Sensitivity of Magnetic Resonance Imaging in Detection of Choroidal Metastases

Abstract

Introduction: The objective of this study was 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, reevaluated 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%; limited to eyes with full complement of pre- and post-gadolinium sequences). Post-gadolinium 3D fluid-attenuated inversion recovery (FLAIR) sequence with fat suppression 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 to detect CM improved from 50% to 76% with focused reinterpretation. Increased utilization of the post-gadolinium 3D FLAIR sequence and increased ocular scrutiny in cancer patients undergoing brain imaging may facilitate earlier diagnosis of CM.

Keywords: Breast cancer; Choroidal metastasis; Lung cancer; Metastasis; Oncology; Radiology.

Fig. 1.

Fundus photography (a) of woman with history of metastatic colorectal adenocarcinoma reveals a macular CM (bounded by white arrows) with subfoveal fluid by optical coherence tomography (b), measuring 0.7 mm in thickness by B scan (c). The lesion is present on axial post-gadolinium brain volume imaging (d) but is difficult to distinguish from adjacent enhancing choroid. Similarly, it can be seen on axial post-gadolinium T1-weighted imaging with fat suppression from a dedicated orbit protocol (e), but the lesion is subtle and difficult to distinguish from adjacent enhancing choroid. It is readily identified on the post-gadolinium, fat-suppressed CUBE FLAIR image (f), as there is less enhancement of normal choroid on this sequence, and fat suppression makes the lesion more conspicuous. The lesion was not seen on routine T1-weighted or T2-weighted images (not shown).