Contrast enhanced ultrasound evaluation of the kidney

Abstract

In most centers, the fi rst intention method used for kidney evaluation is ultrasonography, both in B and Doppler modes. CEUS evaluation adds valuable information; therefore it should be part of routine examination. Unfortunately, this is not always possible, given the high costs of dedicated ultrasound machines. However, the fi nal cost will be lower than if CT or MRI assessment is used, in addition, the patient is not exposed to ionizing radiation, and the diagnosis can be made in the same place and in a very short time interval. Also, because the ultrasound contrast agent is not excreted by the kidneys, CEUS can also be used in acute or chronic renal failure, as opposed to CT evaluation. Given the rich vasculature of the kidney, ultrasound contrast agent administration improve the visualization of avascular
areas (small cysts, abscesses, hematomas, ruptures and renal infarctions) and of areas with very few vessels (if microbubbles are seen in the septa of complex cystic lesions, there is a high suspicion of malignancy). Also, a sensitive differential diagnosis can be made between malignant or benign tumors and normal anatomical variant, or between acute pyelonephritis and small micro-abscesses. Kidney CEUS could be used in the diagnosis of renal vascular diseases, in which, it appears that the prospects are good, especially for renal transplantation, where often repetitive evaluation is required. Studies are still needed to establish clear criteria for the differential diagnosis between malignant and benign renal focal lesions.