title: Characterisation of small hypoattenuating hepatic lesions in multi-detector CT (MDCT) in patients with underlying extrahepatic malignancy: added value of contrast-enhanced MR images.
abstract: OBJECTIVE
  To retrospectively assess the value of adding gadolinium-enhanced dynamic imaging to standard ununenhanced magnetic resonance imaging (MRI) for characterising hypoattenuating hepatic lesions that are too small to characterise with multi-detector computed tomography (MDCT).
  
  
  METHODS
  Informed consent was waved, and institutional review board approval was obtained. Three hundred and forty-six small (≤ 2 cm) lesions (63 metastatic, 283 benign) in 183 patients with underlying carcinoma who underwent hepatic MRI after CT were retrospectively analysed. Two radiologists independently reviewed images and diagnoses were graded on an ordinal scale from 1 (definitely benign) to 5 (definitely malignant). Receiver operating characteristic analysis was used. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were also determined.
  
  
  RESULTS
  The areas under the curve of the ununenhanced images alone and with dynamic images were 0.837 and 0.850 for reader 1 (p = 0.616) and 0.771 and 0.783 for reader 2 (p = 0.700). Descriptive statistical values demonstrated sensitivities of 76% and 80%, specificities of 93% and 95%, PPVs of 69% and 79%, NPVs of 95% and 95% and accuracies of 90% and 92%, respectively.
  
  
  CONCLUSIONS
  The value of adding three-phase contrast-enhanced MRI to unenhanced imaging did not reach statistical significance for characterising small hypoattenuating hepatic lesions on MDCT.
authors.affiliation: Department of Diagnostic Radiology, Institute of Gastroenterology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Song-Ee
authors.initials: SE
authors.lastname: Baek
authors.forename: Mi-Suk
authors.initials: MS
authors.lastname: Park
authors.forename: Hye Sook
authors.initials: HS
authors.lastname: Hong
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Chung
authors.forename: Joon Seok
authors.initials: JS
authors.lastname: Lim
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine