Analysis of different contrast enhancement patterns after microbubble-based contrast agent injection in liver hemangiomas with atypical appearance on baseline scan.
BACKGROUND
We describe different possible enhancement patterns in liver hemangiomas with atypical appearance on baseline ultrasound after microbubble-based contrast agent injection.


METHODS
From a series of 253 consecutive lesions that were indeterminate on baseline ultrasound and then scanned after injection of air-filled microbubble contrast agent, 65 focal liver lesions were retrospectively selected on the basis of a diagnosis of liver hemangioma on multiphase contrast-enhanced computed tomography (n = 23), magnetic resonance imaging (n = 27), or histology (n = 15). Each lesion was scanned during arterial phase (30 s after microbubble injection) and late phase (5 min after injection). On-site sonologists performed retrospective assessment of contrast-enhancement patterns by consensus.


RESULTS
Centripetal fill-in preceded (n = 50) or not preceded (n = 3) by peripheral nodular/rim-like enhancement was the prevalently observed contrast-enhancement pattern, equivalent to the typical enhancement pattern of liver hemangiomas on contrast-enhanced computed tomography or magnetic resonance imaging. In the remaining lesions, additional enhancement patterns (diffuse contrast enhancement with rapid fill-in and a late hyper-isoechoic appearance, n = 6; peripheral nodular enhancement with a late hypoechoic appearance, n = 3; or persistent heterogeneous and hyperechoic appearance, n = 3) were observed.


CONCLUSIONS
Different contrast-enhancement patterns are possible in atypical liver hemangiomas after microbubble injection. Typical centripetal fill-in is the prevalent pattern and its evidence allows diagnosis.
Quaia
E
E
Department of Radiology, Cattinara Hospital, University of Trieste, Strada di Fiume 447, Trieste, 34149, Italy. equaia@yahoo.com
Bartolotta
T V
TV
Midiri
M
M
Cernic
S
S
Belgrano
M
M
Cova
M
M
D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006391:Hemangioma / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D011134:Polysaccharides / Q000008:administration & dosage; D014463:Ultrasonography
D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508