Which investigation is most reliable for diagnosing acute appendicitis?

The CT scan is the most reliable investigation for diagnosing acute appendicitis due to its high sensitivity and specificity. It provides detailed cross-sectional images that allow direct visualization of the inflamed appendix, peri-appendiceal fat stranding, and complications like abscess or perforation. This precision helps in accurate diagnosis and timely surgical decision-making, reducing negative appendectomy rates and improving patient outcomes. While ultrasound is useful in certain populations, especially children and pregnant women, it is operator-dependent and less sensitive. Plain X-rays have very limited value in appendicitis diagnosis. MRI is useful when radiation needs to be avoided but is less accessible.
Reference: Schwartz’s Principles of Surgery, 11th Edition.