707 MRI Identifies Unsuspected Liver Dysfunction in Patients After Fontan Procedure

Abstract

Since the development of the original NAFLD activity score (NAS), it became evident that pediatric NAFLD has a distinct histopathological pattern including the presence of portal inflammation (PI). The aim of this study was to develop and validate a new grading score for Pediatric NAFLD that takes into account the presence of PI and the weight of each histological feature. Methods: Our training set consisted of 203 pediatric patients with biopsy-proven NAFLD. The diagnosis of nonalcoholic steatohepatitis (NASH) versus not NASH was based on Brunt criteria. The individual histological features of NAFLD were scored as follows: steatosis (0-3), lobular inflammation (0-3), ballooning (0-2), and portal inflammation (0-2; 0= no PI, 1= mild PI, 2= more than mild). Logistic regression analysis was performed to apply weight to each histological feature (to improve correlation with NASH). The new score was called the Pediatric NAFLD Histological Score or PNHS. A p value < 0.05 was considered statistically significant. The validation set consisted of 100 children with biopsy-proven NAFLD. Results: The mean age of the initial cohort was 12.4 ± 3.4 years, the median BMI percentile was 97% (94%-98%), and significant fibrosis (fibrosis stage ≥ 2) was present in 26 patients (12.8%). NASH was diagnosed in 135 patients with a mean NAS of 4.5 ± 1.4. The mean PNHS in the NASH group was 89 ± 20.5 compared to 21.9 ± 24.5 in not NASH group, p< 0.001. PNHS correlated with the presence of NASH according to pathologist diagnosis better than NAS, p= 0.011. The area under the ROC curve (AUC) for diagnosis of NASH was 0.96 for PNHS. Similar findings were noted in the validation set with AUC of 0.94. Conclusion: PNHS may be used for histological grading of pediatric NAFLD with better correlation with the presence of NASH than NAS. The utility of this score in other populations and in therapeutic trials should be further investigated.