title: Multifocal nodular fatty infiltration of the liver mimicking metastatic disease on CT: imaging findings and diagnosis using MR imaging.
abstract: The aim of this study was to describe the MR appearance of multifocal nodular fatty infiltration of the liver (MNFIL) using T1-weighted in-phase (IP) and opposed-phase (OP) gradient-echo as well as T2-weighted turbo-spin-echo sequences with fat suppression (FSTSE) and without (HASTE). Magnetic resonance imaging examinations at 1.5 T using T1-weighted IP and OP-GRE with fast low angle shot (FLASH) technique, and T2-weighted FSTSE, T2-weighted HASTE of 137 patients undergoing evaluation for focal liver lesions were reviewed. Five patients were identified in whom CT indicated metastatic disease; however, no liver malignancy was finally proven. Diagnosis was confirmed by biopsy (n = 3), additional wedge resection (n = 1) or follow-up MRI 6-12 months later (n = 5). Regarding the identified five patients, the number of focal liver lesions was 2 (n = 2) and more than 20 (n = 3). The MR imaging characteristics were as follows: OP-image: markedly hypointense (n = 5); IP image: isointense (n = 2) or slightly hyperintense (n = 3); T2-weighted FSTSE-image: isointense (n = 5); T2-weighted HASTE image isointense (n = 1); slightly hyperintense (n = 4). On OP images all lesions were sharply demarcated and of almost spherical configuration (n = 5). Further evaluation by histology or follow-up MR imaging did not give evidence of malignancy in any case. Histology revealed fatty infiltration of the liver parenchyma in three patients. Magnetic resonance follow-up showed complete resolution in two patients and no change in three patients. Multifocal nodular fatty infiltration can simulate metastatic disease on both CT and MR imaging. The combination of in-phase (IP) and opposed-phase (OP) gradient-echo imaging can reliably differentiate MNFIL from metastatic disease.
authors.affiliation: Institut für Radiologie, Universitätsklinikum Charité, Humboldt-Universität zu Berlin, Germany.
authors.forename: T J
authors.initials: TJ
authors.lastname: Kröncke
authors.forename: M
authors.initials: M
authors.lastname: Taupitz
authors.forename: D
authors.initials: D
authors.lastname: Kivelitz
authors.forename: I
authors.initials: I
authors.lastname: Scheer
authors.forename: U
authors.initials: U
authors.lastname: Daberkow
authors.forename: B
authors.initials: B
authors.lastname: Rudolph
authors.forename: B
authors.initials: B
authors.lastname: Hamm
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D005234:Fatty Liver / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D014057:Tomography, X-Ray Computed