Submucosal fibroids becoming endocavitary following uterine artery embolization: risk assessment by MRI.

Objective: The purpose of our study was to assess the relationship between the endometrium and submucosal fibroids before and after uterine artery embolization (UAE).

Materials And Methods: Contrast-enhanced pelvic 1.5-T MRI was performed in 49 women before and after UAE over a 2-year period. Dominant (largest diameter) fibroids in intramural, submucosal, subserosal, pedunculated subserosal, and endocavitary locations were assessed on pre- (baseline) and postembolization MRI. Size, locations of dominant fibroids relative to endometrium and serosa before and after embolization were compared. The ratio between the largest endometrial interface and the maximum dimension of the dominant submucosal fibroid (interface-dimension ratio) was determined on baseline MRI. The infarction rate for dominant fibroids was estimated after UAE.

Results: One hundred forty dominant fibroids were identified on baseline MRI. Forty-nine (35%) were intramural, 39 (28%) were submucosal, 34 (24%) were subserosal, eight (6%) were pedunculated subserosal, and 10 (6%) were endocavitary in location on preembolization MRI. After UAE, of 39 dominant submucosal fibroids, 13 (33%) became endocavitary: complete (n = 4), partial (n = 9) on the basis of European Society of Gynaecological Endoscopy (ESGE) classification. The preembolization mean interface-dimension ratio and mean diameters for dominant fibroids that became endocavitary were significantly greater than for those that did not become endocavitary after embolization (0.65 vs 0.32, p < 0.005; 8 vs 5.4 cm, p < 0.05, respectively). All dominant submucosal fibroids showed 100% infarction after UAE.

Conclusion: Submucosal fibroids with an interface-dimension ratio of greater than 0.55 are more likely to migrate into the endometrial cavity after UAE. The majority of these are expelled spontaneously without significant symptoms. Rarely, submucosal fibroids greater than 6 cm in size that become endocavitary may cause postprocedural complications requiring further intervention and medical treatment.