Abstract
BackgroundPatients with chronic kidney disease are at increased risk of cystic kidney disease that requires imaging monitoring in many cases. However, these same patients often have contraindications to contrast-enhanced computed tomography and magnetic resonance imaging. This study evaluates the accuracy of contrast-enhanced ultrasound (CEUS), which is safe for patients with chronic kidney disease, for the characterization of kidney lesions in patients with and without chronic kidney disease.MethodsWe performed CEUS on 44 patients, both with and without chronic kidney disease, with indeterminate or suspicious kidney lesions (both cystic and solid). Two masked radiologists categorized lesions using CEUS images according to contrast-enhanced ultrasound adapted criteria. CEUS designation was compared to histology or follow-up imaging in cases without available tissue in all patients and the subset with chronic kidney disease to determine sensitivity, specificity and overall accuracy.ResultsAcross all patients, CEUS had a sensitivity of 96% (95% CI: 84%, 99%) and specificity of 50% (95% CI: 32%, 68%) for detecting malignancy. Among patients with chronic kidney disease, CEUS sensitivity was 90% (95% CI: 56%, 98%), and specificity was 55% (95% CI: 36%, 73%).ConclusionsCEUS has high sensitivity for identifying malignancy of kidney lesions. However, because specificity is low, modifications to the classification scheme for contrast-enhanced ultrasound could be considered as a way to improve contrast-enhanced ultrasound specificity and thus overall performance. Due to its sensitivity, among patients with chronic kidney disease or other contrast contraindications, CEUS has potential as an imaging test to rule out malignancy.Trial registrationThis trial was registered in clinicaltrials.gov, NCT01751529.
Highlights
Patients with chronic kidney disease are at increased risk of cystic kidney disease that requires imaging monitoring in many cases
Despite the potential for contrast-enhanced ultrasound (CEUS) as a diagnostic option among individuals with chronic kidney disease (CKD), few studies have evaluated CEUS in this population, interest is increasing [34, 35]. In this exploratory pilot study, we sought to investigate the diagnostic accuracy of CEUS for detecting enhancement of kidney lesions, and risk of malignancy, in populations with and without CKD and subsequently determine if this imaging modality has potential to be an alternative screening tool in patients with contraindications to contrast computed tomography (CT) or magnetic resonance (MR)
CKD chronic kidney disease, CT computed tomography, MR magnetic resonance imaging, US ultrasound, RCC renal cell carcinoma aDefined as BMI ≥ 30 bPercentages add to greater than 100% as 11 patients had multiple studies prior to CEUS cBy largest dimension dOne sample was resected in multiple pieces with no histologic diameter available sensitivity of CEUS in these patients was 90%
Summary
Study design and participants We performed a prospective imaging study of CEUS in patients with kidney lesions identified by prior imaging (ultrasound, CT or MR) obtained as part of routine clinical care. Two abdominal radiologists (identified as Reader 1 and Reader 2 with 20 and 15 years’ experience in ultrasound imaging, respectively) not involved in image acquisition independently performed the blinded study reads Both readers participated in a preliminary training session and performed CEUS radiology literature review, from experienced centers such as the University of Calgary, and international ultrasound societies [36]. Readers used both B-mode and CEUS images to answer lesion characteristic questions, classify the lesions as solid or cystic, and if cystic, apply the adapted Bosniak criteria (Additional file 1: Table S1). Two-tailed p-values of
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