Study finds high rates of incidental MRI findings in endometriosis cases

Study finds high rates of incidental MRI findings in endometriosis cases | Image Credit: © megaflopp - © megaflopp - stock.adobe.com.

Incidental findings (IFs) are common on magnetic resonance imaging (MRI) for endometriosis, according to a recent study published in Frontiers in Medicine.¹

Endometriosis, presenting as endometrium-like tissues outside the endometrium and myometrium, can adversely impact the peritoneum, ovaries, intestinal wall, urinary bladder and extra-abdominal structures. Symptoms include chronic pelvic pain, infertility, fatigue, and dyspareunia, and the prevalence in reproductive-aged women is 10% to 15%.

There is also a significantly increased risk of ovarian cancer in women with endometriosis.² A recent study evaluated the prevalence of ovarian cancer in endometriosis patients vs controls. Adjusted hazard ratios in this population ranged from 2.70 for high-grade serous ovarian cancer to 11.15 for clear cell carcinoma.

Endometriosis is usually identified through a laparoscopy, but data has indicated potential from imaging methods such as MRI and transvaginal ultrasound in diagnosis.¹ Current data about the interpretation of IFs on MRI for endometriosis remains lacking, indicating a need for more detailed analysis.

Investigators conducted a study to evaluate the prevalence and distribution of IFs on pelvis MRI for endometriosis. Participants included patients originally assessed in a descriptive cross-sectional single-center study who received MRI for endometriosis from April 2021 to February 2023.

Participants were aged at least 18 years and had clinically suspected pelvic endometriosis based on typical symptoms such as chronic pelvic pain and dyspareunia or based on transvaginal sonography findings. Two 1.5 Tesla scanners and a single 3 Tesla scanner were used to perform MRI scans.

Investigators defined IFs as, “an unrelated imaging abnormality on pelvic MRI for endometriosis.” A radiologist with 8 years’ experience in pelvic MRI identified IFs following a second review of all images. Categories of IF included not significant, moderately significant, and significant.

There were 1771 IFs identified across 303 patients aged a mean 33.4 years. Of 303 examinations, 299 presented with IFs.A single IF was reported in 11 patients, 2 in 30, 3 in 31, 4 in 41, and 5 or more in 186. A mean of 5.8 IFs and median of 6 per patient were found.

The prevalence of IFs did not differ based on significance, nor were differences noted based on deep infiltrating endometriosis (DIE) diagnosis. Mature ovarian teratomas and hydronephrosis were the most common IFs with high clinical significance.

Causative endometriosis on MRI was identified in only 1 in 11 patients with hydronephrosis. The number of IFs with high clinical significance did not significantly differ based on DIE diagnosis on MRI.

Of IFs with moderate clinical significance, leiomyomas without degeneration were the most common, with a rate of 14.5%. This was followed by degenerative changes of the lumbar spine with a rate of 9.5%. Patients with evidence of DIE more often presented with nutcracker anatomy, alongside gallstones.

There were multiple other IFs detected with moderate clinical significance. These included uterine ployp, signs of ovarian failure, cyst of the vaginal wall, degenerated leiomyoma, bicornuate uterus, hepatomegaly, hydrosalpinx, pelvic floor prolapse, and umbilical hernia.

The most common IFs with low clinical significance were acetabular rim ossifications (ARO) and lumbar disc desiccation in 66% and 48.2% of patients, respectively. Patients with evidence of DIE on MRI were significantly more likely to present with ARO and annular fissures of intervertebral discs.

These results indicated common presentations of IFs on pelvic MRI for endometriosis. Though many findings have no or minor consequences, investigators noted that radiologists should remain aware of findings with high clinical significance.

References

1. Harth S, Roller FC, Brose A, Kaya HE. Incidental findings on MRI for the evaluation of endometriosis: prevalence and clinical significance. Front Med (Lausanne). 2024;11:1468860. doi:10.3389/fmed.2024.1468860
2. Krewson C. Study links endometriosis to increased risk of ovarian cancer. Contemporary OB/GYN. July 17, 2024. Accessed October 21, 2024. https://www.contemporaryobgyn.net/view/study-links-endometriosis-to-increased-risk-of-ovarian-cancer