Diagnosing adenomyosis with MRI: a prospective study revisiting the junctional zone thickness cutoff of 12 mm as a diagnostic marker

Objectives To assess the diagnostic accuracy of a junctional zone (JZ) thickness of >= 12 mm and morphological features of the JZ in MRI in diagnosing adenomyosis in a premenopausal study population. Methods This single-center, prospective observational study consecutively enrolled 93 premenopausal women suffering from a benign gynecological condition, from September 2014 to August 2016. Institutional review board approval and written consent were obtained. All participants underwent MRI and hysterectomy with a histopathological examination. MR images were evaluated in a blinded fashion by two independent readers. The maximum junctional zone thickness (JZ(max)), presence of JZ(max) >= 12 mm, and any irregular appearance of the JZ (defined as irregular outer or inner borders, focal thickening, presence of high-intensity signal foci, or fingerlike indentations at the inner border) were documented, and the diagnostic performance was evaluated with the AUC, chi-square test, and multiple regression. Results Adenomyosis was histopathologically confirmed in 57 (61%) of the women. JZ(max) was not positively correlated with adenomyosis diagnosis (AUC=0.57, p=0.26) and did not differ significantly between those with and without adenomyosis (10.3 vs 10.1 mm, p=0.88), nor was a cutoff of JZ(max) >= 12 mm (n=30/57 (53%) vs n=16/36 (44%), p=0.29). The presence of an irregular JZ showed the best association with adenomyosis among the evaluated signs (sensitivity 74% (95% CI, 60, 85); specificity 83% (95% CI, 67, 94) (p<0.001)). Conclusions JZ(max) was not correlated with adenomyosis in the present premenopausal study population, but direct signs of adenomyosis such as irregularities of the JZ provided a good diagnostic accuracy.