Original Article

High definition T2-weighted MR imaging of the female uro- genital supporting system using an external coil

10.34057/PPj.2019.38.03.003

  • VITTORIO PILONI
  • NOEMI LUCCHETTI
  • TOMMASO FELICI
  • JESSICA ANDREATINI
  • FEDERICA PIGNALOSA

Pelviperineology 2019;38(3):78-82

Aim:

To provide evidence of the imaging features of such anatomic structures. Materials and Methods The imaging series of sixtyeight consecutive nulliparous females ( mean age 51.5 ±4.2 yrs, range 18-72 yrs) who underwent pelvic MR examination between April 2017 and June 2019, were reviewed. With no history of lower urinay tract symptoms (LUTs), evacuation dysfunctions or pelvic organ prolapse, clues for the examination included: known or suspected pudendal nerve neuropathy and ano-perianal sepsis. Patients with prior surgery for prolapse repair, partial or total hysterectomy and pelvic reconstruction for neonatal congenital anomalies were excluded. MR images were analyzed for evidence and imaging features of ligaments connecting the urethra, uterus and vagina to the internal boundaries of levator ani hiatus and pelvic side walls. The optimal scan plane for their identification and the frequency with which the various ligaments could be recognized as a distinctive anatomic structure were calculated.

Results:

The axial MR images proved most informative (diagnostic yield as high as 89%); however, tilting the scan plane obliquely, perpendicular to the long axis of the anal canal improved the visibility of some structures in over half the cases. Three groups of ligaments supporting the female urethra were recognized, as follows: the periurethral ligaments (87%), running ventrally to the urethra; the paraurethral ligaments (60%), originating at the two and ten o’clock position of the urethra’s outer border, respectively; and the pubourethral ligament (57%), hammock-like structure in close contact with the posterior aspect of the urethra. On the same plane, the vagina appeared as a three-layer structure showing different morphology in the upper (horizontal line), middle (H-shaped) and lower third ( U-shaped) with faint, low intensity signal lateral attachments seen only occasionally (< 20 %) inside the paracolpium. The parametrium was seen in different proportions as low signal intensity condensations, showing linear (uterosacral and round ligaments, 68% and 96%, respectively), reticular (cardinal ligaments, 81%), or wide fold feature (broad ligaments, 35%), connecting the sides of the uterus to the walls and floor of the pelvis. Finally, the perineal body was better visualized on sagittal than on axial images (only 22%) as a hypointense pyramidal structure between the posterior labial commissure and the anal verge.

Conclusions:

MRI allows precise characterization of most relevant female urogenital supporting structures. In case of pathology, it can be used to guide surgeons and researchers to develop new focal-defect repair techniques.

Keywords: Magnetic resonance imaging; Female pelvis; Urethral support system; Parametrium and paracolpium; Endopelvic ligaments