title: MR imaging of hypervascular lesions in the cirrhotic liver: a diagnostic dilemma.
abstract: Cirrhosis is characterized by a spectrum of hepatocellular nodules that mark the progression from regenerative nodules to low- and high-grade dysplastic nodules, followed by small and large hepatocellular carcinomas (HCCs). Characterization of small nodules on the basis of imaging and histopathologic findings is complicated by an overlap in findings associated with each type of nodule, a reflection of their multistep transitions. Vascularity patterns change gradually as the nodules evolve, with an increasing shift from predominantly venous to predominantly arterial perfusion. Regenerative and low-grade dysplastic nodules demonstrate predominantly portal perfusion and contrast enhancement similar to that of surrounding parenchyma. Differentiation of high-grade dysplastic nodules and well-differentiated HCCs on the basis of dynamic imaging and histologic findings is challenging, with a high rate of false-negative results. Some small nodules that lack hypervascularity may be early HCCs. Progressed small and large HCCs usually present no diagnostic difficulty because of their characteristic findings. Although characterization of hypervascular lesions in the cirrhotic liver is difficult, it is a key step in disease management and is the radiologist's responsibility.
authors.affiliation: Federal University of Rio de Janeiro, Av. Lineu de Paula Machado 896/601, Jardim Botânico, CEP 22470-040, Rio de Janeiro, Brazil. daniella.parente@gmail.com
authors.forename: Daniella B
authors.initials: DB
authors.lastname: Parente
authors.forename: Renata M
authors.initials: RM
authors.lastname: Perez
authors.forename: Antonio
authors.initials: A
authors.lastname: Eiras-Araujo
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Oliveira Neto
authors.forename: Edson
authors.initials: E
authors.lastname: Marchiori
authors.forename: Carolina P
authors.initials: CP
authors.lastname: Constantino
authors.forename: Viviane B
authors.initials: VB
authors.lastname: Amorim
authors.forename: Rosana S
authors.initials: RS
authors.lastname: Rodrigues
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D008103:Liver Cirrhosis / Q000150:complications* / Q000473:pathology*; D008113:Liver Neoplasms / Q000150:complications* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000150:complications* / Q000473:pathology*