Objective: This retrospective study evaluated the diagnostic efficacy of magnetic resonance imaging (MRI) for identifying acute appendicitis during pregnancy.
Patients and methods: This retrospective study enrolled a total of 46 pregnant patients with clinically suspected acute appendicitis who underwent 1.5 T MRI and received a final pathological diagnosis. We evaluated the imaging characteristics associated with patients diagnosed with acute appendicitis, including the appendix diameter, the appendix wall thickness, intra-appendiceal fluid collection, and peri-appendiceal fat infiltration. A bright appendix on T1-weighted 3-dimensional imaging was identified as a negative sign for appendicitis.
Results: Peri-appendiceal fat infiltration had the highest specificity of 97.1% for diagnosing acute appendicitis, whereas increasing appendiceal diameter had the highest sensitivity of 91.7%. The cut-off values for increasing appendiceal diameter and appendiceal wall thickness were 6.55 mm and 2.7 mm, respectively. Using these cut-off values, appendiceal diameter had a sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) of 91.7%, 91.2%, 78.4%, and 96.9%, respectively, whereas these values for appendiceal wall thickness were 75.0%, 91.2%, 75.0%, and 91.2%. The combination of increasing appendiceal diameter and appendiceal wall thickness resulted in an area under the receiver operating characteristic curve value of 0.958 with Se, Sp, PPV, and NPV values of 75.0%, 100.0%, 100.0%, and 91.9%, respectively.
Conclusions: All five MRI signs examined in this study had significant diagnostic value for detecting acute appendicitis during pregnancy, with p-values <0.01. The combined use of increasing appendiceal diameter and appendiceal wall thickness displayed the excellent ability to diagnose acute appendicitis in pregnant women.