Peripheral Nerve Diffusion Tensor Imaging

Preisner, Fabian; Bäumer, Philipp; Wehrstein, Michaela; Friedmann‐Bette, Birgit; Hackbusch, Matthes; Heiland, Sabine; Bendszus, Martin; Kronlage, Moritz

doi:10.1007/s00062-019-00859-0

Cited by 10 publications

(25 citation statements)

References 52 publications

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“…The TW‐FA values reported here (0.60 for the median nerve and 0.56 for the ulnar nerve) are similar to what has been reported despite undergoing track weighting—note that track weighting can be seen as an along‐the‐nerve smoothing 10 . In the sciatic nerve, the minimal detectable difference in FA has been reported as 0.06 (corresponding to ~12%) 29 . The other typical tensor metrics are ADC, AD and RD, which may also reveal information about the underlying nerve anatomy: AD and RD may indicate myelin sheath and axon integrity, 30 whereas reduced ADC may indicate disruption to the nerve cytoskeleton 33 …”

Section: Discussionsupporting

confidence: 86%

“…10 In the sciatic nerve, the minimal detectable difference in FA has been reported as 0.06 (corresponding to ~12%). 29 The other typical tensor metrics are ADC, AD and RD, which may also reveal information about the underlying nerve anatomy: AD and RD may indicate myelin sheath and axon integrity, 30 whereas reduced ADC may indicate disruption to the nerve cytoskeleton. 33 Although standard tensor metrics were also quantified in the proposed framework (eg, see Figures 1 and 2C), we do not report standalone tensor metrics, and instead, we report TW metrics, as track weighting was shown to improve the reproducibility (ie, TW-FA has significantly higher reproducibility than FA) and lead to increased power to detect group differences for a given effect size.…”

Section: Discussionmentioning

confidence: 99%

“…In healthy nerves, FA values have been reported between 0.22 31 and 0.62 32 (for a comprehensive list of FA values in peripheral nerves, see table 4 from ref. 29). The TW‐FA values reported here (0.60 for the median nerve and 0.56 for the ulnar nerve) are similar to what has been reported despite undergoing track weighting—note that track weighting can be seen as an along‐the‐nerve smoothing 10 .…”

Section: Discussionmentioning

confidence: 99%

“…FA is commonly reported in peripheral nerve diffusion analysis and is considered a biomarker for nerve tissue damage. Damaged nerves have relatively lower FA 29 which may indicate reduced myelin sheath integrity 30 . In healthy nerves, FA values have been reported between 0.22 31 and 0.62 32 (for a comprehensive list of FA values in peripheral nerves, see table 4 from ref.…”

Section: Discussionmentioning

confidence: 99%

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A robust framework for characterising diffusion metrics of the median and ulnar nerves: Exploiting state‐of‐the‐art tracking methods

D’Souza

Wang

et al. 2021

J Peripheral Nervous Sys

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Diffusion-weighted imaging has been used to quantify peripheral nerve properties; however, traditional post-processing techniques have several limitations. Advanced neuroimaging techniques, which overcome many of these limitations, have not been applied to peripheral nerves. Here, we use state-of-the-art diffusion analysis tools to reconstruct the median and ulnar nerves and quantify their diffusion properties.Diffusion-weighted MRI scans were obtained from eight healthy adult subjects. Constrained spherical deconvolution was combined with probabilistic fibre tracking to compute track-weighted fibre orientation distribution (TW-FOD). The tensor was computed and used along with the tracks to estimate TW apparent diffusion coefficient (TW-ADC), TW fractional anisotropy (TW-FA), TW axial diffusivity (TW-AD), and TW radial diffusivity (TW-RD). Variability of TW measurements was used to estimate power size information. The population intersession mean (± SD) measurements for the median nerve were TW-FOD 1.30 (±0.17), TW-ADC 1.16 (±0.13) Â 10 À3 mm 2 /s, TW-FA 0.60 (±0.05), TW-AD 2.05 (±0.16) Â 10 À3 mm 2 /s, and TW-RD 0.72 (±0.12) Â 10 À3 mm 2 /s. The corresponding measurements for the ulnar nerve were TW-FOD 1.25 (±0.14), TW-ADC 1.13 (±0.10) Â 10 À3 mm 2 /s, TW-FA 0.56 (±0.06), TW-AD 1.93 (±0.01) Â 10 À3 mm 2 /s, and TW-RD 0.74 (±0.12) Â 10 À3 mm 2 /s. Based on these measurements, a sample size of 37 would be sufficient to detect a 10% difference in any of the measured TW metrics. A sample size of 20 would be large enough to detect within-subject differences as small as 2.9% (TW-AD, ulnar nerve) and between-subject differences as small as 3.8% (TW-AD, ulnar nerve).

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

A robust framework for characterising diffusion metrics of the median and ulnar nerves: Exploiting state‐of‐the‐art tracking methods

D’Souza

Wang

et al. 2021

J Peripheral Nervous Sys

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“…While the ICC is a widely used index of reliability, it depends not only on the measurement error itself but also on the variance of the measured parameter in the examined cohort [38][39][40]. To provide a parameter of measurement imprecision that is independent of the variance of the biomarker in the test cohort, we here additionally report the SEM for all assessed biomarkers.…”

Section: Discussionmentioning

confidence: 99%

Reliability and reproducibility of sciatic nerve magnetization transfer imaging and T2 relaxometry

et al. 2021

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Objectives To assess the interreader and test-retest reliability of magnetization transfer imaging (MTI) and T2 relaxometry in sciatic nerve MR neurography (MRN). Materials and methods In this prospective study, 21 healthy volunteers were examined three times on separate days by a standardized MRN protocol at 3 Tesla, consisting of an MTI sequence, a multi-echo T2 relaxometry sequence, and a high-resolution T2-weighted sequence. Magnetization transfer ratio (MTR), T2 relaxation time, and proton spin density (PSD) of the sciatic nerve were assessed by two independent observers, and both interreader and test-retest reliability for all readout parameters were reported by intraclass correlation coefficients (ICCs) and standard error of measurement (SEM). Results For the sciatic nerve, overall mean ± standard deviation MTR was 26.75 ± 3.5%, T2 was 64.54 ± 8.2 ms, and PSD was 340.93 ± 78.8. ICCs ranged between 0.81 (MTR) and 0.94 (PSD) for interreader reliability and between 0.75 (MTR) and 0.94 (PSD) for test-retest reliability. SEM for interreader reliability was 1.7% for MTR, 2.67 ms for T2, and 21.3 for PSD. SEM for test-retest reliability was 1.7% for MTR, 2.66 ms for T2, and 20.1 for PSD. Conclusions MTI and T2 relaxometry of the sciatic nerve are reliable and reproducible. The values of measurement imprecision reported here may serve as a guide for correct interpretation of quantitative MRN biomarkers in future studies. Key Points • Magnetization transfer imaging (MTI) and T2 relaxometry of the sciatic nerve are reliable and reproducible. • The imprecision that is unavoidably associated with different scans or different readers can be estimated by the here presented SEM values for the biomarkers T2, PSD, and MTR. • These values may serve as a guide for correct interpretation of quantitative MRN biomarkers in future studies and possible clinical applications.

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Quantitative magnetic resonance neurography in chronic inflammatory demyelinating polyradiculoneuropathy: A longitudinal study over 6 years

Preisner,

Pitarokoili,

Lueling

et al. 2023

Ann Clin Transl Neurol

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ObjectiveTo evaluate magnetic resonance neurography (MRN) for the longitudinal assessment of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).MethodsProspective examination of twelve CIDP patients by neurological assessment, MRN, and nerve conduction studies in 2016 and 6 years later in 2022. Imaging parameters were compared with matched healthy controls and correlated with clinical and electrophysiological markers. The MRN protocol included T2‐weighted imaging, diffusion tensor imaging (DTI), T2 relaxometry, and magnetization transfer imaging (MTI).ResultsNerve cross‐sectional area (CSA) was increased in CIDP patients compared to controls (plexus: p = 0.003; sciatic nerve: p < 0.001). Over 6 years, nerve CSA decreased in CIDP patients, most pronounced at the lumbosacral plexus (p = 0.015). Longitudinally, changes in CSA correlated with changes in the inflammatory neuropathy cause and treatment validated overall disability sum score (INCAT/ODSS) (p = 0.006). High initial nerve CSA was inversely correlated with changes in the INCAT/ODSS over 6 years (p < 0.05). The DTI parameter fractional anisotropy (FA) showed robust correlations with electrodiagnostic testing both cross‐sectionally and longitudinally (p < 0.05). MTI as a newly added imaging technique revealed a significantly reduced magnetization transfer ratio (MTR) in CIDP patients (p < 0.01), suggesting underlying changes in macromolecular tissue composition, and correlated significantly with electrophysiological parameters of demyelination (p < 0.05).InterpretationThis study provides evidence that changes in nerve CSA and FA reflect the clinical and electrophysiological course of CIDP patients. Initial nerve hypertrophy might predict a rather benign course or better therapy response.

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Peripheral Nerve Diffusion Tensor Imaging

Cited by 10 publications

References 52 publications

A robust framework for characterising diffusion metrics of the median and ulnar nerves: Exploiting state‐of‐the‐art tracking methods

A robust framework for characterising diffusion metrics of the median and ulnar nerves: Exploiting state‐of‐the‐art tracking methods

Reliability and reproducibility of sciatic nerve magnetization transfer imaging and T2 relaxometry

Quantitative magnetic resonance neurography in chronic inflammatory demyelinating polyradiculoneuropathy: A longitudinal study over 6 years

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