APPENDICITIS - USE OF ARROWHEAD SIGN FOR DIAGNOSIS AT CT

PURPOSE: To determine the frequency of collection of a contrast medium in the upper portion of the cecum, which the authors call the arrowhe ad sign, on computed tomographic (CT) scans of the lower abdomen and t o assess the sensitivity and specificity of this sign for appendicitis . MATERIALS AND METHODS: One hundred consecutive patients clinically s uspected of having appendicitis prospectively underwent helical CT lim ited to the lower abdomen. Contrast media were administered orally and by means of an enema. Each scan was reviewed for the arrowhead sign, and the findings were correlated with surgical and pathologic results or clinical follow-up findings. RESULTS: The arrowhead sign was presen t in 17 of 56 cases (30%) of appendicitis and in no case of excluded a ppendicitis. It allowed the unequivocal diagnosis of appendicitis in f our cases (7%) of otherwise non-specific right lower-quadrant inflamma tion and in one case (2%) of subtle appendicitis seen at CT. CONCLUSIO N: The arrowhead sign is an often present, highly specific sign of app endicitis that can add specificity to the diagnosis of right lower-qua drant inflammatory processes at CT.