Abstract:Objectives: Clinical and histological studies have found evidence that nerve ischemia is a major contributor to diabetic neuropathy (DN) in type 2 diabetes (T2D). The aim of this study was to investigate peripheral nerve microvascular permeability using dynamic contrast enhanced (DCE) magnetic resonance neurography (MRN) to analyze potential correlations with clinical, electrophysiological, and demographic data. Methods: Sixty-five patients (35/30 with/without DN) and 10 controls matched for age and body mass … Show more
“…1 . Arterial input function (AIF) was determined through a semimanual process as described in detail elsewhere [ 29 ]. Subsequently, the constant of volume transfer between plasma and the extravascular extracellular compartment (K trans ), the volume fraction of extravascular extracellular space per unit volume of tissue (V e ) and the blood plasma volume per unit volume of tissue (V p ), which represent the main radiological outcome parameters, were calculated in accordance with the extended Tofts model with 𝐶𝑀(𝑡) representing the model tissue contrast agent concentration at time t [ 30 ]: Fig.…”
Section: Methodsmentioning
confidence: 99%
“…Previous studies demonstrated that dynamic contrast enhanced (DCE) magnet resonance imaging (MRI) allows the assessment of peripheral nerve microcirculation [ 17 ]. Recent studies established DCI MRI of the sciatic nerve as a novel imaging biomarker in patients with type 2 diabetes [ 18 – 20 ]. It was found that a decrease of the sciatic nerve capillary permeability was associated with a decline of electrophysiologic parameters and an increase in clinical neuropathy scores, such as the neuropathy deficit score that allows diagnosis of LFN but not SFN [ 20 ].…”
Section: Introductionmentioning
confidence: 99%
“…Recent studies established DCI MRI of the sciatic nerve as a novel imaging biomarker in patients with type 2 diabetes [ 18 – 20 ]. It was found that a decrease of the sciatic nerve capillary permeability was associated with a decline of electrophysiologic parameters and an increase in clinical neuropathy scores, such as the neuropathy deficit score that allows diagnosis of LFN but not SFN [ 20 ]. In opposition to this, the results from preclinical studies suggest that an increased permeability of the blood-nerve barrier poses an important contributor to the development of painful DPN via an increased intraneural influx of cells and molecules [ 21 – 23 ].…”
Introduction/aims
Diabetic small fiber neuropathy (SFN) is caused by damage to thinly myelinated A‑fibers (δ) and unmyelinated C‑fibers. This study aimed to assess associations between quantitative sensory testing (QST) and parameters of peripheral nerve perfusion obtained from dynamic contrast enhanced (DCE) magnetic resonance neurography (MRN) in type 2 diabetes patients with and without SFN.
Methods
A total of 18 patients with type 2 diabetes (T2D, 8 with SFN, 10 without SFN) and 10 healthy controls (HC) took part in this cross-sectional single-center study and underwent QST of the right leg and DCE-MRN of the right thigh with subsequent calculation of the sciatic nerve constant of capillary permeability (Ktrans), extravascular extracellular volume fraction (Ve), and plasma volume fraction (Vp).
Results
The Ktrans (HC 0.031 min−1 ± 0.009, T2D 0.043 min−1 ± 0.015; p = 0.033) and Ve (HC 1.2% ± 1.5, T2D: 4.1% ± 5.1; p = 0.027) were lower in T2D patients compared to controls. In T2D patients, compound z‑scores of thermal and mechanical detection correlated with Ktrans (r = 0.73; p = 0.001, and r = 0.57; p = 0.018, respectively) and Ve (r = 0.67; p = 0.002, and r = 0.69; p = 0.003, respectively). Compound z‑scores of thermal pain and Vp (r = −0.57; p = 0.015) correlated negatively.
Discussion
The findings suggest that parameters of peripheral nerve microcirculation are related to different symptoms in SFN: A reduced capillary permeability may result in a loss of function related to insufficient nutritional supply, whereas increased capillary permeability may be accompanied by painful symptoms related to a gain of function.
“…1 . Arterial input function (AIF) was determined through a semimanual process as described in detail elsewhere [ 29 ]. Subsequently, the constant of volume transfer between plasma and the extravascular extracellular compartment (K trans ), the volume fraction of extravascular extracellular space per unit volume of tissue (V e ) and the blood plasma volume per unit volume of tissue (V p ), which represent the main radiological outcome parameters, were calculated in accordance with the extended Tofts model with 𝐶𝑀(𝑡) representing the model tissue contrast agent concentration at time t [ 30 ]: Fig.…”
Section: Methodsmentioning
confidence: 99%
“…Previous studies demonstrated that dynamic contrast enhanced (DCE) magnet resonance imaging (MRI) allows the assessment of peripheral nerve microcirculation [ 17 ]. Recent studies established DCI MRI of the sciatic nerve as a novel imaging biomarker in patients with type 2 diabetes [ 18 – 20 ]. It was found that a decrease of the sciatic nerve capillary permeability was associated with a decline of electrophysiologic parameters and an increase in clinical neuropathy scores, such as the neuropathy deficit score that allows diagnosis of LFN but not SFN [ 20 ].…”
Section: Introductionmentioning
confidence: 99%
“…Recent studies established DCI MRI of the sciatic nerve as a novel imaging biomarker in patients with type 2 diabetes [ 18 – 20 ]. It was found that a decrease of the sciatic nerve capillary permeability was associated with a decline of electrophysiologic parameters and an increase in clinical neuropathy scores, such as the neuropathy deficit score that allows diagnosis of LFN but not SFN [ 20 ]. In opposition to this, the results from preclinical studies suggest that an increased permeability of the blood-nerve barrier poses an important contributor to the development of painful DPN via an increased intraneural influx of cells and molecules [ 21 – 23 ].…”
Introduction/aims
Diabetic small fiber neuropathy (SFN) is caused by damage to thinly myelinated A‑fibers (δ) and unmyelinated C‑fibers. This study aimed to assess associations between quantitative sensory testing (QST) and parameters of peripheral nerve perfusion obtained from dynamic contrast enhanced (DCE) magnetic resonance neurography (MRN) in type 2 diabetes patients with and without SFN.
Methods
A total of 18 patients with type 2 diabetes (T2D, 8 with SFN, 10 without SFN) and 10 healthy controls (HC) took part in this cross-sectional single-center study and underwent QST of the right leg and DCE-MRN of the right thigh with subsequent calculation of the sciatic nerve constant of capillary permeability (Ktrans), extravascular extracellular volume fraction (Ve), and plasma volume fraction (Vp).
Results
The Ktrans (HC 0.031 min−1 ± 0.009, T2D 0.043 min−1 ± 0.015; p = 0.033) and Ve (HC 1.2% ± 1.5, T2D: 4.1% ± 5.1; p = 0.027) were lower in T2D patients compared to controls. In T2D patients, compound z‑scores of thermal and mechanical detection correlated with Ktrans (r = 0.73; p = 0.001, and r = 0.57; p = 0.018, respectively) and Ve (r = 0.67; p = 0.002, and r = 0.69; p = 0.003, respectively). Compound z‑scores of thermal pain and Vp (r = −0.57; p = 0.015) correlated negatively.
Discussion
The findings suggest that parameters of peripheral nerve microcirculation are related to different symptoms in SFN: A reduced capillary permeability may result in a loss of function related to insufficient nutritional supply, whereas increased capillary permeability may be accompanied by painful symptoms related to a gain of function.
“…The research suggested an age-related decline in nerve permeability and a positive correlation between nerve microvascular permeability and body mass index. 54…”
Section: Imaging Biomarkers Of Peripheral Nerves Eajazi Et Al 97mentioning
confidence: 99%
“…In a separate study, Jende et al 54 used DCE to explore peripheral nerve perfusion in individuals with type 2 diabetes. The study documented connections between microvascular perfusion parameters (K trans and V e ) and nerve conduction characteristics, suggesting increased microvascular permeability enhances blood supply to nerve structures.…”
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.
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