Characterizing renal cell carcinoma ablation cavities using 3D contrast enhanced ultrasound time intensity curve analysis

摘要

Treatment of renal cell carcinoma (RCC) using ablation techniques is becoming increasingly common as a means for preserving renal function in poor surgical candidates. Despite concerns related to renal insufficiency, which is common in patients with renal disease, the current standard for imaging surveillance following ablation remains contrast-enhanced CT or MRI. Contrast-enhanced ultrasound (CEUS) relies on encapsulated microbubbles to visualize blood flow and carries no renal contraindications. Our group has demonstrated the feasibility of two dimensional (2D) CEUS for monitoring RCC recurrence following cryoablation. The purpose of this study was to expand previous findings with 2D CEUS to a larger patient population more prone to RCC recurrence and to explore the potential for detecting recurrence using volumetric CEUS. In addition, volumetric time-intensity curve analysis was applied to compare central and peripheral ablation cavity enhancement to the surrounding tissue. Initial results using this form of analysis appear capable of differentiating RCC recurrence from fat necrosis or scarring (both of which result in peripheral contrast-enhancement within the ablation cavity). Recurrent RCC had similar blood flow kinetics and intensity to normal tissue, which had average intensities of 147.1 arbitrary units (a.u.) and 141.5 a.u. respectively. Non-recurrent RCC ablation cavities exhibited a characteristic organization of higher peripheral intensity 35.7 a.u. compared to central intensity 29.8 a.u., with and generally a later contrast wash-in relative to the normal renal tissue.