Acute appendicitis in children: ultrasound and CT findings in negative appendectomy cases.
BACKGROUND
To decrease the negative appendectomy rate in children, knowledge of the misleading imaging findings on US and CT in negative appendicitis cases is important.


OBJECTIVE
To evaluate the negative appendectomy rate and describe the imaging findings of US and CT that lead radiologists to misdiagnose acute appendicitis in children.


METHODS
From 2007 to 2013, 374 children operated for suspected appendicitis were proved to either have acute appendicitis (n = 348) or to be negative for appendicitis (n = 26) on pathological reports. Negative appendectomy rates were compared among imaging modalities, age groups and genders. We retrospectively reviewed US and CT findings from negative appendectomy cases.


RESULTS
The overall negative appendectomy rate was 7.0% (26/374). There were no statistically significant differences among the subgroups. The most common misleading presentations on US were sonographic tenderness (9/16, 56%) and non-compressibility (9/16, 56%). The most common misleading finding on CT were the presence of an appendicolith or hyperdense feces (5/12, 42%). Periappendiceal fat inflammation was observed in only one case of negative appendicitis on US and on CT.


CONCLUSIONS
Radiologists can misdiagnose children with equivocal diameters of appendices as having acute appendicitis when sonographic tenderness or non-compressibility is present on US and when an appendicolith or hyperdense feces is noted on CT. The possibility of negative appendicitis should be borne in mind when periappendiceal fat inflammation is absent or minimal in indeterminate cases.
Department of Radiology, Seoul National University College of Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea.
Seong Ho
SH
Kim
Young Hun
YH
Choi
Woo Sun
WS
Kim
Jung-Eun
JE
Cheon
In-One
IO
Kim
D000208:Acute Disease; D000293:Adolescent; D001062:Appendectomy; D001064:Appendicitis / Q000175:diagnosis* / Q000453:epidemiology* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D003951:Diagnostic Errors / Q000517:prevention & control* / Q000706:statistics & numerical data*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014463:Ultrasonography / Q000706:statistics & numerical data*