Pelvic organ movements in asymptomatic nulliparous and symptomatic premenopausal women with pelvic organ prolapse in dynamic MRI: a feasibility study comparing midsagittal single-slice with multi-slice sequences

Comparison of urethral parameters in females presenting cystoceles with and without stress urinary incontinence based on dynamic magnetic resonance imaging: are they different?

PURPOSE

To compare urethral parameters between cystocele patients with and without stress urinary incontinence (SUI) and explore factors influencing SUI in cystocele patients via dynamic MRI.

METHODS

The two-dimensional parameters evaluated included the paravaginal defects, levator ani muscle defects, urethral length, urethral funnel shape, bladder neck funnel width, bladder neck funnel depth, urethral angle, posterior vesicourethral angle, and anterior bladder protrusion. The three-dimensional parameters included the proximal urethra rotation angle, the distal urethra rotation angle, bladder neck mobility, urethral midpoint mobility, and external urethral meatus mobility. The independent samples t test was used for continuous variables, and the chi-square test was used for categorical variables. Binary logistic regression was used to identify factors independently associated with SUI in cystocele patients.

RESULTS

The baseline parameters were similar between the 2 groups. Cystocele patients with SUI had a significantly higher point Aa (1.63 ± 1.06 cm vs. 0.81 ± 1.51 cm, p = 0.008); more anterior bladder protrusion (33.3% vs. 11.4%, p = 0.017); greater bladder neck mobility (36.38 ± 11.46 mm vs. 28.81 ± 11.72 mm, p = 0.005); mid-urethral mobility (22.94 ± 6.50 mm vs. 19.23 ± 6.65 mm, p = 0.014); and external urethral meatus mobility (22.42 ± 8.16 mm vs. 18.03 ± 8.51 mm, p = 0.022) than did cystocele patients without SUI. The other urethral parameters were similar in the groups (p > 0.05). Binary logistic regression showed that bladder neck mobility was independently associated with SUI in females with cystoceles (odds ratio, 1.06; 95% CI 1.015-1.107; p = 0.009).

CONCLUSION

Cystocele patients with SUI have a higher point Aa, more anterior bladder protrusion, and greater urethral mobility than those without SUI. Bladder neck mobility is independently associated with SUI in females with cystoceles.

REGISTRATION NUMBER

NCT03146195.

Assessment of pelvic organ prolapse with the Pelvic Inclination Correction System: defining the normal range and threshold to pathology

PURPOSE

To define the normal range and threshold values for pathologic prolapse on MRI using the PICS line and assess its correlation with the pubococcygeal line (PCL).

METHODS

This prospective, IRB-approved study included 20 nulliparous volunteers and 18 prolapse patients (POP-Q Stage ≥ 2). Organ positions (bladder, cervix, anorectal junction) relative to PICS and PCL were measured on dynamic MRI. Differences in organ position were compared. Receiver-operating characteristic (ROC) analysis was performed to identify cutoff values for prolapse using the PICS line. The correlation between PICS and PCL measurements was tested with Spearman's rank correlation.

RESULTS

In volunteers, median bladder and cervix positions measured to the PICS at rest were - 2.7 cm and - 5.3 cm compared to - 1.9 cm and - 2.7 cm in patients (p < 0.001). During straining, bladder and cervix were at - 0.9 cm and - 3.2 cm in volunteers versus + 2.5 cm and + 2.5 cm in patients (p < 0.001). Correlation was strong for PICS and PCL measurements for all three compartments (δ = 0.883-0.970, p ≤ 0.001). AUCs of PICS for the anterior and middle compartment were 0.98 (95% confidence interval [CI] 0.96-1.00, p < 0.001) and 0.96 (95% CI 0.89-1.00, p < 0.001) for differentiating patients from healthy volunteers. AUC for the posterior compartment was 0.76 (95% CI 0.57-0.96, p = 0.034).

CONCLUSION

PICS measurements reliably differentiate patients from volunteers in the anterior and middle compartment. Future studies need to identify a reliable threshold for the posterior compartment. PICS and PCL measurements are strongly correlated.

Quantitative 3D Analysis of Levator Ani Muscle Subdivisions in Nulliparous Women: MRI Feasibility Study

BACKGROUND

The levator ani muscle (LAM) is crucial for pelvic floor stability, yet its quantitative MRI assessment is only a recent focus. Our study aims to standardize the quantitative analysis of the LAM morphology within the 3D Pelvic Inclination Correction System (3D-PICS).

METHODS

We analyzed 35 static MR datasets from nulliparous women examining the pubovisceral (PVM), iliococcygeal (ICM), coccygeal (COC), and puborectal muscle (PRM). The PVM consists of three origin-insertion pairs, namely the puboanal (PAM), puboperineal (PPM) and pubovaginal muscle (PVaM). The analysis included a quantitative examination of the morphology of LAM, focusing on the median location (x/y/z) (x: anterior-posterior, y: superior-inferior, z: left-right) of the origin and insertion points (a), angles (b) and lengths (c) of LAM. Inter-rater reliability was calculated.

RESULTS

Interindividual variations in 3D coordinates among muscle subdivisions were shown. In all, 93% of all origin and insertion points were found within an SD of <8 mm. Angles to the xz-plane range between -15.4° (right PRM) and 40.7° (left PAM). The PRM is the largest pelvic muscle in static MRI. The ICC indicated moderate-to-good agreement between raters.

CONCLUSIONS

The accurate morphometry of the LAM and its subdivisions, along with reliable inter-rater agreement, was demonstrated, enhancing the understanding of normal pelvic anatomy in young nulliparous women.

MRI characterization of pelvic floor ligaments in nulliparous women: Technique development and morphometry within the 3D pelvic inclination correction system (3D-PICS)

PURPOSE

The aim of the MRI-study was to evaluate the visibility of the pelvic floor ligaments and to analyze the ligament morphometry in 3D space.

METHODS

Twenty-two nulliparous women underwent MRI with a ligament specific protocol. MR datasets were evaluated using the 3D Pelvic Inclination Correction System (3D-PICS). The round ligament (RL), sacrospinous ligament (SSL), sacrotuberous ligament (STL), urogenital diaphragm (UGD) and uterosacral ligament (USL) were analyzed. Qualitative and quantitative analysis was performed. 3D coordinates for origin and insertion points were determined relative to the symphysis; subsequently lengths and angles were calculated. Interrater reliability was calculated to validate the point determination method.

RESULTS

Moderate to good visibility was reported for the RL, the SSL, the STL and the UGD. Standard deviation of the points analyzed in the different dimensions vary from 1.5 mm to 21.3 mm. Origin and insertion points of the ligaments are found within a mean standard distance of 10.7 mm. The highest variability was seen in insertion points of RL, with a standard distance of 25.4 mm. The interrater reliability was good to very good (range of intraclass correlation coefficients (ICC) from 0.58 to 0.96), except for the UGD ventral points (ICC from 0.27 to 0.55).

CONCLUSIONS

This in-vivo MRI technique development study offers first exact data describing the pelvic floor ligaments in nulliparous women in 3D-PICS. Visibility, exact 3D coordinates of the origin and insertion points, lengths, angles and interrater reliability assessed for all parameters were evaluated morphometrically.