Hansen et al correlated CT findings with histologic severity of acute appendicitis. The authors are from the Mayo Clinic at Scarsdale, Arizona.


CT findings associated with severe appendicitis:

(1) extraluminal air

(2) diameter of the appendix

(3) fat stranding

(4) fecalith

(5) dependent fluid

(6) radiologist's opinion of the findings


Appendiceal diameter was divided into groups as:

(1) < 5 mm

(2) 5 - 9 mm

(3) 10 - 14 mm

(4) > 15 mm

Based on my personal experience a diameter <= 5 mm only rarely shows inflammation while a diameter >= 9 mm almost always does.


Additional common findings (Figure page 1305):

(7) abscess or phlegmon

(8) appendiceal wall enhancement

(9) lymphadenopathy

(10) focal apical cecal thickening

(11) arrowhead sign (collection of contrast medium in the upper portion of the cecum)

(12) cecal bar

(13) terminal ileal wall thickening


Other findings:

(14) sigmoid wall thickening

(15) diffuse cecal wall thickening



• The histologic grading scoring system may be suboptimal. Grade 1 was minimal, Grade 3 was extreme (gangrenous) and Grade 2 is everything in-between. Needless to say, most patients fit into Grade 2.

• The authors refer to an ordinal logistic regression model but do not provide the details.


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