Serial MR imaging of small arterially-enhancing liver lesions in patients with chronic liver disease.
OBJECTIVE
To determine the significance of small arterially-enhancing liver lesions seen with magnetic resonance imaging (MRI) in patients with chronic liver disease.


METHODS
Our institutional review board approved this retrospective study, without requiring informed consent. Over a two-year period, 258 consecutive patients with cirrhosis or chronic hepatitis underwent multiphase three-dimensional, gadolinium-enhanced, breath-hold gradient-echo MRI. From this group, 29 patients underwent at least one follow-up MR study. When a small (< or = 20 mm) arterially-enhancing lesion was detected, the maximum diameter shape, signal intensities (T1-weighted and T2-weighted), and pattern of enhancement were evaluated to assess the associations between the imaging appearance on initial MR exam and subsequent behavior on follow-up imaging. Statistical testing was performed with JMP Statistical Software (SAS, Inc., Cary, NC) and StatXact 7 Statistical Software for Exact Nonparmetric Inference (Cytel, Inc., Cambride, MA).


RESULTS
Sixty-five small (< or = 20 mm) arterially-enhancing lesions were detected in 29 patients. Ten of 65 lesions (15%) in nine patients were subsequently proven to represent hepatocellular carcinoma (HCC), while the remaining lesions either disappeared (46) or remained stable in size (9). Of the 10 lesions subsequently proven to represent HCC, eight lesions converted from hypo- or isointense to hyperintense on subsequent T2-weighted MRI (p < 0.001), seven lesions converted from hyper- or isointense to hypointense on subsequent T1-weighted images (p < 0.001), seven lesions demonstrated growth on subsequent MRI exam (mean increase in mean diameter = 1.4 cm), and five lesions subsequently developed rim enhancement that was not initially present.


CONCLUSIONS
Small, arterially-enhancing lesions detected with MRI have a low likelihood of representing HCC, and MRI follow-up of such lesions is a reasonable approach. Lesions that increase in size, convert to hypointense on subsequent T1W images, convert to hyperintense in T2W images, or develop rim enhancement on follow-up MRI images are concerning and should prompt consideration of intervention.
Korpraphong
Pornpim
P
Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. Pfuang@yahoo.com
Leyendecker
John R
JR
Hildebolt
Charles F
CF
Narra
Vamsri
V
Bae
Klongtae Ty
KT
Brown
Jeffrey J
JJ
D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000628:therapy; D002908:Chronic Disease; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006521:Hepatitis, Chronic / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D008103:Liver Cirrhosis / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D003287:Contrast Media; D005682:Gadolinium