Appendicitis: use of arrowhead sign for diagnosis at CT.
OBJECTIVE
To determine the frequency of collection of a contrast medium in the upper portion of the cecum, which the authors call the arrowhead sign, on computed tomographic (CT) scans of the lower abdomen and to assess the sensitivity and specificity of this sign for appendicitis.


METHODS
One hundred consecutive patients clinically suspected of having appendicitis prospectively underwent helical CT limited 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 present in 17 of 56 cases (30%) of appendicitis and in no case of excluded appendicitis. It allowed the unequivocal diagnosis of appendicitis in four cases (7%) of otherwise non-specific right lower-quadrant inflammation and in one case (2%) of subtle appendicitis seen at CT.


CONCLUSIONS
The arrowhead sign is an often present, highly specific sign of appendicitis that can add specificity to the diagnosis of right lower-quadrant inflammatory processes at CT.
Rao
P M
PM
Department of Radiology, Massachusetts General Hospital, Boston 02114, USA.
Wittenberg
J
J
McDowell
R K
RK
Rhea
J T
JT
Novelline
R A
RA
D001064:Appendicitis / Q000000981:diagnostic imaging*; D001466:Barium Sulfate; D002432:Cecum / Q000000981:diagnostic imaging; D003287:Contrast Media; D003974:Diatrizoate Meglumine; D006801:Humans; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D001466:Barium Sulfate; D003974:Diatrizoate Meglumine