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CC BY-NC-ND 4.0 · Indian J Radiol Imaging 2025; 35(01): 081-087
DOI: 10.1055/s-0044-1789231
Original Article

Ghost Sign on Diffusion-Weighted Imaging Generated Apparent Diffusion Coefficient Map: Additional MRI Diagnostic Marker for Extremity Osteomyelitis

Angela He 
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Mina Guirguis
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Flavio Duarte Silva
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Oganes Ashikyan
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Parham Pezeshk
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Naveen Rajamohan
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Karim Salhadar
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Yin Xi
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
,
Avneesh Chhabra
1   Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, United States
2   Department of Orthopedic Surgery, UT Southwestern Medical Center, Dallas, Texas, United States
3   Department of Radiology, Johns Hopkins University, Maryland, United States
4   Department of Radiology, Walton Centre for Neuroscience, Liverpool, United Kingdom
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Funding None.
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Abstract

Objective The aim of this study was to determine the sensitivity and specificity and inter-reader reliability of previously known “ghost sign” and “penumbra sign” on T1-weighted (T1W) imaging and “ghost sign” on apparent diffusion coefficient (ADC) map in osteomyelitis (OM) of the extremities.

Materials and Methods In this cross-sectional retrospective study, two fellowship-trained musculoskeletal readers blinded to final diagnosis of OM versus no OM were asked to report the penumbra sign and ghost sign on T1W images and ghost sign on ADC map, as well as diagnosis of OM. Cohen's kappa was used. Diagnostic performance measures including sensitivity, specificity, and accuracy were calculated.

Results A sample of 178 magnetic resonance imaging (MRI) scans of pathology-proven cases were included in this study, with 41 being positive for OM and 137 being negative for OM. There was a fair inter-reader agreement for imaging signs, and moderate agreement of 0.60 for OM. The sensitivities of the penumbra sign on T1W imaging, ghost sign on T1W imaging, and ghost sign on ADC map for OM are 3.7, 9.8, and 19.5%, respectively, while their respective specificities are 98.9, 97.8, and 94.5%, respectively. All three imaging signs showed a similar (good) accuracy of 76 to 78%.

Conclusion The ghost sign on ADC can be used as an additional marker for OM and is a similarly highly specific but a more sensitive sign for OM than the conventionally used penumbra sign and ghost sign on T1W imaging.

Key Points

  • The ghost sign on ADC can be used as a helpful indicator of osteomyelitis.

  • Across two fellowship-trained musculoskeletal readers, there was a fair inter-reader agreement for imaging signs and moderate agreement for OM.

  • The ghost sign on ADC is a similarly highly specific but a more sensitive sign for osteomyelitis than the conventionally used penumbra sign and ghost sign on T1W imaging. All three imaging signs showed a similar (good) accuracy of 76 to 78%.

Keywords

osteomyelitis - MRI - ghost sign - DWI - penumbra sign

Note

Ghost sign on ADC is a highly specific MRI sign that can be used as an additional marker for identifying infected bone and diagnosing OM by radiologists.




Publikationsverlauf

Artikel online veröffentlicht:
26. August 2024

© 2024. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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