title: Comparison between Computer Tomography and Magnetic Resonance Imaging in the Diagnosis of Small Hepatocellular Carcinoma
abstract: Background: Hepatocellular carcinomas (HCCs) less than 2 cm in diameter generally demonstrate a good outcome
  after curative therapy. However, the diagnosis of small HCC can be problematic and requires one or more dynamic
  imaging modalities. This study aimed to compare the sensitivity and agreement between CT and MRI for the diagnosis of
  small HCCs. Methods: CT and/or MRI scans of HCCs (1-2 cm) diagnosed by histopathology or typical vascular pattern
  according to the 2005 AASLD criteria were blindly reviewed by an abdominal radiologist. The reports were defined
  as conclusive/typical when arterial enhancement and washout during the portal/delayed phases were observed and as
  inconclusive when typical vascular patterns were not observed. The sensitivity and Cohen’s kappa (k) for agreement
  were calculated. Results: In 27 patients, 27 HCC nodules (1-2 cm) were included. Diagnosis with a single-imaging
  modality (CT or MRI) was 81 % versus 48 % (p = 0.01). The CT sensitivity was significantly higher than MRI (78 %
  versus 52 %, p = 0.04). Among 27 nodules that underwent both CT and MRI, a discordance in typical enhancement
  patterns was found (k = 0.319, p = 0.05). In cases with inconclusive CT results, MRI gave only an additional 3.7 %
  sensitivity to reach a diagnosis. In contrast, further CT imaging following inconclusive MRI results gave an additional
  29.6 % sensitivity. Conclusions: A single typical imaging modality is sufficient to diagnose small HCCs. Compared
  with MRI, multiphasic CT has a higher sensitivity. The limitations of MRI could be explained by the greater need for
  patient cooperation and the types of MRI contrast agent.
authors.affiliation: Department of Internal Medicine, Faculty of Medicine Songklanagarind Hospital, Prince of Songkla University, Songkhla, Thailand. Email:naichaya@gmail.com
authors.forename: Korn
authors.initials: K
authors.lastname: Lertpipopmetha
authors.forename: Teeravut
authors.initials: T
authors.lastname: Tubtawee
authors.forename: Teerha
authors.initials: T
authors.lastname: Piratvisuth
authors.forename: Naichaya
authors.initials: N
authors.lastname: Chamroonkul
keywords: Small hepatocellular carcinoma; computed tomography; magnetic resonance imaging; sensitivity