Objective To explore the application value of high frequency ultrasound ileocecal localization combined with plasma fibrinogen（FIB） in the diagnosis of appendicitis in children with different pathological types.Methods Sixty-two children with suspected appendicitis in our hospital were enrolled

they were examined by high-frequency ultrasound ileocecal localization combined with FIB

the children were divided into simple appendictitis

suppurative appendicitis and gangrene appendicitis according to pathological type.At the same time

20 healthy children were selected as healthy group.The difference of FIB level among groups were compared.Taken surgical and pathological results as standard

the consistency of ultrasonography in the diagnosis of appendicitis in children with different pathological types were analyzed.The accuracy

sensitivity and specificity of ultrasound combined with FIB level in the diagnosis of appendicitis in children were calculated by ROC curve.Results Sixty of 62 cases were confirmed as acute appendicitis by surgerg and pathology

the overall coincidence rate of ultrasound was 100%. However

compared with the pathological results

the diagnostic consistency of ultrasound for each type of appendicitis was general（Kappa=0.746

P=0.000）. The FIB level of children with simple

suppurative

gangrene appendicitis was gradually aggravated. The FIB level of children with appendicitis in each group was significantly higher than that of the healthy group（all P<0.05）.The area under ROC curve of FIB in the diagnosis of simple appendicitis

suppurative appendicitis and gangrene appendicitis were 0.685

0.743 and 0.785

respectively. The cut-off values were 2.37 g/L

3.68 g/L and 4.72 g/L

respectively. The sensitivity were 70.87%

72.59%

83.09%

respectively. The area under the curve of FIB combined with ultrasound ileocecal localization in the diagnosis of simple appendicitis

suppurative appendicitis and gangrene appendicitis were 0.853

0.872 and 0.895

respectively.The sensitivity were 87.50%

90.91% and 95.45%

and the specificity were 75.00%

61.22% and 73.68%

respectively.Conclusion The application of ultrasound technology is accurate in the diagnosis of appendicitis in children

but it lacks higher sensitivity for less typical appendicitis. High frequency ultrasound ileocecal localization combined with FIB can further improve various types of appendicitis in children

which has important clinical application value.