Utility of Tc-99m mebrofenin scintigraphy in the assessment of infantile jaundice

Booster administration of Tc-99m PMT for delayed static imaging in patients with biliary atresia

OBJECTIVE

Tc-99m N-pyridoxyl-5-methyl-tryptophan (PMT) hepatobiliary scintigraphy has high diagnostic performance for biliary atresia. Our hospital implements standard Tc-99m PMT administration followed by a 6 h static imaging review; booster doses are given in cases requiring 24 h delayed scans. This study aimed to evaluate the diagnostic performance of this method.

METHODS

A total of 37 pediatric patients who underwent Tc-99m PMT biliary scintigraphy were classified into the surgically-diagnosed biliary atresia or non-biliary atresia groups. The absence of tracer accumulation in the small bowel was considered a hepatobiliary scintigraphic diagnosis of biliary atresia. The Clopper-Pearson method was used to calculate the 95% confidence intervals (CIs) for determining the diagnostic accuracy, negative predictive value, positive predictive value, sensitivity, and specificity of Tc-99m PMT biliary scintigraphy.

RESULTS

Among the 37 patients, 12 were classified into the diagnosis of biliary atresia group. Regarding biliary scintigraphy findings, 16 of 37 patients demonstrated tracer accumulation in the small bowel within 6 h of testing. These cases were diagnosed as non-biliary atresia, requiring no further testing or booster administration. In contrast, 21 patients underwent delayed testing requiring booster administration, which revealed 13 without tracer excretion and 11 who were diagnosed with biliary atresia. Among the eight patients with tracer accumulation, only one was diagnosed with biliary atresia. Furthermore, two cases without tracer excretion and seven cases with tracer excretion were clinically diagnosed as non-biliary atresia. The diagnostic performance of our examination was as follows: a diagnostic accuracy of 91.9% (34/37; 95% CIs 78.0-98.3%), sensitivity of 91.6% (11/12; 95% CIs 61.5-99.8%), specificity of 92.0% (23/25; 95% CIs 74.0-99.0%), a positive predictive value of 84.6% (11/13; 95% CIs 54.6-98.0%), and a negative predictive value of 95.8% (23/24; 95% CIs 78.9-99.9%).

CONCLUSIONS

Our protocol for Tc-99m PMT biliary scintigraphy using tracer booster administration demonstrated reliable diagnostic performance for biliary atresia. Notably, 43% of cases did not require booster administration, indicating that lesser radiation exposure may still yield comparable diagnostic accuracy.

Comparison of phenobarbitone and ursodeoxycholic acid in drug-augmented hepatobiliary scintigraphy for excluding the diagnosis of obstructive cholestasis in neonatal cholestasis syndrome

OBJECTIVES

Neonatal cholestasis is a common cause of jaundice among newborns. Hepatobiliary scintigraphy plays an important role in the diagnosis of neonatal cholestasis by ruling out extrahepatic biliary atresia, which is one of the common causes. Phenobarbitone and ursodeoxycholic acid (UDCA) have been used to improve the specificity of hepatobiliary scintigraphy in ruling out obstructive causes of neonatal cholestasis syndrome (NCS). The present study was undertaken to compare the utility of phenobarbitone and UDCA in augmenting hepatobiliary scintigraphy in the evaluation of NCS.

MATERIALS AND METHODS

Seventy-four consecutive patients with NCS referred for hepatobiliary scintigraphy were initially subjected to a baseline scan. Twenty patients showed tracer activity in the intestine within 24 h after injection, thus ruling out obstructive cholestasis. Fifty-four patients who did not show any tracer activity in the intestine were categorized as nonexcretors. Four nonexcretors were lost to follow-up and were excluded from the study. Fifty nonexcretors showing scan features suggestive of obstructive cholestasis were further randomized into those receiving phenobarbitone (n=20), UDCA (n=20), or placebo (n=10). These groups were further evaluated with drug-augmented hepatobiliary scintigraphy, after premedication, for any excretory activity in the intestine.

RESULTS AND CONCLUSION

Out of 50 patients who were evaluated with drug-augmented hepatobiliary scintigraphy two patients from the phenobarbitone group and one patient each from UDCA and placebo groups showed a change in excretory pattern from the baseline scan. However, these results were statistically nonsignificant (P=1.00). In the present study, drug-augmented (phenobarbitone or UDCA) hepatobiliary scintigraphy did not seem to improve the results (negative predictive value) for ruling out an obstructive cause of neonatal cholestasis.

Phenobarbital-enhanced hepatobiliary scintigraphy in the diagnosis of biliary atresia: two decades of experience at a tertiary center

BACKGROUND

Hepatobiliary scintigraphy is highly sensitive for diagnosing biliary atresia; however, its specificity has varied in the literature from 35% to 97%.

OBJECTIVE

The purpose of this study was to re-evaluate the accuracy of phenobarbital-enhanced hepatobiliary scintigraphy in differentiating biliary atresia from other causes of neonatal cholestasis.

MATERIALS AND METHODS

We retrospectively reviewed all hepatobiliary scans of infants with cholestasis at our institution from December 1990 to May 2011. Per our routine protocol the scans were obtained after pretreatment with phenobarbital (5 mg/kg/day for 5 days) to achieve a serum level of ≥15 mcg/ml. Normal hepatic uptake with no biliary excretion by 24 h was considered consistent with biliary atresia.

RESULTS

One hundred eighty-six infants with 210 hepatobiliary scans composed the study group. Forty-three (23%) infants had the final diagnosis of biliary atresia. Hepatobiliary scintigraphy was 100% sensitive, 93% specific and 94.6% accurate in diagnosing biliary atresia. Of the 186, 39/111 (35.1%) term and 2/68 (2.9%) preterm infants had biliary atresia; two of seven children with unknown gestational age also had biliary atresia. Other diagnoses included neonatal hepatitis, total parenteral nutrition cholestasis, Alagille syndrome, cystic fibrosis, choledochal cyst, hypothyroidism, alpha-1 antitrypsin deficiency and persistent cholestasis of unknown etiology.

CONCLUSION

Phenobarbital-enhanced hepatobiliary scintigraphy is highly accurate in differentiating biliary atresia from other causes of neonatal cholestasis. Biliary atresia is rare in premature infants.

Accuracy of hepatobiliary scintigraphy for differentiation of neonatal hepatitis from biliary atresia: systematic review and meta-analysis of the literature

Hepatobiliary scintigraphy is an important diagnostic modality for work-up of neonatal cholestasis. Therefore, our objective was to evaluate the literature regarding the accuracy of hepatobiliary scintigraphy in differentiating biliary atresia from non-biliary atresia causes of cholestasis (collectively called neonatal hepatitis). Our search included Medline, SCOPUS and Google Scholar. Only studies using Tc-99 m-labeled immunodiacetic acid (IDA) derivatives were included. Overall, 81 studies were included in the meta-analysis. Pooled sensitivity and specificity were 98.7% (range 98.1-99.2%) and 70.4% (range 68.5-72.2%), respectively. Factors that increased specificity included the use of radiotracers with high hepatic extraction, administration of hepatic-inducing drugs (such as phenobarbital), use of a calculated dose/kg and administration of a booster dose in cases of non-excretion of the tracer in the bowel. SPECT imaging and duodenal fluid sampling also had high specificity; however, they need further validation because of the low number of studies. Semiquantitative imaging methods do not seem to have any incremental value. We conclude that hepatobiliary scintigraphy using IDA derivatives can be very useful for diagnostic work-up of neonatal cholestasis. To improve the specificity, several measures can be followed regarding type and dose of the radiotracer and imaging protocols. Non-imaging methods seem to be promising and warrant further validation.

Biliary atresia: recent progress

Extrahepatic biliary atresia (EHBA), an inflammatory sclerosing cholangiopathy, is the leading indication for liver transplantation in children. The cause is still unknown, although possible infectious, genetic, and immunologic etiologies have received much recent focus. These theories are often dependent on each other for secondary or coexisting mechanisms. Concern for EHBA is raised by a cholestatic infant, but the differential diagnosis is large and the path to diagnosis remains varied. Current treatment is surgical with an overall survival rate of approximately 90%. The goals of this article are to review the important clinical aspects of EHBA and to highlight some of the more recent scientific and clinical developments contributing to our understanding of this condition.

Hepatobiliary Scintigraphy With SPECT in Infancy

Hepatobiliary scintigraphy (HBS) is an important investigation for the diagnosis of biliary atresia (BA) and its differentiation from causes of conjugated hyperbilirubinemia that do not require surgical intervention. Delayed imaging at 24 hours and phenobarbitone augmentation for 5 days has been required to achieve high sensitivity and specificity with current techniques. This study explores whether adding single photon emission computed tomography (SPECT) performs as well as existing methods without requiring delayed 24-hour imaging and whether the phenobarbitone premedication is necessary in all cases.

METHODS

A retrospective analysis of 105 HBS studies on 94 patients was performed. HBS included SPECT at 4 to 6 hours postinjection when no tracer was seen in the gastrointestinal tract in the first 60 minutes. This was done in 80 patients.

RESULTS

Gastrointestinal activity was seen in 14 patients within 60 minutes. For 4- to 6-hour studies, standard HBS and HBS with SPECT data showed a sensitivity of 100% for the diagnosis of BA. The specificity, accuracy, and positive likelihood ratios (PLR) were 67%, 75%, and 3 (confidence interval [CI]=2.03-4.16) for planar imaging at 4 to 6 hours and 90%, 93%, and 10 (CI=4.42-19) for 4- to 6-hour planar and SPECT imaging. When the 11 patients who had phenobarbitone stimulation were included, the results improved to 97%, 98%, and 30 (CI=7.06-80).

CONCLUSION

The addition of SPECT 4 to 6 hours postinjection of tracer significantly improves the diagnostic accuracy of hepatobiliary scintigraphy compared with planar imaging alone. This accuracy is as good as HBS performed after phenobarbitone stimulation. The combined technique of HBS with SPECT and phenobarbitone has the highest accuracy. Delayed imaging at 24 hours is usually not necessary.

Biliary atresia in infants with prolonged cholestatic jaundice: diagnostic accuracy of hepatobiliary scintigraphy

BACKGROUND

Cholestatic jaundice during infancy is one of the most problematic challenges for pediatricians. Biliary atresia (BA) and neonatal hepatitis syndrome (NHS) are major causes of cholestatic jaundices. Our aim was to compare the diagnostic accuracy of hepatobiliary scintigraphy with liver biopsy and ultrasonography in excluding BA.

METHODS

Seventy consecutive patients, all suffering from prolonged cholestatic jaundice (>1 month), were included. Laparotomy with surgical cholangiography was considered as the gold standard; however, in nine patients, based on the patient's recovery from jaundice and the normalization of laboratory values during the clinical follow-up period (=6-12 months), the diagnosis of NHS was verified and performing laparotomy was unnecessary. All patients underwent hepatobiliary scintigraphy, liver biopsy and ultrasonography and their results were compared.

RESULTS

Based on the gold standards mentioned above, 46 patients (46/70 = 65.7%) had BA. The sensitivity, specificity, PPV, NPV, and accuracy of the hepatobiliary scintigraphy in diagnosis of BA were 90%, 80%, 91.8%, 76.2%, and 84.5%, respectively. The respective values for liver biopsy were 92.5%, 88.9%, 94.9%, 84.2%, and 90.1% and for ultrasonographic analysis were 41.7%, 90.9%, 90.9%, 41.7%, and 66.3%.

CONCLUSION

Hepatobiliary scintigraphy is an important imaging technique in the diagnostic evaluation of infants with prolonged cholestatic jaundice. It is a convenient and reliable method of differentiating BA from NHS, with a diagnostic accuracy superior to that of US but slightly inferior to that of liver biopsy. Ultrasonography is the least sensitive and specific available modality and its findings should be confirmed by scintigraphy or liver biopsy.

Guideline for the evaluation of cholestatic jaundice in infants: recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition

For the primary care provider, cholestatic jaundice in infancy, defined as jaundice caused by an elevated conjugated bilirubin, is an uncommon but potentially serious problem that indicates hepatobiliary dysfunction. Early detection of cholestatic jaundice by the primary care physician and timely, accurate diagnosis by the pediatric gastroenterologist are important for successful treatment and a favorable prognosis. The Cholestasis Guideline Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition has formulated a clinical practice guideline for the diagnostic evaluation of cholestatic jaundice in the infant. The Cholestasis Guideline Committee, consisting of a primary care pediatrician, a clinical epidemiologist (who also practices primary care pediatrics), and five pediatric gastroenterologists, based its recommendations on a comprehensive and systematic review of the medical literature integrated with expert opinion. Consensus was achieved through the Nominal Group Technique, a structured quantitative method. The Committee examined the value of diagnostic tests commonly used for the evaluation of cholestatic jaundice and how those interventions can be applied to clinical situations in the infant. The guideline provides recommendations for management by the primary care provider, indications for consultation by a pediatric gastroenterologist, and recommendations for management by the pediatric gastroenterologist. The Cholestasis Guideline Committee recommends that any infant noted to be jaundiced at 2 weeks of age be evaluated for cholestasis with measurement of total and direct serum bilirubin. However, breast-fed infants who can be reliably monitored and who have an otherwise normal history (no dark urine or light stools) and physical examination may be asked to return at 3 weeks of age and, if jaundice persists, have measurement of total and direct serum bilirubin at that time. This document represents the official recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition on the evaluation of cholestatic jaundice in infants. The American Academy of Pediatrics has also endorsed these recommendations. These recommendations are a general guideline and are not intended as a substitute for clinical judgment or as a protocol for the care of all patients with this problem.

AIIMS clinical score: a reliable aid to distinguish neonatal hepatitis from extra hepatic biliary atresia

It is important to distinguish neonatal hepatitis (NH) from extra hepatic biliary atresia (EHBA) in a neonate presented with jaundice as the former is purely medical management and the latter requires surgical procedure at the earliest. The observations on the critical evaluation of the neonatal jaundice cases led us to propose AIIMS clinical score (ACS) and this retrospective study was designed to evaluate the reliability of the ACS in all the 120 babies with jaundice referred to the pediatric surgery department during the past 10 year period. The ACS described here is based on 5 clinical parameters--Age, Jaundice, Colour of urine and stool and Clinical examination of liver. The accuracy of the hepatobiliary scan (HBS) with respect to the diagnosis of EHBA in this series, as compared to per operative cholangiography (POC) which is considered as the gold standard to distinguish these conditions was only 68%. However, ACS showed a sensitivity of 91.5%, a specificity of 76.3%, positive predictive value of 89.2%, negative predictive value of 80.5% and an overall diagnostic accuracy of 86.6%. ACS is reliable to distinguish NH from EHBA at bedside.

MR cholangiography in the evaluation of neonatal cholestasis

PURPOSE

To evaluate the usefulness of magnetic resonance (MR) cholangiography in excluding biliary atresia as the cause of neonatal cholestasis.

MATERIALS AND METHODS

MR cholangiography was performed on 10 control and 16 jaundiced neonates and infants aged 3 days to 5 months. Diagnosis of biliary atresia (n = 6) was confirmed with surgery and liver biopsy, with or without surgical cholangiography. Diagnosis of neonatal hepatitis (n = 9) was confirmed with clinical follow-up until jaundice resolved. In one infant, paucity of intrahepatic ducts was diagnosed at liver biopsy. MR cholangiography was performed with respiratory-triggered, heavily T2-weighted turbo spin-echo and optional inversion-recovery turbo spin-echo sequences. Diagnosis of biliary atresia was based on nonvisualization of either the common bile duct or common hepatic duct. Cholescintigraphy with technetium 99m disofenin was performed in all 16 jaundiced patients.

RESULTS

In the 10 controls, the nine patients with neonatal hepatitis, and the one infant with paucity of intrahepatic ducts, MR cholangiography clearly depicted the gallbladder and common hepatic and common bile ducts. MR cholangiography was 100% accurate in excluding biliary atresia as the cause of neonatal cholestasis, while 99mTc disofenin cholescintigraphic findings were false-positive in four of 10 patients with nonobstructive cholestasis.

CONCLUSION

MR cholangiography can be used to depict the major biliary structures of neonates and small infants and to exclude biliary atresia as the cause of neonatal cholestasis by allowing visualization of the biliary tract.

Validation of deconvolutional analysis for the measurement of hepatic function in dogs with toxic-induced liver disease

The extraction of the hepatobiliary radiopharmaceutical 99mTc-mebrofenin (Choletec) by the liver can be used to evaluate the severity of hepatocellular disease. The hepatic parenchymal cells extract mebrofenin from the blood by the same active transport mechanism as bilirubin. The ability of the liver to extract 99mTc-mebrofenin is a measure of hepatic parenchymal cell function. In this study, we induced hepatocellular disease by administration of a hepatotoxic drug and compared a direct method of determining the hepatic extraction of 99mTc-mebrofenin to hepatic extraction fraction derived from deconvolutional analysis. We also compared both methods of calculating the hepatic extraction of 99mTc-mebrofenin to liver histopathology. Hepatic extraction fraction derived from deconvolutional analysis correlated very well to the direct measurement technique (R=0.922, p < 0.001). Both methods of determining hepatic extraction correlated well to quantitative histopathology, having the same correlation coefficient and p values. (R=-0.833, p=0.003). As the hepatic extraction 99mTc-mebrofenin decreased, the severity of the histopathologic lesions of the liver increased in a linear fashion. There was a significant correlation of the hepatic excretion T1/2 to quantitative histopathology (R=0.949, p < 0.001). The hepatic excretion T1/2 increased as the severity of the histopathologic lesions of the liver increased. Hepatic extraction (HEF) and excretion of 99mTc-mebrofenin are good predictors of the severity of hepatocellular damage in toxic induced liver disease. This study helps validate the premise that HEF derived from deconvolutional analysis is a good predictor of the actual first pass hepatic extraction of 99mTc-mebrofenin.

Hepatobiliary scintigraphy in children

Hepatobiliary scintigraphy using iminodiacetic (IDA) radiopharmaceuticals provides clinically useful information on the function of the biliary tract in a variety of pathological processes in children, including neonatal jaundice, gallbladder dysfunction, trauma, and liver transplantation. Phenobarbital premedication (5 mg/kg per day for a minimum of 5 days in divided doses) is used in infants who are being examined for neonatal jaundice to increase the accuracy of 99mTc-IDA scintigraphy in differentiating extrahepatic biliary atresia from neonatal hepatitis. Biliary atresia can be ruled out in an infant if a patent biliary tree is shown with passage of activity into the bowel. If no radiopharmaceutical is noted in the bowel on imaging up to 24 hours, distinction between severe hepatocellular disease and biliary atresia cannot be made. The literature reports 91% accuracy, 97% sensitivity, and 82% specificity for hepatobiliary imaging in the diagnosis of biliary atresia. The impairment of both intrahepatic and extrahepatic biliary drainage is an important cause of liver disease in cystic fibrosis. Hepatobiliary scintigraphy in cystic fibrosis has shown characteristic patterns of dilatation of mainly the left hepatic duct, narrowing of the distal common bile duct, gallbladder dysfunction, and delayed bowel transit. Cholecystitis in children may be acalculous. Sensitivity and specificity for the scintigraphic diagnosis of acute acalculous cholecystitis is reported to range from 68% to 93% and 38% to 93%, respectively. Cholescintigraphy in a suspected bile leak provides information generally not available with other techniques, except for direct cholangiography. If the amount of intraperitoneal accumulation of the tracer is greater than that entering the gastrointestinal tract, surgery is usually indicated. Hepatobiliary imaging in children who have undergone liver transplantation will assess graft vascularity, parenchymal function, biliary drainage, presence of a leak, and obstruction.