Contrast-Enhanced Ultrasound Detection and Treatment Guidance in a Renal Transplant Patient With Renal Cell Carcinoma

Abstract

Contrast-enhanced ultrasonography (CEUS) is an imaging modality that shows promise in the detection and characterization of renal masses, as well as treatment through CEUS-guided percutaneous radiofrequency ablation. These techniques may be especially valuable in challenging patients who cannot tolerate traditional contrast agents, such as those with diminished renal function, and those who cannot tolerate more invasive surgical treatment. The following case report details an incidence of renal cell carcinoma in a renal transplant patient whose tumor was diagnosed with CEU and successfully treated with CEUS-guided percutaneous RFA.

Is There a Need to Modify the Bosniak Renal Mass Classification With the Addition of Contrast-Enhanced Sonography?

“…Contrast‐enhanced sonography has the advantage over contrast‐enhanced CT and contrast‐enhanced MRI that lesion vascularity can be monitored in real time for several minutes at high frame rates, as opposed to a few selected images in time . Therefore, timing problems with imaging after contrast agent injection are minimized (Figure ) . Contrast‐enhanced sonography also has the advantage of subtracting out background soft tissue, creating a “contrast‐only image,” which has advantages in detecting small amounts of blood flow and flow in septations and small nodules.…”

“…4 Therefore, timing problems with imaging after contrast agent injection are minimized (Figure 1). 5 Contrast-enhanced sonography also has the advantage of subtracting…”

“…4 Therefore, timing problems with imaging after contrast agent injection are minimized ( Figure 1). 5 Contrast-enhanced sonography also has the advantage of subtracting out background soft tissue, creating a "contrast-only image," which has advantages in detecting small amounts of blood flow and flow in septations and small nodules. The narrow ultrasonic beam also allows for improved visualization of vascularity in small structures such as septations and small mural nodules (Figure 2).…”

“…However, multiple smaller single-site studies had similar findings. [5][6][7][8][9][10][11][12][13][14][15] With the recent US Food and Drug Administration approval of an ultrasound contrast agent for liver applications, it is expected that off-label use of contrastenhanced sonography to characterize renal masses will increase substantially in the United States. It would be beneficial to develop a modification of the Bosniak classification, including contrast-enhanced sonography, to aid in future studies for prospectively determining whether contrast-enhanced sonography can appropriately change clinical management, especially in Bosniak 3 lesions.…”

Contrast-Enhanced Ultrasound-Guided Radiofrequency Ablation of Renal Tumors

“…Though RFA is a relatively new treatment for renal tumors and long-term efficacy remains to be seen, the initial data suggest that not only is it safe and well tolerated by patients, but also has a comparable 5-year success rate to that of partial or total nephrectomy (4,5,8). One of its biggest benefits is that the procedure is renal sparing, and RFA is currently used for small tumors, usually less than 5 cm, in patients who are not candidates for surgical removal (7).…”