{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,31]],"date-time":"2025-12-31T18:37:51Z","timestamp":1767206271172,"version":"build-2238731810"},"reference-count":22,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,3,4]],"date-time":"2025-03-04T00:00:00Z","timestamp":1741046400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background: Diagnosing fracture-related infection (FRI) without clinical confirmatory signs is challenging. [18F]FDG-PET\/CT has been shown to have good diagnostic accuracy. However, direct interpretation criteria are lacking. The aim of this study was to assess the diagnostic value of increased FDG-uptake in locoregional lymph nodes on [18F]FDG-PET\/CT in patients with suspected upper and lower extremity FRI. Methods: This was a retrospective cohort study of patients who underwent [18F]FDG-PET\/CT for suspected extremity FRI in two tertiary referral centers between January 2011 and December 2023. The sensitivity, specificity and diagnostic value of the presence, number and intensity of [18F]FDG uptake in locoregional lymph nodes was assessed. Uptake intensity was measured by calculating the maximum standard uptake value (SUVmax) of the \u2018hottest\u2019 lymph node. All scans were acquired according to the European Association of Nuclear Medicine (EANM) standards, and quantification was performed based on standardized EARL reconstructed images. FRI was diagnosed based on positive intra-operative microbiology results or development of clinical confirmatory signs within six months of follow-up. Results: In total, 124 patients were included in the analysis, with 53 cases of confirmed FRI. The presence of locoregional lymph nodes alone showed poor diagnostic accuracy (sensitivity, 55%; specificity, 68%; diagnostic accuracy, 62%). The number of active lymph nodes showed poor discriminative performance between FRI and non-infectious cases (AUC 0.63). Utilizing the SUVmax of the \u2018hottest\u2019 lymph nodes, moderate discriminative performance was revealed, with an AUC of 0.71. The optimal cutoff point (SUVmax 3.48) resulted in a sensitivity of 72%, a specificity of 78% and a diagnostic accuracy of 75%. A logistic regression model was fitted to calculate the added value of lymph node assessment to the regular [18F]FDG-PET\/CT assessment. This resulted in a sensitivity of 71%, a specificity of 82% and a diagnostic accuracy of 76%. Conclusions: Presence and number of locoregional lymph nodes with increased [18F]FDG-uptake alone has poor diagnostic accuracy for FRI. The SUVmax of the \u2018hottest\u2019 lymph node showed moderate diagnostic performance. Lymph node assessment slightly increased the diagnostic value of regular [18F]FDG-PET\/CT assessment. Based on these results, increased [18F]FDG-uptake in locoregional lymph nodes should only be considered as a suggestive sign for a positive scan result in suspected FRI.<\/jats:p>","DOI":"10.3390\/diagnostics15050616","type":"journal-article","created":{"date-parts":[[2025,3,4]],"date-time":"2025-03-04T04:58:17Z","timestamp":1741064297000},"page":"616","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Diagnostic Value of Increased [18F]FDG Uptake in Locoregional Lymph Nodes on PET\/CT in Patients with Suspected Fracture-Related Infection"],"prefix":"10.3390","volume":"15","author":[{"given":"Paul","family":"Bosch","sequence":"first","affiliation":[{"name":"Department of Surgery, University Medical Center Groningen, University of Groningen, 9712 CP Groningen, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8081-0641","authenticated-orcid":false,"given":"Andor","family":"Glaudemans","sequence":"additional","affiliation":[{"name":"Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, 9712 CP Groningen, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2669-320X","authenticated-orcid":false,"given":"Jean-Paul","family":"de Vries","sequence":"additional","affiliation":[{"name":"Department of Surgery, University Medical Center Groningen, University of Groningen, 9712 CP Groningen, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-0417-1823","authenticated-orcid":false,"given":"Johannes","family":"van Snick","sequence":"additional","affiliation":[{"name":"Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, 9712 CP Groningen, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0917-1108","authenticated-orcid":false,"given":"Justin","family":"Lemans","sequence":"additional","affiliation":[{"name":"Department of Trauma Surgery, University Medical Center Utrecht, University of Utrecht, 3584 CS Utrecht, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Janna","family":"van den Kieboom","sequence":"additional","affiliation":[{"name":"Department of Trauma Surgery, University Medical Center Utrecht, University of Utrecht, 3584 CS Utrecht, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Monique","family":"Hobbelink","sequence":"additional","affiliation":[{"name":"Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, University of Utrecht, 3584 CS Utrecht, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Geertje","family":"Govaert","sequence":"additional","affiliation":[{"name":"Department of Trauma Surgery, University Medical Center Utrecht, University of Utrecht, 3584 CS Utrecht, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9420-2732","authenticated-orcid":false,"given":"Frank","family":"IJpma","sequence":"additional","affiliation":[{"name":"Department of Surgery, University Medical Center Groningen, University of Groningen, 9712 CP Groningen, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,3,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1038\/s41572-022-00396-0","article-title":"Fracture-related infection","volume":"8","author":"Moriarty","year":"2022","journal-title":"Nat. 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