MR imaging findings of ovarian torsion correlate with pathological hemorrhagic infarction

Aim The aim of this study was to clarify the magnetic resonance (MR) imaging findings, including diffusion-weighted imaging (DWI), of hemorrhagic infarction of ovarian torsion. Material and Methods Twelve patients presenting surgically confirmed ovarian masses with torsion were independently evaluated by two radiologists about the following MR findings: presence of ascites, uterine deviation, wall thickening on T2 weighted image (WI), recognition of twisted pedicle on T1/T2WI, and presence of wall enhancement of ovarian lesions on Gd-T1WI. The signal intensities on T1WI and DWI were compared with those of the iliopsoas muscle and the nerve root, respectively. These MR findings were statistically compared between cases of ovarian torsion with histopathologically proven hemorrhagic infarction and those without. Results Pathologically, hemorrhagic infarction of the wall was confirmed in six of twelve cases. Ascites, uterine deviation and twisted pedicle were detected in most cases whether with or without hemorrhagic infarction. The complete absence of wall enhancement was observed in only one case with necrosis. A higher signal intensity of the wall compared to controls was observed in 4/6 and 5/6 cases with infarction on T1WI/DWI, respectively. This was not observed in any cases without infarction. Three out of five cystic lesions with hemorrhagic infarction showed irregular wall thickening on T2WI, and no cystic lesion without hemorrhagic infarction did. Smooth wall thickening was observed in 2/6 cases without hemorrhagic infarction. Conclusion Pathological hemorrhagic infarction of ovarian torsion was associated with several MR imaging findings, including high signal intensity on T1WI/DWI, and irregular wall thickening on T2WI.