Objective
 The increase in obesity in children has caused
 nonalcoholic fatty liver disease to become the most
 important chronic liver disease in the pediatric age
 group. In this study, we aimed to evaluate the portal
 diameter and blood flow velocity in obese children with
 fatty liver (NAFLD) and to compare them with normal
 healthy children.
 Material and Method
 71 obese adolescent patients aged 10-18 years were
 divided into two groups (NAFLD group and non-
 NAFLD group) according to the presence of elevated
 transaminases and the presence of hepatosteatosis
 on ultrasound. 30 healthy adolescents were included
 in the study as the control group. Blood samples
 were taken from each patient for fasting glucose,
 insulin, transaminases, and thyroid functions. Insulin
 resistance was calculated using the HOMA index.
 Portal vein measurements were performed from the
 main portal vein before bifurcation.
 Results
 The portal vein diameter (8.5 ± 0.9 mm) of the NAFLD
 group was statistically significantly wide compared
 to both the control group (7.8 ± 2.0 mm) and the
 non-NAFLD obese group (7.6 ± 1.1 mm) (p= 0.004)
 and (p= 0.002). There was no significant difference
 between the non-NAFLD obese group and the control
 group (p=0.460, p=0.214). There was no significant
 difference between the groups in terms of portal vein
 Vmax, Vmin, RI, S/D. Although there was no difference
 in portal vein diameter in the obese groups classified
 according to insulin resistance, Vmax (33.9 ± 10.3 and
 28.6 ± 10.6 cm/sec, p= 0.03) and Vmin (24.8 ± 6.2 and
 20.5 ± 5.5 cm/sec) were significantly different in the
 insulin resistance group.
 Conclusion
 In this study, it was determined that portal vein diameter
 and flow velocities (Vmax and Vmin) increased in
 obese adolescents with NAFLD. Thus, we suggest
 that resistance develops in hepatic venous flow due
 to hepatic portal vein steatosis, especially in obese
 patients with insulin resistance in adolescence. This
 finding suggests that when fatty liver continues, portal
 diameter will increase in adulthood, leading to portal
 hypertension.