Focal nodular hyperplasia: Lesion characteristics on state-of-the-art MRI including dynamic gadolinium-enhanced and superparamagnetic iron-oxide-uptake sequences in a prospective study

Purpose: To image a cohort of patients with pathology-proven focal nodular hyperplasia (FNH) to assess which characteristics of state-of-the-art magnetic resonance imaging (MRI) of the liver are the most useful for improving the detection and characterization of FNH. Materials and Methods: In 14 patients, pathology-proven FNH (N = 33) were prospectively examined using gadolinium (Gd) and superparamagnetic iron-oxide (SPIO) contrast media. All lesions were evaluated for signal intensity (SI), fatty infiltration, central scar, mode of enhancement with Gd, and uptake of SPIO. The percentage of dynamic contrast enhancement in the arterial, portal, and delayed phases was assessed. The contrast-to-noise ratio (CNR) before and after administration of SPIO contrast was calculated. Results: The SI of the lesions was low to isointense on T1-weighted (T1W) images, and intermediate to isointense on T2W images. Fatty infiltration of the lesions was present in 6%. The percentages of enhancement in the liver and lesion were 110%, 115%, and 95%, and 151%, 182%, and 160%, respectively (P < 0.0001). All lesions showed uptake of SPIO with improved conspicuity of the central scar and septa. The CNR values precontrast and post-Gd/SPIO were significantly different for T1 in- and opposed-phase and black-blood echo-planar imaging (BBEPI). Conclusion: Combining dynamic Gd-enhanced imaging with T1W and T2W sequences after administration of SPIO facilitates comprehensive evaluation of FNH.