Liver hypervascular metastases

Fig. 18.6a-d. Dynamic features of a hypervascular metastasis from athyroid carcinoma after contrast injection (SonoVue). a Conventional grey-scale image shows a hypoechoic lesion, b During the arterial phase 20 s post injection the lesion enhances homogeneously while there is almost no contrast uptake by the liver parenchyma, c Portal venous phase image (43 s post injection) shows enhancement of normal liver and some contrast washout from the lesion (arrow) so that the lesion is isoechoic at this point, d Delayed phase image (4-5 min post injection) with persistent enhancement of the normal liver and almost complete contrast wash-out from the metastasis... 

Liver metastases are frequently multiple. They vary in size and are usually hypodense. In contrast to liver parenchyma, they display relatively sharp contours, with a difference in density of at least 10 -15 HU. In fatty liver, metastases may even appear hyperdense. Liver metastases are mainly supplied by arterial blood. Therefore i.v. (or even intra-arterial) bolus injection of CM produces the best diagnosis the metastasis shows increased CM enrichment during the short hypervascular phase additionally, a peripheral margin forms as a result of the increased concentration of CM. Metastases of 5 -10 mm can be detected. Data in the literature confirm a sensitivity of 65-91% (in breast cancer up to 100%) and a specificity of 81 - 92% with a success rate of 80 - 85%. Proof of metastases clearly depends on the histology of the primary tumour the best diagnostic results are obtained in breast and colon carcinomas. (22,39,50,53,57)... 

Fig. 3.6a-C. MDCT in portal venous phase (a) and MRI with a Tl-w 3D gradient-echo sequence after gadolinium-injection (b) and a T2 -w gradient-echo sequence after injection of the SPIO contrast agent ferucarbotran (c) in a male patient suffering from a colorectal carcinoma in whom atypical resection of a liver metastasis in the right lobe of the liver had been performed previously. Note the postoperative bilioma (marked by the asterisk). In the MDCT examination no further liver lesions can be detected, whereas the gadolinium-enhanced MRI faintly shows a hypervascular lesion arrow). The SPlO-enhanced MRI scan clearly depicts a newly developed metastasis with a high contrast between lesion and adjacent liver parenchyma...

Fig. 39.1a-c. A 25-year-old male patient with a history of a neuroendocrine tumor of the pancreas has developed a solitary liver metastasis. The patient was treated according to the local tumor board, a Shows the hypervascularized lesion located in segment 7 of the liver. Control scan (b) immediately after the ablation with the needle still in place showing a successful ablation confirmed in the scan 24 h after treatment (c)... 

Fig. 11.18a,b. Dynamic helical CT of a hypervascular liver metastasis from non-functioning malignant neuroendocrine pancreatic tumor, a The primary tumor (arrow) and the liver metastasis (arrowhead) are similarly enhanced during the arterial phase of liver enhancement. The parenchyma around the metastasis is less dense than the normal left liver lobe due to steal phenomena. This finding is transitory and not depicted in the later phases of the dynamic study (b)... 

Hypervascular metastases exhibit an early, brief and pronounced signal enhancement in the arterial phase, which fades rapidly in the later phases. These lesions appear hyperintense in the arterial phase, but other hypervascular lesions like HCC, adenoma and FNH may show similar pattern. Hypovascular metastases exhibit a delayed contrast enhancement, which means they appear hypointense in the arterial phase. A maximal lesion-to-liver contrast is reached in the PVR The equilibrium phase is still important, because it can be used for lesion differentiation (i.e. hemangioma versus metastasis). Hemangiomas show persistent enhancement during the equilibrium phase, whereas most metastases appear iso- or hypointense compared to liver parenchyma (Fig. 19.3). 

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