Original Research

Exploration of male urethral sphincter complex using diffusion tensor imaging (DTI)-based fiber-tracking

Corresponding Author

Shantanu Sinha PhD

[email protected]

Muscle Imaging and Modeling Laboratory, Department of Radiology, University of California, San Diego, California, USA

Address reprint requests to: S.S., RIL, Dept. of Radiology, UCSD, 3510 Dunhill St., San Diego, CA 92121. E-mail: [email protected]Search for more papers by this author

Usha Sinha PhD,

Usha Sinha PhD

Department of Physics, San Diego State University, San Diego, California, USA

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Vadim Malis MS,

Vadim Malis MS

Muscle Imaging and Modeling Laboratory, Department of Radiology, University of California, San Diego, California, USA

Department of Physics, University of California, San Diego, California, USA

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Valmik Bhargava PhD,

Valmik Bhargava PhD

Department of Medicine, San Diego VA Health Care System, California, USA

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Kyoko Sakamoto MD,

Kyoko Sakamoto MD

Department of Urology, San Diego VA Health Care System, California, USA

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Mahadevan Rajasekaran PhD,

Mahadevan Rajasekaran PhD

Department of Urology, San Diego VA Health Care System, California, USA

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Shantanu Sinha PhD,

Corresponding Author

Shantanu Sinha PhD

[email protected]

Muscle Imaging and Modeling Laboratory, Department of Radiology, University of California, San Diego, California, USA

Address reprint requests to: S.S., RIL, Dept. of Radiology, UCSD, 3510 Dunhill St., San Diego, CA 92121. E-mail: [email protected]Search for more papers by this author

Usha Sinha PhD,

Usha Sinha PhD

Department of Physics, San Diego State University, San Diego, California, USA

Search for more papers by this author

Vadim Malis MS,

Vadim Malis MS

Muscle Imaging and Modeling Laboratory, Department of Radiology, University of California, San Diego, California, USA

Department of Physics, University of California, San Diego, California, USA

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Valmik Bhargava PhD,

Valmik Bhargava PhD

Department of Medicine, San Diego VA Health Care System, California, USA

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Kyoko Sakamoto MD,

Kyoko Sakamoto MD

Department of Urology, San Diego VA Health Care System, California, USA

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Mahadevan Rajasekaran PhD,

Mahadevan Rajasekaran PhD

Department of Urology, San Diego VA Health Care System, California, USA

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First published: 23 March 2018

https://doi.org/10.1002/jmri.26017

Citations: 13

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Abstract

Background

Urinary incontinence is a major clinical problem arising primarily from age-related degenerative changes to the sphincter muscles. However, the precise anatomy of the normal male sphincter muscles has yet to be established. Diffusion tensor imaging (DTI) may offer a unique insight into muscle microstructure and fiber architecture.

Purpose

To explore the anatomy of the urethral sphincter muscles pertinent to urinary continence function using DT-MRI.

Study Type

Prospective cohort study.

Subjects

Eleven normal male subjects (mean age: 25.4 years); two subjects were scanned in three separate sessions to assess reproducibility.

Field Strength/Sequence

3T; using a diffusion-weighted spin echo planar sequence.

Assessment

DT parameters including fractional anisotropy (FA), primary (λ₁), secondary (λ₂), and tertiary (λ₃) eigenvalues, Apparent diffusion coefficient and radial diffusivity were analyzed statistically, while tracked muscle fibers were assessed visually.

Statistical Tests

Regional differences (sphincters and longitudinal muscle of the urethra) in the DTI indices were assessed by one-way analysis of variance. A Tukey post-hoc test was used to identify significant differences between muscle regions.

Results

Two sphincter muscles, one proximal near the base of the bladder, corresponding to the lisso-sphincter, and the other distal to the end of the prostate corresponding to the rhabdo-sphincter, surrounding a central urethral muscle fiber bundle, were clearly identified. FA was higher and λ₃ lower in the proximal sphincter muscle compared to the central urethral muscle and the distal sphincter (P < 0.05). The average coefficient of variation ranged from 5–12% for the DTI indices.

Data Conclusion

Since DTI values are known to reflect underlying tissue microarchitecture, significant differences in DTI indices identified here between the muscles of the urethral complex may potentially arise from differences in tissue microarchitecture that may in turn be related to the specific function of the sphincter and other muscles.

Level of Evidence: 1

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2018;48:1002–1011.

References

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Citing Literature

Volume48, Issue4

October 2018

Pages 1002-1011

Exploration of male urethral sphincter complex using diffusion tensor imaging (DTI)-based fiber-tracking

Abstract

Background

Purpose

Study Type

Subjects

Field Strength/Sequence

Assessment

Statistical Tests

Results

Data Conclusion

References

Citing Literature

References

Information

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Exploration of male urethral sphincter complex using diffusion tensor imaging (DTI)-based fiber-tracking

Abstract

Background

Purpose

Study Type

Subjects

Field Strength/Sequence

Assessment

Statistical Tests

Results

Data Conclusion

References

Citing Literature

References

Related

Information