Assessment of Image Post-Processing and of Measuring Assistance Tools in Computed Radiography

Abstract

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.

To what degree is digital imaging reliable? Validation of femoral neck shaft angle measurement in the era of picture archiving and communication systems

“…Challenges to the reliable measurement of the femoral NSA have been identified by other authors. A study by Sanfridsson et al [8] showed that proximal femoral NSA measurements had the highest variance (SD 1.9 u ) of 9 angular measurements generated from radiographic views of the lower limb (mean SD of the other 8 angles was 0.6 u ).…”

“…Measuring assistance tools (MATs) that locate the centre of a circular structure can reduce the variation in measurements of angles and distances. However, the effect of using these tools to measure the proximal femoral NSA has not been shown to be statistically significant [8]. Also, a study comparing digital with conventional techniques for assessing lower limb alignment found no significant difference between the mean values or variation of the measurements [13].…”

“…The study was performed on standard workstations available in clinical areas with a minimum screen size of 48 cm (19 inches). To optimise the measuring process the ''full-screen'' view was used and the image was magnified by a factor of two to maximise resolution [8].…”

Femorotibial Rotation and the Q-Angle Related to the Dislocating Patella

“…We have previously reported on a radiographic system for examination and evaluation of the weight‐bearing knee including a model for measurement of rotation of the femur and the tibia, of the patellar translation and of the Q‐angle (Fig. a, b) (11–14).…”

RADIOGRAPHIC MEASUREMENT OF FEMOROTIBIAL ROTATION IN WEIGHT-BEARING. The influence of flexion and extension in the knee on the extensor mechanism and angles of the lower extremity in a healthy population

“…The CR system was developed to be used on examination equipment for QUESTOR precision radiography (QPR) (7, 21, 24), now known as Standardized Knee Imaging (SKI). The QPR system was modified and adjusted to the CR, different measuring assistance tools (MATs) were developed (23) and the reproducibility has been determined (22). The original QPR system positioned the knee in a “straight” fashion and the degree of flexion was not controlled.…”