CEUS LI-RADS: algorithm, implementation, and key differences from CT/MRI

Abstract

Contrast-enhanced ultrasound (CEUS) is a specialized form of ultrasound (US) performed with an intravenous injection of microbubble contrast agents. It has been successfully used for a variety of applications including characterization of liver tumors. In April 2014, the American College of Radiology (ACR) convened a working group of international experts to develop ACR CEUS Liver Imaging Reporting and Data System (CEUS LI-RADS). An initial version of CEUS LI-RADS was published in August 2016. Although the CEUS LI-RADS concept and principles for liver lesion characterization, using dynamic contrast enhancement features, are similar to those for CT or MRI, there are significant differences between CT/MRI and CEUS LI-RADS. Therefore, CEUS LI-RADS has different diagnostic features and a unique characterization algorithm. The size of a lesion, the type and degree of arterial phase enhancement, the presence of washout, and the timing and degree of washout are the major features used for categorization. This paper describes key differences between CT/MRI and CEUS, and provides a diagnostic algorithm of CEUS LI-RADS with detailed, step-by-step instructions and imaging examples of CEUS LI-RADS categories.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid

“…If these are also inconclusive, a biopsy is needed. If this is negative, the nodule should be followed up every 3-4 months, and if it enlarges or the enhancement pattern changes, diagnostic investigations should be resumed [117].…”

Joint Consensus Statement of the Indian National Association for Study of the Liver and Indian Radiological and Imaging Association for the Diagnosis and Imaging of Hepatocellular Carcinoma Incorporating Liver Imaging Reporting and Data System

“…CEUS can be used as a second-line diagnostic tool indeterminate focal liver lesions on conventional grayscale USG or contrastenhanced CT. [145][146][147][148][149] CEUS can diagnose tumor enhancement with enhancing tumor seen on AP with a sensitivity 88%-100% and specificity of 92.5%, respectively. [145][146][147][148][149] According to a meta-analysis, CEUS can accurately differentiate between benign and malignant focal liver lesions with a sensitivity of 93% and a specificity of 90%, and the diagnostic performance of CEUS is similar to that of contrast enhanced CT (CECT) and contrast enhanced MRI (CEMRI). 150 For lesions seen on CT/MR but not on USG, CEUS can help in localization for tissue diagnosis, allowing for differentiating the central necrotic portion of the tumor from the viable enhancing tissue aiding in targeting tumor for tissue diagnosis.…”

CEUS LI-RADS: a pictorial review

“…Noteworthy, although FLL characterization features using CEUS are similar to those of multiphasic CT and/ or MRI, there are still important differences between these techniques, regarding both features and characterization algorithm [30]. CEUS LI-RADS is intended for the use with purely intravascular microbubble contrast agents-such as Lumason® (in USA)/Sono-Vue® (outside USA) and Definity® (in USA, Canada)/ Luminity® (outside USA, Canada)-which affects washout and "capsule" characterization [11,31,32].…”