Regenerative Nodules

Regenerative nodules frequently arise in cirrhotic livers as a result of heterogeneous regeneration in the grossly distorted liver architecture. These lesions, which are usually less than 5 mm in diameter, show a heterogeneous pattern on MR images. Larger regenerative nodules, measuring more than 5 mm in diameter, can be found in about one third of cirrhotic livers, while nodules larger than 10 mm only occur in about 10% of cases [72].

Regenerative nodules on ultrasound (US) and CT may mimic neoplasms such as HCC, a misinterpretation frequently underlined by the fact that intrahepatic vessels are displaced by mass effects. MRI is superior for the diagnosis of regenerative nodules because of its better soft tissue contrast. The typical nodular pattern which is due to inflammatory fibrous septa surrounding each regenerative nodule is best depicted on mildly T2-weighted images [49].

Approximately 25% of regenerative nodules show an increased deposition of iron compared to surrounding normal liver cells [65]. Hence, their identification as regions with decreased SI on T2-weighted or T1-weighted gradient echo images is improved [64].

Furthermore, the contrast between the fibrous septa and the normal liver parenchyma can be increased by the application of exogenous iron oxide-based contrast agents [18].

As liver cirrhosis with regenerative nodules may also occur in patients suffering from fatty infiltration or presenting with fatty regenerative nodules, out-of-phase T1-weighted imaging is often appropriate to clarify the diagnosis. Since re

Nodular Liver Surface

Fig. 6a, b. Typical findings in hepatic cirrhosis. T2-weighted images (a, b), show nodular contours of the surface of the liver, enlargement of the caudate lobe (arrowin a), ascites and atrophy of the right liver lobe with subsequent hypertrophy of the left lobe. Additionally, a typically empty region in the gallbladder fossa (arrowin b) can be depicted, corresponding to periportal fat

Fig. 6a, b. Typical findings in hepatic cirrhosis. T2-weighted images (a, b), show nodular contours of the surface of the liver, enlargement of the caudate lobe (arrowin a), ascites and atrophy of the right liver lobe with subsequent hypertrophy of the left lobe. Additionally, a typically empty region in the gallbladder fossa (arrowin b) can be depicted, corresponding to periportal fat

Fig. 7a-c. Diffuse regenerative nodules in a cirrhotic liver. On moderately T2-weighted images (a), a nodular pattern of liver parenchyma can be observed. On T1-weighted images (b), some of the regenerative nodules (arrows) display high SI due to iron or fat content. On Tl-weighted contrast-enhanced images (c) the diffuse nodular pattern is displayed more clearly

Fig. 7a-c. Diffuse regenerative nodules in a cirrhotic liver. On moderately T2-weighted images (a), a nodular pattern of liver parenchyma can be observed. On T1-weighted images (b), some of the regenerative nodules (arrows) display high SI due to iron or fat content. On Tl-weighted contrast-enhanced images (c) the diffuse nodular pattern is displayed more clearly generative nodules consist of normal hepatic cells, MRI is the imaging modality of choice to exclude HCC, which can usually be differentiated from regenerative nodules due to its increased SI on T2-weighted images. In some cases, regenerative nodules may appear as slightly hyperintense on Tl-weighted sequences. This is particularly the case when the signal of the surrounding liver parenchyma is reduced due to fibrosis and in cases in which the nodules have accumulated fat [39] (Fig. 7).

Regenerative nodules should be distinguished from nodular regenerative hyperplasia, which is characterized by multiple hyperplastic nodules occurring in a non-cirrhotic liver. These nodules may sometimes mimic cirrhosis, however, they do not show the tendency to accumulate fat or iron [ 13].

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Responses

  • denise
    What are regenerative nodules in liver?
    9 months ago
  • cristian
    How do doctors remove regenerative nodule from liver?
    8 months ago
  • gianni
    Why does doctor want mri of liver nodules?
    2 months ago

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