European Society of Pediatric Radiology survey of perioperative imaging in pediatric liver transplantation: (1) pre-transplant evaluation.

BACKGROUND: Liver transplantation is the state-of-the-art curative treatment in end-stage liver disease. Imaging is a key element for successful organ-transplantation to assist surgical planning. So far, only limited data regarding the best radiological approach to prepare children for liver transplantation is available. OBJECTIVES: In an attempt to harmonize imaging surrounding pediatric liver transplantation, the European Society of Pediatric Radiology (ESPR) Abdominal Taskforce initiated a survey addressing the current status of imaging including the pre-, intra-, and postoperative phase. This paper reports the responses on preoperative imaging. MATERIAL AND METHODS: An online survey, initiated in 2021, asked European centers performing pediatric liver transplantation 48 questions about their imaging approach. In total, 26 centers were contacted and 22 institutions from 11 countries returned the survey. From 2018 to 2020, the participating centers collectively conducted 1,524 transplantations, with a median of 20 transplantations per center per annum (range, 8-60). RESULTS: Most sites (64%) consider ultrasound their preferred modality to define anatomy and to plan surgery in children before liver transplantation, and additional cross-sectional imaging is only used to answer specific questions (computed tomography [CT], 90.9%; magnetic resonance imaging [MRI], 54.5%). One-third of centers (31.8%) rely primarily on CT for pre-transplant evaluation. Imaging protocols differed substantially regarding applied CT scan ranges, number of contrast phases (range 1-4 phases), and applied MRI techniques. CONCLUSION: Diagnostic imaging is generally used in the work-up of children before liver transplantation. Substantial differences were noted regarding choice of modalities and protocols. We have identified starting points for future optimization and harmonization of the imaging approach to multicenter studies.

European Society of Pediatric Radiology survey of perioperative imaging in pediatric liver transplantation: (2) intraoperative imaging.

BACKGROUND: Liver transplantation is the state-of-the-art curative treatment for end-stage liver disease. Imaging is a key element in the detection of intraoperative and postoperative complications. So far, only limited data regarding the best radiological approach to monitor children during liver transplantation is available. OBJECTIVE: To harmonize the imaging of pediatric liver transplantation, the European Society of Pediatric Radiology Abdominal Taskforce initiated a survey addressing the current status of imaging including the pre-, intra- and postoperative phase. This paper reports the responses related to intraoperative imaging. MATERIALS AND METHODS: An online survey, initiated in 2021, asked European centers performing pediatric liver transplantation 48 questions about their imaging approach. In total, 26 centers were contacted, and 22 institutions from 11 countries returned the survey. RESULTS: Intraoperative ultrasound (US) is used by all sites to assess the quality of the vascular anastomosis in order to ensure optimal perfusion of the liver transplant. Vessel depiction is commonly achieved using color Doppler (95.3%). Additional US-based techniques are employed by fewer centers (power angio mode, 28.6%; B-flow, 19%; contrast-enhanced US, 14.3%). Most centers prefer a collaborative approach, with surgeons responsible for probe handling, while radiologists operate the US machine (47.6%). Less commonly, the intraoperative US is performed by the surgeon alone (28.6%) or by the radiologist alone (23.8%). Timing of US, imaging frequency, and documentation practices vary among centers. CONCLUSION: Intraoperative US is consistently utilized across all sites during pediatric liver transplantation. However, considerable variations were observed in terms of the US setup, technique preferences, timing of controls, and documentation practices. These differences provide valuable insights for future optimization and harmonization studies.

European Society of Pediatric Radiology survey of perioperative imaging in pediatric liver transplantation: (3) postoperative imaging.

BACKGROUND: Liver transplantation is the state-of-the-art curative treatment for end-stage liver disease. Imaging is a key element in the detection of postoperative complications. So far, limited data is available regarding the best radiologic approach to monitor children after liver transplantation. OBJECTIVE: To harmonize the imaging of pediatric liver transplantation, the European Society of Pediatric Radiology Abdominal Taskforce initiated a survey addressing the current status of imaging including the pre-, intra-, and postoperative phases. This paper reports the responses related to postoperative imaging. MATERIALS AND METHODS: An online survey, initiated in 2021, asked European centers performing pediatric liver transplantation 48 questions about their imaging approach. In total, 26 centers were contacted, and 22 institutions from 11 countries returned the survey. RESULTS: All sites commence ultrasound (US) monitoring within 24 h after liver transplantation. Monitoring frequency varies across sites, ranging from every 8 h to 72 h in early, and from daily to sporadic use in late postoperative phases. Predefined US protocols are used by 73% of sites. This commonly includes gray scale, color Doppler, and quantitative flow assessment. Alternative flow imaging techniques, contrast-enhanced US, and elastography are applied at 31.8%, 18.2%, and 63.6% of sites, respectively. Computed tomography is performed at 86.4% of sites when clarification is needed. Magnetic resonance imaging is used for selected cases at 36.4% of sites, mainly for assessment of biliary abnormalities or when blood tests are abnormal. CONCLUSION: Diagnostic imaging is extensively used for postoperative surveillance of children after liver transplantation. While US is generally prioritized, substantial differences were noted in US protocol, timing, and monitoring frequency. The study highlights potential areas for future optimization and standardization of imaging, essential for conducting multicenter studies.

Imaging strategy for focal nodular hyperplasia in children: long-term experience from two specialist European centres.

BACKGROUND: Focal nodular hyperplasia (FNH) in children is a rare but benign tumour, which must be differentiated from malignant entities to avoid unnecessary treatment, leading to potential morbidity. OBJECTIVES: To provide data on imaging findings of these lesions with a suggested algorithm for diagnosis, sampling and follow-up. MATERIALS AND METHODS: This retrospective review evaluated imaging of all patients diagnosed with FNH in two tertiary referral centres in Europe between 1975 and 2018. RESULTS: One hundred and four patients with 137 tumours were reviewed. The mean age at presentation was 8.2 years. The median tumour size was 5 cm (range: 0.3-29 cm). Multiple lesions were seen in 16.3% of patients. The male-to-female ratio was 1:2. CONCLUSION: FNH with typical features on imaging can be safely followed up once the diagnosis has been established. The use of contrast-enhanced ultrasound and magnetic resonance imaging allows accurate characterisation in most cases. Histological sampling is only advised when there is diagnostic doubt. Atypical arterial enhancement of FNH should prompt the search for a congenital portosystemic shunt.

Hepatic benign and malignant masses in children: a single UK tertiary centre experience.

PURPOSE: The aim of this study was to review the incidence, spectrum and investigation of liver masses presenting to our tertiary liver unit. METHODS: A retrospective single-centre cohort study of paediatric patients (age < 16 years) diagnosed with a liver mass who were investigated at a UK paediatric hepatobiliary tertiary referral centre. Data relating to the clinical findings at presentation, source of referral, diagnostic investigations and histopathology findings were recorded and analysed. RESULTS: 107 patients were identified between July 2012 and July 2019 (55 females). 69 (64%) patients had benign liver lesions, whereas the remaining 38 (36%) were found to have malignant masses. The liver lesions were most commonly detected incidentally (33%) with the second most common presentation being with palpable mass (29%). 82 (77%) patients were referred from other hospitals. All patients underwent USS, 74% MRI, 36% CT, 5% CEUS, 1% PET and 5% HIDA scan with 47% ultimately undergoing biopsy. 72% of patients had AFP measured. The most common benign liver masses were haemangioma 33 (48%), hepatic cyst 17 (25%) and FNH 12 (19%). Amongst the malignant lesions, 29 (76%) were hepatoblastoma and 3 (8%) were hepatocellular carcinoma. CONCLUSIONS: This large review series demonstrates that just over 1/3 of patients presenting to a paediatric tertiary referral centre with a focal liver lesion had neoplastic liver lesions, despite the published literature commonly stating that 2/3 of paediatric liver masses are malignant.

Paediatric gastrointestinal and hepatobiliary radiology: why do we need subspecialists, and what is new?

We present the case for subspecialisation in paediatric gastrointestinal and hepato-pancreatico-biliary radiology. We frame the discussion around a number of questions: What is different about the paediatric patient and paediatric gastrointestinal system? What does the radiologist need to do differently? And finally, what can be translated from these subspecialty areas into everyday practice? We cover conditions that the sub-specialist might encounter, focusing on entities such as inflammatory bowel disease and hepatic vascular anomalies. We also highlight novel imaging techniques that are a focus of research in the subspecialties, including contrast-enhanced ultrasound, MRI motility, magnetisation transfer factor, and magnetic resonance elastography.

Sonographic features of umbilical catheter-related complications.

Umbilical catheters are commonly used in the neonatal period for blood sampling or for administering medication or parenteral nutrition. The position of the catheter is usually confirmed with radiography. However, many complications associated with the use of umbilical catheters, such as liver collections from extravasation or vascular thrombosis, are not apparent on radiographs but can be easily diagnosed with ultrasound. This pictorial review illustrates the sonographic findings of complications that should be excluded in the sick neonate with an indwelling catheter.

2017 PRETEXT: radiologic staging system for primary hepatic malignancies of childhood revised for the Paediatric Hepatic International Tumour Trial (PHITT).

Imaging is crucial in the assessment of children with a primary hepatic malignancy. Since its inception in 1992, the PRETEXT (PRE-Treatment EXTent of tumor) system has become the primary method of risk stratification for hepatoblastoma and pediatric hepatocellular carcinoma in numerous cooperative group trials across the world. The PRETEXT system is made of two components: the PRETEXT group and the annotation factors. The PRETEXT group describes the extent of tumor within the liver while the annotation factors help to describe associated features such as vascular involvement (either portal vein or hepatic vein/inferior vena cava), extrahepatic disease, multifocality, tumor rupture and metastatic disease (to both the lungs and lymph nodes). This manuscript is written by members of the Children's Oncology Group (COG) in North America, the International Childhood Liver Tumors Strategy Group (SIOPEL) in Europe, and the Japanese Study Group for Pediatric Liver Tumor (JPLT; now part of the Japan Children's Cancer Group) and represents an international consensus update to the 2005 PRETEXT definitions. These definitions will be used in the forthcoming Trial to Pediatric Hepatic International Tumor Trial (PHITT).

Pediatric pancreatic hemangioma: a case report and literature review.

CONTEXT: The pancreas is an unusual site for a hemangioma in an infant. A child with obstructive jaundice caused by a pancreatic hemangioma is presented and management strategies for this benign tumor are discussed. CASE REPORT: A 5-month-old girl presented with a 2-week history of jaundice, pale stools and dark urine. Liver function tests confirmed obstructive jaundice. An abdominal ultrasound scan and magnetic resonance imaging showed an enhancing mass in the head of the pancreas. At laparotomy, a wedge biopsy of the pancreatic tumor was taken and a tube cholecystostomy inserted. Histological examination of the specimen revealed a pancreatic hemangioma with sclerotic features. The high volume of bile loss from the cholecystostomy proved problematic and biliary diversion with a Roux-en-y hepaticojejunostomy was therefore performed. The tumor subsequently regressed spontaneously and was no longer visible on follow-up imaging two years later. The child has since thrived. CONCLUSIONS: Pancreatic hemangiomas are rare and may cause diagnostic confusion. Pancreatic resection should be avoided since the natural history of these benign tumors is that of spontaneous involution. Various strategies can be used to manage any associated obstructive jaundice.

Preoperative imaging of left portal vein at the Rex recess for Rex shunt formation using wedged hepatic vein carbon dioxide portography.

BACKGROUND: In children with extrahepatic portal vein obstruction (EHPVO), formation of a mesentericoportal bypass (Rex shunt) restores hepatopetal flow, relieves portal hypertension, and reduces variceal bleeding and hypersplenism. The Rex shunt is created by inserting a vein graft between the superior mesenteric vein and the umbilical segment (Rex) of the left portal vein within the Rex recess of the liver. The preoperative evaluation of a patient with EHPVO includes an accurate assessment of the venous inflow and outflow. The inflow portal vein is readily assessed by ultrasound and magnetic resonance imaging. The outflow intrahepatic portal vein is harder to assess. We report our experience of patients evaluated with wedged hepatic vein carbon dioxide portography (WHVCP). METHOD: All children referred for venography from October 2001 to October 2007 were prospectively identified, and clinical and radiologic data were reviewed retrospectively. The imaging findings were correlated to findings at surgery. RESULTS: Eleven children (range, 3-14 years, median, 6 years) were referred for preoperative wedged hepatic venography. The left portal vein at the Rex recess was clearly identified in 9 patients (82%). In the other 2 patients (18%), the Rex segment was not identified despite opacification of left and right intrahepatic portal veins; this was taken to indicate an occluded segment. Wedged venography was performed with carbon dioxide in 10 patients (91%). Carbon dioxide was contraindicated in the final patient because of the presence of a ventricular septal defect. CONCLUSION: Our series demonstrates the use of WHVCP as a diagnostic tool in preoperative assessment of the Rex segment of left portal vein in children with extrahepatic portal vein obstruction.

Solitary liver cysts in children: not always so simple.

AIM: Liver cysts in children are uncommon. Many are simple and solitary and do not require intervention. However, this series demonstrates a broad range of potential pathologies, some of which are life-threatening. METHODS: All children referred to our unit during an 8-year period (1998-2005) and found to have a solitary liver cyst were prospectively recorded. Clinical, radiologic, and pathologic features were analyzed. Children with an isolated extrahepatic choledochal cyst and polycystic disease were excluded. RESULTS: Twenty-one children with a liver cyst were identified. Two had undergone unsuccessful surgical intervention before referral. There were 11 prenatally detected cysts. Median gestational age at detection was 22 weeks (19-35 weeks); only 1 was specifically characterized as a liver cyst prenatally. Six of these required surgery: 2 large simple cysts, 2 intrahepatic choledochal cysts, 1 giant complex biliary cyst causing respiratory distress, and 1 ciliated hepatic foregut cyst. Of the 5 cysts remaining under ultrasound surveillance, 4 decreased in size or resolved. In 10 children presenting between birth and 15.8 years, a liver cyst was diagnosed postnatally: 3 huge cystic mesenchymal hamartomas, 1 type V choledochal cyst, 1 hydatid cyst, and 5 simple cysts. Four of these required surgical resection. Simple cysts tended to be small and could be distinguished from other pathologies using a combination of imaging techniques (ultrasound, magnetic resonance imaging/magnetic resonance cholangiopancreatography [MRCP], radionuclide scan). Only 2 of 12 children with "simple" cysts required surgery for symptoms. However, a wide range of other cyst pathologies were found in 9 children, and although none was malignant, some were life-threatening and 7 required resection. CONCLUSIONS: Simple solitary nonparasitic liver cysts rarely cause symptoms or require surgery, but the pediatric surgeon should be aware of the wide range of other types of liver cyst in children to ensure appropriate treatment.

Ciliated hepatic foregut cyst.

A male infant was found to have a large congenital hepatic cyst, first noted in late gestation by prenatal ultrasound scan. The cyst communicated with the biliary tree and was eventually removed completely by an extended right hepatectomy. Histopathologic examination showed a thick-walled, unilocular cyst lined predominantly by ciliated, stratified squamous epithelium with an outer wall composed of smooth muscle cells and fibrous tissue. These features are diagnostic of a ciliated hepatic foregut cyst, a rare congenital malformation with histologic similarities to bronchogenic cysts. The young age of our patient, prenatal detection, large size of the cyst, and a clear communication with the biliary tree have not been previously described with ciliated hepatic foregut cysts.

Preoperative vascular imaging in pediatric liver transplantation.

BACKGROUND/PURPOSE: There is a considerable variation in the use of vascular imaging techniques in the preoperative assessment of children scheduled for liver transplantation. Duplex Doppler ultrasound scan (US), magnetic resonance angiography (MRA), and conventional angiography are used to varying extents. The authors compared the results of preoperative vascular imaging studies with operative findings to determine their accuracy and usefulness. METHODS: Results of preoperative vascular imaging in 37 consecutive children undergoing cadaveric liver transplantation were compared with operative findings. Those undergoing relatively elective transplantations were investigated by US and MRA (group 1), whereas those requiring urgent transplants were assessed only by US (group 2). RESULTS: The median age of the cohort (15 boys; 22 girls) was 4 years (19 days to 16 years) and the median weight was 17 kg (2.9 to 82 kg). In group 1 (n = 26), 20 children had a normal-caliber, patent portal vein at transplant and 6 had a narrow but patent portal vein requiring venous reconstruction in 4. The sensitivity and specificity of MRA in the detection of an abnormally narrow portal vein were 100% (6/6) and 95% (19/20), respectively. If reversed or absent flow in the portal vein on US was taken as an indication of a potentially abnormal vein, the sensitivity and specificity of Doppler US were 83% (5/6) and 95% (19/20), respectively. Magnetic resonance angiography revealed arterial anomalies in 4 children but failed to detect small accessory hepatic arteries in 5. The single patient with an aberrant vena cava was identified by MRA. In group 2 (n = 11), venous findings at operation and on US were concordant in 10 (91%) cases; one infant with reversed flow in the portal vein on US had a thrombosed vein at surgery. Magnetic resonance angiography was useful in 2 patient groups: those with reversed flow on Doppler US or suspected portal vein thrombosis in whom an abnormal portal vein was present in 86% (6/7) and infants with the biliary atresia splenic malformation syndrome who had multiple venous and arterial anomalies. CONCLUSIONS: A detailed Doppler examination of the hepatic vasculature by an experienced sonographer/radiologist provides sufficient vascular imaging for most children scheduled for cadaveric liver transplantation. Routine MRA is recommended in children with the biliary atresia splenic malformation syndrome and in those with abnormal duplex Doppler US findings. Although there are limited data in this study, MRA is also valuable in children with Budd-Chiari syndrome, liver tumors, or a previous portosystemic shunt.

Multidisciplinary management of surgical disorders of the pancreas in childhood.

OBJECTIVES: To describe the frequency and range of pancreatic disorders in children requiring surgical intervention and to highlight the importance of multidisciplinary management. METHODS: An audit of all children under 17 years of age referred with surgical disorders of the pancreas or pancreatitis to a regional pediatric gastroenterology unit in the United Kingdom during a 10-year period. A retrospective chart review of clinical features, pathology and outcome was undertaken. RESULTS: Surgical intervention was required for the following pancreatic disorders: persistent hyperinsulinemic hypoglycemia of infancy (n = 4), pancreatic tumors (n = 5), pancreaticobiliary malunion (n = 12), pancreatic trauma (n = 6) and pancreatitis (n = 10). The indications for surgery in acute pancreatitis were a persistent pseudocyst (n = 1) and treatment of an underlying cause of pancreatitis (n = 4); in chronic pancreatitis, surgery was used to treat symptomatic pancreatic duct strictures (n = 4). One child died of a progressive lymphoma but all others who underwent surgery are alive and well. All 33 children with acute pancreatitis, including four with pancreatic necrosis, survived. CONCLUSIONS: Surgery for pancreatic disorders in children is rarely required but may be necessary a) for definitive management of primary pancreatic pathology, b) to treat sequelae of acute or chronic pancreatitis and c) to treat an underlying cause of pancreatitis. There is a broad spectrum of potential pathologies. These patients are best managed by a multidisciplinary team approach.