Balancing Radiation and Accuracy: Is Low-Dose Computed Tomography Necessary after Conclusive Ultrasonography in Acute Appendicitis?

Background: Acute appendicitis requires timely diagnosis to prevent complications and unnecessary surgery. While ultrasonography (USG) is widely used as the first-line modality, computed tomography (CT) offers higher diagnostic accuracy at the cost of radiation exposure. Low-dose CT (LDCT) has emerged as an alternative; however, its necessity following a conclusive USG remains uncertain. Materials and Methods: This prospective study included 80 patients aged 15–45 years with suspected acute appendicitis. All underwent graded compression USG followed by low-dose noncontrast CT (~3 mSv). Imaging findings were correlated with histopathology. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated, and receiver operating characteristic curves were generated. Results: Histopathology confirmed appendicitis in 85% of cases. USG demonstrated sensitivity of 92.7%, specificity of 75.0%, and accuracy of 90.0%, whereas LDCT showed sensitivity of 85.3%, specificity of 58.3%, and accuracy of 81.3%. There was no statistically significant difference between the modalities ( P > 0.05). LDCT was superior in detecting complications. Conclusion: USG demonstrates high diagnostic accuracy and can serve as the primary imaging modality. LDCT should be reserved for equivocal cases or suspected complications, supporting a “USG-first, conditional LDCT” approach to minimize radiation exposure.