Abstract
Peripheral neuropathy is a prevalent and debilitating condition affecting millions
of individuals globally. Magnetic resonance neurography (MRN) and ultrasonography
(US) are noninvasive methods offering comprehensive visualization of peripheral nerves,
using anatomical and functional imaging biomarkers to ensure accurate evaluation.
For optimized MRN, superior and high-resolution two-dimensional and three-dimensional
imaging protocols are essential. The anatomical MRN and US imaging markers include
quantitative measures of nerve and fascicular size and signal, and qualitative markers
of course and morphology. Among them, quantitative markers of T2-signal intensity
ratio are sensitive to nerve edema-like signal changes, and the T1-mapping technique
reveals nerve and muscle tissue fatty and fibrous compositional alterations.
The functional markers are derived from physiologic properties of nerves, such as
diffusion characteristics or blood flow. They include apparent diffusion coefficient
from diffusion-weighted imaging and fractional anisotropy and tractography from diffusion
tensor imaging to delve into peripheral nerve microstructure and integrity. Peripheral
nerve perfusion using dynamic contrast-enhanced magnetic resonance imaging estimates
perfusion parameters, offering insights into nerve health and neuropathies involving
edema, inflammation, demyelination, and microvascular alterations in conditions like
type 2 diabetes, linking nerve conduction pathophysiology to vascular permeability
alterations.
Imaging biomarkers thus play a pivotal role in the diagnosis, prognosis, and monitoring
of nerve pathologies, thereby ensuring comprehensive assessment and elevating patient
care. These biomarkers provide valuable insights into nerve structure, function, and
pathophysiology, contributing to the accurate diagnosis and management planning for
peripheral neuropathy.
Keywords
peripheral neuropathy - magnetic resonance neurography - T2-signal intensity ratio
- diffusion-weighted imaging - diffusion tensor imaging
