A prospective multicenter study at 10 institutions in 5 countries has validated the efficacy of the American College of Radiology (ACR) contrast-enhanced ultrasound Liver Imaging Reporting and Data System (CEUS LI-RADS®?). Preliminary findings have determined that the CEUS LR-5 classification for hepatocellular carcinoma (HCC) is 100% specific, and that CEUS has high clinical value for noninvasive HCC diagnosis, according to research presented at RSNA 2019 in Chicago.
HCC is the fifth-most common cancer in the world. Imaging is essential for diagnosis. In August 2016, the ACR published CEUS LI-RADS as a standardized reporting system for liver nodules in patients at risk for HCC. It makes recommendations for technique, interpretation reporting, and data collection.
“Challenges exist today for the acceptance of contrast-enhanced ultrasound to diagnose liver cancer,” said presenter Andrej Lyshchik, MD, PhD, Associate Professor of Diagnostic Radiology at Einstein Medical Center of Thomas Jefferson University Hospital in Philadelphia, PA. “These include lack of protocol standardization, poorly defined diagnostic features of malignancy, an overlap in traditional diagnostic criteria for HCC, intrahepatic cholangiocarcinoma (ICC), and liver metastasis, and substantial reporting variability. Additionally, there is lack of contrast-enhanced ultrasound integration in HCC imaging algorithms.”
The study was conducted to validate and determine the diagnostic performance of CEUS for HCC detection, said Dr. Lyshchik. Other institutions in the study were the University of Alberta in Calgary and Edmonton, Canada; the University of Bologna in Italy; the University of Bern in Switzerland; Kings College in London; and Swedish Medical Center in Seattle; Stanford University; University of California-San Diego; University of Texas Southwestern Medical Center in Dallas; and Vanderbilt University in Nashville, TN.
A patient population of 402 individuals, mostly male, with a total of 439 nodules were recruited for the study. Mean nodule size was 2.4 ± 1,1 cm. The CEUS exam was adequate for 418 patients, or 95% of the study cohort.
Liver disease etiology was representative of the general population. It included hepatitis B (10%), hepatitis C (44%), nonalcoholic steatohepatitis (ICC) (21%), alcohol-related disease (2%), and a variety of other causes.
“We can report findings on 298 cases. The majority (69%) were diagnosed with HCC, and 4% with other malignancies. Thirteen percent were benign, and 14% were indeterminate, patients who either died or dropped out of the study. We expect to report final results for the remaining 104 cases soon,” said Dr. Lyshchik.
Patients initially underwent either a contrast-enhanced ultrasound study, or either a computed tomography (CT) or magnetic resonance imaging (MRI) scan. Patients with nodules rated LI-RADS-1 or LI-RADS-2 underwent no further studies. The remaining patients underwent the other exam. Cases designated LI-RADS-3 from both exams were diagnosed as benign. Patients with LI-RADS-4 as well as LI-RADS-M, indicating possible malignancy, underwent biopsy. Patients with malignant tumors (LI-RADS 5) on any type of exam also had a biopsy.
Specificity of CEUS LI-RADS 5 was 98% for HCC diagnosis, compared to CT and MRI at 96%. Sensitivity was 60% and 51%, respectively. Dr. Lyshchik said he hoped that these would improve when additional data were acquired at the conclusion of the study.
There were three false positive results: One was a high-grade dysplastic nodule on MRI; one was ICC, classified as LI-RADS-5 on both CEUS and MRI; and the third was a 1.4 cm ICC-HCC lesion categorized as LI-RADS-M on MRI.
“We are very pleased to say that the CEUS LR-5 classification is highly specific for HCC, and confirms the high clinical value of CEUS for noninvasive diagnosis of HCC,” Dr. Lyshchik said.
RSNA2019: Validating contrast-enhanced LI-RADS classifications. Appl Radiol.