How reliable are Hounsfield-unit measurements in forensic radiology?

Ruder, Thomas D.; Thali, Yannick; Schindera, Sebastian T; Torre, Simon A Dalla; Zech, Wolf-Dieter; Thali, Michael J; Ross, Steffen; Hatch, Gary M (2012). How reliable are Hounsfield-unit measurements in forensic radiology? Forensic science international, 220(1-3), pp. 219-223. Shannon: Elsevier Scientific Publ. Ireland 10.1016/j.forsciint.2012.03.004

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OBJECTIVE: To assess the reliability of computed tomography (CT) numbers, also known as Hounsfield-units (HU) in the differentiation and identification of forensically relevant materials and to provide instructions to improve the reproducibility of HU measurements in daily forensic practice. MATERIALS AND METHODS: We scanned a phantom containing non-organic materials (glass, rocks and metals) on three different CT scanners with standardized parameters. The t-test was used to assess the influence of the scanner, the size and shape of different types of regions-of-interest (ROI), the composition and shape of the object, and the reader performance on HU measurements. Intra-class correlation coefficient was used to assess intra- and inter-reader reliability. RESULTS: HU values did not change significantly as a function of ROI-shape or -size (p>0.05). Intra-reader reliability reached ICC values >0.929 (p<0.001). Inter-reader reliability was also excellent with an ICC of 0.994 (p<0.001). Four of seven objects yielded significantly different CT numbers at different levels within the object (p<0.05). In 6/7 objects the HU changed significantly from CT scanner to CT scanner (p<0.05). CONCLUSION: Reproducible CT number measurements can be achieved through correct ROI-placement and repeat measurements within the object of interest. However, HU may differ from CT-scanner to CT-scanner. In order to obtain comparable CT numbers we suggest that a dedicated Forensic Reference Phantom be developed.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Service Sector > Institute of Legal Medicine > Forensic Medicine 04 Faculty of Medicine > Service Sector > Institute of Legal Medicine > Forensic Imaging 04 Faculty of Medicine > Service Sector > Institute of Legal Medicine
UniBE Contributor:	Ruder, Thomas, Zech, Wolf-Dieter, Thali, Michael, Ross, Steffen, Hatch, Gary
ISSN:	0379-0738
Publisher:	Elsevier Scientific Publ. Ireland
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:21
Last Modified:	05 Dec 2022 14:05
Publisher DOI:	10.1016/j.forsciint.2012.03.004
PubMed ID:	22534158
Web of Science ID:	000305706600042
URI:	https://boris.unibe.ch/id/eprint/6884 (FactScience: 211933)