24/08/2026
MRI Defecography
MRI defecography (MR defecography) is a dynamic pelvic-floor MRI examination used to assess pelvic floor dysfunction, anore**al evacuation problems, and disorders such as rectocele, enterocele, intussusception, and pelvic organ prolapse.
1. Patient preparation
* Explain the procedure clearly because the examination requires the patient to strain and evacuate during imaging.
* Check MRI safety screening and contraindications.
* Usually the patient should empty the bladder before the examination, depending on the department protocol.
* Re**al filling is commonly performed with ultrasound gel or another MR-compatible contrast/filling agent.
* Follow the radiologist’s/local protocol regarding bowel preparation and diet.
2. Patient positioning
Usually:
* Supine position on the MRI table.
* Pelvis centered in the magnet.
* Use a pelvic phased-array coil.
* Keep the patient as comfortable and private as possible.
* Explain beforehand exactly when they will be asked to squeeze, relax, bear down and evacuate.
3. Re**al preparation/filling
A typical technique is:
1. Patient lies on the examination table.
2. Approximately 100–200 mL of ultrasound gel may be introduced into the re**um, depending on institutional protocol and patient tolerance.
3. The patient is positioned appropriately.
4. Obtain initial static/anatomic images.
The exact volume and filling material vary considerably between institutions and scanner protocols—follow your radiologist’s protocol.
4. Basic MRI sequences
A typical protocol may include:
Sequence Purpose
Sagittal T2 Pelvic anatomy and dynamic assessment
Axial T2 Pelvic floor/anatomical assessment
Coronal T2 Pelvic floor and organ relationships
Sagittal dynamic/balanced sequence Real-time movement
Axial/coronal dynamic images Additional pelvic-floor assessment
Post-evacuation images Residual gel and structural abnormalities
Dynamic sequences should have high temporal resolution so that pelvic-floor movement can be evaluated.
5. Dynamic phases — MOST IMPORTANT
The technologist should clearly communicate with the patient.
A. Rest
* Patient relaxes normally.
* Acquire baseline images.
B. Squeeze
* Ask the patient to contract the pelvic-floor/a**l muscles.
* Maintain the contraction for the required imaging period.
C. Strain / Valsalva
* Ask the patient to bear down as if having a bowel movement.
* This demonstrates pelvic-floor descent and prolapse.
D. Evacuation / defecation
* Patient is instructed to evacuate the re**al gel.
* Dynamic images are continuously acquired during evacuation.
6. What the technologist should watch for
From a technical perspective, make sure:
* The entire a**l ca**l and pelvic floor are included.
* The pubore**alis region is adequately visualized.
* The patient understands the commands before dynamic imaging begins.
* There is minimal patient movement unrelated to the examination.
* Dynamic imaging covers the complete rest → squeeze → strain → evacuation sequence.
* Images are saved in the correct series/order.
* If evacuation is incomplete, document it according to departmental practice.
7. Common abnormalities assessed
The radiologist may evaluate for:
* Anterior rectocele
* Posterior rectocele
* Enterocele
* Sigmoidocele
* Intussusception
* Internal re**al prolapse
* External re**al prolapse
* Pelvic-floor descent
* Cystocele
* Uterine/vaginal prolapse
* Anismus / paradoxical pubore**alis contraction
8. Important technologist tip
The dynamic portion is the key part of MR defecography. Excellent static images alone are not sufficient.
Before scanning, explain the commands:
“Relax → squeeze → bear down → evacuate.”
A patient who does not understand these instructions can produce a technically inadequate examination even when the MRI sequences are otherwise excellent.
If you’re setting up this examination on a GE, Siemens or Philips MRI, I can also give you a  complete MR defecography protocol with sequence names, planes, FOV, slice thickness, TR/TE, dynamic timing and patient instructions.
