SecondOpinion: Anatomy-Aware Gated Reasoning for Efficient Medical Image Analysis
This work addresses the inefficiency of conventional medical image analysis models that uniformly process all cases regardless of complexity. The authors propose SecondOpinion, a dual-stream framework wherein a primary stream rapidly handles all inputs, while an anatomically guided auxiliary stream is activated only when a learnable gating mechanism—GateKeeper—deems the initial prediction unreliable. Crucially, the gate is explicitly trained as a binary correctness classifier, enabling on-demand invocation of anatomical reasoning. Results on chest X-ray and pelvic fracture datasets demonstrate that the model matches or exceeds state-of-the-art performance, with auxiliary stream activation rates ranging from 9.23% to 45.71%, closely aligned with task difficulty. This approach significantly enhances computational efficiency and task adaptability.