What causes a poorly defined endometrial-myometrial junction (EMJ) after hysteroscopic endometrial ploughing?

Causes of Poorly Defined EMJ After Hysteroscopic Endometrial Ploughing

A poorly defined endometrial-myometrial junction (EMJ) after hysteroscopic endometrial ploughing is most commonly caused by iatrogenic disruption of the junctional zone architecture from the mechanical trauma of the ploughing technique itself, which creates longitudinal scarring and disrupts the normal tissue planes between endometrium and myometrium.

Primary Mechanism: Iatrogenic Junctional Zone Disruption

The hysteroscopic ploughing technique involves longitudinally scoring the inner uterine walls to release scar contraction and create a fresh, blood-supplied surface for endometrial regeneration 1. This mechanical disruption inherently damages the junctional zone—the inner third of myometrium between endometrium and myometrium—which normally appears as a distinct low-signal intensity band on imaging 2.

Direct Surgical Effects

• Mechanical trauma from cold scissors creates longitudinal furrows through the endometrial-myometrial interface, disrupting the normal architectural boundaries that define the EMJ on imaging 1
• Scar formation and tissue remodeling following the ploughing procedure can obscure the normal tissue planes, making the junction poorly discernible on both ultrasound and MRI 1
• Loss of the normal junctional zone architecture occurs when the ploughing extends into the inner myometrium, eliminating the distinct tissue layer that normally creates imaging contrast 2

Secondary Contributing Factors

Pre-existing Adenomyosis

• Underlying adenomyosis may have been present before the procedure and is characterized by poor definition of the endomyometrial junction as a cardinal imaging feature 3
• Internal adenomyosis specifically involves endometrial implants scattered throughout the myometrium with enlargement of the junctional zone, making the EMJ inherently poorly defined 4
• Deep adenomyosis with significant endometrial penetration into the myometrium creates heterogeneous myometrial echotexture that obscures normal boundaries 5

Post-Procedural Inflammation and Edema

• Inflammatory microenvironment in the junctional zone following surgical trauma can cause tissue edema and altered signal characteristics that blur the EMJ 2
• Hemorrhagic foci and fluid accumulation in the immediate post-operative period can create imaging artifacts that obscure the normal junction 3

Imaging Characteristics of Poorly Defined EMJ

On MRI (T2-Weighted Images)

• Loss of the normal low-signal intensity junctional zone that typically provides contrast between endometrium and myometrium 6
• Heterogeneous signal intensity in the inner myometrium where the ploughing occurred, preventing clear delineation of tissue boundaries 3
• Absence of the enhancing subendometrial line on dynamic contrast-enhanced sequences, which normally helps define the EMJ in postmenopausal patients 6

On Ultrasound

• Heterogeneity of myometrial echotexture with loss of the normal hypoechoic junctional zone appearance 3
• Echogenic islands representing disrupted tissue architecture intermixed with hypoechoic areas of smooth muscle 3
• Pseudowidening of the endometrium due to irregular boundaries between endometrium and myometrium 3

Clinical Implications and Pitfalls

Diagnostic Challenges

• Difficulty distinguishing post-surgical changes from pathology: The poorly defined EMJ after ploughing can mimic adenomyosis, making it challenging to assess for recurrent intrauterine adhesions or new pathology 3
• Impaired assessment of myometrial invasion: If endometrial pathology develops later, the disrupted EMJ makes it difficult to evaluate for myometrial invasion on imaging 6

Important Caveats

• Time-dependent changes: The EMJ appearance may improve over months as tissue remodeling occurs and endometrium regenerates, though complete restoration of normal architecture is unlikely 1
• Baseline imaging is critical: Pre-procedure MRI or ultrasound documenting the baseline EMJ appearance helps distinguish surgical changes from pre-existing pathology 3
• Consider adenomyosis screening: Given that adenomyosis itself causes poorly defined EMJ and may have been the underlying reason for the intrauterine adhesions requiring ploughing, retrospective assessment for pre-existing adenomyosis is warranted 2, 4