Value of Radiologic Imaging in Orbital Inflammatory Diseases: Diagnostic Accuracy and the Assessment of Activity

Abstract

Purpose : Radiologic orbital imaging plays an essential role in the diagnosis and management of orbital inflammatory diseases. However, there is a paucity of studies verifying the diagnostic value of orbital imaging. In this single-center retrospective cohort study, we investigated the diagnostic accuracy of orbital imaging in diagnosing various orbital inflammatory diseases and the ability for detecting active inflammation.

Methods : We collected 77 scans of 53 patients (50 computed tomography (CT) scans; 27 magnetic resonance (MR) imaging scans). Clinical diagnoses included thyroid eye disease (TED) (n=41), non-specific orbital inflammation (NSOI) (n=22), Sarcoidosis (n=6), IgG4-related orbital disease (IgG4-ROD) (n=5), and granulomatosis with polyangiitis (GPA) (n=3). One experienced neuroradiologist interpreted the scans, made the most likely diagnosis, and assessed the inflammation activity blind to clinical findings. The concordance rate between clinical and radiological diagnosis was evaluated. Sensitivity and specificity of orbital imaging in detecting active inflammation as judged by the treating physician were analyzed in TED and NSOI scans.

Results : The concordance rate was greatest in GPA (100%), followed by TED (95.1%), and NSOI (68.2%). Orbital imaging alone could not diagnose Sarcoidosis or IgG4-ROD. Orbital imaging had a sensitivity of 69.2% (95% confidence interval (CI), 0.48-0.85) and a specificity of 93.3% (95% CI, 0.66-0.99) to predict active TED. The sensitivity was 73.3% (95% CI, 0.45-0.90), and the specificity was 42.9% (95% CI, 0.12-0.79) for the detection of active inflammation in NSOI.

Conclusions : Radiologic orbital imaging is highly accurate for the diagnosis of GPA and TED, but not for NSOI, Sarcoidosis, and IgG4-ROD. Orbital imaging showed moderate sensitivity and high specificity for predicting active TED. The performance for detecting active inflammation was lower in NSOI than TED. Additional studies are required to compare the value of MR to CT and to determine if neoplastic disease can be reliably identified by imaging.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.