[Diagnosis of thoracic outlet syndrome by angio-MRI]

To evaluate the sequences and maneuvers recommended for the study of the thoracic outlet syndrome (TOS) and the usefulness of magnetic resonance imaging (MRI) in demonstrating its etiology.

We present a study of eight patients with clinical presentation suggestive of TOS. All underwent MRI, gadolinium-enhanced angio-MRI with the arms extended along the body and with postural maneuvers of abduction and elevation of the arms, plain-film chest x-rays, and digital angiography. The anatomic characteristics of the superior aperture of the thorax were analyzed on both sides before and during postural maneuvering. Likewise, the permeability of the vessels and integrity of the brachial plexus was studied.

In two cases, angio-MRI demonstrated thrombosis, of the subclavian artery in one case and of the subclavian vein in the other, caused by a cervical rib, which was confirmed at plain-film chest x-ray. In one case, angio-MRI demonstrated stenosis of the subclavian artery on abduction, secondary to hypertrophy of the anterior scalene muscle, and digital angiography showed the same findings. In two cases, angio-MRI showed vascular thrombosis, arterial in one case and venous in the other, without evidence of anatomic anomalies; these findings were confirmed at digital angiography. In two cases, no pathological findings were observed at MRI, angio-MRI, or digital angiography. In one case, MRI showed the presence of a cervical rib without vascular repercussions.

Gadolinium-enhanced angio-MRI is useful in the evaluation of TOS. It is important to examine patients at rest and during different postural maneuvers. In many cases it is possible to determine the cause of vascular compression.