Real-time freehand 3D ultrasound imaging

Real-time freehand 3D ultrasound (US) has attracted much attention in clinical practices because it provides interactive feedback to help the clinicians acquire not only high-quality images but also timely information of the scanning area, which is necessary in intraoperative examinations. In this study, we developed a real-time freehand 3D US imaging system which can obtain volume reconstruction and visualisation during data acquisition at real-time level. Based on two popular algorithms, i.e. squared distance weighted interpolation (SDW) and Bezier interpolation, we designed corresponding parallel computing methods that were implemented on the graphics processing unit (GPU) to incrementally reconstruct and display the tissues being scanned using Visualisation toolkits (VTK). With a typical B-scan image size of 302 × 268 at an acquisition rate of 25 Hz and a preset volume size of 90 × 81 × 192, the system achieved an incremental reconstruction-visualisation rate of up to 32 frames/s and 119 frames/s for the SDW and Bezier algorithms, respectively, achieving the real-time 3D US.

实时徒手三维超声（3D ultrasound, US）在临床实践中广受关注，因其可提供交互式反馈，帮助临床医师不仅获取高质量超声图像，还能及时获得扫描区域的相关信息——这正是术中检查不可或缺的核心要素。本研究中，我们研发了一款实时徒手三维超声成像系统，可在数据采集过程中实现实时级别的容积重建与可视化。本方案基于两种主流算法，即平方距离加权插值（squared distance weighted interpolation, SDW）与贝塞尔插值（Bezier interpolation），设计了适配的并行计算方法，并在图形处理器（graphics processing unit, GPU）上实现；借助可视化工具包（Visualisation toolkits, VTK），可对正在扫描的组织进行增量式重建与显示。在典型B型扫描图像尺寸为302×268、采集帧率为25Hz，且预设容积尺寸为90×81×192的条件下，该系统针对平方距离加权插值与贝塞尔算法，分别实现了最高32帧/秒与119帧/秒的增量式重建-可视化帧率，成功达成实时三维超声的性能指标。