Sensitivity and specificity of the individual CT signs of appendicitis: experience with 200 helical appendiceal CT examinations.
OBJECTIVE
Our goal was to determine the sensitivity, specificity, and diagnostic value of individual signs at helical appendiceal CT.


METHODS
Two hundred helical appendiceal CT scans (100 appendicitis and 100 normal appendix cases) were interpreted for individual signs of appendicitis. Scan findings were correlated with appendectomy or clinical follow-up results.


RESULTS
Individual CT signs identified and their sensitivity and specificity, respectively, included fat stranding (100%, 80%), enlarged (> 6 mm) unopacified appendix (93%, 100%), focal cecal apical thickening (69%, 100%), adenopathy (62%, 66%), appendolith(s) (44%, 100%), arrowhead sign (23%, 100%), paracolic gutter fluid (18%, 86%), abscess (11%, 100%), cecal bar (10%, 100%), extraluminal air (8%, 97%), phlegmon (7%, 99%), ileal (3%, 86%) or sigmoid (3%, 95%) wall thickening, and diffuse cecal wall thickening (0%, 91%).


CONCLUSIONS
Individual appendiceal CT signs of appendicitis vary in sensitivity, specificity, and thus diagnostic value. An enlarged appendix with periappendiceal fat stranding occurs in 93% of appendicitis CT cases. Less common but specific signs [cecal apical changes, appendolith(s) are usually present in the remaining appendicitis cases. Some signs seen with appendicitis (adenopathy, fat stranding, adjacent bowel wall thickening, fluid) can also be noted with alternative conditions, and in these cases normal appendix identification is the key to excluding appendicitis.
Rao
P M
PM
Department of Radiology, Massachusetts General Hospital, Boston 02114, USA.
Rhea
J T
JT
Novelline
R A
RA
D000038:Abscess / Q000000981:diagnostic imaging; D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000388:Air; D001062:Appendectomy; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000601:surgery; D001065:Appendix / Q000000981:diagnostic imaging; D001202:Ascitic Fluid / Q000000981:diagnostic imaging; D002137:Calculi / Q000000981:diagnostic imaging; D002429:Cecal Diseases / Q000000981:diagnostic imaging; D002481:Cellulitis / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007077:Ileal Diseases / Q000000981:diagnostic imaging; D008297:Male; D008640:Mesenteric Lymphadenitis / Q000000981:diagnostic imaging; D008875:Middle Aged; D011446:Prospective Studies; D011856:Radiographic Image Enhancement / Q000379:methods*; D012680:Sensitivity and Specificity; D012810:Sigmoid Diseases / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media