Pelvic Collections on MRI in Patients With Ileal Pouches, and a Feasibility Study of Dynamic MRI Enema and Defaecating MRI Pouchography

Ulcerative Colitis Ulcerative Colitis (UC) is the most common of the inflammatory bowel diseases, with approximately 146,000 sufferers in the UK (NICE, 2011). Unlike other inflammatory bowel diseases, the inflammation in UC affects only the large bowel, starting at the rectum and extending proximally (towards the mouth end of the gut). Three in four patients are managed with medical treatments with acceptable control of their disease, but patients may require surgical removal of their large bowel for several reasons. The one in four patients who have their colon removed (colectomy) either need an emergency operation for infection, perforation or bleeding, or a planned operation for failure of medical management, intolerance to medication, cancer or steroid dependence (1). Because the inflammation is confined only to the colon, this surgery is curative.

Having removed the large bowel, there are options with regard to what to do with the end of the remaining small bowel, the ileum. In 1978 Professor Sir Alan Parks and Professor John Nicholls publicised their operation for 'restorative proctocolectomy' (RPC) folding and suturing together loops of small bowel to create a 'pouch' to take over the reservoir function of the rectum, and giving the patient the chance of continence without the need for a stoma (2,3). This operation has become extremely popular over the last 38 years, and is considered internationally to be the gold standard for 'restorative proctocolectomy' in patients who choose not to have a permanent stoma (4).

The operation has been refined in the years since it's introduction (5), with roughly two thirds of patients enjoying acceptable function. However, the complications associated with creating an RPC; notably pelvic sepsis, fistulae, poor mechanical function and inflammation, mean that the cumulative rate of pouch failure is roughly 5% at five years, and up to 15% at 15 years (Ryoo et al. 2014; Remzi et al. 2015; Sherman et al. 2014; R. et al. 2012; Papadopoulos et al. 2010).

Pouch-Related Septic Complications St Mark's Hospital has one of the largest UK cohorts of patients with RPCs, and is a tertiary referral centre for pouch complications. Of the reasons for pouch failure, chronic pelvic sepsis is the major cause, at 50 to 60%. This is a long term infection in the pelvis around or near the pouch, causing inflammation and poor function.

The pouch itself may become inflamed, known as pouchitis, and the cause for this is unknown, but it is hypothesised that the inflammation is caused by a change in the type of bacteria present in the pouch as opposed to the small bowel when it was in normal continuity.