Lumbar plexus in patients with chronic inflammatory demyelinating polyradiculoneuropathy: Evaluation with simultaneous T₂ mapping and neurography method with SHINKEI

Objective: To evaluate the usefulness of simultaneous T₂ mapping and neurography with nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI) in the lumbar plexus to distinguish patients with chronic inflammatory demyelinating polyneuropathy (CIDP) from healthy controls. Methods: Our institutional review boards approved this retrospective study, and written informed consent was waived. 10 patients with CIDP from 2015 to 2017 were studied along with 5 healthy controls on a 3 T scanner. The T₂ relaxation time and the size of the dorsal root ganglia and nerves of the lumbar plexus at L3-S1 were measured. Statistical analyses were performed with the Mann-Whitney U test and a receiver operating characteristics analysis. Results: The T₂ relaxation times of the dorsal root ganglia and the nerves of the lumbar plexus were longer in the CIDP patients (133.34 ± 41.36 and 130.40 ± 47.78 ms) compared to the healthy controls (114.69 ± 24.90 and 83.72 ± 17.51 ms, p = 0.0265 andp < 0.0001, respectively). The sizes of the nerves were larger in the CIDP patients (6.19 ± 2.28 mm) compared to the controls (4.54 ± 0.86 mm, p < 0.0001). However, there was no significant difference between the sizes of the ganglia in the CIDP patients and the controls. The receiver operating characteristics analysis revealed that the T₂ relaxation time of the nerves was best at distinguishing the CIDP patients from the controls (Az = 0.848). Conclusion: Patients with CIDP could be distinguished from healthy controls using simultaneous T₂ mapping and neurography with SHINKEI in the lumbar plexus. Advances in knowledge: Patients with CIDP could be distinguished from healthy controls using simultaneous T₂ mapping and neurography with SHINKEI in the lumbar plexus.