MRI of the Anal Sphincter

deSouza, Nandita M.; Puni, Rakesh; Kmiot, W. A.; Bartram, Clive I.; Hall, A. S.; Bydder, Graeme M.

doi:10.1097/00004728-199509000-00010

Cited by 67 publications

(29 citation statements)

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“…One study showed that MRI was less accurate than anal endosonography (93), however, others disagree (89). A major contribution of anal MRI has been the recognition of external sphincter atrophy (94) and how this may adversely affect sphincter repair (95). Atrophy may also be present without pudendal neuropathy (96).…”

Section: Magnetic Resonance Imaging (Mri)mentioning

confidence: 99%

Diagnosis and Management of Fecal Incontinence

Rao

2004

Am J Gastroenterology

286

295

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DEFINITIONFecal incontinence is defined as either the involuntary passage or the inability to control the discharge of fecal matter through the anus. Clinically there are three subtypes (a) passive incontinence-the involuntary discharge of stool or gas without awareness; (b) urge incontinence-the discharge of fecal matter in spite of active attempts to retain bowel contents, and (c) fecal seepage-the leakage of stool following otherwise normal evacuation. The severity of incontinence can range from the unintentional elimination of flatus to the seepage of liquid fecal matter or sometimes the complete evacuation of bowel contents. Not surprisingly, these events cause considerable embarrassment, which in turn can lead to a loss of self-esteem, social isolation, and a diminished quality of life (1). EPIDEMIOLOGYAlthough fecal incontinence affects people of all ages, its prevalence is disproportionally higher in women, in the elderly, and in nursing home residents. Estimates of its prevalence vary greatly and depend on the clinical setting, the influence of social stigma, the definition of incontinence, and the frequency of occurrence.In the U.S. householder survey, frequent leakage of stool or fecal staining for more than 1 month was reported by 7.1% and 0.7% of the population, respectively (2). In contrast, two or more episodes of fecal incontinence per month were reported by 0.8% of patients presenting to primary care clinics in the UK (3). In an elderly (>65 yr) self-caring population, fecal incontinence occurred at least once a week in 3.7% of subjects and in more men than women (men:women = 1.5:1) (4). In contrast, 25-35% of institutionalized patients (5) and 10-25% of hospitalized geriatric patients (6) suffer from fecal incontinence. In the United States, fecal incontinence is the second leading cause for placement in nursing homes (6).In a survey of 2,570 households, comprising 6,959 individuals, the prevalence of at least one episode of incontinence during the previous year was 2.2%; among these 63% were women, 30% were >65 yr of age, 36% were incontinent of solid stool, 54% of liquid stool, and 60% of flatus (7). Furthermore, in another prospective survey of patients attending either a gastroenterology or a primary care clinic, over 18% reported fecal incontinence at least once a week (8). Only one third had ever discussed the problem with a physician (8). When stratified for the frequency of episodes, 2.7% of patients reported daily incontinence, 4.5% weekly, and 7.1% once per month (8). In another survey, fecal incontinence was associated with urinary incontinence in 26% of women attending a Uro/Gyn Clinic (9). A higher incidence of mixed fecal and urinary incontinence was also reported in nursing home residents (10, 11).The cost of health care related to fecal incontinence includes items that can be measured such as the evaluation, diagnosis and treatment of incontinence, medications, the use of disposable pads and other ancillary devices, skin care, and nursing care. Approximately $400 million/year we...

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Section: Magnetic Resonance Imaging (Mri)mentioning

confidence: 99%

Diagnosis and Management of Fecal Incontinence

Rao

2004

Am J Gastroenterology

286

295

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“…On coronal images, the thickness of all anal muscles may be compared; such comparison makes external sphincteric atrophy easy to detect (Fig 11). Several studies have demonstrated a good correlation between atrophy as seen at endoanal MR imaging and the findings at surgery and histopathologic investigation of the biopsy specimens (8,9). Therefore, endoanal MR imaging is of major importance in the preoperative assessment of fecal incontinence.…”

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confidence: 98%

Endoanal MR Imaging of the Anal Sphincter in Fecal Incontinence

Rociu¹,

Stoker²,

Zwamborn³

et al. 1999

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Fecal incontinence is a major medical and social problem. The most frequent cause is a pathologic condition of the anal sphincter. Endoanal magnetic resonance (MR) imaging allows detailed visualization of the normal anatomy and pathologic conditions of the anal sphincter. The hyperintense internal sphincter appears as a continuation of the smooth muscle of the rectum; the hypointense external sphincter surrounds the lower part of the internal sphincter. A sphincteric defect is seen as a discontinuity of the muscle ring. Scarring appears as a hypointense deformation of the normal pattern of the muscle layer. Two external sphincteric patterns may be misdiagnosed as defects: a posterior discontinuity (often seen in young male patients) and an anterior discontinuity (often seen in female patients). Atrophy of the external sphincter is easily detected on coronal MR images by comparing the thicknesses of all anal muscles. Endoanal MR imaging is superior to endoanal ultrasonography because of the multiplanar capability and higher inherent contrast resolution of the former. Use of endoanal MR imaging may lead to better selection of candidates for surgery and therefore better surgical results. Endoanal MR imaging is the most accurate technique for detection and characterization of sphincteric lesions and planning of optimal therapy.

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“…Two types of coils are currently in use. One is a cylindric saddle-geometry receiver coil, which ranges from 6 to 10 cm in length and from 7 to 12 mm in diameter (2,4,6,7). The coil is placed in a rigid, thin protective cover and immobilized with an external clamp.…”

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confidence: 99%

Endoluminal MR Imaging of the Rectum and Anus: Technique, Applications, and Pitfalls

Stoker

Rociu²,

Aw³

et al. 1999

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Anorectal diseases (eg, fecal incontinence, perianal and anovaginal fistulas, anorectal tumors) require imaging for proper case management. Endoluminal magnetic resonance (MR) imaging has become an important part of diagnostic work-up in such cases. Optimal endoluminal MR imaging requires careful attention to patient preparation, imaging protocols, and potential pitfalls in interpretation. Comfortable positioning and the use of an antiperistaltic drug are vital for adequate patient preparation. Selected sequences and imaging planes are used in imaging protocols tailored for specific diseases. In fecal incontinence, three-dimensional sequences allow detailed demonstration of the anal anatomy and related defects. In perianal and anovaginal fistulas, longitudinal imaging planes help determine the superior extent of the abnormality. In anorectal tumors, T1-weighted turbo spin-echo MR imaging can help detect extension into the perirectal fat and T2-weighted turbo spin-echo MR imaging is used to optimize contrast between tumor and the rectal wall. Off-axis and radial imaging planes are used in all anorectal diseases to minimize partial volume effects. Potential pitfalls include various parts of the normal anal anatomy mimicking sphincter defects, veins and hemorrhoids mimicking fistulas and abscesses, and overhanging tumor mimicking more extensive tumor. Adequate patient preparation combined with proper technique and a knowledge of potential pitfalls will allow optimal endoluminal MR imaging of the rectum and anus. MR, 757.121411, 757.121413 • Rectum, neoplasms, 757.30 RadioGraphics 1999; 19:383-398 1 From the Departments of Radiology (J.S., E.R., A.W.Z., J.S.L.) and Surgery (W.R.S.), University Hospital Rotterdam Dijkzigt, Erasmus University Rotterdam, the Netherlands, and the Department of Radiology, Academic Medical Center, P.O. Box 22700, 1100 DE Amsterdam, the Netherlands (J.S., J.S.L.). Recipient of a Certificate of Merit award for a scientific exhibit at the 1997 RSNA scientific assembly.

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MRI of the Anal Sphincter

Cited by 67 publications

References 0 publications

Diagnosis and Management of Fecal Incontinence

Diagnosis and Management of Fecal Incontinence

Endoanal MR Imaging of the Anal Sphincter in Fecal Incontinence

Endoluminal MR Imaging of the Rectum and Anus: Technique, Applications, and Pitfalls

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