Department of Medical Physics & Biomedical Engineering, UCL Centre for Medical Image Computing, University College London, Gower Street, London, WC1E 6BT, UK.
Department of Computer Science, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK.
Med Phys. 2018 Apr;45(4):1408-1414. doi: 10.1002/mp.12814. Epub 2018 Mar 9.
Image-guided systems that fuse magnetic resonance imaging (MRI) with three-dimensional (3D) ultrasound (US) images for performing targeted prostate needle biopsy and minimally invasive treatments for prostate cancer are of increasing clinical interest. To date, a wide range of different accuracy estimation procedures and error metrics have been reported, which makes comparing the performance of different systems difficult.
A set of nine measures are presented to assess the accuracy of MRI-US image registration, needle positioning, needle guidance, and overall system error, with the aim of providing a methodology for estimating the accuracy of instrument placement using a MR/US-guided transperineal approach.
Using the SmartTarget fusion system, an MRI-US image alignment error was determined to be 2.0 ± 1.0 mm (mean ± SD), and an overall system instrument targeting error of 3.0 ± 1.2 mm. Three needle deployments for each target phantom lesion was found to result in a 100% lesion hit rate and a median predicted cancer core length of 5.2 mm.
The application of a comprehensive, unbiased validation assessment for MR/US guided systems can provide useful information on system performance for quality assurance and system comparison. Furthermore, such an analysis can be helpful in identifying relationships between these errors, providing insight into the technical behavior of these systems.
将磁共振成像（MRI）与三维（3D）超声（US）图像融合的图像引导系统，用于进行靶向前列腺针活检和前列腺癌的微创治疗，越来越受到临床关注。迄今为止，已经报道了广泛的不同精度估计程序和误差指标，这使得比较不同系统的性能变得困难。
提出了九项措施来评估 MRI-US 图像配准、针定位、针引导和整体系统误差的准确性，目的是提供一种使用经会阴 MR/US 引导方法估计仪器放置精度的方法。
使用 SmartTarget 融合系统，确定 MRI-US 图像对准误差为 2.0±1.0mm（均值±标准差），整体系统仪器靶向误差为 3.0±1.2mm。对于每个靶标病变体，进行三次针部署，结果显示病变命中率为 100%，预测癌症核心长度的中位数为 5.2mm。
对 MR/US 引导系统进行全面、无偏的验证评估，可以为质量保证和系统比较提供有关系统性能的有用信息。此外，这种分析有助于识别这些误差之间的关系，深入了解这些系统的技术行为。
