The Comparison of Accuracy of Contrast Enhanced Ultrasound on Diagnosis of Small Renal Masses and Distinguishing Renal Cell Carcinomas From Other Renal Masses, With Biopsy

Patients with an incidentally discovered small renal masses (SRM) < 4 cm in diameter are included. All patients will undergo biopsy for tissue diagnosis. Most patients will be followed by imaging. Study intervention includes low MI US to be performed following both bolus and infusion injection of Definity contrast. Presence and absence of vascularity, pattern of vascularity, and TIC values will be correlated with the final pathology to find features differentiating benign from malignant masses.