The urogynecological side of pelvic floor MRI: the clinician’s needs and the radiologist’s role

MRI of the pelvic floor in female patients with stress urinary incontinence, pre- and postoperative and/or physiotherapy: analysis of the defect-specific approach

Background

Stress urinary incontinence (SUI) is a common disabling pelvic floor dysfunction, particularly among aging women. Magnetic resonance imaging (MRI) with dynamic sequences has been proven reliable for detecting pelvic floor weaknesses, especially with multiple compartments defects. Since surgical and non-surgical management options exist, detailed imaging analysis and comprehension of the various surgical and non-surgical interventions are crucial for surgical planning and postoperative evaluation. However, patients often present with recurrent or new symptoms after surgery, where MR imaging is necessary to detect complications in this setting. We aimed to analyze MR images pre- and postoperative/intervention using the defect-specific approach aiming at better understanding of the underlying complication and/or the cause of recurrence.

Results

Thirty female patients with SUI were included in the study; 20 underwent surgery, 6 were treated by physiotherapy only, while 3 patients underwent both surgery and physiotherapy and 1 patient was treated conservatively. According to their clinical symptoms, patients with successful surgical/physiotherapy outcome were 18 cases (60%), while unsuccessful group comprised of 12 cases (40%) is classified as follows: persistent complaints subgroup 7 patients (23.3%), de novo complaint subgroup 2 patients (6.7%), while the complicated subgroup is comprised of 2 patients (6.7%) and the persistent/de novo complaints subgroup of the unsuccessful group is composed of 1 case (3.3%). They all underwent MRI of the pelvic floor with a standardized technique, pre- and postoperative/physiotherapy. Changes in level III endopelvic fascia defects between the pre- and postoperative/physiotherapy studies were statistically significant (p = 0.045). Urinary bladder and uterine descent were also found statistically significant between the pre- and postoperative/physiotherapy studies (p = 0.001 and p = 0.029, respectively). Comparing successful and unsuccessful groups pre- and postoperative/therapy, levator plate angle (LPA) was found statistically significant as well (p = 0.039 preoperative and p = 0.001 postoperative).

Conclusions

Analysis of the pre- and postoperative static and dynamic MRI sequences along with proper understanding of the preformed intervention can pinpoint the underlying pathology leading to the recurrent or de novo symptom and/or complications. The defect-specific approach can help determine the underlying pelvic floor defect by altering the MRI techniques tailored for each patient according to their complaint.

The establishment of a 3D anatomical coordinate system for defining vaginal axis and spatial position

BACKGROUND AND OBJECTIVE

Pelvic organ prolapse (POP), the herniation of the pelvic organs toward the vaginal opening, is a common pelvic floor disorder (PFD) whose etiology is poorly understood. Traditional methods for evaluating POP are often constrained to external vaginal examination, limited to 2D, or have poor reproducibility. We propose a reliable 3D anatomic coordinate system for standardized 3D assessment of pelvic anatomy using magnetic resonance imaging (MRI).

METHODS

The novel 3D anatomic reference system is based on six bony landmarks of the pelvis manually identified in MRI: the ischial spines and the superior and inferior pubic points of the left and right pubic symphysis. The origin of this system is defined as the midpoint of the ischial spines. The reproducibility and applicability of the pelvic coordinate system were evaluated by (1) implementing it in a new method to quantify vaginal position and axis (angulation) in 3D space from MRI segmentations of the vagina and (2) computing the intraclass correlation (ICC) on coordinate system and vaginal measures. The MRI analysis was performed by four non-medically trained observers on five pelvic MRI datasets on approximately five separate occasions.

RESULTS

Overall, all bony landmarks had excellent intra-observer reliability and inter-observer reliability (ICC>0.90); intra-observer reliability was moderate-to-good among the vaginal position parameters (0.5<ICC≤0.90) and moderate for the vaginal axis angles (0.50<ICC≤0.75); inter-observer reliability was moderate in the vaginal position coordinates and vaginal axis measures. On average, within-observer differences in the vaginal position and angle measures relative to the overall mean were <1 mm and <1°, respectively.

CONCLUSIONS

The proposed anatomic coordinate system and vaginal analysis approach allow quantitative assessment of pelvic anatomy that is robust to the experience level of the observer. The application of these methods in radiographic studies will give new insight into the underlying anatomic changes involved in the pathogenesis of POP and other PFDs and help better understand their etiology.

Solitary rectal ulcer syndrome (SRUS): observational case series findings on MR defecography

OBJECTIVE

Radiological findings in solitary rectal ulcer syndrome (SRUS) are well described for evacuation proctography (EP) but sparse for magnetic resonance defecography (MRD). In order to rectify this, we describe the spectrum of MRD findings in patients with histologically proven SRUS.

MATERIALS AND METHODS

MRD from twenty-eight patients (18 female; 10 males) with histologically confirmed SRUS were identified. MRD employed a 1.5-T magnet and a standardized technique with the rectal lumen filled with gel and imaged sagittally in the supine position, before, during, and after attempted rectal evacuation. A single radiologist observer with 5 years' experience in pelvic floor imaging made the anatomical and functional measurements.

RESULTS

Sixteen patients (10 female) demonstrated internal rectal intussusception and 3 patients (11%) demonstrated complete external rectal prolapse. Anterior rectoceles were noted in 12 female patients (43%). Associated anterior and middle compartment weakness (evidenced by excessive descent) was observed in 18 patients (64%). Cystocele was found in 14 patients (50%) and uterine prolapse was noted in 7 patients (25%). Enterocoeles were detected in 5 patients (18%) and peritoneocoele in 5 patients (18%). None had sigmoidocoele. Sixteen patients (57%) demonstrated delayed voiding and 13 patients (46%) incomplete voiding, suggesting defecatory dyssynergia.

CONCLUSION

MRD can identify and grade both rectal intussusception and dyssynergia in SRUS, and also depict associated anterior and/or middle compartment descent. Distinction between structural and functional findings has important therapeutic implications.

KEY POINTS

MRD can identify and grade both rectal intussusception and dyssynergia in patients with SRUS. MRD is an acceptable substitute to evacuation proctography in assessing anorectal dysfunctions when attempting to avoid ionizing radiation. SRUS influences the pelvic floor globally. MRD depicts associated anterior and/or middle compartment prolapse.

Tactile and Ultrasound Image Fusion for Functional Assessment of the Female Pelvic Floor

INTRODUCTION

The true etiology of pelvic organ prolapse and urinary incontinence and variations observed among individuals are not entirely understood. Tactile (stress) and ultrasound (anatomy, strain) image fusion may furnish new insights into the female pelvic floor conditions. This study aimed to explore imaging performance and clinical value of vaginal tactile and ultrasound image fusion for characterization of the female pelvic floor.

METHODS

A novel probe with 96 tactile and 192 ultrasound transducers was designed. Women scheduled for a urogynecological visit were considered eligible for enrollment to observational study. Intravaginal tactile and ultrasound images were acquired for vaginal wall deformations at probe insertion, elevation, rotation, Valsalva maneuver, voluntary contractions, involuntary relaxation, and reflex pelvic muscle contractions. Biomechanical mapping has included tactile/ultrasound imaging and functional imaging.

RESULTS

Twenty women were successfully studied with the probe. Tactile and ultrasound images for tissues deformation as well as functional images were recorded. Tactile (stress) and ultrasound (strain) images allowed creation of stress-strain maps for the tissues of interest in absolute scale. Functional images allowed identification of active pelvic structures and their biomechanical characterization (anatomical measurements, contractive mobility and strength). Fusion of the modalities has allowed recognition and characterization of levator ani muscles (pubococcygeal, puborectal, iliococcygeal), perineum, urethral and anorectal complexes critical in prolapse and/or incontinence development.

CONCLUSIONS

Vaginal tactile and ultrasound image fusion provides unique data for biomechanical characterization of the female pelvic floor. Bringing novel biomechanical characterization for critical soft tissues/structures may provide extended scientific knowledge and improve clinical practice.

How to develop and sustain a successful pelvic floor MRI practice

PURPOSE

Magnetic resonance imaging (MRI) of the pelvic floor has become a commonly requested diagnostic tool for pelvic floor assessment. We provide a practical guide for developing, growing, and troubleshooting a dedicated pelvic floor imaging service.

METHODS

The authors provide an organized approach to the development of a pelvic floor MRI program based on the experience of the SAR Pelvic Floor Disease Focused Panel in academic and private practice settings. Topics addressed include creating interest, staff education, patient preparation both before and after arrival to the imaging center, image acquisition, reporting, and troubleshooting.

RESULTS

Using the organization and approach in this guide, the challenge of growing this relatively complex imaging program can be simplified. Familiarity with best practices and established techniques used by successful programs will allow new sites to avoid early pitfalls and quickly develop a mature and autonomous workflow.

CONCLUSIONS

The development and growing of a pelvic floor MRI program presents its own set of challenges and unique workflow issues which can create anxiety in both patients and providers. We systematically present an approach to streamline the development of a successful pelvic floor MRI program.

Multimodality imaging of pelvic floor anatomy

The pelvic floor is composed of a network of muscles, ligaments, and fasciae, which provide active and passive support for the pelvic organs. Impairment of these pelvic floor elements can result in a variety of functional abnormalities and single or multicompartment organ prolapse. Knowledge of normal pelvic floor anatomy can aid the radiologist in understanding the complex nature of pelvic floor dysfunction and is important for comprehensive image interpretation. This article provides an overview of normal anatomy of the pelvic floor as seen on magnetic resonance imaging, ultrasound, and fluoroscopic studies performed in the evaluation of pelvic floor function.

Magnetic Resonance Imaging of the Female Pelvic Floor: Anatomy Overview, Indications, and Imaging Protocols

This article reviews different approaches for describing pelvic floor anatomy; "Classic 3-Compartment Approach", "Active and Passive Conceptual Approach" and "Multilayered System Approach". However, these approaches cannot explain pathogenesis of various dysfunctions. "Functional 3-Part Pelvic Supporting Systems Approach" a new, more function-based classification of the pelvic floor support system is introduced in which all structures that contribute to same function are grouped under 1 system. Indications for MR imaging of pelvic floor dysfunction, patients' preparation, static, dynamic and MR Defecography imaging protocols are detailed according to the concordance of experts in two recently published consensus papers.

Cystocele and functional anatomy of the pelvic floor: review and update of the various theories

INTRODUCTION AND HYPOTHESIS

We updated anatomic theories of pelvic organ support to determine pathophysiology in various forms of cystocele.

METHODS

PubMed/MEDLINE, ScienceDirect, Cochrane Library, and Web of Science databases were searched using the terms pelvic floor, cystocele, anatomy, connective tissue, endopelvic fascia, and pelvic mobility. We retrieved 612 articles, of which 61 matched our topic and thus were selected. Anatomic structures of bladder support and their roles in cystocele onset were determined on the international anatomic classification; the various anatomic theories of pelvic organ support were reviewed and a synthesis was made of theories of cystocele pathophysiology.

RESULTS

Anterior vaginal support structures comprise pubocervical fascia, tendinous arcs, endopelvic fascia, and levator ani muscle. DeLancey's theory was based on anatomic models and, later, magnetic resonance imaging (MRI), establishing a three-level anatomopathologic definition of prolapse. Petros's integral theory demonstrated interdependence between pelvic organ support systems, linking ligament-fascia lesions, and clinical expression. Apical cystocele is induced by failure of the pubocervical fascia and insertion of its cervical ring; lower cystocele is induced by pubocervical fascia (medial cystocele) or endopelvic fascia failure at its arcus tendineus fasciae pelvis attachment (lateral cystocele).

CONCLUSIONS

Improved anatomic knowledge of vaginal wall support mechanisms will improve understanding of cystocele pathophysiology, diagnosis of the various types, and surgical techniques. The two most relevant theories, DeLancey's and Petros's, are complementary, enriching knowledge of pelvic functional anatomy, but differ in mechanism. Three-dimensional digital models could integrate and assess the mechanical properties of each anatomic structure.