GI Radiography

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Imaging Findings
Plain CT using oral contrast was performed. Study shows an inflamed appendix with presence of air in the lumen. Peri-appendiceal stranding of mesenteric fat is noted. Air is seen outside the lumen of the appendix, suggestive of perforation.

Diagnosis
Acute perforated appendicitis. This finding was confirmed on surgery.

Discussion
In most patients presenting with acute appendicitis, the clinical features are usually typical and imaging studies may not be indicated. However, many studies have shown that the diagnosis may be incorrect due to an alternative pathology in the right iliac fossa such as caecal diverticulitis, mesenteric adenitis-illeitis complex, torsion/ rupture of ovarian cyst, or ureteral calculi.

There is strong evidence that imaging with ultrasound and CT can be of substantial diagnostic value in the diagnosis of acute appendicitis. 

CT has become the primary imaging tool for patients suspected to have acute appendicitis. CT displays more accuracy as compared to USG in detecting acute appendicitis, as well as perforation. The percentage of negative appendectomy can be significantly reduced by USG & CT imaging. The standard protocol in imaging acute appendicitis is as follows: if ultrasound can pick up acute appendicitis, CT imaging in the patient can be avoided (although the detection of appendicular perforation is significantly higher with CT compared to USG), but if the USG is negative for acute appendicitis and cannot detect any other abnormal pathology as a cause of acute abdomen, CT should follow. Value of thinner slices (5 mm compared to 10 mm) also improves the diagnosis of acute appendicitis.

References
Karakas SP et al. Acute Appendicitis in children: comparison of clinical diagnosis with USG & CT. Pediatric Radiology 2000 Feb; 30 (2): 94-8.

Contribution
Dr. Sanjeev Mani, MD
Bandra Holy Family Hospital, Mumbai