Validity of Focused Abdominal CT scan [FACT] for the diagnosis of acute appendicitis in clinically/sonographically equivocal cases.

PURPOSE:  To determine the validity of focused (unenhanced) abdominal CT scan [FACT] in clinically/sonographically equivocal cases of acute appendicitis taking histopathology as gold standard. SUBJECTS AND METHODS :  A cross sectional prospective study of 90 patients with clinical/sonographical suspicion of acute appendicitis referred for FACT to radiology department of Dr.Ziauddin Hospital Karachi over a period of 1 year. Out of these 90, 48 were males and 42 were females. The results were compared with surgical and histopathological findings. RESULTS: Out of 90 patients, CT diagnosis of acute appendicitis was made in 83 patients (92.22%) and 82 patients (98.79%) were diagnosed as acute appendicitis on histopathology following surgery and one patient (1.2%) was diagnosed as having non-inflamed appendix on histopathology (negative appendectomy).  CT showed no signs of acute appendicitis in 7 patients which were operated on the basis of clinical suspicion and 5 patients (true negative) showed non-inflamed appendix. (1 patient- omental infarction, 2 patients-ovarian pathology and 2 patients-ileal perforation) and 2 patients showed appendicitis on histopathology (false negative). Therefore, FACT showed 97.61% sensitivity, 83.33% specificity and 96.66% diagnostic accuracy for acute appendicitis. CONCLUSION: This study proves that focused (unenhanced) abdominal computed tomography scan (FACT) is highly accurate and quick method to exclude or diagnose appendicitis in patients who are clinically/sonographically equivocal for acute appendicitis. It is also helpful in reducing negative appendectomies. KEY WORDS: Acute appendicitis; appendectomy; focused unenhanced computed tomography scan; accuracy