Role of Contrast Enhanced Ultrasound in Differentiation between Benign and Malignant Solid Renal Masses

Abstract

The widespread use of imaging techniques such as ultrasonography, CT, and MRI haveincreased the incidental discovery of asymptomatic renal tumors. If sufficiently large orsuspicious malignancy, these tumors may undergo biopsy or surgical removal. The accuracy of conventional B-mode alone, or in combination with color Doppler ultrasound (CDUS) in the detection and characterization of renal masses, is considered to be less reliable than CEUS.

CEUS is always performed after conventional B-mode US and must, therefore, be regardedas a combination of both methods. CEUS is noninvasive, repeatable, real-time, inexpensive imag¬ing modality that uses a purely intravascular con¬trast agent (Red blood cell size). CEUS can improve the detection and characterization of renal malignancies especially the isoechoic lesions.It is useful particularly in patients with end-stage renal failure and von Hippel–Lindausyndromthose patients with contraindications for the use of CT or MR im¬aging contrast agents.

CEUS is a valuable tool increasing the sensitivity and specific¬ity for characterization of solid renal masses by assessment of the neoplastic circulation because it exquisitely demonstrates the macro- and microvascular enhancement to compet that of CT and MR imaging. Since the availability of US contrast agents especiallysocond generation contrast agents provide the important characteristic of microbubbles for their stability,strong enhancement and provide enough time for examination. In other cases, imaging suchas CT and MRI are requested on a regular basis for follow up. These follow up strategies are expensiveand have well defined complications. The promise of CEUS is particularly significant in thisregard, given its many potential advantages over theother modalities, not least among them its ability to beused in patients with renal failure.