ABSTRACT
Aim:
The aim is to study intrahepatic biliary architecture in patients following Kasai’s portoenterostomy for extrahepatic biliary atresia using magnetic resonance cholangiopancreatography (MRCP).
Materials and Methods:
It is a prospective observational study in a cohort of patients who have survived with a complete jaundice-free period for at least 1 year. MRCP was done to look for various intrahepatic architectural changes during their last visit. Findings were correlated with liver functions and growth and development.
Results:
Twenty-one patients were included in the study. The male-to-female sex ratio was 1.6:1, the median age at surgery was 75 days (18–140 days), and the median age at magnetic resonance imaging (MRI) was 4 years (18 months–18 years). More than 2 years of follow-up was in seven patients. Left lobe hypertrophy was observed in six patients, right lobe hypertrophy was in three patients, intrahepatic biliary tract dilatation was in five patients, and altered signal intensity between intrahepatic ducts was seen in five patients. In addition, hypointense foci in the spleen were seen in one patient. Twelve children had normal weight for their age, ten children had the normal height for their age, and gamma-glutamyl transferase was elevated in all children. Only four children had a history of fever and jaundice.
Conclusions:
The patients who survive after successful surgical intervention have near-normal liver gross architecture as on MRI/MRCP. Occasional findings of dilatation and lobar atrophy/hypertrophy are possible, especially in those with a history of cholangitis. The survivors also have acceptable growth parameters and normal liver functions.
KEYWORDS: Biliary atresia, extrahepatic biliary atresia, liver architecture, magnetic resonance cholangiopancreatography, magnetic resonance imaging
INTRODUCTION
Biliary atresia (BA) is a progressive obliterative cholangiopathy where the morphology of the liver is expected to undergo changes. The incidence of BA ranges from 1 in 10,000 to 1 in 16700 live births, with a stable incidence over the last several decades. There is a female preponderance of 1.5 to 1.7:1.[1] The extrahepatic ducts are not entirely absent in BA; they remain, rather, as a combination of obliterated fibrous chords. Most frequently, the entire extrahepatic ductal system is obliterated; the most common variant, occurring in nearly 20%, is characterized by patency of the gallbladder and the cystic and common ducts. Little is known about intrahepatic bile ducts following a successful Kasai’s portoenterostomy (KPE) for extrahepatic BA (EHBA). The histologic characteristics of the ductile remnant at the portal plate are a highly significant predictor of clinical outcome.[2,3,4] The jaundice-free period after successful surgery in EHBA has improved since 1951. Deteriorations still occur in the follow-up period.[5] However, the cause for this deterioration has not yet been ascertained. The postoperative period is often complicated by recurrent cholangitis, portal hypertension, and nutritional complications such as fat, protein, and vitamin deficiencies.[6] The cirrhotic changes in such patients, particularly the time-course changes, are also unclear. Caruso et al. have comparatively assessed the role of abdominal ultrasound (US) and magnetic resonance imaging (MRI) in predicting long-term medical outcomes in native liver survivor patients with EHBA after KPE, and concluded that patients with good medical outcomes after surgical correction (KPE) the US and MRI may both predict long-term outcome.[7]
In this study, we have explored the hepatic and biliary architecture in survivors of EHBA after Kasai’s procedure using magnetic resonance cholangiopancreatography (MRCP). MRI of the jaundice-free survivor is a noninvasive way of assessing the progression and status of the disease. It may pick up abnormalities even before clinical and biochemical deterioration.
MATERIALS AND METHODS
Patients who underwent KPE from the year 2000 onward were followed up. It is a cross-sectional observational study in a cohort of 21 patients who have survived with a complete jaundice-free period for at least 1 year after KPE. MRCP was done to look for various intrahepatic architectural changes. Findings were correlated with liver functions and growth and development. MRI was performed on either 1.5 or 3 tesla scanners, and the sequences used were T1-spoiled gradient echo (in and opposed phase), HASTE, T2 fat suppression, TRUFISP, thick slab MRCP images, and 3D RESTORE. The MRI findings were evaluated by a pediatric radiologist with more than 10 years of experience and interest in pediatric hepatobiliary imaging. Biochemical parameters – serum bilirubin (direct and indirect), serum glutamic-oxaloacetic transaminase/serum glutamic-pyruvic transaminase, gamma-glutamyl transferase (GGT), and prothrombin time – were recorded. Anthropometric parameters were also recorded and compared with the radiological findings. Institute ethical committee clearance was obtained. Descriptive statistics (frequency, percentage, median, and interquartile range) are used to present the data.
RESULTS
Twenty-one patients were included in the study. The male-to-female sex ratio was 1.6:1 (13 males, 8 females), the median age at surgery was 75 days (18–140 days), and the median age at surgery in boys was 75 days and in girls was 84 days [Figure 1]. The median age at (MRI) was 4 years (18 months–18 years). The median level of bilirubin (direct) was 12 mg/dL (6.5–18) at the time of surgery. The median level of bilirubin (total) was 1.8 mg/dL (0.5–2.4) at the time of evaluation by MRI. More than 2 years of follow-up was in seven patients.
Figure 1.
Age distribution of the patients at the time of surgery (KPE)
Magnetic Resonance Imaging findings
Left lobe hypertrophy was observed in six patients, right lobe hypertrophy was in three patients, intrahepatic biliary tract dilatation was in five patients [Figures 2 and 3], and altered signal intensity between intrahepatic ducts was seen in five patients. Hypointense foci in the spleen were seen in one patient. The liver had a peripheral enhancing area along the liver capsule in five patients.
Figure 2.
Nonhomogeneous liver parenchyma with focal bile duct ectasia (arrow)
Figure 3.
Central ductal dilatation (arrowhead) and left hepatic duct dilatation (white arrow)
The following MRI findings were notable and have been demonstrated in the images.
Figure 4 Coronal T2-weighted image showing portojejunostomy anastomosis (asterisk) with prominent intra-hepatic biliary radicles (arrows). Figure 5 Axial T2-weighted image showing nodular liver margins (arrows) and heterogeneous signal intensity of liver parenchyma with peripheral liver showing hyperintense signal (asterisk). Figure 6 Coronal T2-weighted image showing volume redistribution of liver parenchyma with right lobe hypertrophy (asterisk) and left lobe atrophy (circle).
Figure 4.
Coronal T2-weighted image showing Porto-jejunostomy anastomosis (asterisk) with prominent intra-hepatic biliary radicles (arrows)
Figure 5.
Axial T2-weighted image showing nodular liver margins (arrows) and heterogeneous signal intensity of liver parenchyma with peripheral liver showing hyperintense signal (asterisk)
Figure 6.
Coronal T2-weighted image showing volume redistribution of liver parenchyma with right lobe hypertrophy (asterisk) and left lobe atrophy (circle)
Figure 7 Coronal BTFE (balanced turbo field echo) image showing changes of portal hypertension in the form of dilated portal vein and splenomegaly. Figure 8 Axial T2-weighted image showing intra-hepatic biliary radicle dilatation (arrows) with heterogeneous liver signal intensity.
Figure 7.
Coronal T2-weighted image showing volume redistribution of liver parenchyma with right lobe hypertrophy (asterisk) and left lobe atrophy (circle)
Figure 8.
Axial T2-weighted image showing intrahepatic biliary radicle dilatation (arrows) with heterogeneous liver signal intensity
None of the children had a bile lake pattern. In addition, the portal vein was normal in all, and a normal pancreatic duct was documented in all patients and none had ascites at the time of examination [Table 1].
Table 1.
Distribution of age at surgery and Magnetic Resonance Imaging findings at evaluation
| Serial number | Sex | Age (days) at KPE | Notable MRI findings at evaluation |
|---|---|---|---|
| 1 | Male | 92 | The liver had a peripheral enhancing area along the liver capsule |
| 2 | Male | 60 | Right lobe hypertrophy, left lobe atrophy, intrahepatic biliary radicle dilatation, the liver had a peripheral enhancing area along the liver capsule |
| 3 | Female | 75 | Altered signal intensity between intrahepatic ducts |
| 4 | Male | 52 | Left lobe hypertrophy |
| 5 | Male | 90 | Intrahepatic biliary radicle dilatation |
| 6 | Female | 64 | The liver had a peripheral enhancing area along the liver capsule |
| 7 | Male | 60 | Right lobe hypertrophy |
| 8 | Female | 84 | The liver had a peripheral enhancing area along the liver capsule |
| 9 | Female | 84 | Left lobe hypertrophy |
| 10 | Female | 95 | Altered signal intensity between intrahepatic ducts |
| 11 | Male | 75 | Altered signal intensity between intrahepatic ducts |
| 12 | Female | 85 | Left lobe hypertrophy |
| 13 | Male | 90 | Left lobe hypertrophy |
| 14 | Female | 95 | The liver had a peripheral enhancing area along the liver capsule |
| 15 | Male | 140 | Intrahepatic biliary radicle dilatation, dilated portal vein with splenomegaly, hypointense foci in spleen |
| 16 | Male | 60 | Intrahepatic biliary radicle dilatation |
| 17 | Male | 62 | Right lobe hypertrophy |
| 18 | Male | 78 | Left lobe hypertrophy |
| 19 | Female | 75 | Left lobe hypertrophy |
| 20 | Male | 18 | Altered signal intensity between intrahepatic ducts |
| 21 | Male | 60 | Intrahepatic biliary radicle dilatation |
MRI: Magnetic resonance imaging, KPE: Kasai’s portoenterostomy
GGT was elevated in all the study subjects. Only four children had a history of fever and jaundice last year.
Correlation of the Magnetic Resonance Imaging findings with biochemical parameters and anthropometry findings
For the comparative analysis of the MRI findings, we divided our cohort of patients into three subgroups as per their weight for age (WFA), height for age (HFA), and weight for height (WFH).
Eight patients (five females and three males) had normal WFA, HFA, and WFH. Ten children had the normal height for their age but <50 percentile Clinical Growth Charts of Centers for Disease Control and Prevention (CDC chart) in their WFA. This indicates that these children were in an acute phase of malnutrition. On evaluating their biochemical parameters, it was revealed that they were the children with raised total bilirubin (higher than the median value) at the time of evaluation. There was no correlation with the abnormal liver architecture on MRI in these three subgroups. The MRI findings were found to be an adjunctive tool to detect and document acute and chronic liver derangement. Still, they had no direct correlation with anthropometric measures and the general well-being of children who had undergone KPE.
DISCUSSION
MRI and CT of the abdomen have been routinely performed in the preoperative workup of end-stage EHBA patients who are being taken up for liver transplantation. This is done to identify congenital anomalies or cirrhosis-related modifications or conditions that can require changes in surgical technique during transplantation. However, jaundice-free patients after a successful KPE may have evolving architectural changes that may not be picked up by the routine follow-up strategies currently employed. How early they appear, and their significance has not been studied in detail. Our study aimed at exploring a cohort of successful KPE patients noninvasively using MRI and documenting the various changes in the liver architecture in these patients.
To address this issue, Takahashi et al. performed periodic MRIs in 19 postoperative EHBA patients, followed over a minimum of 2 years.[8] They divided their cohort of patients into three groups based on serum bilirubin levels and levels of serum GGT. They found that patients who reported higher bilirubin levels and GGT developed positive findings in the MRI evaluation. As per their observations, they recommended that MRI is useful in evaluating liver functions and the prognosis of EHBA patients after KPE. The same author has published time-course changes in the liver of BA patients on MRI and concluded that adequate areas of liver tissue with the near-normal structure were indicative of good and poor prognosis, respectively. Shortly after portoenterostomy, these segmental changes developed in each liver segment and could be detected on MRI.[9] We have reported similar findings in our cohort of patients. In addition, we have correlated the anthropometric measures with the MRI findings to document the general well-being of the survivor. It was also found that the median age of these children at the time of assessment was 29 months (18–36 months), suggesting that even in the survivors, the first 36 months of life is a crucial phase of remission. Children who cross this age have fewer chances of developing acute liver derangements. Three children had normal WFH but were at lower than the 50th percentile (CDC chart) mark in WFA, meaning that these children had chronic malnutrition. This may be attributed to chronic poor liver function. In this study, we can clearly say that MRI can be used as an adjunctive tool to detect and document architectural changes in the liver in due course of the disease but does not correlate with general well-being measured by anthropometry and liver functions. It, however, gives an insight into the progress of architectural changes in the survivors of KPE, which may help in deciding the further course of management of the disease.[7]
Limitations
Being a cross-sectional study, the follow-up duration of the study subjects is heterogeneous. Histopathological correlation of the radiologic findings is also lacking. A longitudinal prospective study with histopathological correlation is expected to provide the missing links beyond what has been obtained from the current study.
CONCLUSIONS
The patients who survive after successful surgical intervention have near-normal liver gross architecture as on MRI/MRCP. Occasional findings of dilatation and lobar atrophy/hypertrophy are possible, especially in those with a history of cholangitis. The survivors also have acceptable growth parameters and normal liver functions.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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