Peripheral nerve perfusion by dynamic contrast-enhanced magnetic resonance imaging: demonstration of feasibility

Abstract

Purpose: The aim of this study was to establish dynamic contrast-enhanced perfusion in peripheral nerves for determination of blood-nerve permeability (K) and nerve blood volume (NBV) in peripheral neuropathies as compared with healthy controls.

Methods: The study was approved by the institutional ethics committee, and written informed consent was obtained from all participants. Forty-three controls (24 women, 19 men; age, 48.7 ± 17.5 years) and 59 patients with peripheral neuropathy (28 women, 31 men; age, 52.7 ± 12.4 years) were examined by a standard protocol including a T1-weighted dynamic contrast-enhanced sequence (time of repetition/time of echo, 4.91/1.64; 10 slices; resolution 0.8 × 0.6 × 3.0 mm3). Time - signal intensity analysis was performed by normalizing to pre-bolus arrival and calculating the mean contrast uptake (MCU) for each patient. Further analyses were performed by customized software to calculate K trans and NBV. Statistical analysis included 2-sided Student's t tests of controls versus patients, receiver operating characteristic analysis, and subgroup analysis of patients according to etiologies of neuropathy.

Results: Time-signal intensity analysis showed significantly increased contrast uptake in patients as compared with controls (MCU, 1.29 ± 0.15 vs 1.18 ± 0.08; P < 0.001). This was caused mainly by an increase in K trans (0.046 ± 0.025 vs 0.026 ± 0.016 min(-1); P < 0.001) and less by an increase in NBV (3.9 ± 2.6 vs 3.0 ± 1.9 mL/100 mL; P = 0.12). This trend was true for all etiologies except entrapment neuropathies. Excluding these, receiver operating characteristic analysis found an area under the curve of 0.78 (95% confidence interval, 0.69-0.89) for MCU and 0.77 (95% confidence interval, 0.65-0.90) for K to discriminate neuropathy from control.

Conclusions: Dynamic contrast-enhanced perfusion is a feasible technique to assess K trans and NBV in peripheral nerves and may be used in future investigations on peripheral neuropathies.