title: Solid hypervascular liver lesions: accurate identification of true benign lesions on enhanced dynamic and hepatobiliary phase magnetic resonance imaging after gadobenate dimeglumine administration.
abstract: OBJECTIVE
  To evaluate hepatobiliary phase magnetic resonance imaging with gadobenate dimeglumine for differentiation of benign hypervascular liver lesions from malignant or high-risk lesions.
  
  
  METHODS
  Retrospective assessment was performed of 550 patients with 910 hypervascular lesions (302 focal nodular hyperplasia [FNH], 82 nodular regenerative hyperplasia [NRH], 59 hepatic adenoma or liver adenomatosis [HA/LA], 329 hepatocellular carcinomas [HCC], 12 fibrolamellar-HCC [FL-HCC], 21 peripheral cholangiocarcinomas [PCC], 105 metastases). Imaging was performed before and during the arterial, portal-venous, equilibrium, and hepatobiliary phases after gadobenate dimeglumine administration (0.05 mmol/kg). Histologic confirmation was available for ≥1 lesion per patient, except for patients with suspected FNH (diagnosis based on characteristic enhancement/follow-up). Lesion differentiation (benign/malignant) on the basis of contrast washout and lesion enhancement (hypo-/iso-/hyperintensity) was assessed (sensitivity, specificity, accuracy, PPV, and NPV) relative to histology or final diagnosis.
  
  
  RESULTS
  On portal-venous or equilibrium phase images, washout was not seen for 208 of 526 (39.5%) malignant (HCC, FL-HCC, PCC, metastases) and high-risk (HA/LA) lesions. Conversely, only 5 of 384 (1.3%) true benign lesions (FNH/NRH) showed washout. Taking washout as indicating malignancy, the sensitivity, specificity, and accuracy for malignant lesion identification during these phases was 61.8%, 98.7%, and 77.4%. On hepatobiliary phase images, 289 of 302 FNH, 82 of 82 NRH, 1 of 59 HA or LA, 62 of 341 HCC or FL-HCC, and 2 of 105 metastases were hyperintense or isointense. Taking iso- or hyperintensity as an indication for lesion benignity, the sensitivity, specificity, accuracy, PPV, and NPV for benign lesion identification was 96.6%, 87.6%, 91.4%, 85.1%, and 97.3%, respectively.
  
  
  CONCLUSIONS
  Hepatobiliary phase imaging with gadobenate dimeglumine is accurate for distinguishing benign lesions from malignant or high-risk lesions. Biopsy should be considered for hypointense lesions on hepatobiliary phase images after gadobenate dimeglumine.
authors.affiliation: Department of Diagnostic Radiology, Ospedale Cà Foncello, Treviso, Italy. gmorana@ulss.tv.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Morana
authors.forename: Luigi
authors.initials: L
authors.lastname: Grazioli
authors.forename: Miles A
authors.initials: MA
authors.lastname: Kirchin
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Bondioni
authors.forename: Niccolò
authors.initials: N
authors.lastname: Faccioli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Guarise
authors.forename: Günther
authors.initials: G
authors.lastname: Schneider
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003287:Contrast Media / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D006801:Humans; D008107:Liver Diseases / Q000175:diagnosis* / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism; D008875:Middle Aged; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine