Objective: To evaluate functional and morphometric magnetic resonance neurography of the dorsal root ganglion and peripheral nerve segments in patients with Fabry painful neuropathy. Methods: In this prospective study, the lumbosacral dorsal root ganglia and proximal peripheral nerve segments of the lower extremity were examined in 11 male patients with Fabry disease by a standardized 3T magnetic resonance neurography protocol. Volumes of L3 to S2 dorsal root ganglia, perfusion parameters of L5-S1 dorsal root ganglia and the spinal nerve L5, and the cross-sectional area of the proximal sciatic nerve were compared to healthy controls. Results: Dorsal root ganglia of patients with Fabry disease were symmetrically enlarged by 78% (L3), 94% (L4), 122% (L5), 115% (S1), and 119% (S2) (p < 0.001). In addition, permeability of the blood-tissue interface was decreased by 53% (p < 0.001). This finding was most pronounced in the peripheral zone of the dorsal root ganglion containing the cell bodies of the primary sensory neurons (p < 0.001). Spinal nerve permeability showed no difference between patients with Fabry disease and controls (p = 0.7). The sciatic nerve of patients with Fabry disease at the thigh level showed an increase in cross-sectional area by 48% (p < 0.001). Conclusions: Patients with Fabry disease have severely enlarged dorsal root ganglia with dysfunctional perfusion. This may be due to glycolipid accumulation in the dorsal root ganglia mediating direct neurotoxic effects and decreased neuronal blood supply. These alterations were less pronounced in peripheral nerve segments. Thus, the dorsal root ganglion might play a key pathophysiologic role in the development of neuropathy and pain in Fabry disease.

To develop an in-vivo imaging method for the measurement of dorsal-root-ganglia-(DRG) perfusion, to establish its normal values in patients without known peripheral nerve disorders or radicular pain syndromes and to determine the physiological spatial perfusion pattern within the DRG. This prospective study was approved by the institutional ethics committee and written informed consent was obtained from all participants. 46 (24 female, 22 male, mean age 46.0±15.2years) subjects without known peripheral neuropathies or pain syndromes were examined by a 3Tesla MRI scanner (Magnetom VERIO or TRIO, Siemens AG, Erlangen, Germany) with a VIBE (Volume-Interpolated-Breathhold-Examination) dynamic-contrast-enhanced (DCE) T1-w-sequence (TR/TE 3.3/1.11ms; 24 slices; voxel resolution 1.3×1.3×3.0mm(3)) covered the pelvis from the upper plate of the 5th lumbar vertebra to the 2nd sacral vertebra. Transfer-constant (K(trans)) and interstitial-volume-fraction (interstitial-leakage-fraction, Ve) were modeled for the DRG and spinal nerve by applying the Tofts-model. Statistical analyses included pairwise comparisons of L5/S1 DRG vs. spinal nerve. Furthermore, distinct physiological zones within the S1 DRG were compared (cell body rich area (CBRA) vs. nerve fiber rich area (NFRA)). DRG showed a significantly increased permeability compared to spinal nerve (K(trans) 3.8±1.5 10(-3)/min vs. 1.6±0.9 10(-3)/min, p-value: <0.001) combined with an increased interstitial leakage of contrast agent into the extravascular-extracellular-space (Ve 38.1±19.2% vs. 17.3±9.9%, p-value: <0.001). Parameters showed no statistically significant difference on DRG-level (L5 vs. S1; p-value: 0.62 (K(trans)); 0.17 (Ve)) and -side (left vs. right; p-value: 0.25 (K(trans)); 0.79 (Ve)). Female gender was associated with a significantly increased permeability (K(trans) female 4.3±1.4 10(-3)/min vs. male 3.4±0.9 10(-3)/min, p-value: <0.05) but no statistically significant differences in interstitial leakage (Ve female 40.1±14,1% vs. male 34.5±17.4%, p-value: 0.24). DRG showed distinct spatial distribution patterns of perfusion: K(trans) and Ve were significantly higher in the CBRA than in the NFRA (K(trans) 4.4±1.8 10(-3)/min vs. 1.7±1.2 10(-3)/min, p-value: <0.001 and Ve 40.9±21.3% vs. 15.1±11.7%, p-value: <0.001). Non-invasive and in-vivo measurement of human DRG perfusion by MRI is a feasible technique. DRG show substantially higher permeability and interstitial leakage than spinal nerves. Even distinct physiological perfusion patterns for different microstructural compartments could be observed within the DRG. The technique may become particularly useful for future research on the poorly understood human sensory neuropathies and pain syndromes.

Due to non-Gaussian diffusion behavior at low b values, the optimal b value for reliable diffusion-weighted imaging/diffusion tensor imaging within peripheral nerves should be set at approximately ... Background Diffusion-weighted imaging (DWI) provides specific in vivo information about tissue microstructure, which is increasingly recognized for various applications outside the central nervous ...

To examine the involvement of dorsal root ganglia and peripheral nerves in children with neurofibromatosis type 2 compared to healthy controls and symptomatic adults by in vivo high-resolution magnetic resonance neurography. In this prospective multicenter study, the lumbosacral dorsal root ganglia and sciatic, tibial, and peroneal nerves were examined in 9 polyneuropathy-negative children diagnosed with neurofibromatosis type 2 by a standardized magnetic resonance neurography protocol at 3T. Volumes of dorsal root ganglia L3 to S2 and peripheral nerve lesions were assessed and compared to those of 29 healthy children. Moreover, dorsal root ganglia volumes and peripheral nerve lesions were compared to those of 14 adults with neurofibromatosis type 2. Compared to healthy controls, dorsal root ganglia hypertrophy was a consistent finding in children with neurofibromatosis type 2 (L3 +255%, L4 +289%, L5 +250%, S1 +257%, and S2 +218%, p < 0.001) with an excellent diagnostic accuracy. Moreover, peripheral nerve lesions occurred with a high frequency in those children compared to healthy controls (18.89 ± 11.11 vs 0.90 ± 1.08, p < 0.001). Children and adults with neurofibromatosis type 2 showed nonsignificant differences in relative dorsal root ganglia hypertrophy rates (p = 0.85) and peripheral nerve lesions (p = 0.28). Alterations of peripheral nerve segments occur early in the course of neurofibromatosis type 2 and are evident even in children not clinically affected by peripheral polyneuropathy. While those early alterations show similar characteristics compared to adults with neurofibromatosis type 2, the findings of this study suggest that secondary processes might be responsible for the development and severity of associated polyneuropathy.