Prognosticating WHO/ISUP Grade in Clear Cell Renal Cell Carcinoma: Insights from Amide Proton Transfer-weighted MRI

Background: Preoperative prediction of clear cell renal cell carcinoma (ccRCC) grade can support optimal selection of surgical resection strategies. Currently, there is no effective preoperative method for accurately assessing the histologic grade of ccRCC. More precise, non-invasive prediction methods are needed.

Purpose: To investigate the parameter of amide proton transfer-weighted (APTw) MRI for prediction of pathological ccRCC grade and whether the combination of the APTw, Diffusion-Weighted Imaging (DWI), and mDixon MRI techniques can improve the prediction performance.

Materials And Methods: This prospective study included ccRCC patients who underwent multiparametric MRI examinations (including APTw, DWI, and mDixon) along with contrast-enhanced CT or MRI examinations from March 2021 to June 2024. The mean, maximum, minimum, and standard deviation (SD) values from APTw and apparent diffusion coefficient (ADC) imaging of the solid tumor portions and the fat fraction (FF) values from mDixon imaging were measured. The area under the receiver operating characteristic curve (AUC) values for the parameters were calculated to evaluate the diagnostic performance.

Results: A total of 48 ccRCC patients (mean age, 65 years; 32 males) were included, of whom 10 had high-grade ccRCC and 38 had low-grade ccRCC. Compared with low-grade ccRCC, high-grade ccRCC exhibited higher APTw (2.28 % vs. 4.17 %; P < .05), APTw (4.97 % vs. 8.48 %; P < .01), and APTwSD (1.10 vs. 1.75; P < .01) values as well as lower ADC values (1.23 × 10 mm/s vs. 0.94 × 10 mm/s; P < .05). The AUC values for the ability of APTw, APTw, APTwSD, ADC, and these factors combined to distinguish between low-grade and high-grade ccRCC were 0.728, 0.786, 0.832, 0.741, and 0.858, respectively.

Conclusion: APTw, APTw, APTwSD, and ADC values are potential indicators for preoperative prediction of ccRCC pathologic grade. APTw parameters offer certain advantages for use alone or in combination with other parameters.