The accuracy of diagnostic Imaging techniques in patients with a suspected Fracture-related Infection (IFI) trial: study protocol for a prospective multicenter cohort study.

Abstract

IntroductionThe optimal diagnostic imaging strategy for fracture-related infection (FRI) remains to be established. In this prospective study, the three commonly used advanced imaging techniques for diagnosing FRI will be compared. Primary endpoints are (1) determining the overall diagnostic performances of white blood cell (WBC) scintigraphy, fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) in patients with suspected FRI and (2) establishing the most accurate imaging strategy for diagnosing FRI.Methods and analysisThis study is a non-randomised, partially blinded, prospective cohort study involving two level 1 trauma centres in The Netherlands. All adult patients who require advanced medical imaging for suspected FRI are eligible for inclusion. Patients will undergo all three investigational imaging procedures (WBC scintigraphy, FDG-PET and MRI) within a time frame of 14 days after inclusion. The reference standard will be the result of at least five intraoperative sampled microbiology cultures, or, in case of no surgery, the clinical presence or absence of infection at 1 year follow-up. Initially, the results of all three imaging modalities will be available to the treating team as per local protocol. At a later time point, all scans will be centrally reassessed by nuclear medicine physicians and radiologists who are blinded for the identity of the patients and their clinical outcome. The discriminative ability of the imaging modalities will be quantified by several measures of diagnostic accuracy.Ethics and disseminationApproval of the study by the Institutional Review Board has been obtained prior to the start of this study. The results of this trial will be disseminated by publication of peer-reviewed manuscripts, presentation in abstract form at scientific meetings and data sharing with other investigators through academically established means.Trial registration numberThe IFI trial is registered in the Netherlands Trial Register (NTR7490).

Validation of the diagnostic criteria of the consensus definition of fracture-related infection

“…However, only a small number of our patients underwent nuclear imaging (FDG-PET: n = 31, WBC scan: n = 44), which resulted in wide confidence intervals, making it difficult to draw conclusions. Prospective studies are therefore required to gain insight in the diagnostic value of imaging modalities for FRI and their potential added value when combined with certain clinical signs [23] .…”

Definition and diagnosis of fracture-related infection

“…A prospective clinical trial has recently been launched that will hopefully provide more clarity about the optimal imaging strategy for FRI in terms of diagnostic accuracy, cost-effectiveness and how to solve logistic challenges. 22 While awaiting these results, the imaging modality of choice therefore mostly depends on the clinical question to be answered and local availability and experience with the imaging technique of choice.…”

White Blood Cell Scintigraphy for Fracture-Related Infection: Is Semiquantitative Analysis of Equivocal Scans Accurate?

“…Recently, the study protocol for the currently ongoing ‘Imaging techniques in patients with a suspected Fracture-related Infection’ (IFI) trial was published. This prospective multicenter study compares the diagnostic accuracy of MRI, WBC scintigraphy and FDG-PET/CT in patients with suspected FRI [ 13 ]. The results of this study will likely give more insight into alternative diagnostic imaging possibilities for patients with equivocal WBC scintigraphy.…”