Magnetic resonance imaging of anatomic and dynamic defects of the pelvic floor in defecatory disorders

OBJECTIVE: Endoanal ultrasound identifies anal sphincter anatomy, and evacuation proctography visualizes pelvic floor motion during simulated defecation. These complementary techniques can evaluate obstructed defecation and fecal incontinence. Our aim was to develop a single, nonionizing, minimally invasive modality to image global pelvic floor anatomy and motion. METHODS: We studied six patients with fecal incontinence and seven patients with obstructed defecation. The anal sphincters were imaged with an endoanal magnetic resonance imaging (MRI) coil and endoanal ultrasound (five patients). MR fluoroscopy acquired images every 1.4-2 s, using a modified real-time, T2-weighted, single-shot, fast-spin echo sequence, recording motion as patients squeezed pelvic floor muscles and expelled ultrasound gel; no contrast was added to other pelvic organs. Six patients also had scintigraphic defecography. RESULTS: Endoanal ultrasound and MRI were comparable for imaging defects of the internal and external sphincters. Only MRI revealed puborectalis and/or external sphincter atrophy; four of these patients had fecal incontinence. MR fluoroscopy recorded pelvic floor contraction during squeeze and recorded relaxation during simulated defecation. Corresponding comparisons for angle change and perineal descent during defecation were not significant; only MRI, but not scintigraphy, identified excessive perineal descent in two patients. CONCLUSIONS: Pelvic MRI is a promising single, comprehensive, nonradioactive modality to measure structural and functional pelvic floor disturbances in defecatory disorders. This method may provide insights into mechanisms of normal and disordered pelvic floor function in health and disease.     

Prospective Comparison of Hydrogen Peroxide–Enhanced Three-Dimensional Endoanal Ultrasonography and Endoanal Magnetic Resonance Imaging of Perianal Fistulas

PURPOSE: This study was conducted to determine agreement between hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging in the preoperative assessment of perianal fistulas and to compare these results with the surgical findings. METHODS: Twenty-one patients (aged 26–71 years) with clinical symptoms of a cryptoglandular perianal fistula and a visible external opening underwent preoperative hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography, endoanal magnetic resonance imaging, and surgical exploration. The results were assessed separately by experienced observers blinded as to each others findings. Each fistula was described with notice of the following characteristics: classification of the primary fistula tract according to Parks (intersphincteric, transsphincteric, extrasphincteric, or suprasphincteric), horseshoe, or not classified; presence of secondary tracts (circular or linear); and location of an internal opening. RESULTS: The median time between hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging was 66 (interquartile range, 21–160) days; the median time between the last study (hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography or endoanal magnetic resonance imaging) and surgery was 154 (interquartile range, 95–189) days. Agreement for the classification of the primary fistula tract was 81 percent for hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and surgery, 90 percent for endoanal magnetic resonance imaging and surgery, and 90 percent for hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging. For secondary tracts, agreement was 67 percent for hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and surgery, 57 percent for endoanal magnetic resonance imaging and surgery, and 71 percent for hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging in case of circular tracts and 76 percent, 81 percent, and 71 percent, respectively, in case of linear tracts. Agreement for the location of an internal opening was 86 percent for hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and surgery, 86 percent for endoanal magnetic resonance imaging and surgery, and 90 percent for hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging. CONCLUSIONS: For evaluation of perianal fistulas, hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging have good agreement, especially for classification of the primary fistula tract and the location of an internal opening. These results also show good agreement compared with surgical findings. Therefore, hydrogen peroxide–enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging can both be used as reliable methods for preoperative evaluation of perianal fistulas.     

Dynamic Transperineal Ultrasound in the Diagnosis of Pelvic Floor Disorders

PURPOSE: Defecating proctography and more recently, magnetic resonance imaging have both been used for diagnosis in patients with pelvic floor dysfunction. This pilot study assessed the feasibility of dynamic transperineal ultrasound in a range of specific disorders affecting evacuation. METHODS: A protocol of sagittal and transverse transperineal imaging was established defining the infralevator viscera and soft tissues and the margins of the puborectalis muscle. Dynamic measurements were possible for the extent of puborectalis shortening, the anorectal angle, and the movement during straining of the anorectal junction. Calculations were made of the depth of demonstrated rectoceles, the posterior urethrovesical angle, and the movement of the urethrovesical junction. Diagnoses were confirmed by proctography (where appropriate) and clinical examination. RESULTS: Transverse images of the anal sphincter were comparable with those obtained using endoanal ultrasonography. Sagittal images permitted the measurement of puborectalis contraction and the anorectal angle comparable with those obtained during defecography. Cystoceles were able to be diagnosed during closure of the posterior urethrovesical angle and abnormal urethrovesical junction descent during straining. Rectoceles, peritoneoceles, enteroceles, and rectoanal intussusception were readily identified using dynamic transperineal ultrasonography. CONCLUSION: Dynamic transperineal ultrasound is a simple, noninvasive way to assess dynamically the interaction of the pelvic viscera and their relationship to the pelvic floor musculature in patients with evacuatory disorders and pelvic floor dysfunction.     

Dynamic transperineal ultrasound in the diagnosis of pelvic floor disorders: pilot study

PURPOSE: Defecating proctography and more recently, magnetic resonance imaging have both been used for diagnosis in patients with pelvic floor dysfunction. This pilot study assessed the feasibility of dynamic transperineal ultrasound in a range of specific disorders affecting evacuation. METHODS: A protocol of sagittal and transverse transperineal imaging was established defining the infralevator viscera and soft tissues and the margins of the puborectalis muscle. Dynamic measurements were possible for the extent of puborectalis shortening, the anorectal angle, and the movement during straining of the anorectal junction. Calculations were made of the depth of demonstrated rectoceles, the posterior urethrovesical angle, and the movement of the urethrovesical junction. Diagnoses were confirmed by proctography (where appropriate) and clinical examination. RESULTS: Transverse images of the anal sphincter were comparable with those obtained using endoanal ultrasonography. Sagittal images permitted the measurement of puborectalis contraction and the anorectal angle comparable with those obtained during defecography. Cystoceles were able to be diagnosed during closure of the posterior urethrovesical angle and abnormal urethrovesical junction descent during straining. Rectoceles, peritoneoceles, enteroceles, and rectoanal intussusception were readily identified using dynamic transperineal ultrasonography. CONCLUSION: Dynamic transperineal ultrasound is a simple, noninvasive way to assess dynamically the interaction of the pelvic viscera and their relationship to the pelvic floor musculature in patients with evacuatory disorders and pelvic floor dysfunction.     

Dynamic magnetic resonance imaging evaluation of the structural and functional results of postanal repair for neuropathic fecal incontinence

PURPOSE: The aim of this study was to determine whether dynamic magnetic resonance imaging of the pelvic floor can discriminate between patients who improve after postanal repair for neurogenic fecal incontinence and those who remain symptomatic. METHODS: Pelvic floor measurements obtained during dynamic magnetic resonance imaging in eight females whose anal incontinence had improved after postanal repair were compared with those from nine females who remained symptomatic. All subjects also underwent standard anorectal physiology testing. RESULTS: There was no significant difference between groups with respect to any measurement of anterior or middle pelvic floor compartments. Additionally, there was no difference in posterior pelvic floor configuration when symptomatic patients were compared with those who had improved. However, dynamic magnetic resonance measurements revealed patients who remained symptomatic had significantly greater posterior pelvic floor weakness. Anorectal physiology was unable to differentiate between groups. CONCLUSIONS: There is no difference in static pelvic floor measurements when subjects remaining symptomatic after postanal repair are compared with those who have improved. In contrast, dynamic measurements may be able to predict failure in those who demonstrate excessive posterior pelvic floor mobility.     

Dynamic magnetic resonance imaging defecography: a diagnostic alternative in the assessment of pelvic floor disorders in proctology

PURPOSE: Standard diagnostic proctologic procedures in the assessment of pelvic floor disorders include clinical evaluation and endoscopy. Particular aspects of combined pelvic floor disorders, especially those involving more than one pelvic compartment, may remain undetected without additional technical diagnostic procedures such as videoproctoscopy, cinedefecography, or colpocystodefecography. The aim of the study was to review the potentials of dynamic magnetic resonance imaging defecography to elucidate the underlying anatomic and pathophysiologic background of pelvic floor disorders in proctologic patients. PATIENTS AND METHODS: Dynamic magnetic resonance imaging defecography was performed in 20 Patients (13 females) with main diagnoses such as rectal prolapse or intussusception, rectocele, descending perineum, fecal incontinence, outlet obstruction, and dyskinetic puborectalis muscle after clinical evaluation. The investigation was performed on a 1.5 T-magnetic resonance imaging machine in supine position. The rectum was filled with Gd-DTPA enriched ultrasound gel. First a T1/T2 weighted investigation of the pelvis was performed, followed by defecography with evacuation of the rectum. Images were obtained in a sagittal plane in a frequency of 1 image/second (true FISP) at rest and during straining. The obtained magnetic resonance imaging video tapes were analyzed off-line with cinematographic evaluation of bladder base, uterus, and anal canal position in relation to the pubococcygeal line by a blinded radiologist. Investigation time was 20 minutes. RESULTS: In dynamic magnetic resonance imaging defecography of the pelvic floor, 12 patients with descending perineum, 10 rectoceles (10 females), 6 cystoceles (6 females), 4 enteroceles (4 females), 8 intussusceptions (5 females), and a dyskinetic puborectalis muscle in 3 males were detected. In 11 females and 3 males multifocal disorders were found, involving more than one compartment in females, whereas in males complex defects were restricted to the posterior compartment. Magnetic resonance imaging defecography revealed diagnoses consistent with clinical results in 77.3 percent and defects in addition to clinical diagnoses in combined pelvic floor disorders in 34 percent. CONCLUSIONS: In complex pelvic floor disorders, involving more than a single defect, dynamic magnetic resonance imaging represents a convenient diagnostic procedure in females and to a lesser extent in males, in particular in terms of dynamic imaging of pelvic floor organs during defecation. In addition to the clinical assessment, dynamic magnetic resonance imaging had clinical impact in proctologic and interdisciplinary treatment.Presented in part at the 116th German Congress of Surgery, 1999     

Phenotypic variation in functional disorders of defecation

BACKGROUND & AIMS: Although obstructed defecation is generally attributed to pelvic floor dyssynergia, clinical observations suggest a wider spectrum of anorectal disturbances. Our aim was to characterize phenotypic variability in constipated patients by anorectal assessments. METHODS: Anal pressures, rectal balloon expulsion, rectal sensation, and pelvic floor structure (by endoanal magnetic resonance imaging) and motion (by dynamic magnetic resonance imaging) were assessed in 52 constipated women and 41 age-matched asymptomatic women. Phenotypes were characterized in patients by principal components analysis of these measurements. RESULTS: Among patients, 16 had a hypertensive anal sphincter, 41 had an abnormal rectal balloon expulsion test, and 20 had abnormal rectal sensation. Forty-nine patients (94%) had abnormal pelvic floor motion during evacuation and/or squeeze. After correcting for age and body mass index, 3 principal components explained 71% of variance between patients. These factors were weighted most strongly by perineal descent during evacuation (factor 1), anorectal location at rest (factor 2), and anal resting pressure (factor 3). Factors 1 and 3 discriminated between controls and patients. Compared with patients with normal (n = 23) or reduced (n = 18) perineal descent, patients with increased (n = 11) descent were more likely (P < or = .01) to be obese, have an anal resting pressure >90 mm Hg, and have a normal rectal balloon expulsion test result. CONCLUSIONS: These observations demonstrate that functional defecation disorders comprise a heterogeneous entity that can be subcharacterized by perineal descent during defecation, perineal location at rest, and anal resting pressure. Further studies are needed to ascertain if the phenotypes reflect differences in the natural history of these disorders.     

Relationship between symptoms and disordered continence mechanisms in women with idiopathic faecal incontinence

BACKGROUND AND AIMS: Anal sphincter weakness and rectal sensory disturbances contribute to faecal incontinence (FI). Our aims were to investigate the relationship between symptoms, risk factors, and disordered anorectal and pelvic floor functions in FI. METHODS: In 52 women with "idiopathic" FI and 21 age matched asymptomatic women, we assessed symptoms by standardised questionnaire, anal pressures by manometry, anal sphincter appearance by endoanal ultrasound and magnetic resonance imaging (MRI), pelvic floor motion by dynamic MRI, and rectal compliance and sensation by a barostat. RESULTS: The prevalence of anal sphincter injury (by imaging), reduced anal resting pressure (35% of FI), and reduced squeeze pressures (73% of FI) was higher in FI compared with controls. Puborectalis atrophy (by MRI) was associated (p<0.05) with FI and with impaired anorectal motion during pelvic floor contraction. Volume and pressure thresholds for the desire to defecate were lower, indicating rectal hypersensitivity, in FI. The rectal volume at maximum tolerated pressure (that is, rectal capacity) was reduced in 25% of FI; this volume was associated with the symptom of urge FI (p<0.01) and rectal hypersensitivity (p = 0.02). A combination of predictors (age, body mass index, symptoms, obstetric history, and anal sphincter appearance) explained a substantial proportion of the interindividual variation in anal squeeze pressure (45%) and rectal capacity (35%). CONCLUSIONS: Idiopathic FI in women is a multifactorial disorder resulting from one or more of the following: a disordered pelvic barrier (anal sphincters and puborectalis), or rectal capacity or sensation.     

Dynamic pelvic magnetic resonance imaging and cystocolpoproctography alter surgical management of pelvic floor disorders

PURPOSE: Pelvic organ prolapse results in a spectrum of progressively disabling disorders. Despite attempts to standardize the clinical examination, a variety of imaging techniques are used. The purpose of this study was to evaluate dynamic pelvic magnetic resonance imaging and dynamic cystocolpoproctography in the surgical management of females with complex pelvic floor disorders. METHODS: Twenty-two patients were identified from The Johns Hopkins Pelvic Floor Disorders Center database who had symptoms of complex pelvic organ prolapse and underwent dynamic magnetic resonance, dynamic cystocolpoproctography, and subsequent multidisciplinary review and operative repair. RESULTS: The mean age of the study group was 58 ± 13 years, and all patients were Caucasian. Constipation (95.5 percent), urinary incontinence (77.3 percent), complaints of incomplete fecal evacuation (59.1 percent), and bulging vaginal tissues (54.4 percent) were the most common complaints on presentation. All patients had multiple complaints with a median number of 4 symptoms (range, 2–8). Physical examination, dynamic magnetic resonance imaging, and dynamic cystocolpoproctography were concordant for rectocele, enterocele, cystocele, and perineal descent in only 41 percent of patients. Dynamic imaging lead to changes in the initial operative plan in 41 percent of patients. Dynamic magnetic resonance was the only modality that identified levator ani hernias. Dynamic cystocolpoproctography identified sigmoidoceles and internal rectal prolapse more often than physical examination or dynamic magnetic resonance. CONCLUSIONS: Levator ani hernias are often missed by physical examination and traditional fluoroscopic imaging. Dynamic magnetic resonance and cystocolpoproctography are complementary studies to the physical examination that may alter the surgical management of females with complex pelvic floor disorders.Presented at the meeting of The American Society of Colon and Rectal Surgeons, Boston, Massachusetts, June 24 to 29, 2000.No reprints are available.     

Complex perirectal sepsis: clinical classification and imaging

Background The use of specialized imaging to assess cryptogenic fistula-in-ano is selective, aimed at delineation of the site of the internal fistula opening and the relationship of the primary and secondary tracks and collections to the main levator plate. Advanced imaging also permits definition of the destructive effects of perirectal sepsis (e.g. internal or external anal sphincter damage, perineal body destruction and an ano- or rectovaginal fistula), which may require secondary reconstructive surgery. Methods We performed a PubMed search of outcomes for fistula management in the English and non-English literature, and summarized results regarding the accuracy of internal opening and horseshoe detection as well as the operative correlation for cryptogenic and non-cryptogenic fistula-in-ano using endoanal ultrasound (EAUS) and magnetic resonance (MR) imaging. Only literature defining these characteristics was included. Results The advantages and limitations of the main forms of imaging are discussed in this review with emphasis on EAUS and endoanal or pelvic phased-array MR fistulography. The new technique of transperineal sonography is highlighted. A small but important group of patients with complex fistula-in-ano require specialized imaging. There are specific limitations of endoanal ultrasound (EAUS) which necessitate pelvic phased-array MR imaging. Initial work suggests that EAUS may have a role in intraoperative use for image-guided drainage of recurrent abscesses where operative interpretation can be difficult. The coloproctologist in a tertiary referral center must acquire the skills of ultrasound performance in order to successfully treat fistulous disease, suggesting a role for formal imaging accreditation as part of coloproctological training. Conclusion Future studies should determine both what sequential imaging algorithms for imaging are cost-effective as well as predictive of fistula cure.     

Perineal descent and levator ani hernia: a dynamic magnetic resonance imaging study

PURPOSE: Patients with symptomatic pelvic organ prolapse often have multifocal pelvic floor defects that are not always evident of physical examination. In this study, dynamic magnetic resonance imaging of symptomatic patients with pelvic floor prolapse demonstrated unsuspected levator ani hernia. This study was designed to identify any specific symptoms and/or physical findings associated with these hernias.METHODS: Eighty consecutive patients with pelvic organ prolapse, fecal and/or urinary incontinence, or chronic constipation received standardized questionnaires, physical examination, and dynamic magnetic resonance imaging. Fishers exact test was used to compare symptoms and examination findings between patients with or without levator ani hernia.RESULTS: Twelve patients (15 percent) were found to have unilateral (n = 8) or bilateral (n = 4) levator ani hernias on dynamic magnetic resonance imaging. No one specific symptom was directly associated with the presence of a levator ani hernia. Furthermore, levator ani hernias were not found more frequently in patients with previous pelvic floor surgery. Perineal descent on physical examination was associated with the finding of a levator ani hernia in nine patients (P = 0.02). Although not statistically significant, there was a trend toward a lower incidence of levator ani hernia in females using estrogen replacement therapy (P = 0.06).CONCLUSIONS: Patients with symptomatic pelvic organ prolapse and perineal descent on physical examination may have a levator ani hernia. Although the significance of levator ani hernia needs to be determined, the recurrence rate after the surgical management of pelvic organ prolapse remains unacceptably high, and ongoing investigation of all associated abnormalities is warranted.Data were obtained from the Johns Hopkins Pelvic Floor Database. Poster presentation at The American Society of Colon and Rectal Surgery Meeting, Boston, Massachusetts, June 24 to 29, 2000.     

Anatomical considerations in TNM staging and therapeutical procedures for low rectal cancer

BACKGROUND: Separation of the mesoderm-derived muscular structures and the endoderm-derived structures of the hindgut and reclassification of their involvement based on their embryological origin may be of clinical importance in providing anatomical support for a more standardized perineal resection during abdominoperineal resection. The aim of this study was to utilize magnetic resonance images and histological studies of fetal and neonatal specimens to redefine the T3/T4 distinction by reassessment of the intersphincteric plane and the pelvic diaphragm as they pertain to cancer infiltration and as part of the embryological development of the pelvic floor muscles and their connective tissue compartments. MATERIALS AND METHODS: Pelvic floor anatomy was studied in seven newborn children and 120 embryos and fetuses. Anatomical data were completed by magnetic resonance imaging in 82 patients with T3 and T4 rectal cancers (64 T3, 18 T4; 35 women and 47 men) undergoing neoadjuvant chemoradiation for locally advanced (T3 or T4) rectal cancers. RESULTS: Clear demarcation between mesodermal and endodermal structures of the pelvic floor, which is equally evident in plastinated sections and magnetic resonance images, is already visible in early fetal stages. There is a constitutive overlap between the endoderm- and the ectoderm-derived components of the pelvic floor. CONCLUSION: Our data suggest that the current classification of rectal cancer staging is confusing, where the routinely used TNM classification system unnecessarily differentiates between embryologically identical muscular structures. Tumor spread along the musculature of the hindgut beyond the dentate line could possibly explain the occasional involvement of lymph nodes outside the conventional mesorectum.     

盆腔器官脱垂的动态MRI研究进展

盆腔器官脱垂(pelvic organ prolapse,POP)是指由于盆底支持结构薄弱导致的盆腔器官疝出.动态MRI为无放射性、无创、快捷、全面、高分辨率的检查方法,其软组织对比性强,可清晰显示静息位及动态位时盆底肌肉和筋膜组织结构及功能上的变化,了解盆腔多组织器官的状况,为临床提供客观影像学数据.动态MRI常用于...     

A comparison between dynamic pelvic magnetic resonance imaging and videoproctography in patients with constipation

PURPOSE: This study attempts to compare the diagnostic efficacy of dynamic pelvic magnetic resonance imaging with that of videoproctography for the presence of rectocele, sigmoidocele, and intussusception as well as the measurement of anorectal angle and perineal descent in constipated patients. METHODS: Patients volunteering for the study and fulfilling the criteria for videoproctography to evaluate constipation were also scheduled for dynamic pelvic magnetic resonance imaging. Patients undergoing videoproctography were placed in the left lateral decubitus position, after which 50 ml of liquid barium paste was introduced into the rectum. After this, approximately 100 ml of thick barium paste similar to stool in consistency was injected into the rectum, and the patient was instructed to defecate while video images were taken. For dynamic pelvic magnetic resonance imaging, air, to be used as contrast, was allowed to accumulate in the rectumvia examination with the patient in the prone position. A capsule was taped to the perineal skin immediately posterior to the anal orifice for marking. Sagittal and axial T1 images were obtained through the pelvis at 8-mm intervals with dynamic breathhold sagittal images of the anorectal region obtained at rest and during strain and squeeze maneuvers. Total acquisition time per maneuver was approximately 19 seconds. The tests were performed by different examiners blinded to the result of the other evaluation. The investigations were independently interpreted, findings compared, and patients questioned regarding their impression of dynamic pelvic magnetic resonance imaging and videoproctography. RESULTS: From June 1996 to April 1997, 22 patients (15 females) with a mean age of 68 (range, 21–85) years underwent both videoproctography and dynamic pelvic magnetic resonance imaging. Dynamic pelvic magnetic resonance imaging was only able to detect 1 of 12 (8.3 percent) anterior rectoceles and one of two (50 percent) posterior rectoceles identified by videoproctography. It failed to recognize any of the rectoanal intussusception (zero of four) but did show 9 of 12 (75 percent) sigmoidoceles. Significant discrepancy of measurement of the anorectal angle and perineal descent exists between the two studies, and dynamic pelvic magnetic resonance imaging was not able to detect any (0 of 11) of the patients with increased fixed perineal descent and only half (one of two) of the patients with increased dynamic perineal descent noted on videoproctography. All 22 patients preferred dynamic pelvic magnetic resonance imaging over videoproctography because of greater comfort. CONCLUSION: Occasionally, the increased cost of new technology can be justified by the enhanced diagnostic yield. The ability to avoid unnecessary surgery or, conversely, to continue to search for otherwise occult pathology that can be surgically corrected justifies routine application of these new tools. However, this study has shown that, despite a cost of approximately ten times more for dynamic pelvic magnetic resonance imaging than for videoproctography, no clinical changes were made. Thus, on the basis of this study, we cannot endorse the routine application of dynamic pelvic magnetic resonance imaging for the evaluation of constipated patients. In certain selected individuals, it may play a role, but further study is necessary to clarify its exact role.Supported in part by a generous educational grant from the Caporella family.     

Atrophy and Defects Detection of the External Anal Sphincter: Comparison Between Three-Dimensional Anal Endosonography and Endoanal Magnetic Resonance Imaging

Purpose Using endoanal magnetic resonance imaging, atrophy of the external anal sphincter can be established. This aspect has not been thoroughly investigated using three-dimensional anal endosonography. The purpose of this study was to compare prospectively three-dimensional anal endosonography to magnetic resonance imaging in the detection of atrophy and defects of the external anal sphincter in patients with fecal incontinence. In addition, we compared both techniques for anal sphincter thickness and length measurements. Materials and Methods Patients with fecal incontinence underwent three-dimensional anal endosonography and magnetic resonance imaging. Images of both endoluminal techniques were evaluated for atrophy and defects of the external anal sphincter. External anal sphincter atrophy scoring with three-dimensional anal endosonography depended on the distinction of the external anal sphincter and its reflectivity. External anal sphincter atrophy scoring with magnetic resonance imaging depended on the amount of muscle and the presence of fat replacement. Atrophy score was defined as none, moderate, and severe. A defect was defined at anal endosonography by a hypoechogenic zone and at magnetic resonance imaging as a discontinuity of the sphincteric ring and/or scar tissue. Differences between three-dimensional anal endosonography and magnetic resonance imaging for the detection of external anal sphincter atrophy and defects were calculated. In addition, we compared external anal sphincter thickness and length measurements in three-dimensional anal endosonography and magnetic resonance imaging. Results Eighteen patients were included (median age, 58 years; range, 27–80; 15 women). Three-dimensional anal endosonography and magnetic resonance imaging did not significantly differ for the detection of external anal sphincter atrophy (P = 0.25) and defects (P = 0.38). Three-dimensional anal endosonography demonstrated atrophy in 16 patients, magnetic resonance imaging detected atrophy in 13 patients. Three-dimensional anal endosonography agreed with magnetic resonance imaging in 15 of 18 patients for the detection of external anal sphincter atrophy. Using the grading system, 8 of the 18 patients scored the same grade. Three-dimensional anal endosonography detected seven external anal sphincter defects and magnetic resonance imaging detected ten. Three-dimensional anal endosonography and magnetic resonance imaging agreed on the detection of external anal sphincter defects in 13 of 18 patients. Comparison between three-dimensional anal endosonography and magnetic resonance imaging for sphincter thickness and length measurements showed no statistically significant concordance and had no correlation with external anal sphincter atrophy. Conclusion This is the first study that shows that three-dimensional anal endosonography can be used for detecting external anal sphincter atrophy. Both endoanal techniques are comparable in detecting atrophy and defects of the external anal sphincter, although there is a substantial difference in grading of external anal sphincter atrophy. Correlation between three-dimensional anal endosonography and magnetic resonance imaging for thickness and length measurements is poor. Inconsistency between the two methods needs to be evaluated further. Supported in part by grant No. 945-01-013 from the Netherlands Organization for Health Research and Development. Presented in part at the United European Gastroenterology Week, Prague, Czech Republic, September 25 to 29, 2004. Reprints are not available.     

Klassifikation der Beckenbodeninsuffizienz mit Hilfe der Magnetresonanztomographie (MRT) — ein Schritt zur rationalen Therapie

56 patients suffering from descending perineum syndrome (DPS) were investigated protocologically and by dynamic magnetic resonance imaging (dMRI), that was performed after filling the rectum with contrast media. Dynamic magnetic resonance imaging allowed the accurate evaluation of cystoceles, genital prolapses, rectoceles, enteroceles and external rectal prolapses. However, internal rectal prolapses and mucosal prolapses were diagnosed only in 2 of 10 patients. Based on the findings in dMRI, a new classification of descending perineum syndrome was developed dividing DPS in 4 disease stages. Each of these stages is characterized by a typical constellation of MRI results which facilitates the selection of the adequate treatment. In conclusion, dMRI of the pelvic floor is the most important imaging procedure in planning the correct therapy of DPS, thereby making cystography and defaecography dispensable.     

Correlation of endoanal sonography with cross-sectional anatomy of the anal sphincter

BACKGROUND: Anal endosonography has become an important imaging method in the diagnosis of anorectal disorders. However, little information exists as to whether anal endosonography reliably defines pelvic floor structures. The aim of this study was to correlate endoanal sonography with cross-sectional anatomy and histology. METHODS: Endosonographic tomograms were obtained from 9 human cadavers before fixation and cross-sectioning at identical levels. Muscular layers were defined by visual inspection, histology, immunohistology, and morphometry using three-dimensional sphincter reconstructions. RESULTS: Endosonography visualized only two muscular layers, whereas anatomic sections always revealed three. Comparisons revealed identical findings with regard to internal sphincter volumes and asymmetries. However, due to its failure to identify the longitudinal muscle, endosonography largely overestimated external sphincter volumes. In contrast to current beliefs, anatomic studies failed to detect striated muscle fibers within the longitudinal muscle and did not show an intersphincteric space. However, anatomic cross sections demonstrated "anterior bands" as newly described anchoring mechanisms for the anal sphincters. CONCLUSIONS: Anal endosonography supplies accurate information with regard to internal anal sphincter dimensions, but does not reliably outline deeper muscular layers. However, despite these drawbacks, comparisons of modern imaging techniques with cross-sectional anatomy may enhance our understanding of pelvic floor anatomy.     

Radiologic evaluation of anorectal disorders

Defecation is a dynamic event, and although evacuation proctography does not simulate physiologic defecation exactly, it does provide maximal stress to the pelvic floor and image rectal emptying, both of which are required for the diagnosis of certain conditions: MR imaging studies are attractive in that no ionizing radiation is involved, but unless an evacuation study is performed, the features of anismus, trapping in a rectocele, and intussusception cannot be diagnosed. Because these are the main reasons for investigating difficult defecation, the fluoroscopic examination is the simplest and most reliable method. Endoanal ultrasound is an ideal screening examination for incontinence to show internal sphincter degeneration and tears of the internal or external sphincters. The diagnosis of external sphincter atrophy on ultrasound is not yet resolved, and this remains an important indication for endoanal MR imaging.     

Can three-dimensional endoanal ultrasonography detect external anal sphincter atrophy? A comparison with endoanal magnetic resonance imaging

PURPOSE: Anal sphincter atrophy is associated with a poor clinical outcome of sphincter repair in patients with faecal incontinence. Preoperative assessment of the sphincters is therefore relevant. External anal sphincter (EAS) atrophy can be detected by endoanal magnetic resonance imaging (MRI), but not by conventional endoanal ultrasonography (EUS). Three-dimensional EUS allows multiplanar imaging of the anal sphincters and thus enables more reliable anal sphincter measurements. The aim of the present study was to establish whether 3D EUS measurements can be used to detect EAS atrophy. For this purpose 3D EUS measurements were compared with endoanal MRI measurements. METHODS: Patients with symptoms of faecal incontinence underwent 3D EUS and endoanal MRI. Internal anal sphincter (IAS) and EAS defects were assessed on 3D EUS and endoanal MRI. EAS atrophy was determined on endoanal MRI. The following measurements were performed: EAS length, thickness and area. Furthermore, EAS volume was determined on 3D EUS and compared with EAS thickness and area measured on endoanal MRI. RESULTS: Eighteen parous women (median age 56 years, range 32-80) with symptoms of faecal incontinence were included. Agreement between 3D EUS and endoanal MRI was 61% for IAS defects and 88% for EAS defects. EAS atrophy was seen in all patients on endoanal MRI. Correlation between the two methods for EAS thickness, length and area was poor. In addition, correlation was also poor for EAS volume determined on 3D EUS, and EAS thickness and area measured on endoanal MRI. CONCLUSION: Three-dimensional EUS and endoanal MRI are comparable for detecting EAS defects. However, correlation between the two methods for EAS thickness, length and area is poor. This is also the case for EAS volume determined on 3D EUS and EAS thickness and area measured on endoanal MRI. Three-dimensional EUS can be used for detecting EAS defects, but no 3D EUS measurements are suitable parameters for assessing EAS atrophy.     

Management of perianal fistulas in Crohn’s disease:An upto-date review

Perianal disease is one of the most disabling manifestations of Crohn’s disease.A multidisciplinary approach of gastroenterologist,colorectal surgeon and radiologist is necessary for its management.A correct diagnosis,based on endoscopy,magnetic resonance imaging,endoanal ultrasound and examination under anesthesia,is crucial for perianal fistula treatment.Available medical and surgical therapies are discussedin this review,including new local treatment modalities that are under investigation.