APPENDICEAL AND PERI-APPENDICEAL AIR AT CT - PREVALENCE, APPEARANCE AND CLINICAL-SIGNIFICANCE

Aim: Appendiceal air has been reported as both a sign of appendicitis and of a normal appendix both at plain radiography and computed tomogr aphy (CT), It is the aim of this investigation to determine the preval ence, range of appearances, and significance of appendiceal and peri-a ppendiceal air at CT, Patients and Methods: Appendiceal CT scans of 10 0 patients with proven appendicitis and 100 patients with a normal app endix were reviewed for the presence of appendiceal and peri-appendice al air, All cases mere correlated with surgical and pathological findi ngs or clinical follow-up, Results: In 100 CT cases of appendicitis, a ppendiceal and/or peri-appendiceal air was present in one or more form s in 31% of cases, When present, it appeared as intraluminal air bubbl es (38.7%) or air-fluid levels (22.6%), appendolith air (41.9%), intra mural air (16.1%), peri-appendiceal air bubbles (12.9%), or extralumin al air-fluid level(s) (29.0%), Intramural and extraluminal air correla ted with perforation in 60% and 100%, respectively, In 100 CT cases of a normal appendix, air was present in 57%, It was always intraluminal and appeared as small bubbles of air (52.6%), a tubular-shaped air co llection (43.9%), or as an air-fluid level (3.5%), The appendiceal lum en was either airless (43%), or minimally (32%), moderately (18%), or completely filled with air (7%). Conclusion: Air is a common finding a t appendiceal CT in both the normal and inflamed appendix, Intralumina l air is seen in both appendicitis and normal appendices, and cannot b e presumed to indicate a patent lumen and thus a normal appendix, Appe ndolith, intramural and peri-appendiceal air appear diagnostic of appe ndicitis.