To gain new insights into renal perfusion and pathogenesis of acute kidney injury in intensive care unit (ICU) patients, we need new techniques to evaluate renal microcirculation. In addition, a bedside technique applicable in the ICU could be extremely useful for physicians to adjust the optimal therapeutic/preventive modalities for kidney perfusion in each patient. Contrast-enhanced ultrasound (CEUS) has been validated to assess and quantify the microcirculation up to capillary perfusion in several organs. In a recent issue, Schneider and colleagues suggest that CEUS is feasible, well tolerated and able to quantify cortical renal microcirculation in patients undergoing cardiac surgery. In addition, CEUS derived-parameters suggest a decrease in renal perfusion occurring within 24 hours of surgery in patients at risk of acute kidney injury. This study opens up new possibilities for the assessment of cortical renal microcirculation in ICU patients.