Assessing morphological changes in the choroid plexus between standing and supine positions using a rotatable MRI system

The choroid plexus (ChP) is crucial for most cerebrospinal fluid (CSF) secretion. However, few studies have explored the morphology of ChP in a natural upright posture. This study investigated the positional, areal, and volumetric changes of the ChP in response to gravity when comparing supine and upright scanning postures. Thirty-one healthy volunteers underwent MRI scans using an innovative 1.5T rotatable MRI at pitch angles of 0 and 90 employing a 3D magnetization-prepared rapid gradient echo (MP-RAGE) sequence. Based on an in-house ChP segmentation pipeline, gap lengths between the ChP and lateral ventricles (LVEN), ChP surface area, volumes, and signal intensities in different directions were measured. The ChP exhibited a bottom gap decrease (-1.30 mm, P < 0.001), posterior gap increase (1.28 mm, P < 0.001), and bilateral gap growth (0.16 mm, P = 0.015) as well as downward centroidal shift (-1.31 mm, P < 0.001) relative to the LVEN when transitioning from lying to standing positions. Significant distance deviations were noted along the direction of gravity. Along with these positional changes, decreases in surface area (-5.30%, P = 0.021) and volume (-7.53%, P = 0.002) and an increase (11.46%, P < 0.001) in signal intensity of the ChP were observed from lying to standing. This study reveals the positional and volumetric change of the ChP within the LVEN with postural changes and demonstrates its morphology in a typical standing condition. These anatomic changes could provide additional evidence of CSF circulation and intracranial pressure in different postures.