A Layer of Decreased Apparent Diffusion Coefficient at the Endometrial-Myometrial Junction in Uterine Adenomyosis

Abstract

Objectives:To assess the detectability of a low-signal-intensity line within adenomyosis lesions adjacent to the endometrium on apparent diffusion coefficient (ADC) maps, and to establish correlations between these lesions and their possible causes, and more particularly the hormonal changes and magnetic resonance (MR) factors.Materials and methods:MR images were obtained from 110 patients with adenomyosis (age 30–57 y.o.) using 3.0 T or 1.5 T MR units. Recognition of the low-signal-intensity line on ADC map was scored using confidence level. The correlation between recognition of the line and the following factors were examined: magnetic field strength, age group, menstrual cycle phases, history of delivery, and hormonal treatments. Presence of the structure corresponding to the low-signal-intensity line on ADC map was evaluated pathologically in the cases that underwent surgery.Results:The low-signal-intensity line visible on ADC map was recognized in 55/110 patients. The visibility of the line was not significantly related to hormonal status, age, history of delivery, or magnetic resonance imaging (MRI) magnet strength. There were no corresponding pathological structures.Conclusion:One half of the adenomyosis patients showed discrepant appearances in T2-weighted (T2WI) vs. ADC map, but no significant relationship with hormonal changes was found in this study. This result may suggest that the low-signal-intensity line within the junctional zone may be related to a functional phenomenon.

Uterine junctional zone and adenomyosis: comparison of MRI, transvaginal ultrasound and histology

“…One study suggested that differences in a thin layer of restricted water diffusion surrounding the endometrium on an ADC map of patients with adenomyosis might be responsible for changes of the appearance in JZ in adenomyosis. However, this layer was seen in only half of the patients and no pathologic substrate of changes in this layer was found after hysterectomy 63 . Due to physiological, peristaltic and hormonal variations of the JZ in MRI, a strict cut‐off of the JZ thickness as a diagnostic criterion should be used with care in the diagnosis of adenomyosis.…”

“…We identified 27 studies investigating MRI observations of the JZ 4,6,17,26,28,30,36–56 and 12 6,50,51,54,57–64 describing changes due to adenomyosis that are observed on MRI.…”

“…Possible histological observations that could explain the morphological appearance of the JZ in contrast to that of the outer layers of myometrium on imaging are the increased density of SMCs 8,27,29 , decreased extracellular space with lower water content 23,26 and higher vascular density 29 . First, lower interstitial volume on DCE-MRI and low APT signal intensity in the JZ correspond with higher cellular density 23 , low water content 26 and low cytoplasmic nuclear ratio 63 . Second, the higher vascular perfusion, higher tissue blood flow and greater capillary permeability in the JZ compared with the outer myometrial layers, observed by DCE-MRI 2,71 , could be caused by the reported smaller blood-vessel-wall thickness and a gradually decreased elastin distribution in the JZ compared to the outer myometrium 11 .…”

Current facts constituting an understanding of the nature of adenomyosis

“…Adenomyosis is a benign condition of the uterus characterized by the presence of ectopic endometrial glands and stroma below the endometrial-myometrial junction (at a depth of at least 2.5 mm below the basal layer of the endometrium). 1,2 The focuses of endometrial glands and stroma in the myometrium are typically surrounded by its hyperplastic tissue. 3 Lymphatic and vascular channels carry out penetration of normal myometrium.…”

Two-dimensional and three-dimensional imaging of uterus and fallopian tubes in female infertility

“…Clinical symptoms are similar to those of other benign uterine pathologies, and ultrasound plays an important role in its diagnosis. Nevertheless, the best noninvasive imaging diagnostic modality is MR imaging, with high sensitivity (78%-88%) and specificity (67%-93%) (43,44).…”