Use of small bowel imaging for the diagnosis and staging of Crohn's disease--a survey of current UK practice

Objectives

This study used a postal survey to assess the current use of small bowel imaging investigations for Crohn’s disease within National Health Service (NHS) radiological practice and to gauge gastroenterological referral patterns.

Methods

Similar questionnaires were posted to departments of radiology (n = 240) and gastroenterology (n = 254) identified, by the databases of the Royal College of Radiologists and British Society of Gastroenterologists. Questionnaires enquired about the use of small bowel imaging in the assessment of Crohn’s disease. In particular, questionnaires described clinical scenarios including first diagnosis, disease staging and assessment of suspected extraluminal complications, obstruction and disease flare. The data were stratified according to patient age.

Results

63 (27%) departments of radiology (20 in teaching hospitals and 43 in district general hospitals (DGHs)) and 73 (29%) departments of gastroenterology replied. These departments were in 119 institutions. Of the 63 departments of radiology, 55 (90%) routinely performed barium follow-though (BaFT), 50 (80%) CT, 29 (46%) small bowel ultrasound (SbUS) and 24 (38%) small bowel MRI. BaFT was the most commonly used investigation across all age groups and indications. SbUS was used mostly for patients younger than 40 years of age with low index of clinical suspicion for Crohn’s disease (in 44% of radiology departments (28/63)). MRI was most frequently used in patients under 20 years of age for staging new disease (in 27% of radiology departments (17/63)) or in whom obstruction was suspected (in 29% of radiology departments (18/63)). CT was preferred for suspected extraluminal complications or obstruction (in 73% (46/63) and 46% (29/63) of radiology departments, respectively). Gastroenterological referrals largely concurred with the imaging modalities chosen by radiologists, although gastroenterologists were less likely to request SbUS and MRI.

Conclusion

BaFT remains the mainstay investigation for luminal small bowel Crohn’s disease, with CT dominating for suspected extraluminal complications. There has been only moderate dissemination of the use of MRI and SbUS.Crohn’s disease is a chronic inflammatory condition of the bowel that predominately affects the young and requires lifelong medical and often surgical therapy 1]. It affects approximately 60 000 people in the UK (around 1 in 1000), with between 3000 and 6000 new diagnoses made each year. Crohn’s disease can affect the digestive system anywhere from the mouth to the anus, but most commonly affects the small intestine and/or colon. Despite advances in technology, the small bowel remains relatively inaccessible to conventional endoscopic techniques. Thus, radiological imaging plays a major role in the assessment and diagnosis of both luminal small bowel disease and extra-enteric complications.Although barium fluoroscopy and CT remain the conventional tests used to investigate Crohn’s disease, both impart a significant radiation dose to patients 2,3]. This is of major importance given the relative youth of the patient population afflicted by Crohn’s disease 4]. The recently published European evidence-based consensus on the diagnosis and management of Crohn’s disease 5] states “the radiation burden from fluoroscopy and CT is considerable, so alternatives such as ultrasound and MRI should be considered when possible”. Advocates of ultrasound and particularly MRI suggest that these modalities could be the ideal “one stop shop” in Crohn’s disease imaging, allowing evaluation of luminal, mural and extramural disease. There is, however, a relatively small evidence base upon which to rationalise the implementation of new imaging technologies within the NHS, and the extent to which they have been disseminated into routine UK clinical practice is unclear. The purpose of the survey reported here was therefore to assess the current use of individual small bowel imaging investigations for Crohn’s disease within the National Health Service (NHS) radiological practice, and to gauge current gastroenterological referral patterns.