Contrast enhanced ultrasound of cystic renal lesions, from diagnosis up to treatment

Abstract

Ultrasound is the most used interdisciplinary imaging technique in clinical routine for assessment of renal pathologies. This includes the monitoring of cystic renal lesions, which can be classified as non-complicated or complicated and by means of occurrence as solitary or multifocal lesions. The Bosniak-classification (I-IV) classifies renal cysts in 5 different categories and is used for decisions of further clinical treatment. This classification was developed for computed tomography and has been adopted for magnetic resonance imaging as well as contrast-enhanced ultrasound. In the following review article, cystic kidney lesions and their differentiation using contrast-enhanced ultrasound are presented and an overview of the therapy options is given. In interventional procedures, CEUS can make a valuable contribution in histological sampling, reduce radiation exposure and, under certain circumstances, the number of interventions for the patient.

Keywords: Contrast-enhanced ultrasound; intervention; kidney lesion; real-time imaging; tissue vascularization.

Fig. 1

B-mode ultrasound detected a complex cystic lesion (red arrows) with suspicion of an intracystic tumor. In the microflow imaging (yellow arrows) no vascularization is visible.

Fig. 2

Using the dual imaging CEUS setting, with CEUS image of the cyst (white arrows) on the left side and greyscale image on the right side (yellow arrows) of the image. During the contrast examination the lesion doesn't show any contrast uptake. The final diagnosis will be a complex cystic lesion but no malignant finding. According to the Bosniak classification the lesion will be classified as a Bosniak 2F cyst.

Fig. 3

B-mode ultrasound shows an exophytic growing cystic lesion with some enlarged septums (yellow arrows).

Fig. 4

In color doppler examination the lesion (yellow arrows) shows no vascularization only one vessel could be detected.

Fig. 5

Using the dual imaging CEUS setting, with CEUS image of the cystic lesion (white arrows) on the left side and greyscale image on the right side (yellow arrows) of the image. During the contrast arterial examination, the lesion shows a strong contrast uptake.

Fig. 6

Using the dual imaging CEUS setting, with CEUS image of the cyst lesion (white arrows) on the left side and greyscale image on the right side (yellow arrows) of the image. During the contrast examination in the late phase the lesion shows a washout in comparison to the surrounding renal tissue. The final diagnosis will be tumor with some cystic component. According to the Bosniak classification the lesion was classify as a Bosniak 3 cyst. The patient undergoes surgery and the final diagnosis was a cystic renal clear cell carcinoma,

Fig. 7

B-mode ultrasound shows an exophytic growing cystic lesion (yellow arrows).

Fig. 8

Using the dual imaging CEUS setting, with CEUS image of the renal lesion (white arrows) on the left side and greyscale image on the right side (yellow arrows) of the image. During the contrast arterial examination, the lesion shows a moderate contrast uptake, less in comparison to the surrounding renal tissue.

Fig. 9

Using the dual imaging CEUS setting, with CEUS image of the lesion (white arrows) on the left side and greyscale image on the right side (yellow arrows) of the image. During the contrast examination in the late phase the lesion shows a washout in comparison to the surrounding renal tissue. According to finding high suspicion of a papillary renal cell cancer which was later confirmed by surgery and histological workup.

Fig. 10

Patient with deterioration from acute to chronic renal insufficiency underwent renal biopsy to clarify the status. In the follow up ultrasound was performed and detected a peripheral subcapsular pseudoaneurysm (white arrows).

Fig. 11

Using the dual imaging CEUS setting, with CEUS image of the renal lesion (white arrows) on the left side and greyscale image on the right side (yellow arrows) of the image. During the contrast arterial examination, the lesion shows a strong contrast uptake with only one feeding vessel. Additionally, a subcapsular hematoma was detected.

Fig. 12

Patient underwent invention of the kidney. Pseudoaneusyma is seen pre-interventional (white arrows) and after microcoil embolization (yellow arrows).

Fig. 13

B-mode ultrasound detected in the follow up the subcapsular hematoma (yellow arrows) the old pseudoaneurysm is not visible.

Fig. 14

Using the dual imaging CEUS setting, with CEUS image on the left side and greyscale image on the right side of the image. CEUS detected the subcapsular hematoma (white arrow) and confirmed the complete occlusion of the pseudoaneurysm.