Yu.O. Mytsyk, Yu.B. Borys, I.Yu. Dutka, I.V. Dats, S.M. Pasichnyk, D.Z. Vorobets, A.R. Kucher, B.Yu. Borys

Imaging biomarkers based on multiphase CT data in differentiation of renal cell carcinoma

Background. Renal-cell carcinoma (RCC) is one of 10 mostly widely spread malignant tumors in the world. Recently scientists focused on investigation of new imaging biomarkers of RCC based on USG, CT, MRI and radionuclide examinations data in order to increase efficiency of current pathology diagnostics. The goal of this study was to evaluate an efficiency of application of the novel biomarkers based on multiphase CT in differential diagnostics of RCC.

Materials and methods. In total 120 patients with solid renal tumors >4 cm in greatest dimension in whom nephrectomy followed by pathological analysis were enrolled into this retrospective study: 84 (70,0%) with RCC, 14 (11,67%) with transitional cell carcinoma of renal pelvis and 22 (18,33%) with benign renal tumors. We analyzed and compared pathologic and multiphase CT data.

Results. Using of signal intensity with threshold 54,80 HU allowed to differentiate RCC from other renal tumors with sensitivity and specificity accordingly 98,8% and 69,4% (AUC=0,844, 95% CI=0,746-0,942, р<0,001) on excretory CT images. Differentiation of RCC and benign renal tumors using signal intensity with threshold of 61,84 HU demonstrated 79,8% sensitivity and 63,6% specificity (AUC=0,745, 95% CІ=0,599-0,891, р<0,001) on excretory CT images. Differentiation of conventional RCC histologic subtype from non-conventional using signal intensity of nephrographic CT images with threshold 79,39 HU was possible with 71,7% specificity and 54,8% sensitivity (AUC=0,718, 95% CІ=0610-0,826, р=0,001). Identification of papillary and chromophobe subtypes as well as Fuhrman grades of clear-cell RCC was also possible.

Conclusions. Application of radiodensity of tumor measured using multiphase CT as diagnostic imaging biomarker of solid RCC is valuable clinical tool for differentiation of current pathology, its histologic subtypes and Fuhrman grades. The drawback of the method is relatively high radiation exposure of the patient.