Training with direct feedback for inexperienced readers can improve diagnostic accuracy when evaluating abdominal MRIs for acute appendicitis, according to a study published online June 14 in Radiology. The researchers also found the addition of diffusion-weighted (DW) images to conventional MR images improved reader sensitivity.
The versatility of MRI, as well as awareness of radiation-related risks, is likely to drive an increase in the use of MRI in emergency settings, explained authors Marjolein M.N. Leeuwenburgh, MD, of Academic Medical Center, University of Amsterdam, and colleagues. DW imaging in particular has been shown to be beneficial in identifying acute appendicitis because of the conspicuity of an inflamed appendix on DW images.
The problem, according to the authors, is that most radiologists have little experience evaluating MRIs or DW MRIs for acute abdominal conditions, and that’s why additional training may be needed to close the knowledge gap.
To determine the effect of training with direct feedback, nine radiologists and eight residents without experience for evaluating MRIs for acute abdominal conditions evaluated a training set of images from 100 MRI exams of patients suspected of having appendicitis. After each evaluation, the readers received direct feedback designed to improve accuracy, and reader sensitivity and specificity were calculated for every set of 25 cases to track any improvements.
Results showed average reader sensitivity for detecting appendicitis improved from 0.82 before training to 0.92 after, a significant improvement. Average specificity also ticked up from 0.82 to 0.88, though this increase was not statistically significant.
The readers were asked to record a diagnosis after viewing images from conventional MRI sequences and after viewing DW MRIs. Adding DW images improved sensitivity in all readings from 0.80 to 0.87, according to the authors, a finding consistent with previous research.
“In our study, reading additional DW images helped readers to diagnose cases that they previously considered inconclusive and made readers more certain about their positive and negative diagnoses, although the difference was small,” wrote the authors. “These findings suggest that DW imaging is a valuable technique for detecting acute appendicitis.”
Leeuwenburgh and colleagues noted that radiologists and residents performed equally well in evaluating the images for acute appendicitis. In addition to the improvements in accuracy, reading times also decreased significantly after training. For radiologists, times decreased from 5 minutes 8 seconds per image in the first set of cases to 3 minutes 28 seconds in the last set, and for residents, reading times decreased from 7 minutes 50 seconds to 5 minutes 23 seconds.
The authors emphasized that during out-of-office hours, a resident may be the only person available to evaluate an MRI exam, underscoring the need for training. “Both radiologists and residents must have or acquire the ability to scrutinize MR images in patients with acute abdominal conditions.”