Feasibility of diffusion tensor imaging (DTI) with fibre tractography of the normal female pelvic floor

Zijta, Frank M.; Froeling, Martijn; Paardt, Marije P. van der; Lakeman, M. M. E.; Bipat, Shandra; Swijndregt, Alexander D. Montauban van; Strijkers, Gustav J.; Nederveen, Aart J.; Stoker, Jaap

doi:10.1007/s00330-010-2044-8

Cited by 59 publications

(71 citation statements)

References 20 publications

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“…The angle with respect to the x-axis (left-right) is not given, since the x-axis angle is complementary (i.e., 90°angle with y-axis) to the y-axis angle. The FA values in the left and right EAS are 0.28 Ϯ 0.03 and 0.31 Ϯ 0.07, respectively, which are consistent with each other as well as with the established values in the literature (10,40). On the other hand, the FA value in the PB (0.21 Ϯ 0.04) is significantly lower than that in the right and left EAS, a finding consistent with crossing of muscle fibers in this region (33).…”

Section: Dt Image Analysis Of Eas and Tp/bs Musclessupporting

confidence: 90%

Purse-string morphology of external anal sphincter revealed by novel imaging techniques

Mittal

Bhargava

Sheean

et al. 2014

American Journal of Physiology-Gastrointestinal and Liver Physi

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Mittal RK, Bhargava V, Sheean G, Ledgerwood M, Sinha S. Purse-string morphology of external anal sphincter revealed by novel imaging techniques. Am J Physiol Gastrointest Liver Physiol 306: G505-G514, 2014. First published January 23, 2014 doi:10.1152/ajpgi.00338.2013.-The external anal sphincter (EAS) may be injured in 25-35% of women during the first and subsequent vaginal childbirths and is likely the most common cause of anal incontinence. Since its first description almost 300 years ago, the EAS was believed to be a circular or a "donut-shaped" structure. Using three-dimensional transperineal ultrasound imaging, MRI, diffusion tensor imaging, and muscle fiber tracking, we delineated various components of the EAS and their muscle fiber directions. These novel imaging techniques suggest "purse-string" morphology, with "EAS muscles" crossing contralaterally in the perineal body to the contralateral transverse perineal (TP) and bulbospongiosus (BS) muscles, thus attaching the EAS to the pubic rami. Spin-tag MRI demonstrated purse-string action of the EAS muscle. Electromyography of TP/BS and EAS muscles revealed their simultaneous contraction and relaxation. Lidocaine injection into the TP/BS muscle significantly reduced anal canal pressure. These studies support purse-string morphology of the EAS to constrict/close the anal canal opening. Our findings have implications for the effect of episiotomy on anal closure function and the currently used surgical technique (overlapping sphincteroplasty) for EAS reconstructive surgery to treat anal incontinence. external anal sphincter muscle architecture; anal incontinence; childbirth-related injury; magnetic resonance diffusion tensor imaging AN UNDERSTANDING OF THE MORPHOLOGY of the external anal sphincter (EAS), one of the superficial muscles of the pelvic floor, is important, since damage to this muscle may occur in 25-35% of women during vaginal childbirth (34). Injury to the EAS muscle is an important cause of anal incontinence, which has a devastating effect on an individual's quality of life (8). Morphology of the EAS has intrigued many investigators. From the original description by Santorini at the turn of 18th century (27) to the most current texts (2, 19), the EAS is described as a three-component (subcutaneous, superficial, and deep) circular muscle structure (2, 19). Others have argued that the deep part of the EAS is actually the puborectalis muscle (PRM) (7,14,23,25). MRI studies of Hussain et al. (14) and our recent three-dimensional (3-D) ultrasound (US) images, combined with high-definition manometry maps (25), support the idea that the deep part of the EAS is indeed the PRM, because it has a "sling" shape. On the basis of 3-D US images and anal canal pressures obtained by high-definition manometry (HDM), our study shows that the increase in pressure with voluntary contraction of the proximal and distal halves of the anal canal is related to contraction of the PRM and EAS, respectively (25).Another aspect of EAS morphology that has never been questi...

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Section: Dt Image Analysis Of Eas and Tp/bs Musclessupporting

confidence: 90%

Purse-string morphology of external anal sphincter revealed by novel imaging techniques

Mittal

Bhargava

Sheean

et al. 2014

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…The directions of muscle fibers have also been demonstrated using the fiber tracking capabilities of diffusion tensor imaging [11, 13]. This technique holds great potential for mapping levator fibers.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, diffusion tensor imaging (DTI) has allowed visualization of fiber direction in certain portions of the levator [11–13]. However, at present only some regions of the muscle have yielded analyzable tracts and specific angles have not been determined.…”

Section: Introductionmentioning

confidence: 99%

Comparison of muscle fiber directions between different levator ani muscle subdivisions: in vivo MRI measurements in women

et al. 2014

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Introduction and hypothesis This study describes a technique to quantify muscle fascicle directions in the levator ani (LA) and tests the null hypothesis that the in vivo fascicle directions for each LA subdivision subtend the same parasagittal angle relative to a horizontal reference axis. Methods Visible muscle fascicle direction in the each of the three LA muscle subdivisions, the pubovisceral (PVM; synonymous with pubococcygeal), puborectal (PRM), and iliococcygeal (ICM) muscles, as well as the external anal sphincter (EAS), were measured on 3-T sagittal MRI images in a convenience sample of 14 healthy women in whom muscle fascicles were visible. Mean ± standard deviation (SD) angle values relative to the horizontal were calculated for each muscle subdivision. Repeated measures ANOVA and post-hoc paired t tests were used to compare muscle groups. Results Pubovisceral muscle fiber inclination was 41±8.0°, PRM was −19±10.1°, ICM was 33±8.8°, and EAS was −43±6.4°. These fascicle directions were statistically different (p<0.001). Pairwise comparisons among levator subdivisions showed angle differences of 60° between PVM and PRM, and 52° between ICM and PRM. An 84° difference existed between PVM and EAS. The smallest angle difference between levator divisions was between PVM and ICM 8°. The difference between PRM and EAS was 24°. All pairwise comparisons were significant (p<0.001). Conclusions The null hypothesis that muscle fascicle inclinations are similar in the three subdivisions of the levator ani and the external anal sphincter was rejected. The largest difference in levator subdivision inclination, 60°, was found between the PVM and PRM.

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“…In their study of the mouse hindlimb, Heemskerk et al also calculated the PCSA as the dot product of a measured anatomical cross-sectional area and the fiber direction [106] (it should be noted that, like other in vivo imaging-based assessments, this calculation did not normalize fiber lengths based on sarcomere length). DT-MRI-based fiber tracking also has been performed in a variety of human muscles, including the plantarflexor [86, 101, 110, 113], tibialis anterior [97, 107, 109], forearm [100], thigh [114-116], and female pelvic floor [117] muscles. Fiber tracking has been used to study structural alterations to the genioglossus muscle due to an oral appliance [118] and to investigate the effects of chronic lateral patella dislocation, the latter study demonstrating larger lateral force vectors in patients than in controls [115].…”

Section: Diffusion-tensor Mri Of Skeletal Musclementioning

confidence: 99%

Diffusion-tensor MRI-based skeletal muscle fiber tracking

Damon¹,

Buck²,

Ding³

2011

Imaging in Medicine

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A skeletal muscle's function is strongly influenced by the internal organization and geometric properties of its fibers, a property known as muscle architecture. Diffusion-tensor magnetic resonance imaging-based fiber tracking provides a powerful tool for non-invasive muscle architecture studies, has three-dimensional sensitivity, and uses a fixed frame of reference. Significant advances have been made in muscle fiber tracking technology, including defining seed points for fiber tracking, quantitatively characterizing muscle architecture, implementing denoising procedures, and testing validity and repeatability. Some examples exist of how these data can be integrated with those from other advanced MRI and computational methods to provide novel insights into muscle function. Perspectives are offered regarding future directions in muscle diffusion-tensor imaging, including needs to develop an improved understanding for the microstructural basis for reduced and anisotropic diffusion, establish the best practices for data acquisition and analysis, and integrate fiber tracking with other physiological data.

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Feasibility of diffusion tensor imaging (DTI) with fibre tractography of the normal female pelvic floor

Cited by 59 publications

References 20 publications

Purse-string morphology of external anal sphincter revealed by novel imaging techniques

Purse-string morphology of external anal sphincter revealed by novel imaging techniques

Comparison of muscle fiber directions between different levator ani muscle subdivisions: in vivo MRI measurements in women

Diffusion-tensor MRI-based skeletal muscle fiber tracking

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