Diagnostic Performance of MRI in Acute Appendicitis in Adult Population: A Cross-sectional Study

Abstract

Introduction: Acute appendicitis is the most common cause of acute abdomen requiring surgical intervention. The diagnosis of acute appendicitis is primarily clinical which is based upon various signs and symptoms and blood tests. Although the sensitivity of clinical evaluation is high but specificity is very low and requires further evaluation by imaging prior to surgery to avoid unnecessary negative appendectomy. In view of these, current practices involves use of imaging to diagnose acute appendicitis. Magnetic Resonance Imaging (MRI) is an imaging test that can be used to diagnose appendicitis but still not the modality of choice. Computed Tomography (CT) is the modality of choice but causes radiation hazards. MRI is an alternative cross-sectional modality with no radiation issues. Aim: To evaluate the diagnostic performance of MRI in clinically suspected cases of acute appendicitis. Materials and Methods: This cross-sectional study was conducted on 84 clinically suspected cases of appendicitis from September 2020 to November 2021 in a Central Government Hospital Jammu, India. Patients diagnosed as suspected acute appendicitis by surgical specialist underwent MRI abdomen as first line of investigation. Positive cases underwent laparoscopic evaluation followed by laparoscopic appendectomy and histopathological evaluation. The final diagnosis of histopathology report taken as gold standard for evaluation of diagnostic performance of MRI in which sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of MRI for appendicitis was calculated by using STATA Texas (Version 16) statistical analysis software. Results: Out of 84 patients, 70 were males with mean age of 26.66±6.9 years while 14 were females with mean age of 31.2±6.34 years. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, PPV and NPV of MRI for appendicitis is 96.9%, 90%, 9.69, 0.03, 96.9% and 90%, respectively at 95% confidence interval. There is a strong agreement between MRI and histopathological findings with kappa value of 0.87 (p-value <0.0001). Conclusion: The MRI has high sensitivity and specificity for acute appendicitis and has potential to become modality of choice to diagnose acute appendicitis.

Keywords

• diagnosis of appendicitis
• evaluation of appendix
• magnetic resonance imaging