AB148. Urology & reproductive medicine feasibility of dual energy CT unenhanced spectral curve on differential diagnosis between clear cell renal cell carcinoma and renal angiomyolipoma

OBJECTIVE: Due to the lack of typical clinical symptoms and the similarity in radiography of early stage renal cell carcinoma (RCC) and small sized renal angiomyolipoma (RAML), it is usually difficult on the differential diagnosis. In this article, we discovered the feasibility of unenhanced dual energy CT spectral curves in differential diagnosis of RCC and RAML, aiming at providing a new imaging method for the diagnosis and differential diagnosis of RCC and RAML. METHODS: Sixty-six cases of renal tumor under treatment in our institute were retrospectively studied. All these patients were examined through the dual energy CT. Among those patients, 43 cases were pathologically confirmed as clear cell renal cell carcinoma (CCRCC) and 23 cases were RAML. The regions of interest (ROIs) were set on the cross-sectional image of the tumors. Spectral curves were created based on these ROIs, the average CT values at 40–140 keV and the average slopes of the curves were calculated. According to the slopes, the curves were divided into three types (type I–III). The constituent ratios of each spectral curve types in CCRCC and AML groups were calculated. Statistical approaches were employed to check all the results. RESULTS: (I) At 40–140 keV, CT values of CCRCC were higher than RAML, the differences were statistically significant (P=0.00); (II) the difference between the average slope of CCRCC and AML was statistically significant (t=7.31, P=0.00); (III) the constituent ratios of each spectral curve types have shown a statistically significant difference (x(2)=47.33, P=0.00) between CCRCC and RAML. CONCLUSIONS: CCRCC and RAML have significantly different CT values on 40–140 keV and different spectral curve types, unenhanced spectral CT scan provides a new method for diagnosis and differential diagnosis of CCRCC and RAML.