Andrew Williams

Effect of MRI on clinical outcome of recurrent fistula-in-ano

Recurrent fistula-in-ano is usually due to sepsis missed at surgery, which can be identified by MRI. We aimed to establish the therapeutic effect of MRI in patients with fistula-in-ano. We did MRI in 71 patients with recurrent fistula, with further surgery done at the discretion of the surgeon. Surgery and MRI agreed in 40 patients, five (13%) of whom had further recurrence, compared with 16 (52%) of 31 in whom surgery and MRI disagreed (p=0.0005). Further recurrence in all 16 was at the site predicted by MRI. For surgeons who always acted on MRI, further recurrences arose in four of 25 (16%) operations versus eight of 14 (57%) operations for those who ignored imaging (p=0.008). Surgery guided by MRI reduces further recurrence of fistula-in-ano by 75% and should be done in all patients with recurrent fistula.

The clinical course of fistulating Crohn's disease.

Aim : To determine the clinical characteristics, management and outcome of Crohns fistulas from the time of first presentation.

Response of fistulating Crohn's disease to infliximab treatment assessed by magnetic resonance imaging

Aims : To assess fistula track healing after infliximab treatment using magnetic resonance imaging.

Anal sphincter damage after vaginal delivery using three-dimensional endosonography ☆

Objective To determine the incidence and functional consequences of external sphincter trauma compared with other perineal structures using a novel imaging technique, three-dimensional endosonography. Methods Fifty-five nulliparous women (mean age 30 years, range 18–47 years) had three-dimensional anal endosonography, anal manometry, and questionnaire assessment of continence at a median gestation of 33 weeks (23–42 weeks) and 10 weeks (7–22 weeks) after delivery. Results There was ultrasound evidence of postpartum trauma in 13 of 45 women who had a vaginal delivery (29%, confidence interval [CI] 16%, 44%), involving the external sphincter in five (11%, CI 4%, 24%), the puboanalis in nine (20%, CI 10%, 35%), and the transverse perineii in three (7%, CI 1%, 18%). In four, more than one structure was damaged. External sphincter trauma was associated with a significant decrease in squeeze pressure (P = .035) and an increase in incontinence score (P = .02) compared with those without trauma. Tears to the puboanalis or transverse perineii only did not affect pressure or incontinence scores. Coronal imaging of the external anal sphincter was a useful adjunct to the assessment of trauma. Conclusion The overall incidence of trauma to the sphincter complex was similar to that of previous reports, although actual damage to the external sphincter was less common and represented the only functionally significant component.

Magnetic resonance imaging for primary fistula in ano

This was a prospective study designed to determine the therapeutic impact of magnetic resonance imaging (MRI) in primary fistula in ano, and to assess its effect on outcome.

Assessment of external anal sphincter morphology in idiopathic fecal incontinence with endocoil magnetic resonance imaging

The failure of external anal sphincter repair may relate to sphincter atrophy where muscle fibers are replaced by fat, seen on MRI due to the differing signals returned by fat and muscle tissue. Manometry, electrophysiology, and MRI with an endocoil were performed on 34 fecally incontinent patients with intact sphincters on endosonography. The area of the external sphincter was measured in the midcoronal plane, and the percentage fat content calculated. Sphincter muscle area correlated strongly with squeeze pressure (P < 0.001) but not with percentage fat content. There was no relationship between percentage fat and age, weight, anal sensation, squeeze pressure, sphincter length or width, or pudendal nerve terminal motor latency. There was a trend for smaller sphincters to contain a higher percentage fat content (P = 0.059). MRI has established a relationship between function and external sphincter bulk, but not fat content, although smaller muscles may contain more fat.

Potential clinical implications of direction of a trans-sphincteric anal fistula track

The longitudinal direction of a trans‐sphincteric anal fistula track through the anal sphincter complex may have implications regarding fistulotomy.

Prospective assessment of interobserver agreement for endoanal MRI in fecal incontinence.

AbstractBackground: Endoanal magnetic resonance (MR) imaging is a new technique for the assessment of anal sphincter integrity in fecal incontinence and an alternative to anal endosonography. The present study aimed to determine interobserver variation for assessment of anal sphincter integrity using endoanal MR imaging. Methods: Fifty-two consecutive anally incontinent patients underwent MR imaging by using a purpose-built endoanal receiver coil and static 1.0-T magnet. T2-weighted axial, coronal, and sagittal scans were independently assessed by two radiologists who noted external and internal sphincter integrity. Findings were compared and agreement was assessed with the kappa statistic. Results: There was disagreement in 18 of 49 technically adequate studies (37%; κ= 0.46), indicating “moderate” agreement. Agreement was strongest if the sphincters were either both intact or both disrupted. Observers agreed in only one diagnosis of an isolated internal sphincter defect and in no diagnosis of an isolated external sphincter defect. Conclusion: The overall interobserver agreement for assessment of sphincter integrity using endoanal MR imaging is “moderate.” Interobserver agreement using endoanal MR imaging is less than that reported for anal endosonography.