Diagnostic Performance and Description of Morphological Features of Focal Nodular Hyperplasia in Gd-EOB-DTPA-Enhanced Liver Magnetic Resonance Imaging: Results of a Multicenter Trial

Abstract

The aim of this prospective study was to evaluate the diagnostic performance of magnetic resonance imaging (MRI) of the liver with the hepatocellular-specific contrast agent gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in comparison to precontrast MRI and spiral computed tomography (CT) in the specific diagnosis of focal nodular hyperplasia (FNH) and to describe morphologic features and enhancement pattern of FNH. In 176 patients from a phase III multicenter trial, 59 confirmed FNHs were present (13 = histopathology; 46 = imaging follow-up within 12 months before or 3 months after the MRI study). MR examination consisted of precontrast T1- and T2-w sequences, T1-weighted (w) dynamic sequences after bolus-injection of 0.025 mmol Gd-EOB-DTPA (Primovist; Bayer Schering Pharma)/kg bodyweight and T1-w sequences with fat saturation in the hepatocyte-phase after 20 minutes. The number of correctly characterized FNHs was evaluated and compared with that determined on spiral CT in an on-site reading (clinical study) and an off-site reading (3 blinded readers). The morphologic appearance and enhancement patterns of the FNHs were evaluated. Characterization with combined pre- and post-MRI (88.1%) was superior to that achieved with biphasic-enhanced spiral CT (84.7%, not significant) and precontrast MRI (67.8%, P < 0.05) in the clinical study and significantly superior to both precontrast MRI and spiral CT for 2 of 3 blinded readers. Complete or partial enhancement of the lesions was present in the early dynamic phase (arterial and portovenous dynamic phase) in 94% and 85%, respectively. The pattern of lesion enhancement in the early dynamic phase was mainly homogenous (78%-80%); the median contrast-to-noise ratio was -5.9 in T1-w precontrast images, 14.0 in the arterial phase, 2.4 in the portovenous phase, and 2.9 in the equilibrium phase. Enhancement in the hepatocyte-phase after 10 and 20 minutes was observed in 88% and 90% of lesions, respectively. Characterization of FNH provided by Gd-EOB-DTPA-enhanced MRI is superior to that provided by precontrast MRI alone or spiral CT. FNHs show very similar enhancement characteristics to those of other extracellular contrast agents in the early dynamic phase after bolus injection of Gd-EOB-DTPA, after 20 minutes in the liver-specific phase enhancement is regularly seen.