{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T17:04:05Z","timestamp":1785431045715,"version":"3.56.0"},"reference-count":27,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T00:00:00Z","timestamp":1785369600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"\u0130stanbul Topkap\u0131 University","award":["GAP2025-003"],"award-info":[{"award-number":["GAP2025-003"]}]},{"award":["GAP2025-003"],"award-info":[{"award-number":["GAP2025-003"]}],"id":[{"id":"https:\/\/ror.org\/00g241p78","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Accurate delineation of brain tumours on contrast-enhanced MRI remains difficult because lesions can be small, irregular, and weakly separated from adjacent tissue. This study developed BG-YOLO11s, a boundary-guided single-stage instance-segmentation model for T1 contrast-enhanced MRI. Methods: The public Figshare\/Cheng dataset, comprising 3064 slices from 233 patients, was converted to YOLO polygon annotations and evaluated using a fixed 70\/15\/15 image-level split (2144\/459\/461 slices). Because patient identifiers were not retained in the exported image-and-polygon data, the split was not guaranteed to be patient-disjoint. B\u00e9zier Contour Augmentation generated two contour-perturbed training samples per original slice while leaving validation and test data unchanged. BG-YOLO11s extended YOLO11s-seg with dilated context aggregation in the backbone, boundary-enhanced feature fusion in the neck, and a prototype refinement module with differentiable boundary-aware supervision in the segmentation head. Results: In a single run on the held-out image-level test split, BG-YOLO11s achieved 92.4% precision, 88.7% recall, 94.6% mask mAP@50, 68.9% mAP@50\u201395, and 86.5% IoU. Relative to YOLO11s-seg, the corresponding gains were 3.8 points in mAP@50, 5.8 points in mAP@50\u201395, and 4.1 points in IoU. A progressive ablation produced incremental gains along the fixed module-addition sequence, but it did not isolate all component interactions or quantify run-to-run uncertainty. Conclusions: BG-YOLO11s improved single-run mask-overlap estimates under the present image-level benchmark. Patient-disjoint retraining, repeated-seed statistics, boundary-specific metrics, complete failure pattern auditing, and external multi-sequence validation are required before broader clinical or deployment claims can be made.<\/jats:p>","DOI":"10.3390\/diagnostics16152407","type":"journal-article","created":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T16:15:00Z","timestamp":1785428100000},"page":"2407","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["BG-YOLO11s: Boundary-Guided YOLO11 with B\u00e9zier Contour Augmentation for Brain Tumour Segmentation in T1-CE MRI"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0562-4931","authenticated-orcid":false,"given":"Mustafa","family":"Yurdakul","sequence":"first","affiliation":[{"name":"Department of Computer Engineering, K\u0131r\u0131kkale University, K\u0131r\u0131kkale 71450, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Javanshir","family":"Zeynalov","sequence":"additional","affiliation":[{"name":"Department of Electronics and Information Technologies, Faculty of Architecture and Engineering, Nakhchivan State University, AZ 7012 Nakhchivan, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4364-9144","authenticated-orcid":false,"given":"Merve","family":"Ersoy","sequence":"additional","affiliation":[{"name":"Department of Computer Engineering, \u0130stanbul Topkap\u0131 University, \u0130stanbul 34394, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4135-2091","authenticated-orcid":false,"given":"Faruk","family":"\u00d6zger","sequence":"additional","affiliation":[{"name":"Department of Computer Engineering, I\u011fd\u0131r University, I\u011fd\u0131r 76000, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6670-2169","authenticated-orcid":false,"given":"Ishak","family":"Pacal","sequence":"additional","affiliation":[{"name":"Department of Computer Engineering, I\u011fd\u0131r University, I\u011fd\u0131r 76000, T\u00fcrkiye"},{"name":"Department of Computer Engineering, Faculty of Engineering and Natural Sciences, Fenerbahce University, Istanbul 34758, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"432","DOI":"10.1016\/S0140-6736(18)30990-5","article-title":"Primary brain tumours in adults","volume":"392","author":"Lapointe","year":"2018","journal-title":"Lancet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1231","DOI":"10.1093\/neuonc\/noab106","article-title":"The 2021 WHO classification of tumors of the central nervous system: A summary","volume":"23","author":"Louis","year":"2021","journal-title":"Neuro-Oncology"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"vi1","DOI":"10.1093\/neuonc\/noae145","article-title":"CBTRUS statistical report: Primary brain and other central nervous system tumors diagnosed in the United States in 2017\u20132021","volume":"26","author":"Price","year":"2024","journal-title":"Neuro-Oncology"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"iii1","DOI":"10.1093\/neuonc\/noab200","article-title":"CBTRUS statistical report: Primary brain and other central nervous system tumors diagnosed in the United States in 2014\u20132018","volume":"23","author":"Ostrom","year":"2021","journal-title":"Neuro-Oncology"},{"key":"ref_5","first-page":"229","article-title":"Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries","volume":"74","author":"Bray","year":"2024","journal-title":"CA Cancer J. 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