Texture Analysis of Uterine-Derived T2-Weighted Imaging in Patients With Primary Dysmenorrhea Across Different Menstrual Phases

Purpose: Primary dysmenorrhea (PDM) affects 45%–95% of menstruating women. However, the mechanism of PDM is still unclear; abnormal uterine structure may be one of the causes of PDM. But the subtle structural changes of the uterus during the menstrual phase cannot be seen by the naked eye. Here, we perform magnetic resonance imaging (MRI) texture analysis to precisely quantify the subtle changes of the uterus in patients with PDM. Methods: Fifty-one patients with PDM and 49 healthy controls (HCs) underwent pelvic MRI during the menstrual and periovulatory phases and were included in this study. Sagittal T2-weighted images were uploaded into 3D slicer software for textural analysis of uterine structures (myometrium, junctional zone, endometrium). SPSS software was used for all statistical analyses of demographics and texture parameters. Results: We found a phase × group interaction in small-zone emphasis (SZE) (p = 0.006, (Formula presented.) = 0.144) and zone percentage (ZP) (p = 0.007, (Formula presented.) = 0.148). The changes of textural characteristics of the myometrium were smaller in patients with PDM from preovulatory to menstrual phase compared with HCs. Additionally, we found the changes in SZE and ZP in the myometrium across the menstrual cycle were positively correlated with pain intensity in patients with PDM during menstrual phase. Conclusions: Our study demonstrates that patients with PDM exhibit persistent subtle uterine abnormalities across the menstrual cycle, suggesting that PDM represents a continuous pathophysiological state rather than a transient menstrual-phase disorder. We propose texture analysis may provide a novel objective method for the early detection and prevention of PDM.