Targeted ROI Scanning Strategy for Octa with Uniform Spatial-Temporal Sampling

Optical coherence tomography angiography (OCTA) is a non-invasive imaging technique that provides depth-resolved visualization of microvascular networks without exogenous contrast agents. However, traditional scanning strategies suffer from limitations including non-uniform sampling, incompatible with the BM-scan mode, inflexible field of view (FOV) shapes and data redundancy due to unnecessary coverage of non-target areas. To address these issues, this study proposes a novel targeted ROI scanning strategy for OCTA that enables customizable FOVs while ensuring uniform spatial and temporal sampling. It discretizes the ROI into evenly distributed sampling points, groups them into equivalent B-scans, and employs a dynamic timing mechanism with flyback compensation to maintain consistent inter-frame intervals. This mechanism supports the widely used BM-scan protocol and avoids the need for post-acquisition resampling, thereby reducing interpolation artifacts and improving computational efficiency. Simulations and in vivo experiments on animal anterior segments and retinas demonstrate that the proposed strategy enables circular FOVs and achieves imaging quality comparable to the traditional raster scanning strategy, while reducing the scanning area to 81.1%, achieving an 18.9% reduction in acquisition time and a 23.3% improvement in scanning efficiency. In summary, the proposed strategy provides a framework with the potential for customizable FOVs and achieves high efficiency without compromising imaging quality, making it highly suitable for OCTA scientific research and clinical diagnosis.