Tuesday, 30 June 2015

xrayoftheweek 26: dynamic pelvic floor MRI (proctogram)

The latest #xrayoftheweek is a special one linked to a talk I'm giving this morning (or will have given if you are reading this after 1 pm on Wednesday 1st July!) about Pelvic Floor Imaging at the UKRC meeting in Liverpool. This is the UK's largest radiology conference and I am delighted to have been invited to talk about this.

This video is the dynamic evacuation sequence used to evaluate for the presence and degree of prolapse of the pelvic organs. Read on below to learn about what this video shows.

This sequence is acquired as a movie, by repeating a single sagittal (down the middle) slice in the same location multiple times. The temporal resolution (frame rate) is greater than 2 frames per second. Approximately 100 ml of ultrasound gel is first inserted per anally, no other contrast or injection is required. The patient is asked to try to evacuate the gel - I must emphasise that in order to achieve results like this, time must be spent explaining the procedure to the patient so that they understand the rationale for being asked to do this. My experience tells me that evacuation of the gel is achieved far more easily when the patient has been given a thorough and detailed explanation about the test.

On this particular video, the main findings are marked descent of the bladder and rectum during evacuation, and formation of an anterior rectocoele. The red arrow points to the cystocoele (bladder prolapse) and the green arrow to the rectocoele (bulge of anterior/front wall of rectum into posterior/back wall of vagina).

This test helps to evaluate the size of abnormality when someone is suspected of having pelvic organ prolapse from the clinical assessment. Note that normal x-ray proctography can usually only evaluate the rectum and small bowel (small bowel prolapse into the pelvis is known as an enterocoele) - unless the test is made invasive and contrast is instilled into the bladder and vagina. This is one of the major benefits of having the test under MRI.

In addition to the dynamic sequences, I also look at the structural sequences, specifically for signs that may indicate defects in either "endopelvic fascia" or the muscles, as they may contribute to the prolapse. Two specific signs are the saddlebag sign - this is sagging of the lateral aspect of the bladder, and the drooping moustache sign - this is sagging of the fat which lies in front of the bladder. 

Images of saddlebag and Merv Hughes (famous Australian cricketer taken from Google Images)

You can find more videos about my radiology work on my YouTube channel, and more posts and images about pelvic floor imaging on the dedicated page on this site.