[CEUS-diagnosis of solid renal tumors]

CLINICAL ISSUE: Renal lesions are detected earlier, often as a result of ultrasound examinations. However, the imaging-based differential diagnosis of different tumour entities remains challenging STANDARD RADIOLOGICAL METHODS: All renal tumours >1cm should be evaluated for malignancy by computed tomography (CT) or magnetic resonance imaging (MRI). If an angiomyolipoma diagnosis cannot be established with imaging, further diagnostics are appropriate or if malignant progression is suspected, then multidisciplinary discussion for TNM-staging based uro-oncologic therapy is usual. METHODICAL INNOVATIONS: Contrast-enhanced ultrasound (CEUS) gives clear information about the microperfusion of renal tumours. PERFORMANCE: CEUS is helpful for the differentiation of renal cysts and especially papillary renal cell carcinomas. Moreover, CEUS advances renal tumour detection compared to Bmode and Doppler ultrasound per se. Cortical pseudolesions may be confidently ruled out using CEUS. ACHIEVEMENTS: Clear differentiation of benign and malignant renal lesions >1cm remains challenging, and only in rare cases is it possible with CEUS alone. Nevertheless CEUS is, in combination with other ultrasound techniques, eminently suitable for diagnosing focal pyelonephritis, renal abscesses and suspected renal lymphoma and supports the planning of ultrasound-assisted tumour biopsies. PRACTICAL RECOMMENDATIONS: Combining different imaging techniques is essential to accurately diagnose renal tumors. These imaging results (including the ultrasound/CEUS clips) should be viewed by the multidisciplinary cancer tumour board to facilitate individual treatment concepts for each patient.