The current role of imaging techniques in faecal incontinence

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.

Magnetic resonance imaging of pelvic floor disorders

Physical examination alone is often inadequate for evaluation of pelvic floor dysfunction. Magnetic resonance imaging (MRI) is a robust modality that can provide high-quality anatomic and functional evaluation of the pelvic floor. Although lack of standardized technique and radiologist inexperience may be relative deterrents in universal acceptance of pelvic floor MRI, the role of MRI is increasing as it is technically feasible on most magnets and offers some advantages over the traditional fluoroscopic defecography. This review focuses on the technical and interpretational aspects of anatomic and functional pelvic floor MRI.

Does conventional defecography has a role to play in evaluation of evacuatory disorders in Indian population?

Barium studies are one of the best investigations for evaluating submucosal and extrinsic mass lesions. However, barium studies bring less money, are operator dependent and one of the more difficult investigations for radiologists to master. Economic factors have acted as powerful disincentives for performing gastrointestinal (GI) fluoroscopy in most radiology practices. In this pictorial essay, we discuss the role of conventional defecography in evaluating evacuatory disorders in the Indian population.

Dose-effect relationships for individual pelvic floor muscles and anorectal complaints after prostate radiotherapy

PURPOSE

To delineate the individual pelvic floor muscles considered to be involved in anorectal toxicity and to investigate dose-effect relationships for fecal incontinence-related complaints after prostate radiotherapy (RT).

METHODS AND MATERIALS

In 48 patients treated for localized prostate cancer, the internal anal sphincter (IAS) muscle, the external anal sphincter (EAS) muscle, the puborectalis muscle (PRM), and the levator ani muscles (LAM) in addition to the anal wall (Awall) and rectal wall (Rwall) were retrospectively delineated on planning computed tomography scans. Dose parameters were obtained and compared between patients with and without fecal urgency, incontinence, and frequency. Dose-effect curves were constructed. Finally, the effect of an endorectal balloon, which was applied in 28 patients, was investigated.

RESULTS

The total volume of the pelvic floor muscles together was about three times that of the Awall. The PRM was exposed to the highest RT dose, whereas the EAS received the lowest dose. Several anal and rectal dose parameters, as well as doses to all separate pelvic floor muscles, were associated with urgency, while incontinence was associated mainly with doses to the EAS and PRM. Based on the dose-effect curves, the following constraints regarding mean doses could be deduced to reduce the risk of urgency: ≤ 30 Gy to the IAS; ≤ 10 Gy to the EAS; ≤ 50 Gy to the PRM; and ≤ 40 Gy to the LAM. No dose-effect relationships for frequency were observed. Patients treated with an endorectal balloon reported significantly less urgency and incontinence, while their treatment plans showed significantly lower doses to the Awall, Rwall, and all pelvic floor muscles.

CONCLUSIONS

Incontinence-related complaints show specific dose-effect relationships to individual pelvic floor muscles. Dose constraints for each muscle can be identified for RT planning. When only the Awall is delineated, substantial components of the continence apparatus are excluded.

Time-resolved MRI after ingestion of liquids reveals motility changes after laparoscopic sleeve gastrectomy--preliminary results

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is generally considered a restrictive procedure. However, studies with nuclear medicine techniques have demonstrated that gastric motility changes occur following LSG. These motility changes could represent complementary mechanisms of weight loss. Therefore, we analyzed the stomach motility before and after LSG by means of dynamic MRI.

METHODS

In this prospective pilot study, five female patients with a mean BMI of 51.6 kg/m(2) underwent MRI 1 day before LSG and 6 days and 6 months after LSG. Dynamic steady-state free precession sequences were used to analyze the gastric motility after ingestion of 500 ml water with a temporal resolution of 0.86 s. Axial image stacks were also repeatedly acquired to determine the intragastric fluid volume over time.

RESULTS

Mean excess body mass index loss was 60.6% after 6 months. Dynamic analysis showed that antral propulsive peristalsis was preserved immediately after surgery and during follow-up, but fold speed increased significantly from 2.7 mm/s before LSG to 4.4 mm/s after 6 months. The sleeve itself remained without recognizable peristalsis in three patients and showed only uncoordinated or passive motion in two patients. Consequently, the fluid transport through the sleeve was markedly delayed, whereas the antrum showed accelerated propulsion with the emptying half-time decreasing from 16.5 min preoperatively to 7.9 min 6 months after surgery.

CONCLUSIONS

Owing to the LSG procedure, the stomach is functionally divided into a sleeve without propulsive peristalsis and an accelerated antrum. Accelerated emptying seems to be caused by faster peristaltic folds.

Dynamic MR defecography with an open-configuration, low-field, tilting MR system in patients with pelvic floor disorders

PURPOSE

This study was undertaken to explore the capabilities of an open-configuration, low-field, tilting, magnetic resonance (MR) system for investigating pelvic floor disorders and to compare the results obtained with the patient in the semiorthostatic and supine positions.

MATERIALS AND METHODS

Eighteen female patients with a diagnosis of pelvic floor disorder (physical examination and conventional defecography) underwent dynamic MR defecography (MRD) with a 0.25-T tilting MR system (G-scan, Esaote). Images were obtained after administration of contrast agent into the rectum, bladder and vagina in both the orthostatic and supine positions. Three-dimensional T2-weighted hybrid contrast-enhanced (HYCE) sequences and dynamic T1-weighted gradient echo (GE) sequences were acquired at rest, during maximal contraction of the anal sphincter, straining and defecation.

RESULTS

Good image quality was obtained in 15/18 patients; three presented severe artefacts due to motion, and three had incontinence, which hampered the functional studies. Better anatomical detail was obtained with MRD compared with conventional defecography. Three prolapses were observed in the semiorthostatic position only, and seven were found to be more severe in the orthostatic than in the supine position.

CONCLUSIONS

Dynamic MRD with an open-configuration, low-field, tilting MR system is a feasible and promising tool for studying the pelvic floor. Larger series are necessary to assess its real diagnostic value.

Comparison of anorectal manometry to endoanal ultrasound in the evaluation of fecal incontinence

BACKGROUND

Fecal incontinence (FI) is a common clinical condition with a negative impact on the quality of life. Commonly performed tests to evaluate FI include anorectal manometry (ARM) and endoanal ultrasonography (EAU). Objective of our study was to compare the results of these 2 tests in a cohort of patients with FI.

METHODS

Retrospective study of 27 patients (20 women) referred to the gastrointestinal motility clinic for FI. EAU and ARM were performed in all patients. Demographic data and information regarding etiology of FI was also recorded.

RESULTS

Mean age of the patients was 56 years (range 26-87 years). Etiology of FI was obstetric trauma in 4, pelvic surgery in 9, pelvic trauma in 3, pelvic radiation in 1, and idiopathic in 8. Based on the ARM data, 14 of 27 had a weak external sphincter squeeze pressure and 3 had impaired rectal sensation, whereas with the EAU there was thinning of the external anal sphincter in 3 and complete disruption in 1, and abnormalities of the internal anal sphincter (IAS) in 7 of 27 with thinning, and defects. Overall, only 2 of 27 had normal findings by combined ARM and EAU.

CONCLUSIONS

Although the yield of finding major sphincter defects was low, only a small percentage of patients had a normal ARM or EAU. When there are degrees of external anal sphincter thinning or partial or complete disruption of the sphincters, a good correlation with ARM is achieved. EAU and ARM are complimentary investigations for the thorough assessment of the anal sphincter apparatus.

Dynamic MR imaging of the pelvic floor: a pictorial review

Pelvic floor dysfunctions involving some or all pelvic viscera are complex conditions that occur frequently and primarily affect adult women. Because abnormalities of the three pelvic compartments are frequently associated, a complete survey of the entire pelvis is necessary for optimal patient management, especially before surgical correction is attempted. With the increasing use of magnetic resonance (MR) imaging in assessing functional disorders of the pelvic floor, familiarity with normal imaging findings and features of pathologic conditions are important for radiologists. Dynamic MR imaging of the pelvic floor is an excellent tool for assessing functional disorders of the pelvic floor such as pelvic organ prolapse, outlet obstruction, and incontinence. Findings reported at dynamic MR imaging of the pelvic floor are valuable for selecting patients who are candidates for surgical treatment and for choosing the appropriate surgical approach. This pictorial essay reviews MR imaging findings of pelvic organ prolapse, fecal incontinence, and obstructed defecation. Supplemental material available at http://radiographics.rsnajnls.org/cgi/content/full/e35v1/DC1.

Correlative anatomy of the anus and rectum

An overview of the normal anatomy of the anus and rectum is provided with an emphasis on correlative imaging, including computed tomography, magnetic resonance, and ultrasound. The major clinically important structures that can be assessed with these imaging modalities are reviewed.

Bowel management for paediatric patients with faecal incontinence

This review assesses the incidence and aetiology of faecal incontinence in childhood. We then systematically address the presentation, clinical assessment, investigation and management of these children. Under management, both medical and surgical approaches and their complications are discussed.

Radiologic evaluation of pelvic floor disorders

Several imaging modalities are available ranging from fluoroscopic techniques to ultrasonography and MRI for the evaluation of patients with pelvic floors disorders. High-resolution ultrasonography and MRI not only provide superior delineation of the pelvic floor anatomy but also reveal pathology and functional changes. This article focuses on standard imaging procedures including defecography, ultrasonography, and MRI and discusses its use in clinical practice by illustrating both normal and abnormal patterns.

Dynamic MR defecography of the posterior compartment: Indications, techniques and MRI features

Pelvic floor weakness is characterized by abnormal symptomatic displacement of pelvic organs. It represents a complex clinical problem most commonly seen in middle-aged and elderly parous women. Its diagnosis remains difficult in many cases, since these disorders typically present with nonspecific symptoms, such as pelvic pain, incontinence and constipation. Fluoroscopic colpocystodefecography has been proven to surpass physical examination in the detection and characterization of functional abnormalities of the anorectum and surrounding pelvic structures. Similarly, MR defecography, performed either with an open- or closed-configuration unit, appears to be an accurate imaging technique to assess clinically relevant pelvic floor abnormalities. Moreover, MR defecography negates the need to expose the patient to harmful ionizing radiation and allows excellent depiction of the surrounding soft tissues of the pelvis. In this manuscript, we review the techniques and indications of MR defecography, and illustrate the MRI features of a vast array of morphologic and functional pelvic floor disorders, with emphasis on the posterior pelvic compartment (anorectum).