Accuracy and reliability of measurements obtained from computed tomography 3D volume rendered images

Abstract

Forensic pathologists commonly use computed tomography (CT) images to assist in determining the cause and manner of death as well as for mass disaster operations.Even though the design of the CT machine does not inherently produce distortion, most techniques within anthropology rely on metric variables, thus concern exists regarding the accuracy of CT images reflecting an object's true dimensions. Numerous researchers have attempted to validate the use of CT images, however the comparisons have only been conducted on limited elements and/or comparisons were between measurements taken from a dry element and measurements taken from the 3D-CT image of the same dry element.A full-body CT scan was performed prior to autopsy at the Office of the Chief Medical Examiner for the State of Maryland. Following autopsy, the remains were processed to remove all soft tissues and the skeletal elements were subject to an additional CT scan. Percent differences and Bland-Altman plots were used to assess the accuracy between osteometric variables obtained from the dry skeletal elements and from CT images with and without soft tissues. An additional seven crania were scanned, measured by three observers, and the reliability was evaluated by technical error of measurement (TEM) and relative technical error of measurement (%TEM).Average percent differences between the measurements obtained from the three data sources ranged from 1.4% to 2.9%. Bland-Altman plots illustrated the two sets of measurements were generally within 2mm for each comparison between data sources. Intra-observer TEM and %TEM for three observers and all craniometric variables ranged between 0.46 mm and 0.77 mm and 0.56% and 1.06%, respectively. The three-way interobserver TEM and %TEM for craniometric variables was 2.6 mm and 2.26%, respectively. Variables that yielded high error rates were orbital height, orbital breadth, inter-orbital breadth and parietal chord. Overall, minimal differences were found among the data sources and high accuracy was noted between the observers, which prove CT images are an acceptable source to collect osteometric variables.

Using multivariate adaptive regression splines to estimate subadult age from diaphyseal dimensions

“…breadths) (Stull, 2013). Differences were comparable to differences between measurements obtained on computed tomography images and dry bone, error rates noted in prospective growth studies that had controlled radiographic settings, and intra-and inter-observer error rates on dry bone (Green et al, 1946;Maresh, 1955;Gindhart, 1973;Hoffman, 1979;Stull et al, 2014).…”

Integração morfológica e modularidade em crânios das espécies do grupo Rhinella granulosa

“…For the landmarks expected to have higher error in the 3D images because of their positions in the skull or because they were located in thinner bones, only landmarks 4, 8 and 12 corresponded to the expectation. All of them are type I landmarks, agreeing with the findings of other authors working with 3D images of more error in placing landmarks at some particular bone sutures [18,19]. MED and HIGH presented very similar results, indicating that there is no difference in switching the resolutions to visualize the landmarks.…”

Three-Dimensional Model Printing in Oral and Maxillofacial Reconstructive Surgery: Comparison of Three-Dimensional Models and Multislice Computed Tomography Scans

“…The previous research by Stull et al about accuracy and reliability measurement from CT scan data compared to dry skull reveals that CT scan data could be accepted and used as an alternative in measurement [16]. Although there is a difference value between measurement in the 3D model and CT scan data on symphysis of the mandible, this result accords with previous research by Reinbacher et al which compared the 3D model and CT scan/magnetic resonance imaging (MRI) with regard to maxillofacial bone distance.…”