Sanfridsson J, Svahn G, Ryd L, Ahl T L, Sundén P, Jonsson K
Department of Diagnostic Radiology, University Hospital, Lund, Sweden.
Acta Radiol. 1998 Nov;39(6):642-8. doi: 10.3109/02841859809175490.
A system for the examination and measurement of the weight-bearing knee was adapted to computed radiography (CR) and to a picture archiving and communication system (PACS). The examination and measurement system was developed on examination equipment used for QUESTOR precision radiography (QPR). For an easier and more standardised localisation of bony landmarks on the screen, 4 measuring assistance tools (MATs) were developed. The aim of this study was to evaluate the usefulness of the tools developed and of image post-processing, specifically as magnification (zoom) and filtering (edge enhancement), by determining intra-observer variation in the measurement of angles and distances.
The original QPR measurement program, generating 19 angles and distances corrected for parallax and magnification, was converted and installed on a multi-modality workstation (Imtec Image 1200). A CR system (Fuji AC-2) was used for the generation of the related images and the measurements were made on the workstation. Four unilateral examinations of weight-bearing knees were undertaken. These examinations were measured twice under 5 different measurement conditions by 4 viewers.
The most important factor in reducing intra-observer variation was the ability to magnify (zoom) the images. The MATs also reduced variation. Filtering (edge enhancement), however, did not affect precision.
一种用于负重膝关节检查和测量的系统被适配于计算机X线摄影（CR）及图像存档与通信系统（PACS）。该检查和测量系统是在用于QUESTOR精密X线摄影（QPR）的检查设备上开发的。为了在屏幕上更轻松、更标准化地定位骨性标志，开发了4种测量辅助工具（MAT）。本研究的目的是通过确定观察者内角度和距离测量的差异，评估所开发工具及图像后处理（特别是放大[缩放]和滤波[边缘增强]）的有用性。
将生成19个经视差和放大校正的角度和距离的原始QPR测量程序进行转换，并安装在多模态工作站（Imtec Image 1200）上。使用CR系统（富士AC - 2）生成相关图像，并在工作站上进行测量。对4个负重膝关节进行单侧检查。4名观察者在5种不同测量条件下对这些检查进行了两次测量。
减少观察者内差异的最重要因素是图像放大（缩放）的能力。MAT也减少了差异。然而，滤波（边缘增强）并不影响精度。
