Table 2 MR imaging findings of PID. DWI diffusion-weighted imaging, ADC apparent diffusion coefficient
| Tubo-ovarian disease | Morphology | T2 | T1 | Gd–T1 | DWI | ADC | Differential diagnoses |
|---|---|---|---|---|---|---|---|
| Hydrosalpinx | Fluid filled thin-walled tubular structure |  High |  Low |  No enhancement |  Low |  No restriction | - Multilocular cystic adnexal masses |
| Haematosalpinx | Dilated fallopian tube filled with blood products |  Intermediate with dark thick rim, possible “shading sign” in endometriosis |  High |  Slight enhancement of the tubaric wall |  High |  Restriction | - Endometriosis - Ectopic Pregnancy - Adnexal torsion - Trauma - Malignancy |
| Acute salpingitis | Swollen fallopian tube with intramural inflammation |  Wall thickening of the distended tube |  Low |  Wall enhancement |  High signal of the wall |  Restriction of the wall | |
| Pyosalpinx | Bilateral, serpiginous or tubular structure with purulent content and possible fluid-debris levels |  Iso-hyperintense |  Variable |  Enhancement of the thickened wall |  High |  Restriction | |
| Tubo-ovarian abscess | Loss of the normal adnexal structure, formation of a solid-cystic pus-filled inflammatory mass |  Heterogeneous high signal |  Heterogeneous low signal |  Septal and thick rim mucosal enhancement |  High signal of the wall, septa and purulent content |  Restriction of the wall, septa and purulent content | - Ovarian carcinoma - Primary fallopian tube carcinoma |
