False-negative appendicitis at ultrasound: nature and association.
The objective was to describe nature and factors associated with false-negative ultrasound (US) for adult appendicitis. Patients with pathologically proven appendicitis and pre-operative US from January 2011 to May 2013 were included in this retrospective case-control study. They were divided into true-positive and false-negative groups, matched by age and gender. There were 112 patients (40 men, mean age = 40 y, 56 true positives) included. Two factors were found differ significantly: abdominal wall thickness and pain score. Greater abdominal wall thickness (18.6 mm vs. 14.9 mm, p = 0.001) and lower pain score (6.6 vs. 7.5, p = 0.018) were statistically associated with false negativity. The two groups did not differ significantly in terms of weight, height, body mass index, symptom duration, Alvarado score, US examination time, appendix position/size, perforation rate and operator. In conclusion, lower pain score and increased abdominal wall thickness are associated with false negativity in US examinations.
Department of Radiology, Ramathibodi Hospital and Mahidol University, 270 Rama VI Rd, Ratchatewi, Bangkok 10400, Thailand.
Patwadee
P
Piyarom
Department of Radiology, Ramathibodi Hospital and Mahidol University, 270 Rama VI Rd, Ratchatewi, Bangkok 10400, Thailand. Electronic address: Rathachai@gmail.com.
Rathachai
R
Kaewlai
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000000981:diagnostic imaging*; D001065:Appendix / Q000000981:diagnostic imaging*; D016022:Case-Control Studies; D003951:Diagnostic Errors / Q000517:prevention & control*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods
Abdominal wall thickness; Appendicitis; False negativity; Pain score; Ultrasound