Can Ultrasound With Contrast Enhancement Replace Nonenhanced Computed Tomography Scans in Patients With Contraindication to Computed Tomography Contrast Agents?

PURPOSE: Our purpose is to determine the efficacy of ultrasound (US), with the addition of contrast enhancement (CEUS), in the identification and characterization of abdominal pathology compared with nonenhanced computed tomography (CT) scan (NECT). METHODS: This prospective cohort study recruited 197 patients with NECT, the majority with renal failure, to have US, with addition of CEUS, if focal pathology was detected, occurring in 145 patients. Nonenhanced CT scan, US, and CEUS images/video files were presented to 2 blinded readers, in anonymous order. Examination quality and positive observations were recorded. True diagnosis was determined with pathology, follow-up imaging, and clinical notes. Data analysis showed sensitivity of NECT and US in the identification and characterization of pathology and sensitivity of CEUS to characterize abnormalities. RESULTS: Most pathology involved liver (n = 87), kidney (n = 35), and peritoneum (n = 13). Ultrasound alone was superior to NECT in the identification of hepatic and renal pathology, with both performing poorly at characterization. With addition of CEUS, characterization of hepatic and renal pathology reached 100%. Nonenhanced CT is superior to US in identification of peritoneal pathology, especially in large patients. Further solid and hollow organ pathology identified and characterized was of insufficient size to draw conclusions. CONCLUSIONS: Nonenhanced CT has limited ability to identify and characterize solid and hollow organ pathology. Ultrasound with the benefit of CEUS is superior to NECT in the characterization of focal liver, kidney, and peritoneal pathology. Contrast-enhanced ultrasound outperforms NECT in evaluation of suspect abdominal pathology in those with renal failure.