{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:51:30Z","timestamp":1787028690674,"version":"build-2736575974"},"reference-count":35,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,18]],"date-time":"2026-02-18T00:00:00Z","timestamp":1771372800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Imaging"],"abstract":"<jats:p>Rheumatoid arthritis (RA) frequently affects the joints of the hands, with joint space narrowing (JSN) representing an important early marker of structural damage. The semi-quantitative Sharp\/van der Heijde (SvdH) scoring system is widely used in clinical practice but is inherently subjective and susceptible to observer variability. Moreover, the complex anatomy of the wrist and substantial overlap of carpal bones pose challenges for automated quantitative assessment of wrist JSN on routine radiographs. This study aimed to introduce a novel quantitative assessment perspective and to clinically validate an automated, compactness-related quantification framework for evaluating wrist JSN in RA. This study initially enrolled 51 patients with RA. After excluding one case with severe carpal fusion that precluded anatomical differentiation, 50 patients (44 females and 6 males) were included in the final analysis. The cohort had a mean age of 61 years (range: 21\u201382), a median symptom duration of 9 years (IQR: 1\u201332), and a median follow-up interval for bilateral hand radiographs of 1.06 years (IQR: 0.82\u20131.30). To quantify global wrist JSN, 10 compactness-related metrics were computed based on the spatial distribution of bone centroids extracted from carpal segmentation masks. These metrics were validated against the wrist JSN subscore of the SvdH score (SvdH-JSN_wrist) and the total Sharp score (TSS) as gold standards. Several distance-based metrics among the compactness-related metrics showed significant negative correlations with the wrist joint space narrowing subscore of the Sharp\/van der Heijde score (SvdH-JSN_wrist). Specifically, mean-pairwise-distance (MPD), root-mean-square-radius (RMSR), and median-radius (R50) showed moderate to strong correlations (r = \u22120.52 to \u22120.63, all p\u22640.0001) that were consistent at BL and FU. Correlations with TSS were weaker overall, with only R50 and its normalized form showing stable negative correlations (r = \u22120.40 to \u22120.43, p &lt; 0.01). Longitudinal analyses showed limited correlations between metric changes and clinical score changes. The proposed automated compactness quantification framework enables objective and reliable assessment of wrist JSN on standard radiographs and complements conventional scoring systems by supporting automated and standardized evaluation of RA-related wrist structural changes.<\/jats:p>","DOI":"10.3390\/jimaging12020087","type":"journal-article","created":{"date-parts":[[2026,2,18]],"date-time":"2026-02-18T11:45:58Z","timestamp":1771415158000},"page":"87","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Automated Compactness Quantitative Metrics for Wrist Bone on Conventional Radiography in Rheumatoid Arthritis: A Clinical Evaluation Study"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-8626-9354","authenticated-orcid":false,"given":"Jiajing","family":"Zhou","sequence":"first","affiliation":[{"name":"Faculty\/Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junmu","family":"Peng","sequence":"additional","affiliation":[{"name":"Faculty\/Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5767-0019","authenticated-orcid":false,"given":"Haolin","family":"Wang","sequence":"additional","affiliation":[{"name":"Faculty\/Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2502-8304","authenticated-orcid":false,"given":"Hiroshi","family":"Kataoka","sequence":"additional","affiliation":[{"name":"Sapporo City General Hospital, Sapporo 060-8604, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masaya","family":"Mukai","sequence":"additional","affiliation":[{"name":"Soen Chuo Hospital, Sapporo 621-1023, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-7943-025X","authenticated-orcid":false,"given":"Tunlada","family":"Wiriyanukhroh","sequence":"additional","affiliation":[{"name":"Faculty\/Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Hokkaido, Japan"},{"name":"Phramongkutklao Hospital and College of Medicine, Bangkok 10400, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7293-7471","authenticated-orcid":false,"given":"Tamotsu","family":"Kamishima","sequence":"additional","affiliation":[{"name":"Faculty\/Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1016\/S1357-2725(03)00259-0","article-title":"Rheumatoid arthritis: Regulation of synovial inflammation","volume":"36","author":"Sweeney","year":"2004","journal-title":"Int. J. Biochem. Cell Biol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1002\/ca.22980","article-title":"Rheumatoid arthritis in review: Clinical, anatomical, cellular and molecular points of view","volume":"31","author":"Sharif","year":"2018","journal-title":"Clin. Anat."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1016\/j.jhsa.2007.09.011","article-title":"Treatment of the wrist in rheumatoid arthritis","volume":"33","author":"Trieb","year":"2008","journal-title":"J. Hand Surg."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1535","DOI":"10.1136\/ard.2008.094128","article-title":"Progression of radiographic joint damage in rheumatoid arthritis: Independence of erosions and joint space narrowing","volume":"68","author":"Smolen","year":"2009","journal-title":"Ann. Rheum. Dis."},{"key":"ref_5","first-page":"591","article-title":"Global epidemiology of rheumatoid arthritis","volume":"18","author":"Finckh","year":"2022","journal-title":"Nat. Rev. Rheumatol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"669","DOI":"10.3899\/jrheum.200367","article-title":"The prevalence of rheumatoid arthritis: A systematic review of population-based studies","volume":"48","author":"Almutairi","year":"2021","journal-title":"J. Rheumatol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1053\/jhsu.2003.50070","article-title":"Longitudinal radiographic analysis of rheumatoid arthritis in the hand and wrist","volume":"28","author":"Leak","year":"2003","journal-title":"J. Hand Surg."},{"key":"ref_8","first-page":"74","article-title":"Joint erosions and patients with early rheumatoid arthritis","volume":"34","year":"1995","journal-title":"Rheumatology"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1136\/annrheumdis-2012-203158","article-title":"EULAR recommendations for the use of imaging of the joints in the clinical management of rheumatoid arthritis","volume":"72","author":"Colebatch","year":"2013","journal-title":"Ann. Rheum. Dis."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1016\/S0950-3579(96)80043-4","article-title":"Plain X-rays in rheumatoid arthritis: Overview of scoring methods, their reliability and applicability","volume":"10","year":"1996","journal-title":"Bailliere\u2019s Clin. Rheumatol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"891","DOI":"10.1002\/art.1780380704","article-title":"Joint space measurement in hand radiographs using computerized image analysis","volume":"38","author":"James","year":"1995","journal-title":"Arthritis Rheum. Off. J. Am. Coll. Rheumatol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2695","DOI":"10.1109\/TBME.2017.2659223","article-title":"Automatic quantification of radiographic wrist joint space width of patients with rheumatoid arthritis","volume":"64","author":"Huo","year":"2017","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"502","DOI":"10.1016\/j.jclinepi.2003.10.014","article-title":"The Sharp\/van der Heijde method out-performed the Larsen\/Scott method on the individual patient level in assessing radiographs in early rheumatoid arthritis","volume":"57","author":"Bruynesteyn","year":"2004","journal-title":"J. Clin. Epidemiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"706","DOI":"10.1002\/art.1780140605","article-title":"Methods of scoring the progression of radiologic changes in rheumatoid arthritis. Correlation of radiologic, clinical and laboratory abnormalities","volume":"14","author":"Sharp","year":"1971","journal-title":"Arthritis Rheum. Off. J. Am. Coll. Rheumatol."},{"key":"ref_15","first-page":"261","article-title":"How to read radiographs according to the Sharp\/van der Heijde method","volume":"27","year":"2000","journal-title":"J. Rheumatol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Wen, J., Liu, J., Xin, L., Wan, L., Jiang, H., Sun, Y., Sun, Y., Wang, X., and Wang, J. (2021). Effective factors on Sharp Score in patients with rheumatoid arthritis: A retrospective study. BMC Musculoskelet. Disord., 22.","DOI":"10.1186\/s12891-021-04742-3"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/0002-9343(83)90473-4","article-title":"Methods of assessing radiographic change in rheumatoid arthritis","volume":"75","author":"Genant","year":"1983","journal-title":"Am. J. Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"130","DOI":"10.1186\/s41747-024-00529-y","article-title":"Image biomarkers and explainable AI: Handcrafted features versus deep learned features","volume":"8","author":"Rundo","year":"2024","journal-title":"Eur. Radiol. Exp."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"108042","DOI":"10.1016\/j.compbiomed.2024.108042","article-title":"Evidence-based XAI: An empirical approach to design more effective and explainable decision support systems","volume":"170","author":"Famiglini","year":"2024","journal-title":"Comput. Biol. Med."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"45","DOI":"10.2478\/v10149-010-0003-4","article-title":"Hand radiograph analysis and joint space location improvement for image interpretation","volume":"1718","year":"2009","journal-title":"Schedae Informaticae"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2177","DOI":"10.1109\/TBME.2015.2512941","article-title":"Automatic quantification of radiographic finger joint space width of patients with early rheumatoid arthritis","volume":"63","author":"Huo","year":"2015","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Kang, B.K., Han, Y., Oh, J., Lim, J., Ryu, J., Yoon, M.S., Lee, J., and Ryu, S. (2022). Automatic segmentation for favourable delineation of ten wrist bones on wrist radiographs using Convolutional Neural Network. J. Pers. Med., 12.","DOI":"10.3390\/jpm12050776"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"648","DOI":"10.1007\/s10278-017-9970-9","article-title":"Computer-based radiographic quantification of joint space narrowing progression using sequential hand radiographs: Validation study in rheumatoid arthritis patients from multiple institutions","volume":"30","author":"Ichikawa","year":"2017","journal-title":"J. Digit. Imaging"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Yang, S., Wang, H., Ikebe, M., Kamishima, T., Ou, Y., and Okutomi, M. (2025, January 15\u201318). AP-DPM: A Dual-Path Merging Network via Adversarial Anatomical Prior Guidance for Wrist Bone Segmentation. Proceedings of the 2025 IEEE International Conference on Bioinformatics and Biomedicine (BIBM), Wuhan, China.","DOI":"10.1109\/BIBM66473.2025.11356216"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"111","DOI":"10.5114\/reum.2018.75523","article-title":"Cartilage and bone damage in rheumatoid arthritis","volume":"56","author":"Ostrowska","year":"2018","journal-title":"Rheumatologia"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1093\/rheumatology\/40.3.297","article-title":"The relationship between soft tissue swelling, joint space narrowing and erosive damage in hand X-rays of patients with rheumatoid arthritis","volume":"40","author":"Kirwan","year":"2001","journal-title":"Rheumatology"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1053\/sarh.2001.28304","article-title":"Modified Sharp method: Factors influencing reproducibility and variability","volume":"Volume 31","author":"Swinkels","year":"2001","journal-title":"Seminars in Arthritis and Rheumatism"},{"key":"ref_28","unstructured":"Maziarz, K., Krason, A., and Wojna, Z. (2021). Deep learning for rheumatoid arthritis: Joint detection and damage scoring in x-rays. arXiv."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"186","DOI":"10.4103\/0970-0358.85339","article-title":"Radiographic imaging of the wrist","volume":"44","author":"Bhat","year":"2011","journal-title":"Indian J. Plast. Surg."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"044502","DOI":"10.1117\/1.JMI.3.4.044502","article-title":"Validation of automatic joint space width measurements in hand radiographs in rheumatoid arthritis","volume":"3","author":"Schenk","year":"2016","journal-title":"J. Med Imaging"},{"key":"ref_31","first-page":"1792","article-title":"Radiographic progression on radiographs of hands and feet during the first 3 years of rheumatoid arthritis measured according to Sharp\u2019s method (van der Heijde modification)","volume":"22","year":"1995","journal-title":"J. Rheumatol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1042","DOI":"10.1093\/rheumatology\/kew020","article-title":"Structural damage in rheumatoid arthritis: Comparison between tendon damage evaluated by ultrasound and radiographic damage","volume":"55","author":"Janta","year":"2016","journal-title":"Rheumatology"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"723","DOI":"10.1016\/j.rdc.2009.10.005","article-title":"Radiographic measures to assess patients with rheumatoid arthritis: Advantages and limitations","volume":"35","author":"Yazici","year":"2009","journal-title":"Rheum. Dis. Clin."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1109\/42.222665","article-title":"Feature extraction in carpal-bone analysis","volume":"12","author":"Pietka","year":"1993","journal-title":"IEEE Trans. Med. Imaging"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/j.radi.2017.11.002","article-title":"Computer-aided detection in musculoskeletal projection radiography: A systematic review","volume":"24","author":"Gundry","year":"2018","journal-title":"Radiography"}],"container-title":["Journal of Imaging"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2313-433X\/12\/2\/87\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,25]],"date-time":"2026-02-25T09:49:52Z","timestamp":1772012992000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2313-433X\/12\/2\/87"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,18]]},"references-count":35,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["jimaging12020087"],"URL":"https:\/\/doi.org\/10.3390\/jimaging12020087","relation":{},"ISSN":["2313-433X"],"issn-type":[{"value":"2313-433X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,18]]}}}