Targeted MRI contrast agents for pediatric hepatobiliary disease

Abstract

New options are available for the magnetic resonance imaging (MRI) assessment of pediatric hepatobiliary disease. This article describes the potential utility for MRI with contrast agents tailored for hepatobiliary imaging. MRI contrast agents that preferentially target the liver may be helpful in characterizing liver masses and bile duct abnormalities in select children. The imaging approach is noninvasive and relatively rapid to perform. It also provides anatomic and functional information and is a radiation-free alternative to other imaging strategies. This relatively new imaging procedure is placed in the context of more established imaging modalities. The pharmacokinetics, technical considerations, and potential applications of these hepatobiliary-specific contrast agents also are discussed.

Figure 1

Typical kinentics of delivery, uptake, and excretion of the hepatobiliary specific agent gadoxetate. Arterial phase imaging at 30 seconds after intravenous injection of gadoxetate shows contrast material in the arteries and early filling of the portal vein and inferior vena cava (ivc). Portal venous phase at 70 seconds shows uniform filling of the arteries, veins, and hepatic parenchyma. At 20 minutes, contrast material has left the vessels, but retained in the liver parenchyma and also excreted in the bile ducts.

Figure 2

Volume-rendered 3D image demonstrating dilated bile ducts and lumen of the common bile duct stent (s) depicted with gadoxetate, a hepatobiliary specific contrast agent. d=duodenum.

Figure 3

Liver masses diagnosed as focal nodular hyperplasia by MRI after injection of a hepatobiliary-specific contrast agent (HSA). This 18 year-old patient has remote history of treated medulloblastoma (in remission) and found to have liver masses on ultrasound (not shown). (A) Dynamic imaging after the injection of the hepatobiliary agent shows rapid uptake into small (arrowhead) and large lesions (arrow) during the arterial phase 20 seconds after administration of HSA. (B) At 70 seconds after injection during the portal venous phase, the lesions are similar in intensity to the liver parenchyma and the smaller lesion is imperceptible. Delayed imaging at 14 minutes shows preferential retention into the disorganized hepatocytes of both lesions (C). Coronal imaging at 20 minutes (D) shows the dominant mass (*) adjacent to the eventual excretion of the HSA into the common bile duct (cbd), gallbladder (gb), duodenum (d) and jejunum (j).

Figure 3

Liver masses diagnosed as focal nodular hyperplasia by MRI after injection of a hepatobiliary-specific contrast agent (HSA). This 18 year-old patient has remote history of treated medulloblastoma (in remission) and found to have liver masses on ultrasound (not shown). (A) Dynamic imaging after the injection of the hepatobiliary agent shows rapid uptake into small (arrowhead) and large lesions (arrow) during the arterial phase 20 seconds after administration of HSA. (B) At 70 seconds after injection during the portal venous phase, the lesions are similar in intensity to the liver parenchyma and the smaller lesion is imperceptible. Delayed imaging at 14 minutes shows preferential retention into the disorganized hepatocytes of both lesions (C). Coronal imaging at 20 minutes (D) shows the dominant mass (*) adjacent to the eventual excretion of the HSA into the common bile duct (cbd), gallbladder (gb), duodenum (d) and jejunum (j).

Figure 3

Liver masses diagnosed as focal nodular hyperplasia by MRI after injection of a hepatobiliary-specific contrast agent (HSA). This 18 year-old patient has remote history of treated medulloblastoma (in remission) and found to have liver masses on ultrasound (not shown). (A) Dynamic imaging after the injection of the hepatobiliary agent shows rapid uptake into small (arrowhead) and large lesions (arrow) during the arterial phase 20 seconds after administration of HSA. (B) At 70 seconds after injection during the portal venous phase, the lesions are similar in intensity to the liver parenchyma and the smaller lesion is imperceptible. Delayed imaging at 14 minutes shows preferential retention into the disorganized hepatocytes of both lesions (C). Coronal imaging at 20 minutes (D) shows the dominant mass (*) adjacent to the eventual excretion of the HSA into the common bile duct (cbd), gallbladder (gb), duodenum (d) and jejunum (j).

Figure 3

Liver masses diagnosed as focal nodular hyperplasia by MRI after injection of a hepatobiliary-specific contrast agent (HSA). This 18 year-old patient has remote history of treated medulloblastoma (in remission) and found to have liver masses on ultrasound (not shown). (A) Dynamic imaging after the injection of the hepatobiliary agent shows rapid uptake into small (arrowhead) and large lesions (arrow) during the arterial phase 20 seconds after administration of HSA. (B) At 70 seconds after injection during the portal venous phase, the lesions are similar in intensity to the liver parenchyma and the smaller lesion is imperceptible. Delayed imaging at 14 minutes shows preferential retention into the disorganized hepatocytes of both lesions (C). Coronal imaging at 20 minutes (D) shows the dominant mass (*) adjacent to the eventual excretion of the HSA into the common bile duct (cbd), gallbladder (gb), duodenum (d) and jejunum (j).

Figure 4

Hepatocellular carcinoma in a 16 year-old. (A) Portal venous phase 3D spoiled gradient echo images imaging with the hepatobiliary specific contrast agent shows early enhancement of the large mass. (A) On delayed imaging the hepatobiliary contrast material is excreted into the bile duct (arrow) and washes out of the mass relative to the liver. These features are typical of malignant tumors such as hepatocellular carcinoma and hepatoblastoma tumor, but atypical for focal nodular hyperplasia.

Figure 4

Hepatocellular carcinoma in a 16 year-old. (A) Portal venous phase 3D spoiled gradient echo images imaging with the hepatobiliary specific contrast agent shows early enhancement of the large mass. (A) On delayed imaging the hepatobiliary contrast material is excreted into the bile duct (arrow) and washes out of the mass relative to the liver. These features are typical of malignant tumors such as hepatocellular carcinoma and hepatoblastoma tumor, but atypical for focal nodular hyperplasia.

Figure 5

Biopsy proven hepatocellular carcinoma in a 12 year-old with cirrhosis. The masses (arrows) rapidly enhanced on the arterial phase (A) and then wash out on delayed imaging (B). Similar to a regenerating nodule, hepatocellular carcinoma will show early enhancement and subsequent washout of contrast material. The wedge shaped area of arterial enhancement in the anterior right liver is a transient phenomenon. Ultrasound (C) and computed tomography (D) reveal the masses but do not provide the level of characterization as on MRI with dynamic contrast enhancement.

Figure 5

Biopsy proven hepatocellular carcinoma in a 12 year-old with cirrhosis. The masses (arrows) rapidly enhanced on the arterial phase (A) and then wash out on delayed imaging (B). Similar to a regenerating nodule, hepatocellular carcinoma will show early enhancement and subsequent washout of contrast material. The wedge shaped area of arterial enhancement in the anterior right liver is a transient phenomenon. Ultrasound (C) and computed tomography (D) reveal the masses but do not provide the level of characterization as on MRI with dynamic contrast enhancement.

Figure 5

Biopsy proven hepatocellular carcinoma in a 12 year-old with cirrhosis. The masses (arrows) rapidly enhanced on the arterial phase (A) and then wash out on delayed imaging (B). Similar to a regenerating nodule, hepatocellular carcinoma will show early enhancement and subsequent washout of contrast material. The wedge shaped area of arterial enhancement in the anterior right liver is a transient phenomenon. Ultrasound (C) and computed tomography (D) reveal the masses but do not provide the level of characterization as on MRI with dynamic contrast enhancement.

Figure 5

Biopsy proven hepatocellular carcinoma in a 12 year-old with cirrhosis. The masses (arrows) rapidly enhanced on the arterial phase (A) and then wash out on delayed imaging (B). Similar to a regenerating nodule, hepatocellular carcinoma will show early enhancement and subsequent washout of contrast material. The wedge shaped area of arterial enhancement in the anterior right liver is a transient phenomenon. Ultrasound (C) and computed tomography (D) reveal the masses but do not provide the level of characterization as on MRI with dynamic contrast enhancement.

Figure 6

Stenosis of the common bile duct in a 4 year-old. Coronal T1-weighted fat suppressed image after orthotopic whole liver transplantation shows focal narrowing of the common bile duct (arrow head). The hepatobiliary targeted contrast material fills the lumen of the common bile duct (arrows). In addition, the liver is increased in signal intensity from residual hepatobiliary specific contrast agent that has yet to be excreted.

Figure 7

Choledochol cyst in a 7 year-old. The hepatobiliary-specific contrast material helps determine the relationship of the cyst with the biliary and pancreatic ducts. (A) The mass located at the head of the pancreas (arrow) projects into the lumen of the duodenum on the T2-weighted fast spin echo fat suppressed image. (B) On the contrast enhanced maximum intensity image, the contrast material excreted by the liver fills the bile ducts and dilated and disorganized accessory ducts of the pancreas (ac) but not the cyst.

Figure 7

Choledochol cyst in a 7 year-old. The hepatobiliary-specific contrast material helps determine the relationship of the cyst with the biliary and pancreatic ducts. (A) The mass located at the head of the pancreas (arrow) projects into the lumen of the duodenum on the T2-weighted fast spin echo fat suppressed image. (B) On the contrast enhanced maximum intensity image, the contrast material excreted by the liver fills the bile ducts and dilated and disorganized accessory ducts of the pancreas (ac) but not the cyst.

Figure 8

Infantile hemangioma in an 18 month-old male. The dynamic phase imaging shows early peripheral enhancement during the arterial phase (A) and gradual peripheral filling towards the center during the portal venous phase (B). However, on the delayed hepatobiliary phase (C) the lesion is darker than the liver, thus, confirming hemangioma and excluding fibronodular hyperplasia. The complex pattern on ultrasound (D) lead to the need for further characterization with MRI.

Figure 8

Infantile hemangioma in an 18 month-old male. The dynamic phase imaging shows early peripheral enhancement during the arterial phase (A) and gradual peripheral filling towards the center during the portal venous phase (B). However, on the delayed hepatobiliary phase (C) the lesion is darker than the liver, thus, confirming hemangioma and excluding fibronodular hyperplasia. The complex pattern on ultrasound (D) lead to the need for further characterization with MRI.

Figure 8

Infantile hemangioma in an 18 month-old male. The dynamic phase imaging shows early peripheral enhancement during the arterial phase (A) and gradual peripheral filling towards the center during the portal venous phase (B). However, on the delayed hepatobiliary phase (C) the lesion is darker than the liver, thus, confirming hemangioma and excluding fibronodular hyperplasia. The complex pattern on ultrasound (D) lead to the need for further characterization with MRI.

Figure 8

Infantile hemangioma in an 18 month-old male. The dynamic phase imaging shows early peripheral enhancement during the arterial phase (A) and gradual peripheral filling towards the center during the portal venous phase (B). However, on the delayed hepatobiliary phase (C) the lesion is darker than the liver, thus, confirming hemangioma and excluding fibronodular hyperplasia. The complex pattern on ultrasound (D) lead to the need for further characterization with MRI.