The accuracy of bowel ultrasound in detecting inflammatory bowel disease

Abstract

Introduction: Inflammatory bowel disease (IBD) is a chronic disease characterised by a chronic relapsing–remitting pattern that causes chronic inflammation in the gastrointestinal tract. This pattern causes long-term bowel damage and complications, such as stenosis and perforation, which affect the patient’s quality of life. Early diagnosis is, therefore, crucial, to ensure effective management of this disease. The diagnostic and monitoring gold standard is a colonoscopic examination with a biopsy. This procedure is invasive and carries the risk of bowel perforation. Therefore, a non-invasive alternative, such as a bowel ultrasound (BUS) examination is advantageous. Therefore, the aim of this study was to determine the accuracy of a BUS examination in the diagnosis of IBD when compared to the gold standard colonoscopy with biopsy. Main research question: What is the accuracy of BUS as a diagnostic imaging modality for the diagnosis of IBD, compared to colonoscopy with biopsy? Methods: The research question was addressed by undertaking a stepwise process to determine the ultrasound accuracy compared to the confirmed (histology) diagnosis (through colonoscopy and biopsy) in patients with IBD. The study population was 77 adult patients with suspected clinical symptoms of IBD, or patients diagnosed with IBD. All participating patients underwent a clinical and biochemical assessment, endoscopic procedures (colonoscopy with biopsy), and an abdominal ultrasound scan of the bowel, which was performed by a single sonographer. Eight ultrasound parameters for IBD were gleaned from the literature and used to perform the BUS examination. The accuracy of BUS for detecting IBD was determined by comparing the BUS diagnosis with the confirmatory diagnosis obtained from the biopsy histological reports. The Fisher’s exact test was performed to determine if a statistically significant association existed between the two variables – the BUS IBD diagnosis and the confirmatory IBD diagnosis – using histological examination at a significance level of 0.05. Fisher’s exact tests were also performed individually on each BUS parameter to determine if a statistically significant association existed between the different diagnostic patient groups. Results: The BUS diagnosis of IBD was accurate in more than 80% of the participating patients in the population. The accuracy estimates of the BUS parameters for the diagnosis of IBD were greater than 80% for bowel wall thickness and vascularity, while the estimates for the other parameters ranged from 66% to 72%. The Fisher’s exact test established a significant association between the BUS diagnosis and the confirmatory diagnosis of IBD (two-tailed p <0.00001). Significance: A BUS is a non-invasive, accurate imaging tool that can be included in the diagnostic workup approach for the primary or first-line examination of IBD. A BUS is a safe, inexpensive procedure that can be used as a screening tool for rapid diagnosis of IBD patients.