Diffusion-weighted MR neurography for the assessment of brachial plexopathy in oncological practice

Background: To evaluate diffusion-weighted MR neurography (DW-MRN) for visualizing the brachial plexus and for the assessment of brachial plexopathy.

Methods: 40 oncological patients with symptoms of brachial plexopathy underwent 1.5 T MRI using conventional MR sequences and unidirectional DW-MRN. The images were independently reviewed by two radiologists. Anatomic visualization of the brachial plexus was scored using a 5 point scale on conventional MR sequences and then combined with DW-MRN. A brachial plexus abnormality was also scored using a 5 point scale and inter-observer agreement determined by kappa statistics. Diagnostic accuracy for brachial plexopathy assessed by conventional MRI alone versus conventional MRI combined with DW-MRN was compared by ROC analysis using reference standards.

Results: DW-MRN significantly improved visualization of the brachial plexus compared with conventional MRI alone (P <0.001). When assessing brachial plexopathy, inter-observer agreement was moderate for conventional MRI (kappa = 0.48) but good for conventional MRI with DW-MRN (kappa = 0.62). DW-MRN combined with conventional MRI significantly improved diagnostic accuracy in one observer (P <0.05) but was similar in the other observer.

Conclusion: DW-MRN improved visualization of the brachial plexus. Combining DW-MRN with conventional MRI can improve inter-observer agreement and detection of brachial plexopathy in symptomatic oncological patients.