The Use of Gadoxetic Acid–Enhanced MRI as a Diagnostic Tool in Cases of Biliary Atresia: A Two-Case Report

Abstract

Early diagnosis of biliary atresia (BA) remains challenging, although timely recognition is critical for achieving favorable surgical outcomes. We present two infants in whom gadoxetic acid–enhanced MRI demonstrated imaging findings that supported early suspicion of BA. Two neonates with persistent cholestasis underwent routine laboratory evaluation, targeted ultrasonography, and hepatocyte-specific magnetic resonance imaging using gadoxetic acid. This contrast agent is actively taken up by functioning hepatocytes and is normally excreted into the biliary system during the delayed hepatobiliary phase, allowing functional assessment of bile formation and excretion. MRI findings, particularly biliary excretion on delayed images, were evaluated and correlated with intraoperative cholangiography. In both infants, hepatic parenchymal enhancement after contrast administration was preserved, indicating intact hepatocellular uptake. However, no biliary excretion was observed on delayed hepatobiliary-phase images. Intraoperative cholangiography confirmed biliary atresia in both cases. Although the diagnosis of biliary atresia is traditionally based on clinical findings, laboratory parameters, and ultrasonography, these approaches may remain inconclusive in some patients. Our findings suggest that gadoxetic acid–enhanced MRI, by demonstrating preserved hepatocellular uptake with absent biliary excretion, may serve as a useful adjunctive diagnostic tool and contribute to earlier and more confident identification of biliary atresia.

Diagnosing biliary atresia (BA) early in life is one of those tasks in pediatrics that appears straightforward in theory but becomes more complicated in day-to-day practice. BA itself is well recognized: a progressive, fibroinflammatory obstruction of the extrahepatic biliary system that, if left untreated, leads to cirrhosis and liver failure during infancy.^[1] What makes it challenging is that the earliest symptoms overlap considerably with a wide variety of neonatal cholestatic conditions.^[2,3] Jaundice may appear only mildly abnormal at first, and many infants otherwise appear well, at least during the first weeks.

Guidelines clearly state that jaundice persisting beyond the second week of life warrants evaluation for cholestasis.^[4,5] Yet, when conjugated hyperbilirubinemia is detected, clinicians must still determine whether the problem lies within the hepatocytes or the biliary tree. Laboratory values can support suspicion but rarely settle the matter. As a result, imaging becomes essential.

Ultrasonography has long been the first step because it is fast, safe, and capable of demonstrating subtle structural changes. Some sonographic features—such as a nondistensible gallbladder, a triangular cord sign, or occasionally an enlarged hepatic artery—can point toward BA, although experience shows that these findings are not equally apparent in every infant.^[6–8] It is not unusual to encounter cases in which ultrasonography raises suspicion but leaves enough uncertainty that the clinician hesitates to proceed immediately to invasive testing.

In recent years, hepatocyte-specific magnetic resonance imaging using gadoxetic acid has increasingly been utilized as an adjunctive technique in the evaluation of neonatal cholestasis, as it allows combined assessment of hepatic perfusion and biliary excretory function within a single examination.^[9,10] Following intravenous administration, gadoxetic acid demonstrates extracellular behavior during the early dynamic phases, with arterial- and portal venous–phase images acquired in accordance with standard contrast-enhanced liver MRI protocols to evaluate hepatic perfusion and parenchymal enhancement patterns.^[9,11] Hepatobiliary-phase imaging is routinely obtained approximately 20 minutes after contrast administration and enables functional assessment of biliary excretion, which under normal circumstances results in visualization of the intrahepatic bile ducts and biliary tree.^[12] In the setting of biliary obstruction, hepatic parenchymal enhancement may remain preserved, whereas contrast excretion into the biliary system is absent or markedly reduced, reflecting impaired bile drainage rather than primary hepatocellular dysfunction.^[10,13] When clinically indicated, extended delayed hepatobiliary-phase imaging can be performed to further evaluate bile secretion and flow dynamics beyond purely anatomic assessment and may assist in differentiating biliary atresia from other causes of neonatal cholestasis.^[10,13,14]

The two cases described here illustrate how this functional signature on MRI assisted in the early evaluation process and ultimately contributed to timely surgical management. Informed consent was obtained from the patients’ families.

Case Report

Case 1

A 7-week-old female infant was referred from an outside institution for evaluation of prolonged jaundice and a concomitant urinary tract infection. A urine culture obtained prior to referral revealed growth of Klebsiella species. Physical examination revealed scleral icterus and hepatomegaly, while the stool color was reported as yellow. Laboratory investigations demonstrated a cholestatic pattern, with elevated alkaline phosphatase, gamma-glutamyl transferase, and both total and direct bilirubin levels. Abdominal ultrasonography demonstrated a small gallbladder with an abnormal configuration. On hepatocyte-specific magnetic resonance imaging using gadoxetic acid, the gallbladder appeared contracted, with no contrast accumulation, and no contrast opacification of the common bile duct was observed (Fig. 1). These findings were considered highly suggestive of biliary atresia. The patient subsequently underwent surgical intervention, achieved clinical stabilization, and was discharged following an uneventful postoperative course. No complications were observed during follow-up.

Figure 1.

Magnetic resonance imaging findings in Case 1. (a) Coronal T2-weighted HASTE image demonstrates a contracted gallbladder. (b) Coronal T2-weighted HASTE image shows non-visualization of the common bile duct. (c) Hepatocyte-specific magnetic resonance imaging demonstrates absence of contrast excretion into the common bile duct. (d) Hepatocyte-specific magnetic resonance imaging shows a contracted gallbladder without intraluminal contrast accumulation. The combination of absent visualization of the biliary tree on T2-weighted images and lack of biliary contrast excretion despite preserved hepatic parenchymal enhancement is consistent with biliary atresia.

Case 2

An 8-week-old female infant was referred from an outside institution for evaluation of prolonged jaundice. Laboratory evaluation revealed elevated total and direct bilirubin levels, as well as increased aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and gamma-glutamyl transferase levels. Physical examination demonstrated hepatosplenomegaly, and the stool color was described as pale yellow to whitish. Abdominal ultrasonography revealed an abnormally configured gallbladder with nonvisualization of the extrahepatic bile ducts. Hepatocyte-specific magnetic resonance imaging demonstrated a contracted gallbladder without contrast accumulation, and the common bile duct could not be visualized (Fig. 2). The diagnosis of biliary atresia was confirmed by surgical exploration, and operative management was performed. During postoperative follow-up, persistent elevation of liver enzyme and bilirubin levels was noted, along with ongoing acholic stools. The patient remains under close clinical follow-up.

Figure 2.

Magnetic resonance imaging findings in Case 2. (a) Axial T2-weighted HASTE image demonstrates a contracted gallbladder. (b) Coronal T2-weighted TRUFI image shows non-visualization of the common bile duct. (c) Hepatobiliary-phase hepatocyte-specific MRI demonstrates a contracted gallbladder without intraluminal contrast accumulation. (d) Hepatobiliary-phase image shows absence of contrast excretion into the common bile duct. These findings, combining morphologic abnormalities with absent biliary contrast excretion, are consistent with biliary atresia.

Discussion

Early differentiation of biliary atresia from other causes of neonatal cholestasis remains a central challenge in pediatric imaging, largely because diagnostic delay has direct and irreversible consequences. Progressive biliary obstruction in untreated biliary atresia rapidly leads to fibrosis and cirrhosis, often within the first months of life, substantially reducing the likelihood of successful portoenterostomy and increasing the need for early liver transplantation.^[1,2] Because the therapeutic window for an optimal surgical outcome is narrow, timely and accurate diagnosis is critical, and radiologic findings play a disproportionately important role in guiding early clinical decision-making.

In routine practice, the diagnostic workup relies on a combination of clinical presentation, laboratory parameters, and ultrasonography. However, these findings may remain inconclusive in a subset of patients, particularly in early or atypical cases. Ultrasonography, while indispensable, is subject to operator dependency and variability in the visibility of classic signs, such as gallbladder abnormalities or the triangular cord sign.^[6–8] In this context, imaging modalities that provide functional information in addition to morphologic assessment are of particular value.

Hepatocyte-specific MRI using gadoxetic acid offers a unique advantage by allowing evaluation of hepatic perfusion and biliary excretory function within a single examination. Following intravenous administration, early dynamic phases—including arterial and portal venous imaging—are performed according to standard liver MRI protocols and primarily reflect hepatic perfusion and parenchymal enhancement patterns.^[9,11] These phases, while useful, are often insufficient on their own to distinguish obstructive from nonobstructive causes of cholestasis.

The hepatobiliary phase, routinely acquired after the dynamic sequences, provides functional insight into biliary excretion. Under normal conditions, contrast excretion results in visualization of the intrahepatic bile ducts and biliary tree. In biliary atresia, however, a characteristic dissociation may be observed: hepatic parenchymal enhancement appears preserved, whereas excretion into the biliary system is absent or markedly reduced, reflecting impaired bile drainage rather than primary hepatocellular dysfunction.^[10,12,13] When initial hepatobiliary-phase images remain equivocal, extended delayed imaging can further clarify excretory behavior, emphasizing the importance of late-phase assessment in suspected obstructive pathology.^[10,12,14]

The cases presented here illustrate how delayed hepatobiliary-phase findings contributed to diagnostic confidence in situations in which conventional imaging alone did not provide definitive answers. By highlighting the absence of biliary excretion despite preserved parenchymal uptake, gadoxetic acid–enhanced MRI supported early suspicion of biliary atresia and facilitated timely surgical referral. Given the rapid progression to cirrhosis associated with delayed diagnosis, the incorporation of hepatocyte-specific MRI—particularly careful evaluation of delayed hepatobiliary-phase images—may represent a meaningful adjunct to the diagnostic algorithm for neonatal cholestasis.

Conclusion

Early and accurate differentiation of biliary atresia from other causes of neonatal cholestasis is essential, as diagnostic delay is closely associated with rapid progression to fibrosis and cirrhosis and directly affects the success of portoenterostomy. In the cases presented, gadoxetic acid–enhanced MRI demonstrated a consistent functional pattern characterized by preserved hepatic parenchymal enhancement with absent biliary excretion. When interpreted together with clinical findings and ultrasonography, this dissociation reduced diagnostic uncertainty and supported timely surgical evaluation. Given the narrow therapeutic window in biliary atresia and the limitations of conventional imaging in early or atypical presentations, careful assessment of hepatobiliary-phase and extended delayed images provides clinically meaningful information regarding bile drainage. Within this context, hepatocyte-specific MRI may be used as a valuable adjunctive imaging modality in the diagnostic evaluation of biliary atresia and may contribute to earlier and more reliable diagnosis in selected patients.

Disclosures

Ethics Approval

This is a single case report, and therefore ethics committee approval was not required in accordance with institutional policies.

Informed consent

Informed consent for publication of the clinical information and images was obtained from the parents or legal guardians of both patients.

Conflict of Interest

The authors declare that there is no conflict of interest.

Financial Disclosure

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Use of AI for Writing Assistance

No generative artificial intelligence was used to generate patient data, images, analyses, or scientific conclusions.

Authorship Contributions

Concept – H.O., M.A., N.U.; Design – H.O., M.A., N.U.; Supervision – H.O., M.A., N.U.; Results − H.O., M.A., N.U.; Materials − H.O., M.A., N.U.; Data collection &/or processing – H.O., M.A., N.U.; Analysis and/or interpretation – H.O., M.A., N.U.; Literature search – H.O., M.A., N.U.; Writing – H.O., M.A., N.U.; Critical review – H.O., M.A., N.U.

Peer-review

Externally peer-reviewed.