The value of contrast-enhanced ultrasound in diagnosis of renal cell carcinoma subtyping

Abstract

Objective The purpose of this study was to evaluate the value of contrast-enhanced ultrasound in diagnosis of renal cell carcinoma subtyping. Methods 206 cases with renal tumors were confirmed by pathology and surgery from June 2012 to June 2014, including 113 male cases and 93 female cases.The mean age was 54 years (range 23-80 years). The subtype of renal tumor included clear cell carcinoma in 147 cases, papillary cell carcinoma in 32 cases, chromophobe cell carcinoma in 27 cases. All patients were received the CEUS before operation.The enhancement patterns, degree of enhancement, the appearance of necrosis and the time-intensity curve by contrast-enhanced ultrasound were analyzed. Results Enhancement patterns of CEUS were showed by fast in and fast out in 63.9%(94/147)cases with clear cell carcinoma, 59.4%(19/32) cases with papillary cell carcinoma, 51.9%(14/27) cases with chromophobe cell carcinoma.Statistical significant diference was shown among those subtype groups (P<0.05). Most of the clear cell carcinomas (127/147, 86.4%) showed hyperenhancing.While, the papillary renal cell carcinoma (22/32, 68.8%) and chromophobe cell carcinoma (15/27, 55.6%) showed hypoenhancing (P<0.05). The rate of necrosis in clear renal cell carcinoma was 62.6% (92/147), and 59.4%(19/32) in papillary cell carcinoma. necrosis area accounted for only 18.5% (5/27)in chromophobe cell carcinoma (P<0.05). In the time-intensity curve analysis, the initial time, the average arrival time, the time to peak and area under the curve in renal cortex was (11.06±2.75)s, (23.42±2.79)s, (27.47±3.02)dB, (35.01±2.94)dB, respectively. Significant differences in those items were found in clear cell carcinoma, which was(8.01±1.89)s, (20.05±3.01)s, (30.03±2.98)dB, (37.64±4.01)dB respectively, compared with those in cortex ( P<0.05). The arrival time, time to peak, peak intensity and area under the curve in papillary cell carcinoma were (11.12±2.43)s, (27.29±3.54)s, (20.13±2.67)dB, (34.67±3.24)dB, respectively.The curve showed the time to peak was higher and the peak intensity were lower than those of renal cortex ( P<0.05). The arrival time, time to peak, peak intensity and area under the curve in chromophobe cell carcinoma were (11.32±2.90)s, (22.21±3.62)s, (22.02±2.52)dB, (28.67±3.65)dB, respectively.The curve demonstrated peak intensity and area under the curve were lower than those of surrounding renal cortex (P<0.05). The increase of tumor diameter after contrast-enhanced ultrasound in clear cell carcinoma was about (0.35±0.11)cm and in nonclear cell carcinoma was about (0.23±0.10)cm ( P<0.05). Conclusion The contrast-enhanced ultrasound played an important role in diagnosis and subtype renal cell carcinoma. Key words: Renal cell carcinoma; Contrast-enhanced ultrasound; Pathological; Time-intensity curve