TY  - JOUR
AB  - BACKGROUND: In contrast to the brain, fibers within peripheral nerves have distinct monodirectional structure questioning the necessity of complex multidirectional gradient vector schemes for DTI. This proof-of-concept study investigated the diagnostic utility of reduced gradient vector schemes in peripheral nerve DTI. METHODS: Three-Tesla magnetic resonance neurography of the tibial nerve using 20-vector DTI (DTI20) was performed in 10 healthy volunteers, 12 patients with type 2 diabetes, and 12 age-matched healthy controls. From the full DTI20 dataset, three reduced datasets including only two or three vectors along the x- and/or y- and z-axes were built to calculate major parameters. The influence of nerve angulation and intraneural connective tissue was assessed. The area under the receiver operating characteristics curve (ROC-AUC) was used for analysis. RESULTS: Simplified datasets achieved excellent diagnostic accuracy equal to DTI20 (ROC-AUC 0.847-0.868, p ≤ 0.005), but compared to DTI20, the reduced models yielded mostly lower absolute values of DTI scalars: median fractional anisotropy (FA) ≤ 0.12; apparent diffusion coefficient (ADC) ≤ 0.25; axial diffusivity ≤ 0.96, radial diffusivity ≤ 0.07). The precision of FA and ADC with the three-vector model was closest to DTI20. Intraneural connective tissue was negatively correlated with FA and ADC (r ≥ -0.49, p < 0.001). Small deviations of nerve angulation had little effect on FA accuracy. CONCLUSIONS: In peripheral nerves, bulk tissue DTI metrics can be approximated with only three predefined gradient vectors along the scanner's main axes, yielding similar diagnostic accuracy as a 20-vector DTI, resulting in substantial scan time reduction. RELEVANCE STATEMENT: DTI bulk tissue parameters of peripheral nerves can be calculated with only three predefined gradient vectors at similar diagnostic performance as a standard DTI but providing a substantial scan time reduction. KEY POINTS: • In peripheral nerves, DTI parameters can be approximated using only three gradient vectors. • The simplified model achieves a similar diagnostic performance as a standard DTI. • The simplified model allows for a significant acceleration of image acquisition. • This can help to introduce multi-b-value DTI techniques into clinical practice.
AU  - Foesleitner, O.*
AU  - Sulaj, A.
AU  - Sturm, V.*
AU  - Kronlage, M.*
AU  - Preisner, F.*
AU  - Kender, Z.
AU  - Bendszus, M.*
AU  - Szendroedi, J.
AU  - Heiland, S.*
AU  - Schwarz, D.*
C1  - 70359
C2  - 55528
CY  - Prinz-eugen-strasse 8-10, A-1040 Vienna, Austria
TI  - Diffusion tensor imaging in anisotropic tissues: Application of reduced gradient vector schemes in peripheral nerves.
JO  - Eur. Radiol. Exp.
VL  - 8
IS  - 1
PB  - Springer Wien
PY  - 2024
SN  - 2509-9280
ER  - 

TY  - JOUR
AB  - Background: Previous studies on magnetic resonance neurography (MRN) found different patterns of structural nerve damage in type 1 diabetes (T1D) and type 2 diabetes (T2D). Magnetization transfer ratio (MTR) is a quantitative technique to analyze the macromolecular tissue composition. We compared MTR values of the sciatic nerve in patients with T1D, T2D, and healthy controls (HC). Methods: 3-T MRN of the right sciatic nerve at thigh level was performed in 14 HC, 10 patients with T1D (3 with diabetic neuropathy), and 28 patients with T2D (10 with diabetic neuropathy). Results were subsequently correlated with clinical and electrophysiological data. Results: The sciatic nerve’s MTR was lower in patients with T2D (0.211 ± 0.07, mean ± standard deviation) compared to patients with T1D (T1D 0.285 ± 0.03; p = 0.015) and HC (0.269 ± 0.05; p = 0.039). In patients with T1D, sciatic MTR correlated positively with tibial nerve conduction velocity (NCV; r = 0.71; p = 0.021) and negatively with hemoglobin A1c (r = − 0.63; p < 0.050). In patients with T2D, we found negative correlations of sciatic nerve’s MTR peroneal NCV (r = − 0.44; p = 0.031) which remained significant after partial correlation analysis controlled for age and body mass index (r = 0.51; p = 0.016). Conclusions: Lower MTR values of the sciatic nerve in T2D compared to T1D and HC and diametrical correlations of MTR values with NCV in T1D and T2D indicate that there are different macromolecular changes and pathophysiological pathways underlying the development of neuropathic nerve damage in T1D and T2D. Trial registration: https://classic.clinicaltrials.gov/ct2/show/NCT03022721 . 16 January 2017. Relevance statement: Magnetization transfer ratio imaging may serve as a non-invasive imaging method to monitor the diseases progress and to encode the pathophysiology of nerve damage in patients with type 1 and type 2 diabetes. Key points: • Magnetization transfer imaging detects distinct macromolecular nerve lesion patterns in diabetes patients. • Magnetization transfer ratio was lower in type 2 diabetes compared to type 1 diabetes. • Different pathophysiological mechanisms drive nerve damage in type 1 and 2 diabetes. Graphical Abstract: [Figure not available: see fulltext.].
AU  - Mooshage, C.M.*
AU  - Schimpfle, L.
AU  - Tsilingiris, D.
AU  - Kender, Z.
AU  - Aziz-Safaie, T.*
AU  - Hohmann, A.*
AU  - Szendroedi, J.*
AU  - Nawroth, P.*
AU  - Sturm, V.*
AU  - Heiland, S.*
AU  - Bendszus, M.*
AU  - Kopf, S.
AU  - Jende, J.M.E.*
AU  - Kurz, F.T.*
C1  - 69737
C2  - 55201
CY  - Prinz-eugen-strasse 8-10, A-1040 Vienna, Austria
TI  - Magnetization transfer ratio of the sciatic nerve differs between patients in type 1 and type 2 diabetes.
JO  - Eur. Radiol. Exp.
VL  - 8
IS  - 1
PB  - Springer Wien
PY  - 2024
SN  - 2509-9280
ER  -