Incorporating Clinical Guidelines through Adapting Multi-modal Large Language Model for Prostate Cancer PI-RADS Scoring
Tiantian Zhang, Manxi Lin, Hongda Guo, Xiaofan Zhang, Ka Fung Peter Chiu, Aasa Feragen, Qi Dou
TL;DR
This work tackles automatic PI-RADS scoring for prostate cancer by embedding the PI-RADS Clinical Guideline (PICG) into an automated pipeline using a guideline network built on a Multi-modal Large Language Model (MLLM). It introduces a two-stage fine-tuning strategy with a domain adapter to adapt 3D MRI data and a PICG-to-instructions stage to produce PICG-guided image features, which are aligned with scoring-network representations via KL-divergence-based distillation. Experiments on a public MRI dataset and a private heterogeneous test set demonstrate consistent accuracy and error reductions across multiple state-of-the-art scoring networks, validating the approach’s effectiveness and generalizability. The method is model-agnostic and requires no additional annotations or network changes, offering a practical plug-in to enhance real-world PI-RADS scoring and potentially improve interpretability.
Abstract
The Prostate Imaging Reporting and Data System (PI-RADS) is pivotal in the diagnosis of clinically significant prostate cancer through MRI imaging. Current deep learning-based PI-RADS scoring methods often lack the incorporation of common PI-RADS clinical guideline~(PICG) utilized by radiologists, potentially compromising scoring accuracy. This paper introduces a novel approach that adapts a multi-modal large language model (MLLM) to incorporate PICG into PI-RADS scoring model without additional annotations and network parameters. We present a designed two-stage fine-tuning process aiming at adapting a MLLM originally trained on natural images to the MRI images while effectively integrating the PICG. Specifically, in the first stage, we develop a domain adapter layer tailored for processing 3D MRI inputs and instruct the MLLM to differentiate MRI sequences. In the second stage, we translate PICG for guiding instructions from the model to generate PICG-guided image features. Through such a feature distillation step, we align the scoring network's features with the PICG-guided image features, which enables the model to effectively incorporate the PICG information. We develop our model on a public dataset and evaluate it on an in-house dataset. Experimental results demonstrate that our approach effectively improves the performance of current scoring networks. Code is available at: https://github.com/med-air/PICG2scoring
