Objective:

To compare the direct signs of clear cell renal cell carcinoma (CCRCC) on 64-row spiral CT with pathological grading.

Methods:

A total of

34 CCRCC cases confirmed by surgical pathology in Huangshan People's Hospital during Feb. 2015 and May. 2018 were selected. The plain scan and multiphase contrast-enhanced scan images of 64-row spiral CT before surgery were analyzed and compared with the pathological grading. The CT direct signs of CCRCC included tumor shape

size

density

enhancement degree

enhancement modality

and presence of false envelope

etc. In accordance with the pathological grading criteria of World Health Organization (WHO)/International Society of Urological Pathology (ISUP)

CCRCC was classified into grades Ⅰ to Ⅳ

of which Ⅰ-Ⅱ was defined as low-grade (

n

=28)

Ⅲ-Ⅳ as high-grade (

n

=6). The data were collected and analyzed.

Results:

Compared with low-grade CCRCC

high-grade CCRCC lesions had more irregular shape (3 cases with irregular shape in high-grade group

accounting for 50.0%

and 2 cases with irregular shape in low-grade group

accounting for 7.1%)

higher density during plain scan (5 cases with slightly high density in high-grade group

accounting for 83.3%

and only 3 cases with slightly high density in low-grade group

accounting for 10.7%)

lower enhancement degree during corticomedullary phase [the differencein enhancement degree between high-grade CCRCC and ipsilateral renal cortex was (-16.112.3) HU

and that between lowgrade CCRCC and ipsilateral renal cortex was (7.07.5) HU

]

and lower enhanced attenuation during parenchymal phase [the average attenuation value was (-7.75.4) HU in low-grade group

and (-17.37.3) HU in high-grade group

]

. The differences were statistically significant (

P

＜0.05).

Conclusion:

The CT direct signs of CCRCC could provide a basis for WHO/ISUP pathological grading and help to formulate a preoperative plan.