Correlation of Renal Mass Pathologic Grade and Contrast Enhanced Ultrasound (CEUS)

Overview

Patients with renal lesions suspicious for renal cell carcinoma (RCC) have a variety of different treatment pathways available to them. Imaging surveillance is being used frequently on smaller renal masses, and radiologists are being asked to biopsy more renal lesions to better guide decision making by urology. This is in large part due to the pathologic grade of renal masses having been shown to correlate with patient outcomes. The World Health Organization (WHO) or Fuhrman grade is the standard grading scale used by pathologists for RCC. The goal of this study will be to correlate contrast enhanced ultrasound findings with the pathologic grade of RCC. Specifically, the investigators hypothesize that tumors with different pathologic grades will show different patterns of qualitative enhancement, as well as different perfusion kinetics.

Renal malignancies are relatively common, with lifetime risk ranging from 1 in 48 in men to 1 in 83 in women, of which RCC is the most common. RCC comes in a variety of subtypes, and pathologic grade has been shown to be one factor that correlates with patient prognosis \[Novara et al\]. The most commonly used pathologic grading systems are the WHO or Fuhrman scale, which rely on histologic features of the tumor such as nuclear size, irregularity, and nucleolar prominence. Care of patients with RCC depends on a number of factors, including size and pathologic grade. As such, radiologic surveillance with CT and MRI is common, and percutaneous biopsy of renal masses for the purpose of pathologic grading is also relatively common. While percutaneous biopsy of renal masses is the least invasive way to obtain tissue, these still carry risks, especially of hemorrhage give the vascular nature of the kidneys and RCC. Contrast enhanced ultrasound has been shown to have the ability to differentiate renal masses from normal background renal parenchyma \[Barr et al\]. It has the unique ability to be used in patients with renal dysfunction as it is excreted by the liver and lungs. As such, it is well suited for use in patients with underlying renal pathology. This study will aim to use contrast enhanced ultrasound to evaluate the qualitative and quantitative features of renal masses prior to surgical removal, and then evaluate for correlation of these features with pathologic grading following surgery.