Radiology: Application of choroidal plexus volume and permeability in the clinical spectrum of Alzheimer's disease in cranial MRI

Alzheimer's disease (AD) is the most common form of dementia and is characterized by extracellular amyloid plaques and intracellular accumulation
of tau protein.
The deposition of both amyloid and tau proteins can lead to neurodegeneration, which ultimately leads to cognitive decline and memory loss
.
There is growing evidence that failure to clear the accumulation of these proteins rather than overproduction of proteins is responsible for
the development of AD.
Most of the suggested pathways of clearance are related to cerebrospinal fluid (CSF), including degradation and cellular absorption, transport across the blood-brain barrier and blood-CSF barrier, massive flow of interstitial fluid, and absorption of CSF into the circulatory and lymphatic systems
.
The choroid plexus (CP) is a versatile structure that not only produces CSF but also forms a blood-CSF barrier through tight connections between choroidal epithelial cells that provide nutrients, a clearance system, and immune surveillance
.

In CP, bifurcated endothelial cells of choroidal capillaries constitute the first layer of the blood-CSF barrier, and changes in permeability may lead to an increase in the inflow of bloodborne toxic substances into the CSF and a decrease
in the inflow of essential nutrients into the CSF.
At the same time, susceptibility to CP may also be affected
by calcification in the elderly and AD patients.
However, to our knowledge, only a few MRI studies on CP in elderly patients (65 years of age) and AD patients have been reported
.

Recently, a study published in the journal Radiology evaluated the different stages of cognitive impairment and the differences in CP volume, CP permeability and CP susceptibility in the clinical AD spectrum, which provided a reference for
further clarifying the pathophysiology and disease process of AD in clinical practice.

This retrospective study evaluated patients with cognitive impairment who underwent 3.
0T cranial MRI between January 2013 and May 2020, including dynamic contrast enhancement (DCE) imaging and quantitative susceptibility atlas (QSM).

。 Automatic segmentation of CP volume using 3D T1-weighted sequence; Use DCE MRI to determine volume transfer constant (i.
e.
, Ktrans) and partial plasma volume (i.
e.
, Vp), and assess susceptibility using QSM
.
Age, sex, education, lipoprotein Eε4 allele status and volume measurements were adjusted for multivariate linear regression, and the effects
of CP volume (ratio to intracranial volume) on cognition were evaluated.

A total of 532 patients with cognitive impairment (mean age, 72 years±9 [SD]; 388 women) were included in the study
.
Seventy-eight had subjective cognitive impairment (SCI), 158 had early mild cognitive impairment (MCI), 149 had advanced MCI, and 147 had AD
.
Of these, 132 patients underwent DCE MRI and QSM
.
Patients in more severe stagesCP volume was larger (ratio of intracranial volume×103: SCI was 0.
9±0.
3, early MCI was 1.
0±0.
3, late MCI was 1.
1±0.
3, AD was 1.
3±0.
4; P<.
001 p=".
03") and Vp(r" .
01> were negatively correlated
.

Figure Comparison of choroid plexus (CP) volumes (red) from four representative 3.
0T cranial MRI scans according to disease stage in the cognitive impairment spectrum.

Patients with Alzheimer's disease (AD) have a larger CP volume than those with
subjective cognitive impairment (SCI) or mild cognitive impairment (MCI).
All of the patients were 75-year-old women

This study showed that in patients with cognitive impairment who underwent 3.
0T cranial MRI, the choroid plexus (CP) volume was higher in the late stages of cognitive impairment, and changes in CP permeability were related to
the severity of the disease.
Thus, CP volume and permeability may be potential imaging indicators of cognitive impairment in Alzheimer's disease and are not associated
with amyloid abnormalities or neurodegeneration.

Original source:

Jong Duck Choi,Yeonsil Moon,Hee-Jin Kim,et al.
Choroid Plexus Volume and Permeability at Brain MRI within the Alzheimer Disease Clinical Spectrum.
DOI:10.
1148/radiol.
212400