1) Identify clinical and imaging characteristics of the two most common primary pediatric hepatic malignancies: hepatoblastoma and hepatocellular carcinoma. 2) Apply an up-to-date imaging strategy for pediatric patients with hepatoblastoma and hepatocellular carcinoma.

lin.cheng@perspectum.com

Non-invasive objective diagnostic methods are urgently needed in paediatric liver diseases, such as autoimmune hepatitis (AIH) and primary sclerosing cholangitis (PSC). Iron-corrected T1 (cT1) generated from a multiparametric MRI method LiverMultiScanTM (LMS) has been shown to correlate with biopsy-assessed inflammation and fibrosis in adults [1]. The biliary tree can be analysed by a novel quantitative MRCP method, MRCP+, quantifying biliary tree volume, local duct diameters, and dilated/strictured regions. Here, we investigate whether biomarkers from LMS and MRCP+ can differentiate AIH, PSC and healthy controls in the paediatric setting.

In this prospective study, 49 paediatric patients (6-18 yrs.; AIH: n=41; PSC/AIH overlap syndrome: n=8) and 20 healthy age-matched controls underwent LMS and T2w MRCP imaging on 1.5T Siemens Avanto-fit. cT1(median, interquartile range), T2*, fat fraction, etc. were generated from LMS, and 20 biliary system metrics were generated from MRCP+; in total 25 variables were fit to logistic regression models to discriminate healthy, AIH and PSC patients. Stepwise logistic regression was used to select optimal combinations of variables to stratify individuals by disease. ROC analysis was performed for the selected predictors and their combinations.

Median cT1 and the sum of dilation severity are the optimal predictors for classifying healthy from disease group (p=0.015 and 0.013, respectively), and their combination yields the strongest predictor (AUC=0.86). Four individual predictors: fat fraction, median cT1, number of ducts with candidate strictures, and length percentage of strictured or dilated ducts, can significantly differentiate AIH from non-AIH (p=0.038, 0.003, 0.024 and 0.023, respectively); ROC curves indicate that their combination is the strongest predictor for AIH (AUC=0.83). The number of ducts with candidate strictures is the strongest predictor for discriminating PSC (p=0.003) and yields AUC of 0.85, which shows MRCP+ has the potential to objectively differentiate PSC from non-PSC.

LiverMultiScan and quantitative MRCP have the potential to aid radiologists with the assessment of paediatric liver diseases including AIH and PSC.

A novel non-invasive method using multiparametric MRI and quantitative MRCP (MRCP+) can predict healthy/AIH/PSC objectively, thus aid clinicians with the diagnosis of paediatric liver diseases.

Objective: Spectral CT can provide meaningful multi-parameter diagnostic information for clinic. However, the normal values of liver energy spectrum analysis in children are still unclear. In this study, the normal range of liver energy spectrum analysis in children with enhanced GSI was assessed by fixed-time injection of iodine contrast agent based on their body weight.

MATERIALS: Thirty children with body mass greater than 20 kg and non-hepatic lesions underwent abdominal CT enhancement from January to February 2019 were selected. All children underwent abdominal CT enhancement using the Revolution GSI model. All patients were given iodine contrast medium of 300 mg I/ml at 1.5 ml/kg and fixed contrast medium injection time of 24 seconds. (Table 1)Portal vein phase was selected for evaluation, and the delay time was fixed at 56 seconds after injection. The values of 70 KeV, iodine water value(mg/ml), water iodine value(mg/ml)and Effective-Z atomic number of 8 segments of liver were measured by Couinaud liver segmentation method(Fig.1). All data were tested by single sample T test, and the 70 KeV, iodine water value, iodine water value, Effective-Z atomic sequence value and body weight of each segment were displayed by scatter plot.

Results: The body weight of 30 samples ranged from 20.1 kg to 65.0 kg, with an average of 29.60 + 12.26 kg. Single sample T test showed no significant changes in liver energy spectrum 70 keV, iodine water value, water iodine value and Effective-Z atomic number of children with different body weight (Table 2). The scatter plot showed that the 70 keV value of each liver segment increased with the increase of body weight, while the trend lines of iodine water value, water iodine value and atomic sequence value showed a steady trend(Fig.2).

CONCLUSION: The normal CT value of children's liver parenchyma obtained by traditional enhanced examination is not reliable, but the normal values of iodine water, water iodine and Effective-Z atomic number of children's liver obtained by fixed time injection of iodine contrast agent can be trusted.

CLINICAL RELEVANCE/APPLICATION:The determination of normal values of multi-parameters of children's liver energy spectrum CT can reflect the characteristics and functional status of children's liver more comprehensively, so as to obtain more accurate and comprehensive diagnosis.

dr.alaa_yonis@yahoo.com

To evaluate the type and grade of pancreatic injury in children on CT and correlate it with management and outcome. To evaluate MRI findings of pancreatic trauma and correlate it with CT grades of pancreatic injury.

Retrospective review of children with pancreatic injury over 16 years period was performed to note mechanism of injury, injury severity score(ISS), associated abdominal injuries, management and interventions performed, and outcome. All CT and MR images were re-reviewed by two radiologists and pancreatic injuries were classified according to the American Association for the Surgery of Trauma (AAST)

Of 3,265 children presented with trauma during the study period, only 28 (0.86%) children ( M:F 19:9; mean age 7.14 yrs; age range1-15yrs) had pancreatic injury. 27 had CT of the abdomen with 26 of them performed on the day of trauma. According to AAST, there were 5 (19%) grade I, 9 (33%) grade II, 8 (30%) grade III, and 3 (11%) grade IV. No pancreatic parenchymal injury was identified in 2 (7%) patients with isolated fluid around the pancreas and mesentery. Associated injuries were seen in 93% cases. MRI was performed in 10 children on day 0-330 (median 41 day) of trauma. Pancreatic duct injury was seen on 5/10 and pseudocyst on 4/10. Signal intensity difference in pancreatic parenchyma (SIDPP) and caliber difference in duct (CDD) proximal and distal to the injury site was seen in 5/10 children, 2/10 showed only SIDPP, 1/10 showed only CDD and 1/10 showed atrophy of body and tail with ductal dilatation. Two patients died because of multiorgan injuries, 9 patients (mainly with grade III and IV injuries)underwent surgery and/or ERCP and 16 patients (mostly grade I&II)were treated conservatively. AAST grading of pancreatic injury on CT correlated with type of management (p=0.0001).

CT grading of injury correlates with management and guides intervention and/or surgery versus conservative treatment. MRI is useful for assessing ductal injury and secondary changes in pancreatic parenchyma and the PD, and it should be performed when the status of the PD is not clear on CT

CT grading of pediatric pancreatic injury is crucial as it correlates with subsequent management. MRI is useful for assessing ductal injury and secondary changes in pancreatic parenchyma.

calletoroj@email.chop.edu

To compare renal diffusion tensor imaging (DTI) parameters in patients with or without ureteropelvic junction (UPJ) obstruction.

Patients that underwent functional MR urography (MRU) with renal DTI were retrospectively selected. Kidneys deemed normal on T2-weighted images and functional parameters (i.e. time to peak, calyceal transit time and renal transit time) were used as control kidneyss and compared to kidneys with morphologic findings of UPJ obstruction and renal transit time >490 seconds. DTI included a 20-direction DTI with b-values of b=0 s/mm2 and b=400 s/mm2. Diffusion Toolkit and TrackVis were used for analysis and segmentation. TrackVis was used to draw regions of interest (ROI) covering the entire volume of the renal parenchyma, excluding the collecting system. Fibers were reconstructed using a deterministic fiber tracking algorithm. Whole kidney ROI based analysis was performed to obtain cortico-medullary measurements (Fractional anisotropy (FA), ADC and track length) for each kidney. T-tests compared means with statistical significance defined at p<0.05.

118 normal kidneys from 102 patients (mean age 8.0 ± 5.8 years; 58 males and 44 females) were compared to 18 kidneys from 16 patients (10.4 ± 6.8 years; 9 males and 7 females) with UPJ Obstruction. Mean FA values were significantly lower (0.31 ± 0.07; n=18) in kidneys with UPJ obstruction than normal kidneys (0.40 ± 0.08; n=118) (p<0.001). ADC was marginally significantly different (p= 0.01) and track length was not significantly different (p= 0.24).

DTI derived fractional anisotropy (FA) appears to discriminate between normal kidneys and those with UPJ obstruction, in the future, FA could potentially be used to monitor renal damage in patients with UPJ obstruction obviating the need for contrast administration and thus shortening exam length.

DTI of the kidney is feasible in a clinical setting and can provide complementary functional information in patients with UPJ obstruction.

g.chambers@nhs.net

Describe imaging features of pediatric focal nodular hyperplasia (pFNH) in a large cohort and propose clinical, radiological and surgical management

Imaging of 87 children with 105 pFNH lesions from 1977-2018 were evaluated by 2 radiologists for features such as size, number, echogenicity/density/intensity, presence of central scar and enhancement pattern. All patients referred from 1996 were assessed for symptoms, risk factors, initial management, follow up and outcome. Results were used to form management guidelines for future patients.

87 patients (70% female) with 105 lesions were analysed. 8 patients (9.2%) had multiple pFNH. Size ranged from 1-13.7cm. Ultrasound (US) imaging was available for 82 patients, CT in 32 patients and MRI in 44 patients. pFNH are iso-/hyperechoic on US (68/82) with arterial Doppler flow in 75% (36/48). Contrast US shows typical enhancement in 86% (6/7). On CT, pFNH are iso-/hypodense (30/32) pre-contrast with typical enhancement in 79.5% (31/39). On MRI, pFNH are iso-/hypointense on T1 (37/44), iso-/hyperintense on T2 (42/44), hyperintense on diffusion (23/28) and show typical enhancement in 71.8% (28/39). 50 patients were referred after 1996: 74% females, mean age 8.9 years old with 46% symptomatic. Mean length of follow-up was 5.2 years. Mean long axis diameter pFNH lesion at diagnosis was 5.9cm. 74% of patients underwent watchful waiting and 26% surgical resection. Of the watchful waiting patients 25 (67.5%) had lesional growth, 6 (16.2%) showed stability and 6 (16.2%) showed lesional decrease. 9 (24.3%) of the observed patients eventually had surgery. 92% of patients were asymptomatic at the end of follow-up with no significant difference in the surgical and observational groups.

pFNH is a rare tumour which can be large, multiple, atypical on imaging and a weaker predisposition for females than in adults. Atypical cases require histological confirmation to exclude differential diagnoses such as adenoma. We propose a conservative approach to treatment given that surgery has risks and complications. Surgery should be considered first line in patients presenting with compressive abdominal symptoms.

These results offer a clinico-radiological strategy for the diagnosis and management of these rare pediatric liver tumours, which will help clinicians triage their patients towards wathcful wating, radiological intervention or surgery.

judy.squires@chp.edu

1) Learn basic principles for performing contrast-enhanced ultrasounds for focal liver lesion evaluation. 2) Identify imaging characteristics of common focal liver lesions, including how to distinguish benign from malignant lesions.

anupindi@email.chop.edu

1) Define the current terminology of subtypes of pancreatitis in children. 2) Describe the current and emerging imaging techniques for pediatric pancreatitis. 3) Examine the common congenital anomalies which lead topancreatitis.

879760449@qq.com

To determine if characteristic features on computed tomographic and (or) magnetic resonance imaging can differentiate pancreatoblastoma(PB) and solid pseudopapillary tumours (SPTs) of the pancreas in children.

The clinical and imaging data of 34 children with pancreatoblastoma(PB) and solid pseudopapillary tumours (SPTs) that were confirmed by surgeries were retrospectively analyzed,including 20 cases of SPTs and 14 cases of PB. The size, margin, calcification, hemorrhage, proportion of solid component, intratumoral vessels, encapsulation of the tumor, dilatation of pancreatic duct, peripancreatic vessel invasion, distance metastasis status, and the apparent diffusion coefficient(ADC) values of the two groups were analyzed and key diagnostic points were identified. Statistical analysis was performed using the χ2 test and the Student's t test.

All children with SPTs were more than 5 years old which was significant older than children with PB( p=0.000);There was no significant sex differential between SPTs and PB(p=0.148). Mean maxisimum tumour size in PB was signifcantly larger than SPTs (p=0.001). PB presented with more calcification(p=0.002), intratumoral vessels(p=0.000), vascular invasion(p=0.000) and distant metastasis(p=0.003) comparison with SPTs, while SPTs were more prone to hemorrhage(p=0.033) and had a higher mean ADC value(p=0.019). There were no significant statistical differentiation in tumor capsule(p=0.442), dilatation of pancreatic duct(p=1.000), and cystic degeneration area over than 50% of tumor volume(p=0.719) between two groups of tumors.

CT and (or) MRI is helpful in the differential diagnosis of pancreatoblastoma(PB) and solid pseudopapillary tumors (SPTs) of pancreas in children.Pancreatoblastomas were usually presented as large tumors with calcification,intratumoral vessel,vascular invasion and distant metastasis comparison with SPTs,while SPTs had a tendency to intratumoral hemorrhage and higher ADC values.

SPT is the most common pancreatic tumor in children; And pancreatoblastoma(PB) is considered the most common malignant tumor in children in the first decade. Differential diagnosis of these two tumors is very important for clinical because of different prognosis. Our result demonstrated that CT and (or) MRI is helpful in the differential diagnosis of PB and SPTs of the pancreas in children.

xingsipei14@163.com

This study used a fixed-time injection of iodine contrast agent based on the body mass of the child to evaluate the normal range of the analysis of the pancreatic energy spectrum of the children in the GSI spectrum enhancement examination.

Thirty children with a body mass greater than 20 kg and a non-pancreatic lesion with abdominal CT enhancement were selected from 2019.1 to 2019.2. All patients underwent GSI spectroscopy CT enhancement examination using GE revolution CT. Four scan protocols (four groups) were scanned according to body weight (Table 1), and a uniform contrast protocol was used: 300 mgI was given according to the weight of the child per ml Iodine contrast agent 1.5ml/kg, and use 24s fixed contrast injection time method. All patients underwent an image evaluation of the portal vein phase. The phase delay time was 56s after the contrast agent injection. The ROI of the head, body and tail of the pancreas was selected (Fig. 1), and the four energy spectrum analysis values of 70KeV, iodine water value, water iodine value and atomic number were measured. The single sample statistics were drawn using SPSS software. (Table 2).

This indicates that the four energy spectrum analysis values of 70KeV, iodine water value, water iodine value and atomic number obtained are relatively fixed in children with pancreatic energy spectrum GSI enhanced CT examination using fixed-time injection of iodine contrast agent.

Contrast fixed injection time method according to different body weight to give different doses of iodine contrast agent, can ensure that children of different body weight under the contrast agent program and relatively fixed weight of iodine contrast agent, iodine contrast agent dose absorbed by human tissue Not affected by weight. Under the scanning scheme and the contrast agent scheme, the iodine dose is relatively constant, and is not affected by body weight, and the energy spectrum analysis value is relatively fixed, and the result has credibility under the scheme.

Therefore, under this method, the energy spectrum analysis value can be used as a reference value for the normal energy spectrum analysis of the GSI enhanced CT examination of the pancreatic energy spectrum for the clinician to perform functional and component diagnosis based on the numerical value.

alex.menys.09@ucl.ac.uk

A relationship between small bowel motility and inflammatory activity in Crohn's Disease is now well described in adults against endoscopic and histopathological measures of activity. This retrospective study explores this relationship between terminal ileal (TI) motility in children against a symptomatic endpoint.

A review of a pediatric hospitals imaging database was performed to identify subjects with good quality MRE studies and a clinical appointment ±1mo to determine a clinical score for disease activity (PGA, a 4 point score 1 = no disease to 4 = severe). 68 subjects were identified (mean age 13.2, range 6 to 19) with dynamic 'cine' imaging through the terminal ileum. The dynamic imaging was processed, blind to any clinical data, with a previously validated motility assessment algorithm (GIQuant®, Motilent, London, UK). A consultant radiologist delineated the TI on each subject within 5cm of the ileocecal valve and the motility score derived. The TI was used as an repeatably identifiable reference to enable comparison between subjects. The TI motility score was correlated against the symptom score and the cohort split into clinically active disease PGA >1 and non-active = 1. The mean difference between groups was assessed with U-Test.

The median TI motility was 0.2 (range 0 to 0.6) and the median PGA symptom score was 1 (range 1 to 4). The correlation between the two measures was R = -0.32, P = 0.011. The mean motility score of those with active disease was 0.18 , compared to 0.26 for those without active disease, a statistically significant difference of 0.08, P = 0.003.

Subjects with reduced terminal ileal motility appeared to have a higher symptom load. These findings broadly support results in adult populations and comparison with an endoscopic or histopathological endpoint at the TI represents an important next step.

MRI is non-invasive, safe and widely available option for monitoring Crohn's Disease activity making it an ideal test for subjects destined to undergo scanning for the rest of their lives. Biological therapy is now widely used in children to control inflammation. These drugs are very expensive. A rapid and objective biomarker of disease response like motility, espeically one that does not require gadolinium, is imporant to driving efficient spending in IBD.

jsandber@stanford.edu

Current standard of practice for evaluating bowel inflammation in Crohn's disease (CD) includes magnetic resonance imaging (MRI). Despite MRI having a high sensitivity/specificity for detecting bowel wall inflammation; it requires oral contrast, long scan times, high costs and sedation in younger patients. Alternatively, contrast enhanced ultrasound (CEUS) provides quick evaluation of bowel at bedside without the need for sedation. The purpose of our study is to compare CEUS to MRI for evaluation of bowel inflammation in Crohn's disease in pediatric patients.

Between April 2018 and January 2019, 20 patients, 11 females and 9 males (mean 14.2yr [8mo-20.7yr]) with biopsy proven CD, underwent contrast enhanced MRI (GE Discovery) and CEUS. Greyscale US (Philips, GE or Siemens machine, 9-18L probes) was performed to identify thickened bowel loops, followed by injection of Lumason contrast (Bracco Imaging). CEUS was interpreted by a single radiologist with 15 years experience while the MRIs were interpreted by numerous pediatric radiologists. Enhancement, mucosal disruption, mucosal/submucosal wall thickness, and pericolonic inflammation were noted. Concordance between MRI and CEUS was assessed retrospectively.

CEUS sensitivity to detect bowel inflammation when seen on MRI was 100%. Enhancement concordance was 85% (17/20). The 3 discordant biopsy proven CD cases showed no enhancement or wall thickening on MRI but had thickened enhancing bowel loops on CEUS. Wall thickness was not statistically significant between MRI and CEUS (p=0.25), confidence in accurately measuring mucosal/submucosal layers was possible only with US. Mucosal disruption was more often seen with US (n=10) than MRI (n=2). Pericolonic inflammation was found equally (n=13).

In this small sample of pediatric patients, CEUS was superior to MRI in detecting bowel inflammation in CD patients. Bowel US involves using high frequency linear US probes providing detailed evaluation and visualization of bowel wall layers. MRI remains essential for initial diagnosis of CD as CEUS has a limited field of view. Thus, CEUS may have great potential for follow-up.

Contrast enhanced ultrasound has the potential to enhance our ability to detect bowel inflammation and avoid inherent limitations of MRI.

drgovindchavhan@yahoo.com

1) To explain hemodynamic disturbances associated with elevated systemic venous pressure in children with Fontan surgery. 2) To discuss abdominal complications in children with failing Fontan circuit. 3) To discuss role of imaging and strategies to optimally image these complications.