Application of shear-wave elastography to estimate the stiffness of the male striated urethral sphincter during voluntary contractions

Stafford, Ryan E., Aljuraifani, Rafeef, Hug, Francois and Hodges, Paul W. (2017) Application of shear-wave elastography to estimate the stiffness of the male striated urethral sphincter during voluntary contractions. BJU International, 119 4: 619-625. doi:10.1111/bju.13688


Author Stafford, Ryan E.
Aljuraifani, Rafeef
Hug, Francois
Hodges, Paul W.
Title Application of shear-wave elastography to estimate the stiffness of the male striated urethral sphincter during voluntary contractions
Journal name BJU International   Check publisher's open access policy
ISSN 1464-410X
1464-4096
Publication date 2017-04-01
Year available 2016
Sub-type Article (original research)
DOI 10.1111/bju.13688
Open Access Status Not yet assessed
Volume 119
Issue 4
Start page 619
End page 625
Total pages 7
Place of publication Chichester, West Sussex, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2018
Language eng
Formatted abstract
Objectives: To investigate whether increases in stiffness can be detected in the anatomical region associated with the striated urethral sphincter (SUS) during voluntary activation using shear-wave elastography (SWE); to identify the location and area of the stiffness increase relative to the point of greatest dorsal displacement of the mid urethra (i.e. SUS); and to determine the relationship between muscle stiffness and contraction intensity.

Subjects and Methods: In all, 10 healthy men participated. A linear ultrasound (US) transducer was placed mid-sagittal on the perineum adjacent to a pair of electromyography electrodes that recorded non-specific pelvic floor muscle activity. Stiffness in the area expected to contain the SUS was estimated via US SWE at rest and during voluntary pelvic floor muscles contractions to 5%, 10% and 15% maximum. Still image frames were exported for each repetition and analysed with software that detected increases in stiffness above 150% of the resting stiffness.

Results: Pelvic floor muscle contraction elicited an increase in stiffness above threshold within the region expected to contain the SUS for all participants and contraction intensities. The mean (SD) ventral–dorsal distance between the centre of the stiffness area and region of maximal motion of the mid-urethra (caused by SUS contraction) was 5.6 (1.8), 6.2 (0.8), and 5.8 (0.7) mm for 5%, 10% and 15% maximal voluntary contraction, respectively. Greater pelvic floor muscle contraction intensity resulted in a concomitant increase in stiffness, which differed between contraction intensities (5% vs 10%, P < 0.001; 5% vs 15%, P < 0.001; 10% vs 15%, P = 0.003).

Conclusion: Voluntary contraction of the pelvic floor muscles in men is associated with an area of stiffness increase measured with SWE, which concurs with the expected location of the SUS. The increase in stiffness occurred in association with an increase in perineal surface electromyography activity, providing evidence that stiffness amplitude relates to general pelvic floor muscle contraction intensity. Future applications of SWE may include investigations of patient populations in which dysfunction of the SUS is thought to play an important role, or investigation of the effect of rehabilitation programmes that target this muscle.
Keyword Elastography
Male
Pelvic floor
Stiffness
Striated urethral sphincter
Ultrasonography
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Health and Rehabilitation Sciences Publications
 
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