GI – Liver

  • Liver Iron Quantification with MR Imaging: A Primer for Radiologists
  • Comparison of Acute Transient Dyspnea after Intravenous Administration of Gadoxetate Disodium and Gadobenate Dimeglumine: Effect on Arterial Phase Image Quality Key Points

    “Intravenous gadoxetate disodium [Eovist] can result in acute self-limiting dyspnea that can have a deleterious effect on arterial phase MR image quality and occurs significantly more often than with intravenous gadobenate dimeglumine.”

  • Focal hepatic lesions in Gd-EOB-DTPA enhanced MRI: the atlas
  • Follow-up of Patients at Low Risk for Hepatic Malignancy with a Characteristic Hemangioma at US Key Points

    “For the purposes of this study, a typical hepatic hemangioma was considered to be present when the lesion was (a) well defined, homogeneously hyperechoic with or without central hypoechoic areas, and without posterior shadowing, or (b) hypoechoic or isoechoic with a hyperechoic rim. The presence of posterior acoustic enhancement was not considered in this analysis.”

    “We considered patients to be at high risk for hepatic malignancy if they had a prior history or current evidence of malignant neoplasm, primary hepatic malignancy, or chronic hepatic disease at the time of the initial US examination.”

    “Hepatic hemangioma is the most common benign hepatic tumor, with an approximate prevalence of 4% of the population and a frequency at autopsy of up to 7.3%.”

    “Lesions known to simulate hemangiomas include metastases from a variety of primary tumors and hepatocellular carcinomas. Benign lesions such as focal fat, liver adenoma, and focal nodular hyperplasia can also occasionally mimic hemangioma.”

    “Patients with a known extrahepatic malignancy capable of metastasizing to the liver and patients at risk for hepatocellular carcinoma should undergo additional imaging to confirm the diagnosis of hemangioma or to prove the presence of a hepatic malignancy.”

    “It is controversial whether additional imaging is necessary when a suspected hemangioma is identified in a patient without any of the previously mentioned risk factors for malignancy.”

    “In applying the results of our study to one’s own clinical practice, one can choose to exclude patients with abnormal liver function test results or other potential risk factors (such as multiple lesions or large lesions) from one’s low-risk group.”

    “In conclusion, results of this study show that a hepatic lesion with a US appearance typical of hemangioma is extremely unlikely to be a malignancy, provided that the patient has no prior or current evidence of an extrahepatic malignancy or chronic hepatic disease. On the basis of these results, we no longer recommend follow-up examinations of any type on our patients who fit into this group.”

  • Hypervascular Liver Lesions on MRI
  • Focal Hepatic Lesions: Diagnostic Value of Enhancement Pattern Approach with Contrast-enhanced 3D GRE MR Imaging
  • Dual Gradient-Echo In-Phase and Opposed-Phase Hepatic MR Imaging: A Useful Tool for Evaluating More Than Fatty Infiltration or Fatty Sparing
  • LI-RADS: A Case-based Review of the New Categorization of Liver Findings in Patients with End-Stage Liver Disease Key Points

    “[Focal perfusion alterations] are areas of arterial phase hyperenhancement most frequently caused by nontumorous arterioportal shunts or focal obstruction of a parenchymal portal vein branch. These alterations are usually peripheral, wedge shaped, and isointense relative to the surrounding parenchyma on T1- and T2-weighted MR images, and can be confidently characterized as LR-1; however, perfusion alterations can occasionally be nodular in contour and difficult to distinguish from a true enhancing lesion. Areas of nodular arterial phase hyperenhancement seen exclusively during the arterial phase are more appropriately categorized as LR-2, but if corresponding abnormalities (eg, increased T2 signal) can be seen on unenhanced images or with other sequences, perfusion alterations are considered unlikely, and the observation should be categorized as either LR-3 or LR-4 depending on its size and nonvascular features.” 

  • The Focal Hepatic Hot Spot Sign Key Points

    “In the presence of superior vena cava obstruction, the left hepatic lobe may occasionally demonstrate areas of focally increased blood flow in the collateral veins that can be seen on images. Typically, the collateral venous pathway comprises the internal mammary vein that connects to the left portal vein via the paraumbilical vein.”

    “The flow of blood through the collateral veins may result in areas of focally increased blood flow to the liver. Specifically, an area of increased activity in segment IV of liver (ie, within the medial segment of the left hepatic lobe in what was formerly known as the quadrate lobe) has been well documented in patients with superior vena cava obstruction; this area of increased activity can be seen on 99mTc–sulfur colloid scans of the liver and spleen and is referred to as the focal hepatic hot spot sign. The equivalent of this sign may also be seen on contrast material–enhanced computed tomographic (CT) scans.”

    “Some other causes of hepatic hot spots include Budd-Chiari syndrome, liver abscess, hemangioma, focal nodular hyperplasia, and hepatocellular carcinoma. With the exception of Budd-Chiari syndrome, which causes the hot spot sign to occur in the caudate lobe, all other entities can cause the hot spot sign to occur anywhere in the liver, including segment IV.”