{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T09:54:43Z","timestamp":1781862883614,"version":"3.54.5"},"reference-count":19,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T00:00:00Z","timestamp":1777852800000},"content-version":"vor","delay-in-days":3,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T00:00:00Z","timestamp":1777593600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Int J of Urology"],"published-print":{"date-parts":[[2026,5]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>In boys with non\u2010palpable testis (NPT), the affected side may present as a viable testis (VT) or a nonviable testis (NVT), the latter representing true monorchidism. This study evaluated the utility of ultrasonography (US) for predicting monorchidism and testicular location in unilateral NPT.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We retrospectively reviewed boys with unilateral NPT who underwent preoperative US between 2009 and 2025. Testicular volumes were converted to age\u2010adjusted standard deviation (SD) scores. A rule\u2010based model classified NVT when the affected testis was visualized with an SD score \u2264 cutoff A and the unaffected testis had an SD score \u2265 cutoff B. If the affected testis was not visualized, an SD score \u2265 cutoff C for the unaffected testis indicated NVT; remaining cases were classified as VT. Predictions were compared with intraoperative findings. Receiver operating characteristic analysis determined optimal cutoffs. Internal validation using repeated stratified five\u2010fold cross\u2010validation and bootstrap resampling assessed model performance and threshold stability. US\u2010based localization was also compared with surgical findings.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Sixty\u2010nine boys were included; surgery identified 51 NVT and 18 VT. Optimal cutoffs were A\u2009=\u2009\u22122.60, B\u2009=\u2009+0.45, and C\u2009=\u2009+0.60. The model achieved an AUC of 96.1%, with 100% sensitivity, 92.2% specificity, 81.8% positive predictive value, and 100% negative predictive value. Internal validation showed median AUCs of 90.0% and 89.4%, with stable thresholds. Localization accuracy was 66.6%.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>A rulebased US model may predict monorchidism in unilateral NPT with a very low risk of misclassifying VT as NVT, despite its limited ability to determine testicular location.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1111\/iju.70482","type":"journal-article","created":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T12:15:53Z","timestamp":1777896953000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Novel Prediction Model for Monorchidism in Boys With Unilateral Nonpalpable Testes: Diagnostic Utility of Preoperative Ultrasonography"],"prefix":"10.1111","volume":"33","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-7989-6748","authenticated-orcid":false,"given":"Yuki","family":"Muranishi","sequence":"first","affiliation":[{"name":"Department of Renal and Genitourinary Surgery Hokkaido University Graduate School of Medicine  Sapporo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4444-7958","authenticated-orcid":false,"given":"Takahiro","family":"Osawa","sequence":"additional","affiliation":[{"name":"Department of Renal and Genitourinary Surgery Hokkaido University Graduate School of Medicine  Sapporo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3930-0233","authenticated-orcid":false,"given":"Yurie","family":"Hirata","sequence":"additional","affiliation":[{"name":"Department of Renal and Genitourinary Surgery Hokkaido University Graduate School of Medicine  Sapporo 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Hokkaido University Hospital  Sapporo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoichi M.","family":"Ito","sequence":"additional","affiliation":[{"name":"Data Science Center, Promotion Unit Institution of Health Science Innovation for Medical Care, Hokkaido University Hospital  Sapporo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masafumi","family":"Kon","sequence":"additional","affiliation":[{"name":"Department of Renal and Genitourinary Surgery Hokkaido University Graduate School of Medicine  Sapporo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takashige","family":"Abe","sequence":"additional","affiliation":[{"name":"Department of Renal and Genitourinary Surgery Hokkaido University Graduate School of Medicine  Sapporo 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