Diagnostic evaluation of small renal masses: Value of contrast-enhanced US in comparison to multidetector CT

Purpose: We investigated the value of contrast-enhanced ultrasound (CEUS) in the diagnostic evaluation of small renal masses (<4cm) comparing this method to the findings in multidetector CT (MDCT).

Materials and methods: In 102 patients (mean age 53 years) 143 small renal masses (107 malignant, 36 benign) were divided in 2 groups (group A: 53 lesions <2cm; group B: 90 lesions with 2–4cm). During CEUS enhancement patterns of the lesions were examined with the Cadence Contrast Pulse Sequencing technology (CPS, Acuson®) in a bolus technique. Diagnosis was established by pathohistology and/or multiphase MDCT.

Results: CEUS showed enhancement in 123 small renal masses. Twenty lesions presented themselves unenhanced. A strong arterial enhancement was only found in malignant lesions. CPS improved the diagnostic accuracy compared to unenhanced US (84%, vs. 47%) and no significant difference in the diagnostic accuracy could be found between group A and B. In comparison to CEUS the diagnostic accuracy of MDCT was lower in group A and equal in group B.

Conclusion: Contrast-enhanced US with CPS was superior to unenhanced US in the diagnostic evaluation of small renal masses. In lesions smaller than 2cm the contrast-enhanced US with CPS was also superior to multiphasic multidetector CT.