Presentation
Recent anterior resection for colorectal cancer. Rectal discharge.
Patient Data
Defect of posterior aspect of anastomosis with presacral collection with enhancing margins. Non-obstructed small bowel is adherent to apex of collection.
Water soluble contrast enema
This study was 6 months following the prior CT. Persistent leak from posterior aspect of anastomosis into a collection in the presacral space.
CT acquired due to increased pelvic pain, to assess for the possibility of drainable collection.
Interval improvement in pelvic appearances, with no fluid collection and now presacral soft tissue thickening.
Given the CT appearances suggesting possible resolution of the collection, MRI was acquired to provide further information.
At the level of the anastomosis, there is a 2 cm blind-ending thick-walled chronic cavity, with surrounding presacral space fibrosis. No other abnormalities.
Volume T2 acquisitions, pre and post introduction of 120 ml of sterile ultrasound gel per anally.
Low signal band of presacral fibrosis, with no residual fluid collection, and with no passage of gel outside of the lumen of the bowel, indicating a healed leak.
Case Discussion
This case highlights the strengths and weaknesses of different modalities in the assessment of pelvic anastomotic leaks. The leak is clearly delineated on CT and water-soluble contrast enema. On the second CT, no residual collection is visible but the subsequent MRI shows there is a small contained cavity, due to the superior soft tissue resolution of MRI. The final MRI, acquired using an MRI enema protocol, shows the value of using this modality to determine the current status of pelvic inflammation, as well as assess the integrity of the anastomosis, with no radiation imparted.