Objective To investigate the prediction of Fuhrman histopathological grade of T1 clear cell renal cell carcinoma (ccRCC) by multi-slice computed tomography (MSCT) signs and enhancement parameters.

Methods The clinical and imaging data of 66 patients with T1 stage ccRCC diagnosed by postoperative histopathology in Kunshan Hospital Affiliated to Jiangsu University from January 2014 to March 2021, including 40 males and 26 females, aged (58.3±14.9) years, were analyzed retrospectively. All patients were divided into low-(Ⅰ −Ⅱ) and high-grade group (Ⅲ−Ⅳ) in accordance with the Fuhrman histopathological classification. The plain and enhanced images of MSCT of the patients in the two groups were analyzed, and the differences in MSCT signs and enhancement parameters between the two groups were compared. The predictive effectiveness of the observation indicators was analyzed. T-test was used to compare the measurement data with normal distribution; Chi square test or Fisher's exact test was used to compare the counting data between groups; Kappa test was used to compare the consistency of measurement results between two physicians. The "gold standard" was Fuhrman histopathological grading. The receiver operating characteristic curve was drawn, and area under curve (AUC) was calculated. Independent risk factors were evaluated by binary Logistic regression analysis.

Results The MSCT findings of the two groups were statistically significant in terms of tumor morphology, internal structure (cystic degeneration and necrosis), lobulation sign, pseudocapsule, capsule invasion, and tumor enhancement homogeneity (Fisher's exact test, χ²=8.800, 7.830; all P<0.05). The CT value, CT difference, enhancement ratio, and enhancement index of tumor focus in the low-grade group were higher than those in the high-grade group ((169.03±36.50) HU vs. (132.90±16.28) HU, (133.92±37.31) HU vs. (95.40±19.84) HU, 4.09±1.61 vs. 2.79±1.09, 1.45±1.13 vs. 0.91±0.81, respectively), and the difference was statistically significant (t=2.180−5.082, all P<0.05). The AUC of the four MSCT enhancements parameters were 0.849 (95%CI: 0.744–0.953, P<0.001), 0.848 (95%CI: 0.748–0.948, P<0.001), 0.741 (95%CI: 0.621–0.861, P<0.001), and 0.757 (95%CI: 0.637–0.878, P<0.001), the optimal critical values were 152.5 HU, 120.5 HU, 3.356, and 0.953, respectively. The Yoden indexes were 0.739, 0.655, 0.439 and 0.478. Multivariate Logistic regression analysis results show that pseudocapsule was an independent predictor of Fuhrman histopathological grading (OR=0.082, 95%CI: 0.007–0.908, P<0.05).

Conclusions The manifestations of plain and enhanced MSCT images of ccRCC are diverse. Combined with the CT value, CT difference, enhancement ratio, and enhancement index of tumor lesions in the corticomedullary phase are helpful in the prediction of Fuhrman histopathological grading. Pseudocapsules can be used as an independent predictor.