Thoracic outlet syndrome in 3T MR neurography-fibrous bands causing discernible lesions of the lower brachial plexus.

[thoracic outlet syndrome]

To investigate whether targeted magnetic resonance neurography (MRN ) of the brachial plexus can visualise fibrous bands compressing the brachial plexus and directly detect injury in plexus nerve fascicles .High -resolution MRN was employed in 30 patients with clinical suspicion of either true neurogenic thoracic outlet syndrome (TOS ) or non-specific TOS . The protocol for the brachial plexus included a SPACE (3 D turbo spin echo with variable flip angle ) STIR (short tau inversion recovery ), a sagittal-oblique T 2 -weighted (T 2 W ) SPAIR (spectral adiabatic inversion recovery ) and a 3 D PDW (proton density weighted ) SPACE . Images were evaluated for anatomical anomalies compressing the brachial plexus and for abnormal T 2 W signal within plexus elements . Patients with abnormal MR imaging findings underwent surgical exploration .Seven out of 30 patients were identified with unambiguous morphological correlates of TOS . These were verified by surgical exploration . Correlates included fibrous bands (n = 5 ) and pseudarthrosis or synostosis of ribs (n = 2 ). Increased T 2 W signal was detected within compressed plexus portion (C 8 spinal nerve , inferior trunk , or medial cord ) and confirmed the diagnosis .The clinical suspicion of TOS can be diagnostically confirmed by MRN . Entrapment of plexus structures by subtle anatomical anomalies such as fibrous bands can be visualised and relevant compression can be confirmed by increased T 2 W signal of compromised plexus elements .• MR neurography (MRN ) can aid the diagnosis of thoracic outlet syndrome (TOS ). • Identifiable causes of TOS in MRN include fibrous bands and bony anomalies . • Increased T 2 W signal within brachial plexus elements indicate relevant nerve compression . • High positive predictive value allows confident and targeted indication for surgery .