sparse-View CBCT Reconstruction via Reusable Token Pool

SparseTokenGS is a Gaussian-based, feed-forward method for sparse-view cone-beam CT reconstruction that uses a reusable token pool to maintain scan-wide context during decoding. Anchor Token Fusion and Point-Token Attention query this shared pool at anchors and query coordinates, preserving local Gaussian priors while enabling reconstruction in a single forward pass without per-scan optimization. Experiments on chest, dental, volcanic rock, and chicken datasets show that SparseTokenGS achieves superior reconstruction quality, achieving 29.51 dB PSNR and 0.842 SSIM from only six dental projections and maintaining separable tooth-and-pulp structures for root‑canal localization.

By Zihan Deng, Zhenzhen Gong, Yujie Liu, Jiaxin Gong, Dingkun Liu, Kexian Xie, Yixing Huang, Peng Jin, Tianye Niu, Zhisheng Wang, Fenglin Liu, Hongming Shan, Lequan Yu
arXiv AI
3d ago

Extremely Sparse-View Computed Tomography from 2D Projections via Pose-Aware Diffusion Priors

The paper introduces a method for extremely sparse‑view computed tomography (xSV‑CT) that learns a pose‑aware diffusion prior from a single 2D projection per training sample. During inference, the diffusion process is guided by measured‑view fidelity, shared‑volume reprojection, and projection‑physics consistency to reconstruct 3D volumes from only 1, 4, or 8 views. Experiments on two public CT datasets show that this approach outperforms or matches baselines that rely on dense‑volume supervision, achieving superior novel‑view synthesis and competitive reconstruction quality.

By Linrui Dai, Jinxiu Liang, Chu Zhou, Mae Yamaguchi, Ryuya Takahashi, Imari Sato
arXiv Computer Vision
Sep 16

Efficient 3D Whole-Body PET Image Denoising via Conditional Rectified Flow With Optimized Sampling Strategy

The paper introduces a one‑pass conditional 3D rectified flow (3D Flow) framework for denoising whole‑body PET images, employing an optimized non‑uniform sampling strategy and a linear‑interpolant velocity‑matching objective. It reconstructs a full 3D volume in about 30 seconds, dramatically faster than multi‑hour 3D diffusion models, while maintaining high global image quality and lesion conspicuity even at ultra‑low doses (down to 1/100 of standard). Zero‑shot transfer tests on independent clinical data demonstrate robust performance across datasets and unseen dose levels.

By Jiale Shen, Guolin Wang, Chenhao Wang, Xinhui Su, Wei Luo, Feng Yu