Assessing Response to Neoadjuvant Radiotherapy and Targeted Therapy in Soft Tissue Sarcoma by IVIM-DWI-derived Tumor Habitat Characteristics

Motivation: Soft tissue sarcoma (STS) can be treated with neoadjuvant radiotherapy (neo-RT) and targeted therapy. However, neo-RT raises wound complication risks, necessitating early treatment efficacy assessment for better clinical planning. Goal(s): To evaluate the pathological response in STS patients undergoing neo-RT and targeted therapy using sub-regional Intravoxel Incoherent Motion (IVIM) parameters. Approach: This prospective study included 21 patients with STS who underwent IVIM imaging. Quantitative IVIM parameters were extracted and analyzed with logistic regression to develop predictive models for treatment response. Results: The combined IVIM model showed a significantly higher AUC (0.952 [95%CI: 0.761-0.999]) in predicting treatment response compared to all individual parameter models. Impact: This study demonstrates that IVIM-based models offer a high-accuracy, non-invasive diagnostic approach for early assessment of treatment response in neo-RT and targeted therapy for STS, supporting personalized treatment strategies.