{
  "id": 685172,
  "title": "RSNA Intracranial Aneurysm Detection — My Approach (Top 5%/ 57th)",
  "url": "/competitions/rsna-intracranial-aneurysm-detection/discussion/685172",
  "author_name": "Wosheng Deng",
  "post_date": "2026-03-27T05:28:14.279000",
  "votes": 0,
  "comment_count": 0,
  "views": 0,
  "content": "<p>The task involves detecting and localizing intracranial aneurysms from <strong>multimodal 3D medical imaging data (CTA / MRA / MRI)</strong>, which is challenging due to:</p>\n<ul>\n<li>Small lesion size  </li>\n<li>Severe class imbalance  </li>\n<li>High variability across imaging modalities  </li>\n</ul>\n<p>My approach focuses on improving signal-to-noise ratio through a <strong>localization-first 3D pipeline</strong> combined with multimodal modeling and ensembling.</p>\n<hr>\n<h3>Key Idea</h3>\n<p><strong>Localization-first 3D pipeline to reduce background noise and improve detection of small lesions.</strong></p>\n<p>Instead of directly performing classification on full-head scans, I first localize relevant anatomical regions and then apply downstream models on refined Regions of Interest (ROI).</p>\n<hr>\n<h3>Approach Overview</h3>\n<p>The solution is built as a <strong>three-stage pipeline</strong>:</p>\n<h4>Stage 1 — Brain ROI Localization</h4>\n<ul>\n<li>A 3D segmentation model (MedNeXt-S) is applied to extract the brain region from full-head scans.  </li>\n<li>This removes irrelevant background and improves downstream efficiency.  </li>\n</ul>\n<h4>Stage 2 — Artery ROI Refinement</h4>\n<ul>\n<li>Within the brain region, a second-stage model focuses on arterial structures.  </li>\n<li>Anatomical priors (e.g., TotalSeg) are used to guide localization.  </li>\n</ul>\n<h4>Stage 3 — Aneurysm Classification</h4>\n<p>Two complementary model families are used:</p>\n<ul>\n<li><p>Transformer-based 3D models  </p>\n<ul>\n<li>Operate on ROI inputs  </li>\n<li>Capture global spatial features  </li></ul></li>\n<li><p>CNN + RNN + Attention models  </p>\n<ul>\n<li>Operate on volumetric sequences  </li>\n<li>Capture temporal/contextual patterns  </li></ul></li>\n</ul>\n<hr>\n<h3>Ensemble Strategy</h3>\n<p>Predictions from multiple models are combined using <strong>weighted ensembling</strong>, which improves robustness and stabilizes performance across validation folds.</p>\n<hr>\n<h3>Result</h3>\n<ul>\n<li>Final Score: <strong>0.70 Mean Weighted AUC-ROC</strong>  </li>\n<li>Rank: <strong>57 / 1147 (Top 5%)</strong>  </li>\n</ul>\n<p>The solution shows strong performance on both:</p>\n<ul>\n<li>Primary label (Aneurysm Present)  </li>\n<li>Auxiliary anatomical labels  </li>\n</ul>\n<hr>\n<h3>Full Implementation</h3>\n<p>For full details, code, and system design:</p>\n<p>GitHub Repository:<br>\n<a href=\"https://github.com/WoshengDeng/rsna-intracranial-aneurysm-detection\" target=\"_blank\">https://github.com/WoshengDeng/rsna-intracranial-aneurysm-detection</a></p>\n<hr>\n<p>This writeup is intentionally concise. The full pipeline and implementation details are available in the GitHub repository.</p>",
  "messages": [
    {
      "id": 3429701,
      "postDate": "2026-03-27T05:28:14.280Z",
      "content": "<p>The task involves detecting and localizing intracranial aneurysms from <strong>multimodal 3D medical imaging data (CTA / MRA / MRI)</strong>, which is challenging due to:</p>\n<ul>\n<li>Small lesion size  </li>\n<li>Severe class imbalance  </li>\n<li>High variability across imaging modalities  </li>\n</ul>\n<p>My approach focuses on improving signal-to-noise ratio through a <strong>localization-first 3D pipeline</strong> combined with multimodal modeling and ensembling.</p>\n<hr>\n<h3>Key Idea</h3>\n<p><strong>Localization-first 3D pipeline to reduce background noise and improve detection of small lesions.</strong></p>\n<p>Instead of directly performing classification on full-head scans, I first localize relevant anatomical regions and then apply downstream models on refined Regions of Interest (ROI).</p>\n<hr>\n<h3>Approach Overview</h3>\n<p>The solution is built as a <strong>three-stage pipeline</strong>:</p>\n<h4>Stage 1 — Brain ROI Localization</h4>\n<ul>\n<li>A 3D segmentation model (MedNeXt-S) is applied to extract the brain region from full-head scans.  </li>\n<li>This removes irrelevant background and improves downstream efficiency.  </li>\n</ul>\n<h4>Stage 2 — Artery ROI Refinement</h4>\n<ul>\n<li>Within the brain region, a second-stage model focuses on arterial structures.  </li>\n<li>Anatomical priors (e.g., TotalSeg) are used to guide localization.  </li>\n</ul>\n<h4>Stage 3 — Aneurysm Classification</h4>\n<p>Two complementary model families are used:</p>\n<ul>\n<li><p>Transformer-based 3D models  </p>\n<ul>\n<li>Operate on ROI inputs  </li>\n<li>Capture global spatial features  </li></ul></li>\n<li><p>CNN + RNN + Attention models  </p>\n<ul>\n<li>Operate on volumetric sequences  </li>\n<li>Capture temporal/contextual patterns  </li></ul></li>\n</ul>\n<hr>\n<h3>Ensemble Strategy</h3>\n<p>Predictions from multiple models are combined using <strong>weighted ensembling</strong>, which improves robustness and stabilizes performance across validation folds.</p>\n<hr>\n<h3>Result</h3>\n<ul>\n<li>Final Score: <strong>0.70 Mean Weighted AUC-ROC</strong>  </li>\n<li>Rank: <strong>57 / 1147 (Top 5%)</strong>  </li>\n</ul>\n<p>The solution shows strong performance on both:</p>\n<ul>\n<li>Primary label (Aneurysm Present)  </li>\n<li>Auxiliary anatomical labels  </li>\n</ul>\n<hr>\n<h3>Full Implementation</h3>\n<p>For full details, code, and system design:</p>\n<p>GitHub Repository:<br>\n<a href=\"https://github.com/WoshengDeng/rsna-intracranial-aneurysm-detection\" target=\"_blank\">https://github.com/WoshengDeng/rsna-intracranial-aneurysm-detection</a></p>\n<hr>\n<p>This writeup is intentionally concise. The full pipeline and implementation details are available in the GitHub repository.</p>",
      "rawMarkdown": "The task involves detecting and localizing intracranial aneurysms from **multimodal 3D medical imaging data (CTA / MRA / MRI)**, which is challenging due to:\n\n- Small lesion size  \n- Severe class imbalance  \n- High variability across imaging modalities  \n\nMy approach focuses on improving signal-to-noise ratio through a **localization-first 3D pipeline** combined with multimodal modeling and ensembling.\n\n---\n\n### Key Idea\n\n**Localization-first 3D pipeline to reduce background noise and improve detection of small lesions.**\n\nInstead of directly performing classification on full-head scans, I first localize relevant anatomical regions and then apply downstream models on refined Regions of Interest (ROI).\n\n---\n\n### Approach Overview\n\nThe solution is built as a **three-stage pipeline**:\n\n#### Stage 1 — Brain ROI Localization\n- A 3D segmentation model (MedNeXt-S) is applied to extract the brain region from full-head scans.  \n- This removes irrelevant background and improves downstream efficiency.  \n\n#### Stage 2 — Artery ROI Refinement\n- Within the brain region, a second-stage model focuses on arterial structures.  \n- Anatomical priors (e.g., TotalSeg) are used to guide localization.  \n\n#### Stage 3 — Aneurysm Classification\n\nTwo complementary model families are used:\n\n- Transformer-based 3D models  \n  - Operate on ROI inputs  \n  - Capture global spatial features  \n\n- CNN + RNN + Attention models  \n  - Operate on volumetric sequences  \n  - Capture temporal/contextual patterns  \n\n---\n\n### Ensemble Strategy\n\nPredictions from multiple models are combined using **weighted ensembling**, which improves robustness and stabilizes performance across validation folds.\n\n---\n\n### Result\n\n- Final Score: **0.70 Mean Weighted AUC-ROC**  \n- Rank: **57 / 1147 (Top 5%)**  \n\nThe solution shows strong performance on both:\n- Primary label (Aneurysm Present)  \n- Auxiliary anatomical labels  \n\n---\n\n### Full Implementation\n\nFor full details, code, and system design:\n\nGitHub Repository:  \nhttps://github.com/WoshengDeng/rsna-intracranial-aneurysm-detection\n\n---\n\nThis writeup is intentionally concise. The full pipeline and implementation details are available in the GitHub repository."
    }
  ],
  "comments": [],
  "raw_markdown_by_id": {
    "3429701": "The task involves detecting and localizing intracranial aneurysms from **multimodal 3D medical imaging data (CTA / MRA / MRI)**, which is challenging due to:\n\n- Small lesion size  \n- Severe class imbalance  \n- High variability across imaging modalities  \n\nMy approach focuses on improving signal-to-noise ratio through a **localization-first 3D pipeline** combined with multimodal modeling and ensembling.\n\n---\n\n### Key Idea\n\n**Localization-first 3D pipeline to reduce background noise and improve detection of small lesions.**\n\nInstead of directly performing classification on full-head scans, I first localize relevant anatomical regions and then apply downstream models on refined Regions of Interest (ROI).\n\n---\n\n### Approach Overview\n\nThe solution is built as a **three-stage pipeline**:\n\n#### Stage 1 — Brain ROI Localization\n- A 3D segmentation model (MedNeXt-S) is applied to extract the brain region from full-head scans.  \n- This removes irrelevant background and improves downstream efficiency.  \n\n#### Stage 2 — Artery ROI Refinement\n- Within the brain region, a second-stage model focuses on arterial structures.  \n- Anatomical priors (e.g., TotalSeg) are used to guide localization.  \n\n#### Stage 3 — Aneurysm Classification\n\nTwo complementary model families are used:\n\n- Transformer-based 3D models  \n  - Operate on ROI inputs  \n  - Capture global spatial features  \n\n- CNN + RNN + Attention models  \n  - Operate on volumetric sequences  \n  - Capture temporal/contextual patterns  \n\n---\n\n### Ensemble Strategy\n\nPredictions from multiple models are combined using **weighted ensembling**, which improves robustness and stabilizes performance across validation folds.\n\n---\n\n### Result\n\n- Final Score: **0.70 Mean Weighted AUC-ROC**  \n- Rank: **57 / 1147 (Top 5%)**  \n\nThe solution shows strong performance on both:\n- Primary label (Aneurysm Present)  \n- Auxiliary anatomical labels  \n\n---\n\n### Full Implementation\n\nFor full details, code, and system design:\n\nGitHub Repository:  \nhttps://github.com/WoshengDeng/rsna-intracranial-aneurysm-detection\n\n---\n\nThis writeup is intentionally concise. The full pipeline and implementation details are available in the GitHub repository."
  }
}