Diagnostic performance of the clear cell likelihood score integrated with cystic degeneration or necrosis on MR imaging for identifying clear cell renal cell carcinoma in cT1 solid renal masses

Abstract Objectives To evaluate the diagnostic value of the clear cell likelihood score (ccLS) integrated with cystic degeneration or necrosis on renal MR imaging for diagnosing clear cell renal cell carcinoma (ccRCC) in cT1 solid renal masses (SRMs). Methods This retrospective study consecutively enrolled patients with pathologically confirmed SRMs who underwent MRI at the First Medical Center of the Chinese PLA General Hospital between January 2022 and February 2024. Three radiologists independently scored all cT1 SRMs using ccLS and ccLS integrated with cystic degeneration or necrosis (cn-ccLS), with discrepancies reconciled by consensus. Sensitivity, specificity, and accuracy were used to assess the performance of ccLS and cn-ccLS. Results A total of 287 patients with 293 masses were included in this study. The sample comprised 229 ccRCCs (78%), 64 other tumors. The sensitivity of cn-ccLS was significantly higher than ccLS (92% vs 74%; p < 0.001), with equal specificity to ccLS (88% vs 91%; p > 0.05). For cT1a and cT1b SRMs, the sensitivity of cn-ccLS was significantly higher than ccLS (cT1a: 90% vs 74%, p < 0.05; cT1b: 98% vs 75%, p < 0.001). Conclusions Incorporating cystic degeneration or necrosis into the ccLS system significantly enhances the diagnostic performance of the ccLS system for ccRCC in cT1 SRMs. However, future validation of the ccLS system through large-sample, multi-center, and prospective studies is still required. Critical relevance statement Incorporating cystic degeneration or necrosis into the ccLS system enhances performance for ccRCC in cT1 SRMs. It may enhance the value of ccLS and assist radiologists in their daily diagnostic work. Key Points The cn-ccLS effectively reduced the proportion of ccRCC among ccLS 3 lesions. cn-ccLS better diagnosed ccRCC for cT1a or cT1b renal masses than ccLS. ccRCC sensitivity was improved, but the impact on non-ccRCC remains unevaluated. Graphical Abstract