Differentiation of Upper Urinary Tract Lesions Using MDCT: Benign Vs Malignant

Abstract

To evaluate the accuracy of multiple detector computed tomography (MDCT) in differentiating benign and malignant lesions of upper urinary tract (UUT). Fifty-four patients with 55 suspected UUT lesions were included in the study. All patients underwent MDCT scan with nephrographic and excretory phases. The unenhanced phase was also performed in 38 cases. The final diagnosis was made by histology in 48 lesions: 43-after surgery, 5-after biopsy and by MDCT follow-up over at least 15 months in the remaining 7 lesions. The following CT features were evaluated: number of lesions, lesion appearance (mass or wall thickening), presence of calcifications, internal border appearance (smooth or irregular), and size and enhancement (presence or absence). The relationship between imaging characteristics and pathology (benign vs malignant) was assessed with logistic regression, univariable diagnostic accuracy, and with classification and regression tree analysis. Patients with mass morphology had a significantly higher probability of malignancy (odds ratio [OR]: 3.73, 95%CI: 1.02-13.72, p = 0.047) compared to patients with thickened wall morphology. The presence of an irregular internal border was also significantly associated with malignancy (OR: 12.14, 95%CI: 2.95-50.06, p < 0.001). No significant associations were found between malignancy and lesion size (p = 0.29), calcifications (p = 0.93) or enhancement (p = 0.68). Mass morphology and irregular internal border are reliable signs to suggest malignancy in UUT lesions.