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.