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Carotid and intracranial stenosis flow quantification using Quantitative magnetic resonance angiography: A combined phantom and subject study.

Ahmed Sobieh1*, Arthur Hackbart1, Till-Karsten Hauser1 and Uwe Klose1
  • 1 University of Tuebingen, Germany

Introduction: Possible stenosis within stents within carotids (ICA) or media cerebral arteries (MCA) cannot be seen in MR imaging due to image artefacts (1). Quantifying of flow could be an alternative to detect stenosis within stents through its physiologic effect. This was examined in phantom and in-vivo measurements in patients with stenosis and healthy controls. Objective: Implement and optimize sequences for spatial and time resolved flow encoding and the estimation of the flow velocity allowing for better characterizing stenosis and assessing its degrees. Methods: A phantom model mimicking normal anatomy of internal carotid and middle cerebral arteries was built composed of 8 and 4 mm tubes connected in Y-shaped form to pulsatile pump pumping 500 ml at rate 60 beat/min. Different degrees of stenosis were applied to one limb while the other remained patent. We scanned with a phase contrast sequence perpendicular to direction of flow. Subsequent measurements were performed on 27 volunteers and 14 patients with stenosis. Results: The flow showed a nonlinear behavior with increasing degree of stenosis. In 8 mm tubes, the flow was stable up to 75 % stenosis while in 4 mm tubes, the flow was stable up to 65 % before decreasing for higher degrees of stenosis. In-vivo, the flow difference within left and right ICAs and MCAs was examined. It ranged from 0.4-11% in healthy controls while for patients; the flow difference was more than 15% depending on degree of stenosis. Patients had reduced flow in stenotic arteries compared to flow in normal volunteers. Conclusion: QMRA is a non invasive tool for flow quantification and grading of stenosis allowing for better patient management and could be used in stented arteries.

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References

1- Frolich AM, Pilgram-Pastor SM, Psychogios MN, Mohr A, Knauth M. Comparing different MR angiography strategies of carotid stents in a vascular flow model: toward stent-specific recommendations in MR follow-up. Neuroradiology. 2011 May;53(5):359-65

Keywords: qmra, Stenosis, Phantom, Flow, quantification

Conference: SAN2016 Meeting, Corfu, Greece, 6 Oct - 9 Oct, 2016.

Presentation Type: Poster Presentation in SAN2016 Conference

Topic: Posters

Citation: Sobieh A, Hackbart A, Hauser T and Klose U (2016). Carotid and intracranial stenosis flow quantification using Quantitative magnetic resonance angiography: A combined phantom and subject study.. Conference Abstract: SAN2016 Meeting. doi: 10.3389/conf.fnhum.2016.220.00054

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Received: 29 Jul 2016; Published Online: 01 Aug 2016.

* Correspondence: Mr. Ahmed Sobieh, University of Tuebingen, Tuebingen, Germany, ahmadsobeih@hotmail.com