Management of complex renal cysts is guided by the Bosniak classification system, which may be inadequate for risk stratification of patients for intervention. Fractional tumor vascularity (FV) calculated from volumetric contrast-enhanced ultrasound (CEUS) images may provide additional useful information.
To evaluate CEUS and FV calculation for risk stratification of patients with complex renal cysts.
This was a pilot prospective study with institutional review board approval involving patients undergoing surgery for Bosniak IIF-IV complex renal cysts. CEUS was performed preoperatively on the day of surgery with two-dimensional (2D) and three-dimensional (3D) imaging and sulfur hexafluoride lipid-type A microspheres as the ultrasound contrast agent.
A custom MATLAB program was used to select regions of interest on CEUS scans. FV was calculated according to FV = 1 - (total nonenhancing area/total lesion area). We assessed the ability of 2D- and 3D-derived percentage FV (2DFV%, and 3DFV%) and Bosniak classification schemes (pre-2019 [P2019B] and post-2019 [B2019]) to predict malignancy, aggressive histology, and upstaging on surgical pathology. Performance was assessed as area under the receiver operating characteristic curve (AUC).
Twenty eligible patients were included in final analysis, of whom 85% (n = 17) had Bosniak IV cysts and 85% (n = 17) had malignant disease on final pathology. Four (24%) of the malignant lesions were International Society of Urological Pathology grade 3-4. The AUC for predicting malignancy was 0.980, 0.824, 0.863, and 0.824 with P2019B, B2019, 2DFV%, and 3DFV%, respectively. When the Bosniak classification was combined with FV%, three models had an AUC of 1, while the combined 2DFV% + B2019 model had AUC of 0.980.
FV is a novel metric for evaluating complex cystic renal masses and enhances the ability of the Bosniak classification system to predict malignancy. This metric may serve as an adjunct in risk stratification for surgical intervention. Further prospective evaluation is warranted.
Cysts in the kidney are currently classified using a scheme called the Bosniak system. We assessed measurement of the percentage of vascular tissue (called fractional vascularity) in cysts on a special type of ultrasound scan. This promising test adds information when combined with the Bosniak system and can help in guiding appropriate treatment.
European urology focus. 2022 Oct 29 [Epub]
Thenappan Chandrasekar, Cassra B Clark, Andrew Gomella, Corinne E Wessner, Shuo Wang, Kibo Nam, Ji-Bin Liu, Flemming Forsberg, Andrej Lyshchik, Ethan Halpern, James R Mark, Costas D Lallas, Leonard G Gomella, Leann Kania, Edouard J Trabulsi, John R Eisenbrey
Department of Urology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA; Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA; Department of Urology, University of California-Davis, Sacramento, CA, USA. Electronic address: ., Department of Urology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA., Department of Radiology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA., Department of Urology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA; Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.