Submitted and edited by Nandita S. Keole, MD, News Science Editorial Board
Goedee HS, Jongbloed BA, van Asseldonk J-TH, Hendrikse J, Vrancken AFJE, Franssen H, Nikolakopoulos S, Visser LH, van der Pol WL, van den Berg LH. (2017). A comparative study of brachial plexus sonography and magnetic resonance imaging in chronic inflammatory demyelinating neuropathy and multifocal motor neuropathy. European Journal of Neurology
This study compared the performance of neuroimaging techniques (e.g. high-resolution ultrasound (HRUS)) and magnetic resonance imaging (MRI), when applied to the brachial plexus, as part of the diagnostic work-up of chronic inflammatory demyelinating neuropathy (CIDP) and multifocal motor neuropathy (MMN). MRI is an established adjunctive diagnostic tool while HRUS is a widely available quantitative bedside tool.
They enrolled 51 consecutive patients with CIDP (n = 24) or MMN (n = 27). The inclusion criterion was a diagnosis of CIDP and MMN (definite, probable and possible. They enrolled treatment naïve patients. Sonographic and MRI studies were performed prior to treatment. The treating physicians were blinded to the neuroimaging results. MRIs were rated by experienced neuroradiologists (blinded to results from HRUS and NCS studies). One author performed all sonographic examinations and was blinded to results from NCS and MRI studies.
Magnetic resonance imaging showed enlargement and/or a pathological T2-hyperintense signal of the brachial plexus in 17/23 (74%) patients with CIDP and 14/28 (50%) patients with MMN. MRI of the brachial plexus was normal in 20/51 (39%) enrolled patients.
HRUS found sonographic enlargement of a brachial trunk (superior, median or inferior) in 18/23 (78%) patients with CIDP and 19/28 (68%) patients with MMN. MRI was normal in 4/23 (17%) patients with CIDP and 8/28 (29%) patients with MMN with an abnormal HRUS. Applying both MRI and HRUS identified 20/23 (87%) patients with CIDP and 22/28 (79%) patients with MMN, further enhancing the diagnostic performance of neuroimaging (from 61–73% to 83%).
The high level of concordance seen in this study suggests that both MRI and sonography of the brachial plexus can be used to support the clinical suspicion of an inflammatory neuropathy.
The study indicates that brachial plexus sonography complements MRI in the diagnostic work-up of patients with suspected CIDP and MMN. Therefore, combined imaging studies could, in the future, be included in the revised diagnostic consensus criteria for chronic inflammatory neuropathies to enhance diagnostic performance. The brachial plexus abnormalities seen on imaging did not aid in further differentiating between CIDP and MMN. The exact pathological or electrophysiological correlates of imaging abnormalities are largely unknown and require further study.