Magnetic resonance imaging and 3-dimensional transperineal ultrasound evaluation of pelvic floor dysfunction in symptomatic women: a prospective comparative study

Abstract

Purpose: The purpose of this study was to investigate magnetic resonance imaging (MRI) and 3-dimensional transperineal ultrasound (3D-TPUS) features of pelvic floor dysfunction (PFD) in symptomatic women in correlation with digital palpation and to define cut-offs for hiatal dimensions predictive of muscle dysfunction.

Methods: This prospective study included 73 women with symptoms suggesting PFD. 3D-TPUS, MRI, and digital palpation of the levator ani muscle were performed in all patients. Levator hiatal antero-posterior (LHap) diameter and area (LH area) were measured at rest and at maximum muscle contraction.

Results: The reduction in LHap diameter and LH area during contraction was significantly less in women with underactive pelvic floor muscle contraction (UpfmC) than in those who had normal pelvic floor muscle contraction by digital palpation (P<0.001). Statistically significant positive correlations (P<0.001) were found between the Modified Oxford Score and 3D-TPUS and MRI regarding the reduction in the LHap diameter (r=0.80 and r=0.82, respectively) and LH area (r=0.60 and r=0.70, respectively). A reduction in LHap of <6.5% on 3D-TPUS and <7.6% on MRI predicted UpfmC with sensitivities of 46.2% and 82.7%, respectively. A reduction in LH area of <3.4% on 3D-TPUS and <3.8% on MRI predicted UpfmC with sensitivities of 75.0% and 88.5%, respectively. MRI was more sensitive in detecting levator avulsion (63.4%) than 3D-TPUS (27.1%).

Conclusion: MRI and 3D-TPUS had strong positive correlations with findings on palpation, and at certain cut-offs for hiatal dimensions, they can be used as complementary and objective tools to improve the accuracy of diagnosis and management planning of PFD.

Keywords: Magnetic resonance imaging; Palpation; Pelvic floor dysfunction; Transperineal ultrasound.

Fig. 1.. A 33-year-old primipara woman with stress urinary incontinence.

Digital palpation revealed good contractility (Modified Oxford Score grade of 4), as well as normal pelvic floor morphology and contractility by both ultrasonography and magnetic resonance imaging (MRI). A. Sagittal 2-dimensional transperineal ultrasonography (TPUS) shows a levator hiatal antero-posterior (LHap) diameter of 5.29 cm at rest. B. Axial 3-dimensional TPUS reveals no muscle avulsion, with a reduction of the hiatal area to 12.67 cm² at contraction. C. MRI sagittal cut shows a reduction in the LHap diameter to 4.77 cm at contraction. D. MRI axial cut shows normal signal and symmetrical thickness of both puborectalis muscles with a reduction in the hiatal area to 12.1 cm² at contraction.

Fig. 2.. A 29-year-old primipara woman with pelvic lump and dyspareunia.

Digital palpation revealed rectocele with no avulsion and a Modified Oxford Score grade of 3. A. Three-dimensional transperineal ultrasonography (TPUS) at contraction revealed no avulsion (hiatal area=15.92 cm² ). B, C. Magnetic resonance imaging axial cuts show laxity and signal change in the right puborectalis muscle, denoting partial avulsion (arrow in B) with a reduction in the hiatal area from 16.13 cm² at rest (B) to 15.69 cm² at contraction (C). D, E. Sagittal 3-dimensional TPUS shows a reduction in the levator hiatal antero-posterior diameter from 67.5 mm at rest (D) to 62.9 mm at contraction (E).

Fig. 3.. A 44-year-old multipara (4 births) woman with a pelvic lump, urinary incontinence, and dyspareunia.

Digital palpation revealed rectocele and cystocele with no avulsion and a Modified Oxford Score grade of 3. A. Three-dimensional transperineal ultrasonography at contraction reveals avulsion (arrow) of the right puborectalis muscle (hiatal area=18.85 cm² ). B, C. Magnetic resonance imaging (MRI) axial cuts show complete avulsion of the right puborectalis muscle (arrow in B) with thinning and fatty changes at rest (B) and contraction (C). D, E. MRI sagittal cuts show a reduction in the levator hiatal antero-posterior diameter from 69.1 mm at rest (D) to 66.4 mm at contraction (E).

Fig. 4.. Receiver operating characteristic (ROC) curve analysis of the percentage decrease of levator hiatal antero-posterior (LHap) diameter and levator hiatal (LH) area on 3-dimensional transperineal ultrasonography (3D-TPUS) and magnetic resonance imaging (MRI).

The graph shows that the LHap diameter on 3D-TPUS has a cutoff value of <6.5% (area under the curve [AUC], 0.64; sensitivity, 46.2%; specificity, 100%), the LHap diameter on MRI has a cut-off value of <7.6% (AUC, 0.84; sensitivity, 82.7%; specificity, 85.7%), the LH area by 3D-TPUS has a cut-off value of <3.4% (AUC, 0.77; sensitivity, 75%; specificity, 81%), and the LH area by MRI has a cut-off value of <3.8% (AUC, 0.9; sensitivity, 88.5%; specificity, 95.8%).