Inter and Intraobserver Variation in Interpretation of Fecal Loading on Abdominal Radiographs

Abstract

Objectives: The current gold standard for the diagnosis of functional constipation is the ROME IV criteria. European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and North American Society for Pediatric Gastroenterology, Hepatology & Nutrition (NASPGHAN) guidelines do not support the use of abdominal X-rays in establishing the diagnosis of constipation. Despite these recommendations, abdominal radiography is frequently performed to diagnose constipation. The objective of our study is to evaluate inter and intraobserver variation in interpretation of fecal loading on abdominal radiographs. Methods: Electronic records of 100 children seen in the emergency room for gastrointestinal symptoms who had an abdominal radiograph performed were included. Four physicians from each specialty including gastroenterology, radiology, and emergency medicine interpreted the radiographs independently. Initially, subjective interpretations, followed by interpretations for intraobserver variation were obtained. Subsequently, all physicians were trained and asked to score the X-rays objectively using Barr and Blethyn scoring systems. Consistency between inter and intraobserver ratings of radiographic interpretation was evaluated using the Kappa coefficient (k) which ranges from 0 (no agreement) to 1.0 (perfect agreement). Results: For subjective interpretations, k values showed a fixed margin k of 0.18 indicating poor agreement among 12 observers. Intraobserver k to look for reproducibility showed significant variability ranging from 0.08 (poor) to 0.61 (fair) agreement. Objective scoring results for Blethyn showed a k of 0.14 indicating poor agreement among 12 providers. Conclusions: Reliability and reproducibility of X-rays for diagnosis and grading of constipation is questionable given poor to fair agreement for both inter and intraobserver comparisons. Our study supports the current recommendation of ESPGHAN and NASPGHAN to not use abdominal X-rays to diagnose constipation.

The Diagnostic Accuracy of Abdominal X-ray in Childhood Constipation: A Systematic Review of the Literature

“…In contrast, another recent study found poor interobserver agreement (Kappa coefficient = 36-48%) among radiologists, pediatric gastroenterologists, and pediatric emergency medicine physicians for the "subjective" interpretation of AXRs and poor (38.4%) and fair inter-observer agreement (60%) for the Blethyn and Barr scores, respectively. The Leech score was unfortunately not studied [36].…”

Faecal incontinence: Retentive, non‐retentive and when to suspect organic pathology

“…The big downside of the abdominal radiograph is that there is little reliability and reproducibility of x-rays for diagnosing and grading constipation given the poor to fair agreement for both inter-and intra-observer comparisons. 53 There is also a tendency to consider even a normal amount of faecal load in the colon as excessive. Colons are always filled with faecal material unless a clean-out has been recently used, and this is particularly true for the ascending colon which remains filled with faeces even after a bowel movement.…”

“…The advantage of the radiograph is that it is only minimally invasive and can be used to monitor or diagnose a patient from a distance (for example when telemedicine is being used) or when a thorough physical and rectal examination is not possible (uncooperative, anxious or morbidly obese child). The big downside of the abdominal radiograph is that there is little reliability and reproducibility of x‐rays for diagnosing and grading constipation given the poor to fair agreement for both inter‐ and intra‐observer comparisons 53 . There is also a tendency to consider even a normal amount of faecal load in the colon as excessive.…”

State of the Art Bowel Management for Pediatric Colorectal Problems: Functional Constipation

“…Patients with FC can present with overflow incontinence secondary to constipation that can be visualized on a contrast enema which helps assess colonic anatomy and stool passage [1]. Some gastroenterological studies do not suggest using radiology for the initial diagnosis of FC [27][28][29] with a complete medical history and throughout physical examination being sufficient for the diagnosis establishment [27,30]. However, patients with persistent constipation referred to a pediatric surgeon require other anatomic causes of constipation to be excluded with a contrast enema.…”