Choroid plexus enlargement in idiopathic normal pressure hydrocephalus and concept proposal for noninvasive volume-reductive therapies.

Aberrant CSF dynamics in idiopathic normal pressure hydrocephalus (iNPH) are associated with excessive CSF volume and impaired resorption. Yet, the role of choroid plexus (CP) size in development and progression of iNPH remains unknown. Moreover, newer noninvasive CP-targeted volume-reductive treatments for iNPH might benefit selected vulnerable patients to avoid problematic long-term ventricular shunting. However, there are no studies to date that describe CP size in iNPH patients. We retrospectively studied brain 3T MRIs for 50 iNPH patients and 50 age and sex-matched healthy controls (HCs). We delineated areas and volumes of lateral ventricular CPs, then statistically compared both cohorts, with significance set at p < 0.05. In iNPH patients, CP volume (1.58-fold) alone, CP volume normalized to total intracranial volume (1.75-fold), and CP areas at four different locations and their combined values (1.24-fold) were highly significantly larger (p < 0.000) in iNPH patients. The novel finding of CP enlargement in iNPH should guide and support future investigations into potentially interrelated pathogenetic mechanisms. It also benefits considerations of new noninvasive targeted therapies (such as MR-guided high intensity focused ultrasound, and radiosurgery) to partially ablate CP and reduce its CSF secretion as a conceivable alternative to conventional ventricular shunting.