Neuroimaging biomarkers for predicting acupuncture treatment response in chronic pain: a systematic review and meta-analysis protocol.

introductionAcupuncture is increasingly recognised as an effective treatment for chronic pain conditions, yet inter-individual variability in treatment response remains a major clinical challenge. Recent neuroimaging studies suggest that baseline brain characteristics may serve as objective biomarkers for predicting therapeutic outcomes, with some achieving classification accuracies exceeding 80%. These findings, however, have not been systematically synthesised. This review will be the first to systematically evaluate whether pre-treatment neuroimaging biomarkers can predict acupuncture treatment response in adults with chronic pain. METHODS AND ANALYSIS: This protocol is reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines. We will search MEDLINE, Embase, Cochrane Central Register of Controlled Trials, PubMed, Web of Science and four Chinese databases (China National Knowledge Infrastructure, Wanfang, VIP and CBM) from inception to the search date without date restrictions. Eligible studies must include adults with chronic pain (≥3 months duration), baseline neuroimaging assessment (functional MRI, structural MRI, positron emission tomography (PET) or single-photon emission computed tomography (SPECT)) and needle-based acupuncture intervention with post-treatment clinical outcomes. Two reviewers will independently screen studies, extract data and assess risk of bias using the Prediction model Risk Of Bias ASsessment Tool, Cochrane Risk of Bias 2.0 and Newcastle-Ottawa Scale. Primary outcomes include predictive performance metrics (accuracy, sensitivity, specificity, area under the curve) and identification of specific brain regions with predictive value. Meta-analysis will be performed using random-effects models when sufficient homogeneous studies are available. Where studies classify responders versus non-responders, diagnostic test accuracy meta-analysis (bivariate/hierarchical summary receiver operating characteristic (ROC models)) will pool sensitivity and specificity. Coordinate-based meta-analysis using activation likelihood estimation will be conducted if 10 or more studies report stereotactic coordinates. The completed review will be reported following the PRISMA 2020 statement. ETHICS AND DISSEMINATION: Ethical approval is not required as this study involves secondary analysis of published data. Findings will be disseminated through peer-reviewed publication and conference presentations. Results are expected to support the development of neuroimaging-based clinical decision tools and to guide future biomarker validation studies. PROSPERO REGISTRATION NUMBER: CRD420261290372.