Functional imaging of the thoracic outlet syndrome in an open MR scanner

Symptoms due to thoracic outlet syndrome may present only in abduction, a p osition that cannot be investigated in conventional MR scanners. Therefore, this study was initiated to test MRI in an open magnet as a method for dia gnosis of thoracic outlet syndrome. Ten volunteers and 7 patients with a cl inical suspicion of thoracic outlet syndrome were investigated at 0.5 T in an open MR scanner. Sagittal 3D SPGR acquisitions were made in 0 and 90 deg rees abduction. In the patients, a similar data set was also obtained in ma ximal abduction. To assess compression, the minimum distance between the fi rst rib and the clavicle, measured in a sagittal plane, was determined. In the neutral position, no significant difference was found between patients and controls. In 90 degrees abduction, the patients had significantly small er distance between rib and clavicle than the controls (14 vs 29 mm; p < 0. 01). On coronal reformatted images, the compression of the bronchial plexus could often be visualised in abduction. Functional MR examination seems to be a useful diagnostic tool in thoracic outlet syndrome. Examination in ab duction, which is feasible in an open scanner, is essential for the diagnos is.