Pelvic inflammatory disease: evaluation of diagnostic accuracy with conventional MR with added diffusion-weighted imaging

To determine the incremental value of magnetic resonance (MR) diffusion-weighted (DW) imaging for the diagnosis of pelvic inflammatory diseases (PID). We added DW sequences to conventional MR imaging in 187 patients with clinically suspected PID. The imaging findings included shape, signal intensity on T1-weighted, T2-weighted, and DW imaging, shade in the peripheral lesions, free pelvic fluid, and lymphadenopathy. Laparoscopic and pathological findings confirmed the diagnosis in all patients. Conventional MR findings were consistent with a diagnosis of PID in 90.7% (117/129) and of non-PID in 93.3% (28/30) of the 159 patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of conventional MR imaging findings vs. the addition of DW imaging to conventional MR protocols for predicting PID were 90.7%, 93.3%, 98.3%, 70.0%, and 91.2% and 98.4%, 93.3%, 98.4%, 93.3%, and 97.5%, respectively. The addition of DW sequences to conventional MR imaging can improve the accuracy of diagnosis in PID.