1. Imaging of the pelvic floor: Ultrasound and MRI
Dr Bruce Allen Horizon Radiology
Acknowledgement to Dr Hans Dietz and Dr Jenny Kruger

2. Clinical application of Pelvic floor imaging
Pelvic floor muscles involved in:
Maintenance of continence
Support of the organs of the pelvis
Vaginal delivery
Failure of these muscles increases risk of:
Urinary and fecal incontinence,
Prolapse of the organs of the pelvis,
Perineal pain and dyspareunia.

3. Ultrasound imaging MRI Cost effective
Do not need expensive machines to do basic imaging
Ultrasound is highly operator dependant
Not difficult to learn
Real time, functional studies easy
MRI
Expensive
Images are easier to understand
Functional studies difficult.

4. 2D imaging - Ultrasound
Until recently 2D ultrasound scanning only methodology used define pathology and normal function of pelvic floor
Abdominally, transvaginal or translabial
Descent of bladder neck, uterus and rectal ampulla during a valsalva
Transperineal ultrasound useful biofeedback measure for patients
Image is in mid-sagittal plane
$12,000 machine.

5. Translabial 2D Ultrasound
Patient is supine, bladder empty ( or standardized filling)
Knees flexed, feet on the table
Transducer covered in glove/condom for hygiene
Placed fairly firmly on the perineum in the mid sagittal orientation.

6. Ultrasound Anatomy

7. Typical 2D image of the pelvic floor muscles
urethra
cranial

8. MRI: Sag midline, normal anatomy
Bony landmarks
20 mins scan time
Anatomy

9. Pelvic floor functional assessment
Training
Contraction
Valsalva

10. Pelvic floor muscle contraction
Contraction assess:
1. Narrowing of the hiatus in the AP diameter
2. Movement of the bladder neck
3. Strength of the PF muscle

11. Contraction: Bladder neck

12. Valsalva: BND

13. Effective valsalva manouevre
Valsalva assess:
Descent of bladder, uterus, rectum. Urethral rotation.
Development of cystocele, prolapse or rectocele
Width of hiatus in the AP diameter

14. MRI: Valsalva. Cystocoele
Functional:
4 min per sequence
Valsalva
defaecation
(training)

15. 2D imaging Measurements of bladder neck descent and urethral rotation.
Ultrasound images showing measurement of bladder neck descent and urethral rotation. Bladder neck descent (BND)= x-r –x-s. (Dietz et al 2004)

16. Clinical use of 2D ultrasound
Still widely used
Bladder, uterine and rectal descent.
Bo, K. and M. Sherburn, Evaluation of female pelvic-floor muscle function and strength. Physical therapy, (3): p , Mar.
Abdominal ultrasound
Athanasiou, S., et al., Direct imaging of the pelvic floor muscles using two-dimensional ultrasound: a comparison of women with urogenital prolapse versus controls.BJOG: An International Journal of Obstetrics and Gynaecology, (7): p
Endovaginal probe
Costantini, S., et al., Perineal ultrasound evaluation of the urethrovesical junction angle and urethral mobility in nulliparous women and women following vaginal delivery. Int Urogynecol J Pelvic Floor Dysfunct, (6): p
Transperineal ultrasound
Dietz, H., Pelvic Floor Ultrasound. Current Medical Imaging Reviews, : p
Dietz, H., B. Haylen, and J. Broome, Ultrasound in the quantification of female pelvic organ prolapse. Ultrasound in Obstetrics and Gynecology, : p

17. 3D ultrasound imaging
3D ultrasound widely used in obstetric scanning so equipment is now readily available
$100,000 – $250,000
Acquisition of volume images allow access to the ‘axial’ plane – previously domain of magnetic resonance imaging.

18. Protocol for 3D pelvic floor imaging
Translabial imaging:
Imaged supine after voiding
Transducer ‘sits’ on the perineum mid-sagittal orientation
Mid-sagittal image on the screen
Symphysis pubis reference point – during movement
Methods highly reproducible (Guaderrama, Yang, Dietz ).

19. 3D US pelvic floor imaging – levator hiatus
Voluson 730 expert system. (Dietz et al 2005)

20. MRI: normal axial anatomy

21. 3D pelvic floor ultrasound – assessing function
Levator hiatus:
‘plane of minimal dimensions’
Smallest distance from the inferior edge of the symphysis pubis to the anal rectal angle
Levator hiatal area bounded by the symphysis pubis anteriorly, anal rectal angle posteriorly, puborectalis/ pubococcygeus laterally.
Hiatal area measures pelvic floor function
Rest
Maximum pelvic floor muscle contraction
Maximum valsalva
(Training).

22. Normal 3D Pelvic Floor

23. 3D imaging: hiatal measurement
A mid-sagittal image. Line indicates plane of minimal dimensions
B corresponding ‘axial’image showing entire levator hiatus

24. Normal Contraction of the hiatus

25. Ballooning of the hiatus on Valsalva

26. Avulsion: Ultrasound. Unilateral

27. Avulsion. MRI. Large unilateral

28. Avusion: Ultrasound. Bilateral
With ballooning.

29. MRI ………………….……….. Ultrasound

30. Conclusions Translabial ultrasound 2D / 3D /4D MRI
Function and anatomy
effective, easy, low cost method for assessment of the PF
Used to confirm/or not the digital diagnosis of PF dysfunction
Biofeedback training
MRI
Anatomy (and function)

31. Effective valsalva manouevre

32. Hiatal measurements at rest