Clinical value of MRI liver-specific contrast agents: a tailored examination for a confident non-invasive diagnosis of focal liver lesions

Abstract

Screening of the liver for hepatic lesion detection and characterization is usually performed with either ultrasound or CT. However, both techniques are suboptimal for liver lesion characterization and magnetic resonance (MR) imaging has emerged as the preferred radiological investigation. In addition to unenhanced MR imaging techniques, contrast-enhanced MR imaging can demonstrate tissue-specific physiological information, thereby facilitating liver lesion characterization. Currently, the classes of contrast agents available for MR imaging of the liver include non-tissue-specific extracellular gadolinium chelates and tissue-specific hepatobiliary or reticuloendothelial agents. In this review, we describe the MR features of the more common focal hepatic lesions, as well as appropriate imaging protocols. A special emphasis is placed on the clinical use of non-specific and liver-specific contrast agents for differentiation of focal liver lesions. This may aid in the accurate diagnostic workup of patients in order to avoid invasive procedures, such as biopsy, for lesion characterization. A diagnostic strategy that considers the clinical situation is also presented.

Octapod iron oxide nanoparticles as high-performance T2 contrast agents for magnetic resonance imaging

“…When the hepatic carcinoma reached 3-5 mm in diameter, we intravenously injected Octapod-30 and Spherical-16 into the nude mice (2 mg Fe per kg) and scanned the animals at a 7T microMRI scanner. As hepatic tumours contain much less active Kupffer cells and macrophages 36 , they do not accumulate iron oxide nanoparticles as efficiently as normal liver tissues do 40,41 . Thus, the hepatic tumours would show pseudo-positive contrast as compared with normal liver tissues.…”

Focal Liver Lesions

“…Small lesions (up to ~2 cm) may show immediate and complete enhancement in the arterial phase, with sustained enhancement in the venous and delayed phases (type I, "flash filling") [31] (Fig. 17.3).…”

“…Nonetheless, a recent meta-analysis showed that the lesion T1 isointensity or hyperintensity at delayed hepatobiliary phase MRI has a high sensitivity (91-100%) and specificity (87-100%) for diagnosing FNH [36]. This feature can be helpful for differentiating FNH from hypervascular metastases or hepatic adenomas (HCA) and hepatocellular carcinomas (HCC) (which do not usually take up liver-specific agents) [31,37]. However, it should be noted that some HCAs (particularly inflammatory HCA and beta-cateninactivated HCA) and HCC can appear isointense or hyperintense at delayed imaging after hepatobiliary contrast media administration.…”

Ressonância magnética do fígado com contraste hepato-específico: experiência clínica inicial no Brasil

“…This paper aims to report the first tests with this substance in a private Radiology service in Brazil, and to advise on key applications and clinical indications. The gadoxetic acid is a contrast medium based on gadolinium, which has an estimated excretion of 50% via the kidney and 50% biliary in healthy patients 3 . Consequently, a single bolus injection of gadoxetic acid allows routine dynamic three-phase studies of the liver in a first step, followed by hepatobiliary evaluation after an interval of about 10-20 minutes.…”

“…In one of the cases evaluated, the patient presented had a prior routine examination suggesting possible surgical indication and the MRI with contrast hepatic-specific identified three additional lesions, which changed the treatment plan. In the context of cirrhotic patients, gadoxetic acid displays good accuracy in differentiating dysplastic nodules from moderately or poorly differentiated HCC nodules 3 . The latter, no longer having typical hepatocytes and viable hepatobiliary architecture, do not exhibit demonstrable enhancement by gadoxetic acid in the hepatobiliary phase ( Figure 3).…”