How should MRI images be obtained for optimal endometriosis detection?

Detecting Pelvic Endometriosis: MRI imaging protocols and techniques

Key Points

Importance:

• MRI is widely used for the evaluation of pelvic endometriosis and thus a standardized protocol regarding its acquisition should be made.

Highlights:

• Panelists comprehensively recommend MRI-image acquisition techniques for the optimal detection of endometriosis.

What’s done here:

• The Society of Abdominal Radiology established a Disease-Focused Panel to improve patient care for patients with endometriosis by publishing a consensus statement on how to optimize MRI studies for the evaluation of patients with endometriosis.

Key Results:

• The consensus statement did not recommend 1.5T over 3.0T MRI systems due to a relative paucity of currently available studies.
• The panel also highly recommended against the use of an endorectal coil that may be used in suspicious of rectal endometriosis, since the mild improvement in image quality did not outweigh the increased cost, invasiveness, and patient discomfort.
• No recommendation was made regarding patient fasting or for bowel preparation due to a lack of evidence in the literature regarding its benefit.
• Vaginal contrast is conditionally recommended due to its potential to depict deep lesions involving the pelvic subperitoneal space.
• Panelists conditionally recommend the use of rectal contrast, especially when posterior compartment involvement is suspected.
• Glucagon administration in order to reduce motion artifacts induced by bowel peristalsis is highly recommended.
• Panelists conditionally recommend moderate bladder distention by not to urinate for at least one hour prior to the exam when anterior compartment involvement is clinically suspected.
• T2-weighted imaging without fat suppression is preferred over "with fat suppression" for the detection of pelvic endometriosis, particularly fibrotic lesions.
• Additionally, T1WI with and without fat suppression in at least two imaging planes is highly recommended.
• Post-contrast, ADC maps, and diffusion-weighted imaging are highly recommended as these improve the ability to differentiate endometriosis from neoplasm or infection.

Limitations: These are panelists’ recommendations based on experience and research studies

Lay Summary

It is well known that the diagnosis of endometriosis for some patients with the chronic pelvic disease is delayed, often for years, due to the disease, patient, and physician-led factors. An area of active study is how ordering physicians can work together to diagnosis endometriosis as early as possible. Discussions on possible screening recommendations and imaging protocols are made more difficult by the fact that endometriosis is a very heterogeneous disease with three main clinical manifestations; ovarian endometriomas, deeply infiltrating endometriosis (DIE), and superficial peritoneal endometriosis.

Although laparoscopy continues to be the gold standard for the diagnosis and treatment of endometriosis, gynecologic surgeons who treat endometriosis patients are increasingly relying on MRI studies before the surgery in order to accurately and efficiently localize endometriosis involvement and make an appropriate surgical plan. The Society of Abdominal Radiology Endometriosis Disease-Focused Panel developed a consensus statement detailing patient preparation and imaging techniques based on other studies and their experience to suggest optimal image acquisition and evaluation of endometriosis on MRI.

An electronic survey sent to multiple institutions, the panelists collected several image acquisition and patient preparation data. These ranged from pre-imaging patient education information to whether a bowel preparation or image contrast was used to obtain a specific MRI sequence image. Transvaginal ultrasound is an excellent tool in the diagnosis of endometriomas but for the detection of DIE, there have been mixed results. This is in part due to the difficulty of fully assessing hard-to-reach areas such as the pouch of Douglas and bladder for endometriosis involvement. However, MRI of the pelvis is now highly recommended when DIE is clinically suspected as it can also be used for surgical planning. The following recommendations are a part of this consensus statement.

First and foremost, patients should receive clear instructions and explanations regarding the MRI examination. This not only educates the patient but also reduces preventable anxiety regarding the study. It is especially necessary in cases where vaginal and/or rectal contrast is used to obtain the study.

The consensus statement did not recommend 1.5T over 3.0T MRI systems due to a relative paucity of currently available studies. The panel also highly recommended against the use of an endorectal coil which is used in suspicious rectal endometriosis, since the mild improvement in image quality did not outweigh the increased cost, invasiveness, and patient discomfort associated with its placement in the rectum.No recommendation was made regarding patient fasting or for bowel preparation due to a lack of evidence in the literature regarding its benefit.

Vaginal contrast is conditionally recommended due to its potential to depict deep lesions involving the pelvic subperitoneal space. Rectal contrast usually involves the placement of 60-180 ml of aqueous gel via a syringe into the rectum. Panelists also conditionally recommend the use of rectal contrast, especially in cases where posterior compartment involvement is suspected.

Glucagon administration in order to reduce motion artifacts induced by bowel peristalsis is highly recommended by the panelists. Panelists conditionally recommend moderate bladder distention by asking patients not to urinate for at least one hour prior to the exam in cases where anterior compartment involvement is clinically suspected. In patients in whom proximal small bowel involvement is suspected, panelists highly recommend against oral contrast utilization for MRI pelvis acquisition and instead ask that MR enterography be considered. T2-weighted imaging (T2WI) without fat suppression is preferred over T2WI with fat suppression for the detection of pelvic endometriosis, particularly fibrotic lesions. Additionally, T1WI with and without fat suppression in at least two imaging planes is highly recommended. Post-contrast, ADC maps, and diffusion-weighted imaging are highly recommended as these improve the ability to differentiate endometriosis from neoplasm or infection.

Research Source: https://pubmed.ncbi.nlm.nih.gov/32193592/