Quantitative magnetic resonance angiography in the evaluation of the subclavian steal syndrome: report of 5 patients.

BACKGROUND AND PURPOSE: The indications for surgical or endovascular treatment of patients with subclavian stenosis (SS) or occlusion remain controversial. Multiple studies have shown that in most patients, SS results in steal that is evident radiographically, but requires no treatment.

METHODS: This report describes 5 cases of SS, analyzed with phase contrast quantitative MRA (QMRA). QMRA provides quantitative blood flow data previously unavailable. A quantitative ischemic forearm challenge is also introduced using the QMRA technique.

RESULTS: A basilar flow index, basilar artery (BA) flow as a percentage of total intracranial flow was defined. This varied from 12.6% to 20.4%. All patients in this report had VA flow reversal. None had BA flow reversal

CONCLUSION: This report features novel methods using QMRA to identify ischemic patterns in the BA indicative of significant subclavian steal syndrome (SSS) in patients with SS.