MR angiography (5, 17) is traditionally divided in “non-contrasted-enhanced” (NCE MRA) and “contrast-enhanced” (CE MRA) techniques. Contrast-enhanced techniques were initially developed to solve some of the problems encountered with non-contrast-enhanced methods, namely the long examination times, pulsated flow artefacts, saturation when the mean bloos flow is slow or when the imaging slice is parallel to the vessel, the characteristic problems of time of flight (TOF) acquisitions, and the need to define a priori beforehand the velocity sensitivity for phase contrast (PC) acquisitions. Currently used contrast-enhanced techniques (7, 8, 15, 18) are based on the acquisition of 3D gradient-echo sequences synchronized at the first passage of contrast nedium by different strategies (detection of a test bolus injection, automated triggering, fluoroscopic imaging). Basically, contrast medium is administered to counteract saturation induced by slow blood flow or flow directed parallel to the imaging slice. Contrast medium serves to obtain a “static” image of vascular structures with acquisition times ranging from a few seconds to 1-2 minutes. To avoid venous contamination, different methods have been used to collect data (centric approach, elliptical-centric phase encoding order, etc.) in an attempt to record first the information relating to low spatial frequencies (contrast data) with respect to high spatial freqencies (detail and contour data).

Neuroradiological diagnostic tools: new MRI perspectives / Agati R.; Simonetti L.; Marliani A.F.; Albini-Riccioli L.; Battaglia S.; Cevolani D.; Ghedin P.; Leonardi M.. - STAMPA. - (2007), pp. 10-20. (Intervento presentato al convegno Endovascular surgery in brain vascular malformations and cerebral ischemic disease. 2nd INternational Course tenutosi a St. Peptersburg. Russia nel 26-27/04/2007).

Neuroradiological diagnostic tools: new MRI perspectives.

CEVOLANI, DANIELA;LEONARDI, MARCO
2007

Abstract

MR angiography (5, 17) is traditionally divided in “non-contrasted-enhanced” (NCE MRA) and “contrast-enhanced” (CE MRA) techniques. Contrast-enhanced techniques were initially developed to solve some of the problems encountered with non-contrast-enhanced methods, namely the long examination times, pulsated flow artefacts, saturation when the mean bloos flow is slow or when the imaging slice is parallel to the vessel, the characteristic problems of time of flight (TOF) acquisitions, and the need to define a priori beforehand the velocity sensitivity for phase contrast (PC) acquisitions. Currently used contrast-enhanced techniques (7, 8, 15, 18) are based on the acquisition of 3D gradient-echo sequences synchronized at the first passage of contrast nedium by different strategies (detection of a test bolus injection, automated triggering, fluoroscopic imaging). Basically, contrast medium is administered to counteract saturation induced by slow blood flow or flow directed parallel to the imaging slice. Contrast medium serves to obtain a “static” image of vascular structures with acquisition times ranging from a few seconds to 1-2 minutes. To avoid venous contamination, different methods have been used to collect data (centric approach, elliptical-centric phase encoding order, etc.) in an attempt to record first the information relating to low spatial frequencies (contrast data) with respect to high spatial freqencies (detail and contour data).
2007
.
10
20
Neuroradiological diagnostic tools: new MRI perspectives / Agati R.; Simonetti L.; Marliani A.F.; Albini-Riccioli L.; Battaglia S.; Cevolani D.; Ghedin P.; Leonardi M.. - STAMPA. - (2007), pp. 10-20. (Intervento presentato al convegno Endovascular surgery in brain vascular malformations and cerebral ischemic disease. 2nd INternational Course tenutosi a St. Peptersburg. Russia nel 26-27/04/2007).
Agati R.; Simonetti L.; Marliani A.F.; Albini-Riccioli L.; Battaglia S.; Cevolani D.; Ghedin P.; Leonardi M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/115428
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