PMC3134033_01
Baseline scan (a) showing a single isoechoic metastasis with maximum diameter of 5.5 x 4.5 cm in segment VIII. In color Doppler examination (b), the lesion shows some peripheral vascularity.
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F1
The patient underwent a B-mode ultrasonographic and a color Doppler examination using a 4-MHz multifrequency convex transducer (fig. 1). In comparison to standard ultrasound (fig. 1), CEUS imaging allowed to readily recognize the morphology and the malignant features of the metastatic lesions due to early contrast medium uptake (fig. 2a, b) and by the rapid washout in the portal (fig. 2c) and late phase (fig. 2d).
In the early arterial phase (a), 16 s after SonoVue injection, the lesion displays a strong enhancement, most of the liver parenchyma being only partially filled with contrast medium. During the arterial phase (b), the lesion shows a strong, homogenous enhancement. In the portal venous phase (c), there is partial washout of contrast medium from the lesion, here appearing hypo-enhancing compared to the homogenously enhancing normal liver. In the delayed phase (d), 4 min after injection of the contrast medium, the lesion shows a hypoechoic, sharply circumscribed punched-out enhancement defect.
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F2
The entire liver was scanned for 5 min in accordance with the maximum circulation time of the contrast agent (fig. 2). In comparison to standard ultrasound (fig. 1), CEUS imaging allowed to readily recognize the morphology and the malignant features of the metastatic lesions due to early contrast medium uptake (fig. 2a, b) and by the rapid washout in the portal (fig. 2c) and late phase (fig. 2d).
Hypovascular liver metastasis in the arterial (a) and hepatocyte phase (b) imaged by a T1-weighted 3D-gradient echo sequence after bolus injection of Gd-EOB-DTPA. In the hepatocyte phase (b), the margins of the lesions appear very clear and sharply delineated from increased contrast between the metastasis (no liver-specific uptake) and surrounding liver parenchyma (regular uptake).
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F3
Gd-EOB-DTPA (Primovist; Bayer Schering Pharma, Berlin, Germany) was administered as a bolus at a dose of 0.025 mmol/kg body weight via an antecubital i.v.-line (fig. 3). The resulting reverse image was comparable to that obtained by MRI performed with liver-specific contrast medium, where the morphology of the lesion resulted from the lack of hepatocyte-specific contrast medium uptake (fig. 3).