RANO 2.0: critical updates and practical considerations for radiological assessment in neuro-oncology

Appropriate response assessment criteria are crucial for accurate evaluation of clinical trial outcomes, and numerous criteria have been proposed to address this need. With the introduction of Response Assessment in Neuro-Oncology (RANO) criteria version 2.0 (RANO 2.0) in 2023, response assessment in gliomas has evolved significantly, requiring both clinicians and radiologists to develop a comprehensive understanding of its modifications and implementation. This review first provides an overview of standard management and imaging schedule in glioma treatment. We then review the basic framework of RANO 2.0, inherited from previous response criteria, with particular emphasis on major modifications to this framework: the implementation of the Brain Tumor Imaging Protocol and the adoption of post-radiation scan as the baseline scan. Additionally, we analyze critical changes in response evaluation and interpretation, specifically focusing on the role of preliminary progressive disease assessment with confirmation scans, and the elimination of T2/FLAIR lesion measurements from enhancing tumor assessment. Through illustrative clinical cases, we demonstrate the practical application of these modifications and discuss the implementation of three distinct imaging-based categories: enhancing tumor, non-enhancing tumor, and tumors with both enhancing and non-enhancing components (in short, mixed tumor). This comprehensive narrative review provides clinicians with practical guidance for implementing RANO 2.0 in their clinical practice.