Segmentation-Based Analysis of T2-and T1-Weighted Dynamic Magnetic Resonance Images Provides Adequate Observer Agreement in the Evaluation of Interstitial Lung Disease

Objective: The aim of the study is to quantify observer agreement in the magnetic resonance imaging (MRI) classification of inflammatory or fibrotic interstitial lung disease (ILD).Methods: Our study is a preliminary analysis of a larger prospective cohort. The MRI images of 18 patients with ILD (13 females; mean age, 65 years) were acquired in a 1.5 T scanner and included axial fat-saturated T2-weighted (T2-WI, n = 18) and coronal fat-saturated T1-weighted images before and 1, 3, 5, and 10 minutes after gadolinium administration (n = 16). The MRI studies were evaluated with 2 different methods: a qualitative evaluation (visual assessment and measurement of few regions of interest; evaluations were performed independently by 5 radiologists and 3 times by 1 radiologist) and a segmentation-based analysis with software extraction of signal intensity values (evaluations were performed independently by 2 radiologists and twice by 1 radiologist). Interstitial lung disease was classified as inflammatory or fibrotic, based on previously described imaging criteria.Results: Regarding the qualitative evaluation, intraobserver agreement was excellent (kappa = 0.92, P < 0.05) for T2-WI and fair (kappa = 0.29, P < 0.05) for T1 dynamic study, while interobserver agreement was moderate (kappa = 0.56, P < 0.05) and poor (kappa = 0.11, P = 0.18), respectively. In contrast, upon segmentation-based analysis, intraobserver and interobserver agreement were excellent for T2-WI (kappa = 0.886, P < 0.001; kappa = 1.00, P < 0.001; respectively); for T1-WI, intraobserver agreement was excellent (kappa = 0.87, P < 0.05) and interobserver agreement was good (kappa = 0.75, P < 0.05).Conclusions: Segmentation-based MRI analysis is more reproducible than a qualitative evaluation with visual assessment and measurement of few regions of interest.