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Contrast-enhanced MR angiography of subclavian steal syndrome: value of the 2D time-of-flight "localizer" sign.

Research paper by Niall N Sheehy, Sorcha S MacNally, Clare S CS Smith, Gerard G Boyle, Prakash P Madhavan, James F M JF Meaney

Indexed on: 24 Sep '05Published on: 24 Sep '05Published in: AJR. American journal of roentgenology



Abstract

Our objective was to determine if direction of flow within the vertebral artery could be reliably determined by evaluation of flow-sensitive, low-resolution 2D time-of-flight (TOF) localizer images taken before 3D contrast-enhanced MR angiography (3D CEMRA) sequences in patients with unsuspected subclavian steal syndrome.Vertebral artery patency on 3D CEMRA in cases in which the vessel is absent on the TOF localizer in association with ipsilateral subclavian artery stenosis indicates reversal of flow in the vertebral artery and confirms the subclavian steal phenomenon. The combination of anatomic imaging with 3D CEMRA with functional information provided by the low-resolution TOF localizer confirms the diagnosis of subclavian steal without additional imaging.