CAR/CSAR Practice Statement on Pelvic MRI for Endometriosis

Abstract Résumé

and Background

| Image acquisition • When assessing for endometriosis with pelvic MRI, either a 1.5 T or 3 T magnet strength scanner can be used.* • When assessing for endometriosis with pelvic MRI, the use of a phased array body coil placed over the pelvis is essential.* • When assessing for endometriosis with pelvic MRI, axial and sagittal T2 sequences are essential. A coronal T2-weighted sequence is not essential but is recommended.† • When assessing for endometriosis with pelvic MRI, an oblique axial T2-weighted sequence (oblique axial along the uterosacral ligaments or oblique perpendicular to the long axis of the uterine body) is optional. • When assessing for endometriosis with pelvic MRI, a 3D T2-weighted sequence (ie, CUBE/SPACE/VISTA) is optional but should not replace conventional T2 sequences if the resolution is not comparable. • When assessing for endometriosis with pelvic MRI, an axial T1 FS sequence is essential. If available, we recommend the routine use of an axial T1-weighted DIXON sequence as this can replace the conventional axial T1 FS and T1 non-FS sequences. If DIXON is unavailable, an axial T1 non-FS sequence can be acquired separately as an option (ie, in addition to the recommended axial T1 FS sequence). A sagittal T1 FS sequence is optional to assess for haemorrhagic foci in the anterior and posterior cul-de-sac.† • When assessing for endometriosis with pelvic MRI, axial diffusion-weighted imaging is not essential but is recommended, particularly if gadolinium is not used or if there is a risk of malignant degeneration. • When assessing for endometriosis with pelvic MRI, the use of intravenous gadolinium contrast is optional and can be considered if there is an increased risk for malignant degeneration or if there is a known adnexal lesion. Patient preparation • When assessing for endometriosis with pelvic MRI, routine use of an antiperistaltic agent is recommended.** • When assessing for endometriosis with pelvic MRI, timing the study according to the menstrual cycle is not recommended.* • When assessing for endometriosis with pelvic MRI, scans are generally performed in the supine position.* • When assessing for endometriosis with pelvic MRI, voiding 1 h prior to the scan to ensure optimal bladder re-distension is recommended.** • When assessing for endometriosis with pelvic MRI, if there is a specific concern for a vaginal or rectal nodule, the use of endoluminal gel (ie, vaginal or rectal) is optional but not essential. • When assessing for endometriosis with pelvic MRI, abdominal strapping is optional.* • When assessing for endometriosis with pelvic MRI, the use of bowel preparation (ie, NPO, fleet enema) is optional. | Image Acquisition 1.5 T Versus 3 T Scanners Coil Standard Orthogonal T2 Sequences Oblique T2 3D T2 T1/T1 Fat-Saturated Sequences Diffusion-Weighted Imaging Gadolinium Susceptibility Weighted Imaging Patient Preparation Use of Antiperistaltic Agents Menstrual Cycle Timing Patient Position Bladder Distension The Use of Endoluminal Gel Abdominal Strapping Bowel Preparation Structured Reporting | MRI OF THE PELVIS [W/WO] CONTRAST | | |---|---| | CLINICAL HISTORY: | | | TECHNIQUE: Sequences: Multisequence, multiplanar MR imaging of the pelvis was performed [with/without/with and without] intravenous contrast. Vaginal contrast: . . . ml of . . . given/not given Rectal contrast: . . . ml of . . . given/not given Buscopan: . . . mg of Buscopan given via . . ./not given [reason] | | | COMPARISON: | | | FINDINGS: | | | MIDDLE COMPARTMENT | | | Uterus: | • Size: [l × w × h in cm]. • Position: Anteverted/Retroverted/Anteflexed/Retroflexed/Midline/Tilted to right/Tilted to left. • Endometrium: Endometrial thickness [in cm]/Intracavitary pathology/IUD • Fibroids: present [describe]/not present • Adenomyosis: Absent/present [describe] • Uterine invasive by endometriosis: Absent/present [give size, location, depth of invasion, distance from endometrium] • Uterine ligaments involvement by endometriosis: Absent/present [describe] | | Right Ovary: | • Size [l × w × h in cm] • Normal/Endometrioma is present measuring l × w × h in cm/A mass is present (if there is a mass, use O-RADS lexicon and classification). • Number of follicles • Deep Endometriosis/adhesions: Absent/present [describe] | | Left Ovary: | • Size [l × w × h in cm] • Normal/Endometrioma is present measuring l × w × h in cm/A mass is present (if there is a mass, use O-RADS lexicon and classification). • Number of follicles • Deep Endometriosis/adhesions: Absent/present [describe] | | Fallopian tubes: | • Normal/Hydrosalpinx [side and size in cm]/Hematosalpinx [side and size in cm] | | POSTERIOR COMPARTMENT | | | Uterosacral ligaments: | • Normal/Involved by endometriosis [describe] | | Retrocervical space and Torus Uterinus: | • Normal/Involved by endometriosis [describe all involved structures with size in cm if applicable] | | Vagina and posterior vaginal fornix: | • Not involved by endometriosis/Involved by endometriosis [give size and location] • Other vaginal pathology: | | Rectovaginal septum: | Normal/abnormal with deep endometriosis nodule [size and involved structures]. | | Rectum: | Normal/Abnormal [for each lesion provide: length of lesion in cm, circumferential extent [%] (distended/nondistended bowel), invasion into muscular wall present or not, distance to anal verge in cm. Provide distance between lesions if multiple] | | ANTERIOR COMPARTMENT | | | Bladder Lesion | Normal/Abnormal [size of lesion, distance from UVJ and trigone, depth of invasion] | | Ureters | Normal/Abnormal [extrinsic or intrinsic, length of involvement, Distance from UVJ, presence or absence of hydronephrosis] | | Round ligaments | Normal/Abnormal [describe lesion and size] | | Vesicouterine space | Normal/Abnormal [size of lesion] | | Vesicovaginal space | Normal/Abnormal [size of lesion] | | Prevesical space | Normal/Abnormal [size of lesion] | | ADDITIONAL SITES OF ENDOMETRIOSIS | | | Additional bowel lesions [sigmoid colon, appendix, small bowel]: | Absent/Present [describe size, location, and depth of invasion if applicable] | | Pelvic side walls: | Normal/Abnormal [describe involved structures and size] | | Nerves: | Normal/Abnormal [describe involved structures and size] | | Abdominal wall: | Normal/Abnormal [describe involved abdominal wall layers and size] | | Inguinal canals: | Normal/Abnormal [describe involved structures and size] | | Uncommon site of endometriosis not included above: | | | OTHERS | | | Use this section to describe other findings in the scan [Lymph nodes, osseous findings, free fluid, soft tissues etc.] | | | IMPRESSION: 1. Uterine adenomyosis: Absent/present 2. Other uterine findings: eg, endometrial polyp(s), IUD, Fibroids etc. 3. Ovarian endometriosis: Absent/present 4. Deep endometriosis: Absent/present 5. Cul-de-sac [rectouterine pouch] obliteration: favoured present/favoured absent 6. Other findings: |

Acknowledgments Declaration of Conflicting Interests Funding ORCID iDs Appendix A | Recommendation | Notes | || |---|---|---|---| | Magnet strength | Either 3 T or 1.5 T can be used | || | 3 T | Better SNR—increased contrast and spatial resolution; lower scan acquisition times. Better tolerance flexibility to add additional sequences. | || | 1.5 T | Preferred if there is concern about susceptibility/motion artifacts, concern of magnetic field inhomogeneity, or medical device compatibility | || | Coil | Phased array coil | Recommended/essential | Essential to improve SNR in pelvic MRI | | Endorectal coil | Not recommended | || | T2 weighted sequences | Axial and sagittal | Recommended/essential | | | Coronal | Recommended but not essential | || | Oblique Axial along uterosacral ligaments OR Oblique Perpendicular to the long axis of the uterus | Optional | || | 3D T2 | Optional | Can help decrease scan time if comparable resolution to standard T2; should not replace conventional T2 sequences if resolution is not comparable. | | | T1 weighted sequences | Axial T1 FS And Axial T1 non-FS | Recommended/essential | | | DIXON | Optional | If available, axial T1-weighted DIXON sequence can replace conventional axial T1 FS and T1 non-FS sequences. | | | Sagittal T1 FS | Recommended but not essential | Can be omitted to decrease scan time/protocol complexity. | | | DWI | Recommended but not essential | Recommended if there is risk of malignant degeneration especially if Gadolinium is not used | | | Intravenous gadolinium | Optional | If there is increased risk for malignant degeneration or a known adnexal lesion. | | | SWI | Not recommended | Appendix B Images Appendix C | Preparation | Recommendation | Notes | | |---|---|---|---| | Routine use of antiperistaltic agent (Buscopan, Glucagon) | Recommended | || | Menstrual cycle timing | Not recommended | || | Patient position | Supine | Recommended | Default for most patients. | | Prone OR feet first | Optional | May be beneficial for claustrophobic patients. | | | Voiding 1 h prior to the scan | Recommended | || | Use of endoluminal (vaginal or rectal) gel | Optional | || | Abdominal strapping | Optional | || | Bowel preparation | Fasting [4 h prior to scan] | Optional | Can help to reduce peristalsis, but the use of an antiperistaltic agent serves this purpose. | | Enema | Optional | Limited evidence, cost and patient discomfort constraints. | Appendix D | Vaginal gel | Rectal gel | |---|---| | 30-50 cc of ultrasound gel via 60 cc catheter tip syringe. To be self-administered by the patient. | Inform the patient that they may experience an urge to defecate. With the patient in decubitus position, a 20-26 F Foley catheter is inserted into the rectum and the balloon is inflated with 20 cc saline. Approximately 180 cc of diluted aqueous gel (mixture of ultrasound gel and water in a 1:1 ratio) is instilled into the rectum via the Foley catheter. The patient is then repositioned supine. |

Cite Cite Cite Download to reference manager If you have citation software installed, you can download citation data to the citation manager of your choice Information, rights and permissions Information Published In

Article versions Authors Metrics and citations Metrics Journals metrics This article was published in Canadian Association of Radiologists Journal. View All Journal MetricsPublication usage* Total views and downloads: 2519 *Publication usage tracking started in December 2016 Publications citing this one Receive email alerts when this publication is cited Web of Science: 2 view articles Opens in new tab Crossref: 4 - Canadian radiology: 2026 update - Mind the gap: underreporting of key compartments in endometriosis MRI with free-text and non-disease-specific templates - Pelvic Puzzles: Imaging Non-Traumatic Emergencies of the Female Pelvis: A Comprehensive Review - Advances in non‐invasive diagnostic tools for endometriosis: A narrative review of the past ten years Figures and tables Figures & Media Tables View Options View options PDF/EPUB View PDF/EPUBAccess options If you have access to journal content via a personal subscription, university, library, employer or society, select from the options below: loading institutional access options CAR members can access this journal content using society membership credentials. CAR members can access this journal content using society membership credentials. Alternatively, view purchase options below: Access journal content via a DeepDyve subscription or find out more about this option.