Özet:

Objectives: The aim of this study is to evaluate the diagnostic value of mean and net enhancement attenuation values, net enhancement percentage in discrimination of Bosniak category 3 and 4 lesions on multiphasic computed tomography (CT). Materials and Methods: A search was performed through the PACS system using the key word “Bosniak cyst” to identify candidates for the study population. Twenty nine patients with Bosniak category 3 and 4 were enrolled in the study. Enhancement values were measured on precontrast, corticomedullary and nephrogram phases. Net enhancement attenuation value and net enhancement percentage were calculated. The presence of calcification on cyst wall/septa, renal vein thrombosis or lymphadenopathy and mean diameter of these complex cystic lesions were utilized. Results: Bosniak category 4 cysts had a significantly higher mean attenuation value compared with that of Bosniak category 3 cysts on corticomedullary and nephrogram phases (167.2±53.6 HU, 99.8±43 HU; p=0.001, p=0.023; respectively). Significant differences were observed between two pathologies with regard to net enhancement value and net enhancement percentage (p=0.003, p=0.015; respectively). By the use of ROC curve analysis, the cut off value of 131 HU for the mean attenuation value of Bosniak category 4 cyst on corticomedullary phase had the appropriate combination of sensitivity of 82% and specificity of 83% with the area under the cure being 0.848±0.081 (95% CI: 0.68-1). Conclusion: Bosniak category 4 cysts had larger net enhancement value and enhancement percentage. A value of >131 HU on corticomedullary phase can be a predictor value for Bosniak category 4 cysts.

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