MRI for pelvic floor dysfunction: can the strain phase be eliminated?

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

PURPOSE

To compare multi-slice (MS) MRI sequences of the pelvis acquired at rest and straining to dynamic midsagittal single-slice (SS) sequences for the assessment of pelvic organ prolapse (POP).

METHODS

This IRB-approved prospective single-center feasibility study included 23 premenopausal symptomatic patients with POP and 22 asymptomatic nulliparous volunteers. MRI of the pelvis at rest and straining was performed with midsagittal SS and MS sequences. Straining effort, visibility of organs and POP grade were scored on both. Organ points (bladder, cervix, anorectum) were measured. Differences between SS and MS sequences were compared with Wilcoxon test.

RESULTS

Straining effort was good in 84.4% on SS and in 64.4% on MS sequences (p = 0.003). Organ points were always visible on MS sequences, whereas the cervix was not fully visible in 31.1-33.3% on SS sequences. At rest, there were no statistically significant differences of organ point measurements between SS and MS sequences in symptomatic patients. At straining, positions of bladder, cervix, and anorectum were + 1.1 cm (± 1.8 cm), - 0.7 cm (± 2.9 cm), and + 0.7 cm (± 1.3 cm) on SS and + 0.4 mm (± 1.7 cm), - 1.4 cm (± 2.6 cm), and + 0.4 cm (± 1.3 cm) on MS sequences (p < 0.05). Only 2 cases of higher-grade POP were missed on MS sequences (both with poor straining effort).

CONCLUSION

MS sequences increase the visibility of organ points compared to SS sequences. Dynamic MS sequences can depict POP if images are acquired with sufficient straining effort. Further work is needed to optimize the depiction of the maximum straining effort with MS sequences.

ACR Appropriateness Criteria® Pelvic Floor Dysfunction in Females

Pelvic floor disorders including pelvic organ prolapse (POP), urinary dysfunction, defecatory dysfunction, and complications after pelvic floor surgery are relatively common in the female population. Imaging tests are obtained when the initial clinical evaluation is thought to be incomplete or inconclusive or demonstrates findings that are discordant with patients' symptoms. An integrated imaging approach is optimal to evaluate the complex anatomy and dynamic functionality of the pelvic floor. Fluoroscopic cystocolpoproctography (CCP) and MR defecography are considered the initial imaging tests of choice for evaluation of POP. Fluoroscopic voiding cystourethrography is considered the initial imaging test for patients with urinary dysfunction. Fluoroscopic CCP and MR defecography are considered the initial imaging test for patients with defecatory dysfunction, whereas ultrasound pelvis transrectal is a complementary test in patients requiring evaluation for anal sphincter defects. MRI pelvis without and with intravenous contrast, MRI pelvis with dynamic maneuvers, and MR defecography are considered the initial imaging tests in patients with suspected complications of prior pelvic floor surgical repair. Transperineal ultrasound is emerging as an important imaging tool, in particular for screening of pelvic floor dysfunction and for evaluation of midurethral slings, vaginal mesh, and complications related to prior pelvic floor surgical repair. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Consensus Definitions and Interpretation Templates for Magnetic Resonance Imaging of Defecatory Pelvic Floor Disorders: Proceedings of the Consensus Meeting of the Pelvic Floor Disorders Consortium of the American Society of Colon and Rectal Surgeons, the Society of Abdominal Radiology, the International Continence Society, the American Urogynecologic Society, the International Urogynecological Association, and the Society of Gynecologic Surgeons

The Pelvic Floor Disorders Consortium (PFDC) is a multidisciplinary organization of colorectal surgeons, urogynecologists, urologists, gynecologists, gastroenterologists, radiologists, physiotherapists, and other advanced care practitioners. Specialists from these fields are all dedicated to the diagnosis and management of patients with pelvic floor conditions, but they approach, evaluate, and treat such patients with their own unique perspectives given the differences in their respective training. The PFDC was formed to bridge gaps and enable collaboration between these specialties. The goal of the PFDC is to develop and evaluate educational programs, create clinical guidelines and algorithms, and promote high quality of care in this unique patient population. The recommendations included in this article represent the work of the PFDC Working Group on Magnetic Resonance Imaging of Pelvic Floor Disorders (members listed alphabetically in Table 1). The objective was to generate inclusive, rather than prescriptive, guidance for all practitioners, irrespective of discipline, involved in the evaluation and treatment of patients with pelvic floor disorders.

MR defecography review

Pelvic floor dysfunction is a relatively common but often complex condition, presenting with a variety of clinical symptoms, especially when it involves multiple compartments. Clinical exam alone is often inadequate and requires a complementary imaging study. Magnetic resonance defecography (MRD) is an excellent noninvasive diagnostic study with its multiplanar capability, lack of ionizing radiation and excellent soft tissue resolution. It can identify both anatomic and functional abnormalities in the pelvic floor and specifically excels in its ability to simultaneously detect multicompartmental pathology and help with vital pre-operative assessment. This manuscript reviews the relevant anatomical landmarks, describes the optimal technique, highlights an approach to the interpretation of MRD, and provides an overview of the various pelvic floor disorders in the different anatomical compartments.

Defecation versus pre- and post-defecation Valsalva maneuvers for dynamic MR assessment of pelvic floor dysfunction

PURPOSE

To compare prevalence and severity of multi-compartment pelvic floor dysfunction between supine magnetic resonance defecography with defecation (MRD) and supine dynamic MRI during Valsalva, both with and without rectal distention.

METHODS

This was an IRB-approved, HIPAA-compliant retrospective review of consecutive patients referred for MR Defecography. MRD protocol included imaging at rest, during pre-defecation Valsalva (Pre-DV), defecation (Def), and post-defecation Valsalva (Post-DV). The Post-DV images were performed after complete evacuation either during the defecation acquisition or, in cases where patient was unable to defecate during the examination, in a conventional toilet. Size of cystocele, vaginal prolapse, anorectal (AR) descent, and enterocele were measured on all acquisitions relative to the pubococcygeal line. Rectocele size was recorded in anteroposterior dimension. The presence or absence of rectal intussusception (RI) was documented. The prevalence, absolute size, and grades of prolapse, rectocele, and RI were compared between the acquisitions using pair-wise ANOVA, Friedman, Dunn pair-wise, and Cochran-Mantel-Haenszel tests.

RESULTS

30 patients were included in the final analysis. Higher prevalence of cystocele, vaginal prolapse, enterocele, AR descent grade 2 or higher, rectocele grade 2 or higher, and RI were seen on Def compared to Post-DV and Pre-DV. Cystocele, vaginal prolapse, enterocele, AR descent, and rectocele sizes were significantly larger on Def compared to Post-DV by 0.7-1.95 cm (p ≤ 0.007). Prolapse in all compartments and rectocele size were significantly larger on Def compared to Pre-DV (p < 0.0001). Cystocele, vaginal prolapse, and enterocele sizes were significantly larger on Post-DV compared to Pre-DV (p < 0.0001). There were significant differences in grading of all types of prolapse and rectocele between the various acquisitions of MRD (p < 0.0001). Cystocele, AR descent, and rectocele grades were significantly higher on Def compared to Post-DV (p range ≤ 0.0002). Grading of all types of prolapse and rectocele was significantly higher on Def compared to Pre-DV (p < 0.0001). Cystocele, vaginal prolapse, and enterocele grades were all significantly higher on Post-DV compared to Pre-DV (p  ≤ 0.0007).

CONCLUSION

Defecation images during supine MRD elicit higher prevalence and size of prolapse of all pelvic compartments in comparison to both pre- and post-defecation Valsalva images. Post-defecation Valsalva images show larger size of anterior and middle compartment prolapse than pre-defecation Valsalva images. Functional evaluation of pelvic floor dysfunction with MRI should include image acquisition during defecation. If Valsalva images are acquired, these should be performed after the defecation acquisition and without rectal distention.

MRI of the Male Pelvic Floor

The pelvic floor is a complex structure that supports the pelvic organs and provides resting tone and voluntary control of the urethral and anal sphincters. Dysfunction of or injury to the pelvic floor can lead to gastrointestinal, urinary, and sexual dysfunction. The prevalence of pelvic floor disorders is much lower in men than in women, and because of this, the majority of the published literature pertaining to MRI of the pelvic floor is oriented toward evaluation of the female pelvic floor. The male pelvic floor has sex-specific differences in anatomy and pathophysiologic disorders. Despite these differences, static and dynamic MRI features of these disorders, specifically gastrointestinal disorders, are similar in both sexes. MRI and MR defecography can be used to evaluate anorectal disorders related to the pelvic floor. MRI can also be used after prostatectomy to help predict the risk of postsurgical incontinence, to evaluate postsurgical function by using dynamic voiding MR cystourethrography, and subsequently, to assess causes of incontinence treatment failure. Increased tone of the pelvic musculature in men secondary to chronic pain can lead to sexual dysfunction. This article reviews normal male pelvic floor anatomy and how it differs from the female pelvis; MRI techniques for imaging the male pelvis; and urinary, gastrointestinal, and sexual conditions related to abnormalities of pelvic floor structures in men.Online supplemental material is available for this article.^©RSNA, 2019.

Supine magnetic resonance defecography for evaluation of anterior compartment prolapse: Comparison with upright voiding cystourethrogram

PURPOSE

To compare utility of supine Magnetic Resonance Defecography (MRD) with upright Voiding Cystourethrogram (VCUG) for evaluation of cystocele and urethral hypermobility (UHM).

METHODS

This was an IRB-approved, HIPAA-compliant, retrospective study of 51 consecutive patients with symptomatic pelvic organ prolapse (POP) and lower urinary tract symptoms who underwent both upright VCUG and supine MRD. Cystocele height was defined in centimeters with reference to the inferior edge of the pubic bone on VCUG and the pubococcygeal line on MRD. Urethral angle at rest (UAR) and during straining (UAS) was measured in degrees between the urethral axis and a vertical line at the external meatus. Pairedt-test and simple linear regression were applied to compare VCUG and MRD data sets. p <  0.05 was considered significant.

RESULTS

The mean cystocele extent was 1.58 cm lower (more inferior to the reference point) (95% CI for the mean difference: 1.21, 1.94;p < 0.0001) on MRD (-2.73 ± 1.99 cm) than on VCUG (-1.16 ± 1.75 cm). Mean UAS on MRD (72.29 ± 26.45) was 31.8 degrees higher compared to that on VCUG (40.45 ± 21.41), (95% CI for mean difference in UAS: 37.57, 26.11; p < 0.0001). Mean UAS-UAR on MRD (74.30 ± 28.50) was 58.6 degrees higher compared to that on VCUG (15.70 ± 11.27) (95% CI for mean difference in UAS-UAR 65.94, 51.26; p < 0.0001). Cystocele size was upgraded in 22 (43.3%) patients on MRD compared to VCUG. Five (9.8%) patients demonstrated UHM on VCUG; 48 (94.1%) patients demonstrated UHM on MRD. The differences between VCUG and MRD scores persisted across the range of VCUG measurements. Cystocele size was significantly larger in POP (+) patients than in POP (-) patients on MRD (p =  0.005) but not on VCUG (p =  0.06).

CONCLUSIONS

Supine MRD demonstrates significantly higher prevalence and degree of cystocele and UHM than upright VCUG, and alters the grade of bladder prolapse in a significant portion of the patient population. Cystocele size on MRD correlates with clinical presence of prolapse symptoms.

Dynamic magnetic resonance imaging of the female pelvic floor-a pictorial review

Pelvic floor dysfunctions represent a range of functional disorders that frequently occur in adult women, carrying a significant burden on the quality of life, and its incidence tends to increase attending to the expected aging of the population. Pelvic floor dysfunctions can manifest as incontinence, constipation, and prolapsed pelvic organs. Since pelvic floor weakness is frequently generalized and clinically underdiagnosed, imaging evaluation is of major importance, especially prior to surgical correction. Given some interobserver variability of soft-tissue measurements, MR defecography allows a noninvasive, radiation-free, multiplanar dynamic evaluation of the three pelvic compartments simultaneously and with high spatial and temporal resolution. Both static/anatomic and dynamic/functional findings are important, since pelvic disorders can manifest as whole pelvic floor weakness/dysfunction or as an isolated or single compartment disorder. Imaging has a preponderant role in accessing pelvic floor disorders, and dynamic MR defecography presents as a reliable option, being able to evaluate the entire pelvic floor for optimal patient management before surgery. The purpose of this article is to address the female pelvic anatomy and explain the appropriate MR Defecography protocol, along with all the anatomic points, lines, angles, and measurements needed for a correct interpretation, to later focus on the different disorders of the female pelvic floor, illustrated with MR defecography images, highlighting the role of this technique in accessing these pathologic conditions.

How to define pathologic pelvic floor descent in MR defecography during defecation?

OBJECTIVES

To assess the extents of pelvic floor descent both during the maximal straining phase and the defecation phase in healthy volunteers and in patients with pelvic floor disorders, studied with MR defecography (MRD), and to define specific threshold values for pelvic floor descent during the defecation phase.

MATERIAL AND METHODS

Twenty-two patients (mean age 51 ± 19.4) with obstructed defecation and 20 healthy volunteers (mean age 33.4 ± 11.5) underwent 3.0T MRD in supine position using midsagittal T2-weighted images. Two radiologists performed measurements in reference to PCL-lines in straining and during defecation. In order to identify cutoff values of pelvic floor measurements for diagnosis of pathologic pelvic floor descent [anterior, middle, and posterior compartments (AC, MC, PC)], receiver-operating characteristic (ROC) curves were plotted.

RESULTS

Pelvic floor descent of all three compartments was significantly larger during defecation than at straining in patients and healthy volunteers (p < 0.002). When grading pelvic floor descent in the straining phase, only two healthy volunteers showed moderate PC descent (10%), which is considered pathologic. However, when applying the grading system during defecation, PC descent was overestimated with 50% of the healthy volunteers (10 of 20) showing moderate PC descent. The AUC for PC measurements during defecation was 0.77 (p = 0.003) and suggests a cutoff value of 45 mm below the PCL to identify patients with pathologic PC descent. With the adapted cutoff, only 15% of healthy volunteers show pathologic PC descent during defecation.

CONCLUSION

MRD measurements during straining and defecation can be used to differentiate patients with pelvic floor dysfunction from healthy volunteers. However, different cutoff values should be used during straining and during defecation to define normal or pathologic PC descent.

Dynamic MRI of the pelvic floor: comparison of performance in supine vs left lateral body position

OBJECTIVE:

To investigate the performance of MR-defecography (MRD) in lateral body position as an alternative to supine position.

METHODS:

22 consecutive patients (16 females; mean age 51 ± 19.4) with obstructed defecation and 20 healthy volunteers (11 females; mean age 33.4 ± 11.5) underwent MRD in a closed-configuration 3T-MRI in supine and lateral position. MRD included T₂ weighted images at rest and during defecation after filling the rectum with 250 ml water-based gel. Measurements were performed in reference to the pubococcygeal line and grade of evacuation was assessed. Image quality (IQ) was rated on a 5-point-scale (5 = excellent).

RESULTS:

In patients grades of middle and posterior compartment descent were similar in both body positions (p > 0.05). Grades of anterior compartment descent were significantly higher in lateral position (21/22 vs 17/22 patients with normal or small descent, p < 0.034). In volunteers grades of descent were similar for all compartments in supine and lateral position (p > 0.05). When attempting to defecate in supine position 6/22 (27%) patients showed no evacuation, while in lateral position only 3/22 (14%) were not able to evacuate. IQ in patients was equal at rest (4.4 ± 0.5 and 4.7 ± 0.6, p > 0.05) and slightly better in supine compared to the lateral position during defecation (4.5 ± 0.4 vs 3.9 ± 0.9, p < 0.017). IQ in volunteers was equal in supine and lateral position (p > 0.05).

CONCLUSION:

In lateral position, more patients were able to evacuate with similar grades of pelvic floor descent compared to supine position. MRD in lateral position may be a valuable alternative for patients unable to defecate in supine position.

ADVANCES IN KNOWLEDGE:

In lateral position, more patients were able to evacuate during MRD. MRD in lateral position may be an alternative for patients unable to defecate in supine position.

Improved Detection of Pelvic Organ Prolapse: Comparative Utility of Defecography Phase Sequence to Nondefecography Valsalva Maneuvers in Dynamic Pelvic Floor Magnetic Resonance Imaging

PURPOSE

To evaluate the utility of a defecography phase (DP) sequence in dynamic pelvic floor MRI (DPMRI), in comparison to DPMRI utilizing only non-defecography Valsalva maneuvers (VM).

MATERIALS AND METHODS

Inclusion criteria identified 237 female patients with symptoms and/or physical exam findings of pelvic floor prolapse. All DPMRI exams were obtained following insertion of ultrasound gel into the rectum and vagina. Steady-state free-precession sequences in sagittal plane were acquired in the resting state, followed by dynamic cine acquisitions during VM and DP. In all phases, two experienced radiologists performed blinded review using the H-line, M-line, Organ prolapse (HMO) system. The presence of a rectocele, enterocele and inferior descent of the anorectal junction, bladder base, and vaginal vault were recorded in all patients using the pubococcygeal line as a fixed landmark.

RESULTS

DPMRI with DP detected significantly more number of patients than VM (p<0.0001) with vaginal prolapse (231/237, 97.5% vs. 177/237, 74.7%), anorectal prolapse (227/237, 95.8% vs. 197/237, 83.1%), cystocele (197/237, 83.1% vs. 108/237, 45.6%), and rectocele (154/237, 65% vs. 93/237, 39.2%). The median cycstocele (3.2cm vs. 1cm), vaginal prolapse (3cm vs. 1.5cm), anorectal prolapse (5.4cm vs. 4.2cm), H-line (8cm vs. 7.2cm) and M-line (5.3cm vs. 3.9cm) were significantly higher with DP than VM (p<0.0001).

CONCLUSIONS

Addition of DP to DPMRI demonstrates a greater degree of pelvic floor instability as compared to imaging performed during VM alone. Pelvic floor structures may show mild descent or appear normal during VM, with marked prolapse on subsequent DP images.

Dynamic Pelvic Magnetic Resonance Imaging Evaluation of Pelvic Organ Prolapse Compared to Physical Examination Findings

OBJECTIVE

To compare dynamic magnetic resonance imaging (dMRI) defecography phase findings with physical examination (PE) grading in the evaluation of pelvic organ prolapse (POP).

METHODS

We retrospectively reviewed 274 consecutive patients who underwent dMRI with defecography. Baden-Walker grading of POP, absolute dMRI values, and grading by dMRI were collected for anterior, apical, and posterior compartments. Anatomically significant POP on PE was defined as Baden-Walker Grade ≥3 and on dMRI by dMRI Grade ≥2. A Spearman's Rank correlation was performed between absolute dMRI values and respective POP grades.

RESULTS

A total of 178 female patients were included. Anatomically insignificant and significant cystoceles had a 26.4% (19/72) and 84.6% (66/78) agreement respectively. Anatomically insignificant and significant apical prolapse had a 2.0% (2/100) and 62.9% (17/27) agreement respectively. Anatomically insignificant and significant posterior prolapse had a 49.5% (51/103) and 78.7% (59/75) agreement respectively. PE detected only 30% (9/30) of total dMRI detected enteroceles and misdiagnosed 10% (3/30) of these patients with a rectocele.

CONCLUSION

The dMRI defecography phase correlated well for anatomically significant prolapse in anterior and posterior compartments. dMRI was superior to PE for enterocele detection and was better able to distinguish an enterocele from a rectocele. Thus, dMRI may have the greatest diagnostic value in cases where the presence of an enterocele is unclear in apical and/or posterior compartments.

Practical guide to dynamic pelvic floor MRI

Pelvic floor dysfunction encompasses a spectrum of functional disorders that result from impairment of the ligaments, fasciae, and muscles supporting the pelvic organs. It is a prevalent disorder that carries a lifetime risk over 10% for undergoing a surgical repair. Pelvic floor weakness presents as a wide range of symptoms, including pain, pelvic pressure or bulging, urinary and fecal incontinence, constipation, and sexual dysfunction. A correct diagnosis by clinical examination alone can be challenging, particularly in cases involving multiple compartments. Magnetic resonance imaging (MRI) allows noninvasive, radiation-free, high soft-tissue resolution evaluation of all three pelvic compartments, and has proved a reliable technique for accurate diagnosis of pelvic floor dysfunction. MR defecography with steady-state sequences allows detailed anatomic and functional evaluation of the pelvic floor. This article provides an overview of normal anatomy and function of the pelvic floor and discusses a practical approach to the evaluation of imaging findings of pelvic floor relaxation, pelvic organ prolapse, fecal incontinence, and obstructed defecation.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1155-1170.