Dr. Alan Wray

Signs: enlarged I dilated (>6 or 7 mm diameter)
Thick wall (TW), wall hyperenhancement (WHE) uniform or stratification
Intraluminal fluid distention, possibly gas if gangrenous
Periappendiceal inflammation / fat stranding (FS)
Extraluminal fluid, gas, or appendicolith
Appendicolith if other findings (does increase likelihood of perforation)
Cecal wall thicking

Diagnosis easy if you can visualize the appendix and there are multiple of the above
findings.

Challenging diagnosis if: - borderline or minimal dilatation
- absent periappendiceal fat stranding
- minimal retroperitoneal fat
- ruptured appendix surrounded by inflammatory mass
- periappendiceal fat stranding but normal appendix
- periappendiceal fat stranding non visualized appendix

Single diameter threshold to simplistic:
-extrapolated from US data
-normal appendix diameter is >6mm. in 42% normal, some were 10mm

Proposed scheme for diagnosing appendicitis on CT (AiR 2005,406-417)
Excluded <6mm or> 6mm with complete gas filling of lumen look elsewhere
Possible 6-10 mm w/o any other CT signs observe if symptomatic
Probable 6-10 mm with TW, WHE, no FS surgery if symptomatic
Definite > 10mm with TW, WHE, FS surgery if symptomatic

CT technique: NECT vs CECT
Advantage of CECT: - increased detection rate (90-94% CECT vs 71-78% NECT)
-More sensitive in early appendicitis when there is no FS
-More sensitive in perforated appendix
-better identifies appendix when surrounded by inflammation
CT findings in “recurrent” and “chronic” appendicits are those of early appendicitis i.e.
wall thickening and wall enhancement but no fat stranding.

Increasing frequency to treat early appendicits with antibiotics and then elective surgery.