Choroid Plexus Volume and Permeability at Brain MRI within the Alzheimer Disease Clinical Spectrum

Background Mounting evidence suggests that the choroid plexus (CP) plays an important role in the pathophysiology of Alzheimer disease (AD), but its imaging profile in cognitive impairment remains unclear. Purpose To evaluate CP volume, permeability, and susceptibility by using MRI in patients at various stages of cognitive impairment. Materials and Methods This retrospective study evaluated patients with cognitive symptoms who underwent 3.0-T MRI of the brain, including dynamic contrast-enhanced (DCE) imaging and quantitative susceptibility mapping (QSM), between January 2013 and May 2020. CP volume was automatically segmented using three-dimensional T1-weighted sequences; the volume transfer constant (ie, <i>K</i>^trans) and fractional plasma volume (ie, <i>V</i>_p) were determined using DCE MRI, and susceptibility was assessed using QSM. The effects of CP volume, expressed as the ratio to intracranial volume, on cognition were evaluated using multivariable linear regression adjusted for age, sex, education, apolipoprotein E ε4 allele status, and volumetric measures. Results A total of 532 patients with cognitive symptoms (mean age, 72 years ± 9 [SD]; 388 women) were included: 78 with subjective cognitive impairment (SCI), 158 with early mild cognitive impairment (MCI), 149 with late MCI, and 147 with AD. Among these, 132 patients underwent DCE MRI and QSM. CP volume was greater in patients at more severe stages (ratio of intracranial volume × 10³: 0.9 ± 0.3 for SCI, 1.0 ± 0.3 for early MCI, 1.1 ± 0.3 for late MCI, and 1.3 ± 0.4 for AD; <i>P</i> < .001). Lower <i>K</i>^trans (<i>r</i> = -0.19; <i>P</i> = .03) and <i>V</i>_p (<i>r</i> = -0.20; <i>P</i> = .02) were negatively associated with CP volume; susceptibility was not (<i>r</i> = 0.15; <i>P</i> = .10). CP volume was negatively associated with memory (<i>B</i> = -0.67; standard error of the mean [SEM], 0.21; <i>P</i> = .01), executive function (<i>B</i> = -0.90; SEM, 0.31; <i>P</i> = .01), and global cognition (<i>B</i> = -0.82; SEM, 0.32; <i>P</i> = .01). Conclusion Among patients with cognitive symptoms, larger choroid plexus volume was associated with severity of cognitive impairment in the Alzheimer disease spectrum. Published under a CC BY 4.0 license. <i>Online supplemental material is available for this article</i>. See also the editorial by Chiang in this issue.