Measuring distortion of skeletal elements in Lodox Statscan-generated images

Abstract

Due to a scarcity of available skeletal material, anthropologists and other practitioners face difficulties with either the creation or validation of techniques used to estimate a biological profile in subadults. To address this problem, radiographic images of living individuals are often used in lieu of dry skeletal elements. However, radiographic images suffer from distortion. Some problems with metric analyses when using radiographic images may be addressed with the Lodox Statscan, an X-ray machine that claims to produce minimal distortion along the scan-axis due to a linear slot-scanning design. The purpose of this research was to measure the distortion of skeletal elements in radiographic images generated from a Lodox Statscan. Skeletal elements subject to multiple imaging variables that affect distortion were radiographed, measured, and then compared to the dry bone measurements through multiple approaches. An 85% percent agreement within a ±1 mm range and a 97% agreement within a ±2 mm range was obtained. Percent difference results demonstrate that slot-axis measurements incurred more distortion than scan-axis measurements (11.8% and 2.7%, respectively). Inclusion of foam results in 4.5% more error than when foam is not included in the image. Angled scan-axis measurements also incurred more distortion than either nonangled slot- and scan-axis measurements. A Bland-Altmanplot reveals an overall agreement between the radiographic and dry bonemeasurements, with most measurements falling within the upper and lower limits. Similar measurement error is found in Statscan radiographic and dry bone measurements; therefore, the Statscan offers a radiographic venue to collect metric data