A Comparative Analysis of Scoring Systems and MRI for Diagnosing Acute Appendicitis in Pregnant Patients

Acute appendicitis (AA) represents the most prevalent indication for general surgical intervention during pregnancy. Despite the development of scoring systems for AA diagnosis, their validation in pregnant patient remains incomplete. Given the growing utilization of magnetic resonance imaging (MRI), evaluating the accuracy of both scoring systems and MRI in diagnosing AA during pregnancy becomes essential.

We identified pregnant patients who underwent MRI for suspected AA between 2013 and 2023. Patients were categorized into AA and control groups based on established other diagnoses or spontaneous resolution of their symptoms. A national database was used to ensure patients who did not seek further medical attention. The Alvarado, Tzanakis, RIPASA, AIR scoring systems, and MRI findings were compared between the two groups.

180 pregnant patients underwent MRI for suspected AA and 28 were diagnosed with AA upon pathology examination. Most patients in the AA group exhibited negative clinical scores (Alvarado 82%, Tzanakis 84%, RIPASA 68%, and AIR 43%). MRI was positive in 79%. Demographic characteristics and clinical presentations were similar between the AA and control groups. The positive predictive values (PPVs) of clinical scores were modest (Alvarado-38%, Tzanakis-57%, RIPASA-22%, and AIR-12%), whereas the negative predictive values (NPVs) were high (80%-86%) across all scoring systems. MRI demonstrated a PPV of 62% and an NPV of 96%.

Despite significant clinical and radiological advancements, diagnosing AA in pregnant patient remains challenging. The discrepancy between clinical scores and MRI finding underscores the complexity of AA diagnosis during pregnancy.