Topology-decoupled end-to-end framework for brain tumor MRI detection: boundary-preserving feature flow and inter-channel correlation distillation

Early and accurate detection of brain tumors is clinically valuable for improving prognosis and guiding treatment. Existing deep-learning methods for magnetic resonance imaging (MRI) brain tumor detection face three difficulties: weak texture at lesion boundaries impairs localization; heterogeneous lesion scales degrade multi-scale detection; and non-maximum suppression (NMS) post-processing limits end-to-end inference. We propose a topology-decoupled end-to-end detection framework based on boundary-preserving feature flow and inter-channel correlation (ICC) distillation. A high-capacity teacher combines a multi-gradient-flow backbone with a gather-and-distribute global fusion mechanism, capturing both pathological boundary textures and anatomical context; a lightweight student is then derived by removing the global-fusion neck while retaining the isomorphic backbone. After comparing five feature distillation methods, we adopt ICC distillation, which aligns Gram matrices of intermediate features and mitigates the background-dominated bias common in medical imaging. Across three random seeds, the ICC-distilled student reaches mAP@0.5 = \(0.7447 ± 0.0226\) , surpassing the plain student ( \(0.7225 ± 0.0169\) ) and matching or exceeding the teacher ( \(0.7386 ± 0.0227\) ). On the BraTS small-lesion stratum it attains 98.7% lesion recall with a false-positive-per-image rate of 0.014. The student achieves this at low cost (6.09M parameters, 11.7 GFLOPs, 168 FPS), suiting resource-constrained clinical deployment.