Sensitivity of Magnetic Resonance Imaging (MRI) in Detection of Choroidal Metastases: A Retrospective Review

Purpose: To determine the sensitivity of brain magnetic resonance imaging (MRI) in the detection of choroidal metastasis (CM) from systemic primary cancers. Methods: A retrospective chart review identified patients with clinically confirmed CM seen on the Oncology Service (Byers Eye Institute) between January 2018 and March 2022. Patients had an MRI brain and/or orbits performed within 3 months of CM diagnosis. Evaluation of CM detection by MRI was then divided into two parts: an initial “standard read,” where determination of CM detection was based solely on the original radiology report, to reflect real-world performance, and a subsequent “dedicated read,” for which a board-certified neuroradiologist, blinded to the laterality and location of the CM, re-evaluated the studies to provide an objective “gold standard” interpretation regarding the radiographic detection of CM. Results: The study included 42 eyes of 40 patients with confirmed CM. On standard read, MRI detection of CM occurred in 21 of 42 eyes (50%), with no significant difference between MRI brain and orbit protocols (p=0.249). Features associated with improved detection were increased tumor basal diameter (p<0.001) and ultrasonographic tumor thickness (p=0.003). On dedicated read, MRI detection of CM improved to 26 of 33 eyes (76%). Post-gadolinium 3D FLAIR sequence was the most sensitive (88%) for CM detection. 42% and 58% of lesions were visualized using conventional pre-gadolinium T1- and T2-weighted imaging, respectively. Conclusions: MRI sensitivity improved from 50% to 76% with focused reinterpretation. Increased utilization of the FLAIR sequence and increased ocular scrutiny may contribute to earlier diagnosis of CM.