[Differential patterns of contrast enhancement in different focal liver lesions after injection of the microbubble US contrast agent SonoVue].
OBJECTIVE
To identify differential contrast enhancement patterns in different focal hepatic lesions after injection of the microbubble contrast agent SonoVue using high or low acoustic power imaging.


METHODS
Forty-seven focal hepatic lesions (1-8 cm) were detected in 45 patients at unenhanced gray-scale ultrasound (US) and evaluated by color Doppler (CD) US with spectral analysis of tumoral vessels. Lesions were subsequently evaluated by US contrast specific modes after IV bolus administration of 2,4-4,8 ml of SonoVue, by intermittent high acoustic power (18 patients) or by continous low acoustic power imaging (27 patients), during arterial, portal and late phase. Subjective evaluation of lesions appearance before and after SonoVue injection was performed. For final diagnosis multiphasic helical CT (21 patients) and/or fine needle US guided biopsy (24 patients) were considered as the reference procedures.


RESULTS
Final diagnoses comprised 22 hepatocellular carcinomas (HCCs; 1,5-6 cm), 2 macroregenerative nodules (RNNs; 1-2 cm), 10 metastasis (2-3,5 cm), 10 hemangiomas (2-6 cm) and 3 focal nodular hyperplasias (FNHs; 1-3 cm). On CD evaluation HCCs revealed peripheral basket shaped (12/22) or intranodular (10/22) arterial pattern while, after SonoVue injection HCCs revealed diffuse contrast enhancement during arterial phase with contrast washout during portal and late phase. Metastases did not reveal flow signals on CD or contrast enhancement after SonoVue injection, except for 2 metastases which revealed peripheral and central vessels on CD and a diffuse contrast enhancement during arterial phase, appearing hypoechoic to the adjacent liver during portal and late phase. RNNs revealed dotted contrast-enhancement during portal and late phase with isoechoic appearance to the adjacent liver. Hemangiomas revealed some peripheral venous flows on CD and a peripheral nodular contrast enhancement during arterial phase with a centripetal fill-in during portal and late phase. FNHs revealed low resistance peripheral or central arterial vessels and a diffuse contrast enhancement during arterial phase, preceded or not by central spoke wheel shaped contrast enhancement, and a persistent iso-hyperechogenicity during portal and late phase.


CONCLUSIONS
SonoVue injection has showed to identify differential contrast enhancement patterns in different focal hepatic lesions.
Quaia
Emilio
E
Istituto di Radiologia, Università degli Studi di Trieste, Ospedale di Cattinara. equaia@yahoo.com
Degobbis
Francesca
F
Tona
Giuseppe
G
Mosconi
Elisa
E
Bertolotto
Michele
M
Pozzi Mucelli
Roberto
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008107:Liver Diseases / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D013459:Sulfur Hexafluoride; D014463:Ultrasonography / Q000379:methods*
D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride