title: Diffusion-weighted magnetic resonance imaging predicts malignant potential in small hepatocellular carcinoma.
abstract: BACKGROUND
  Poor differentiation and microvascular invasion are indicators of poor outcome after hepatectomy for patients with small hepatocellular carcinoma (HCC).
  
  
  OBJECTIVE
  We investigated whether gadoxetic acid-enhanced and diffusion-weighted magnetic resonance imaging (MRI) could predict these factors before hepatectomy.
  
  
  METHODS
  Between July 2008 and April 2012, 75 patients who underwent hepatectomy for small HCCs (diameter: ≤3cm, tumor number: ≤3) were consecutively enrolled. In gadoxetic acid-enhanced MRI, the signal intensity in the tumor was corrected to that in the paraspinous muscles, and the relative enhancement was calculated. In diffusion-weighted imaging, we measured the apparent diffusion coefficient (ADC). We then investigated the correlations between relative enhancement or ADC and histological grade, microvascular invasion and recurrence-free survival.
  
  
  RESULTS
  Poorly differentiated HCCs showed significantly lower ADC than well-differentiated and moderately differentiated HCCs. There was no significant difference in the hepatobiliary phase. Only ADC was an independent predictor of microvascular invasion, and the best cut-off point of its prediction was 1.175×10(-3)mm(2)/s. Additionally, the recurrence-free survival was significantly shorter in low-ADC group than in high-ADC group.
  
  
  CONCLUSIONS
  ADC is useful for predicting poorly differentiated HCCs and microvascular invasion, and low ADC is associated with increased recurrence risk for small HCCs after hepatectomy.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan. Electronic address: okamura_shyuusuke@kurume-u.ac.jp.
authors.forename: Shusuke
authors.initials: S
authors.lastname: Okamura
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Sumie
authors.affiliation: Department of Radiology, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Tonan
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Satani
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Shimose
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Tomotake
authors.initials: T
authors.lastname: Shirono
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Iwamoto
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Aino
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Niizeki
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Tajiri
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Kuromatsu
authors.affiliation: Division of Hepato-Biliary-Pancreatic Surgery, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Okuda
authors.affiliation: Department of Clinical Laboratory Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Nakashima
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Torimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D003287:Contrast Media / Q000008:administration & dosage; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006498:Hepatectomy; D006801:Humans; D007564:Japan; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA
keywords: Apparent diffusion coefficient; Gadoxetic acid; Histological grade; Microvascular invasion