Unpublished research from St Mark's completed at the end of 2015 http://scripties.umcg.eldoc.ub.rug.nl/root/geneeskunde/2016/PloegVvander/ showed that in 68 patients treated for primary idiopathic pouchitis, 38% had an incidental pre-sacral collection identified on MRI, potentially consistent with pelvic sepsis driving the inflammation, rather than the inflammation rising primarily from the pouch itself.