Abstract No. 244 EE: Evaluation of Vascular Stent’s Patency Using Ultra-Short TE MRI

Abstract

PurposeEvaluation of stent’s patency using Magnetic Resonance Angiography (MRA) has been a challenge. The cause is mainly attributed to shielding from radiofrequency signals and susceptibility (ferromagnetic) artifacts. We evaluated the patency of both stainless steel balloon-expandable and nitinol self-expandable stents using a new state of the art Magnetic Resonance Imaging (MRI) sequence that uses echo time (TE) in the order of tens of microseconds. Intraluminal signal was detected in both; giving the way, for the possibility of restenosis evlaution.Materials and MethodsExperiments were performed on a 3.0 Tesla MRI Scanner using a surface coil. Stainless steel balloon-expandable (Wavemax by Abbott Australasia Pty Ltd and Lifestent by Edwards Lifesciences Pty Ltd) and nitinol self-expandable (Luminex by Bard Australia Pty Ltd) were tested. IV tubing filled with Gadolinium chelate (concentration of 0.01 millimole/liter) was placed inside the stent. This phantom was imaged using two sequences: 1) ultra-short TE (UTE) sequence that uses radial readout and TE of 50 microseconds and 2) conventional 3D Spoiled Gradient Recalled Echo (SPGR) sequence.Teaching Points1. Intraluminal signal was detected in the self-expandable stent using either the 3D SPGR or UTE. However, there was significant signal loss within the balloon-expandable stent using the 3D SPGR; however, this signal was largely reclaimed using the UTE Sequence. 2. Using the new UTE Sequence, it is possible to identify intraluminal signal in both balloon-expandable and self-expandable stents. PurposeEvaluation of stent’s patency using Magnetic Resonance Angiography (MRA) has been a challenge. The cause is mainly attributed to shielding from radiofrequency signals and susceptibility (ferromagnetic) artifacts. We evaluated the patency of both stainless steel balloon-expandable and nitinol self-expandable stents using a new state of the art Magnetic Resonance Imaging (MRI) sequence that uses echo time (TE) in the order of tens of microseconds. Intraluminal signal was detected in both; giving the way, for the possibility of restenosis evlaution. Evaluation of stent’s patency using Magnetic Resonance Angiography (MRA) has been a challenge. The cause is mainly attributed to shielding from radiofrequency signals and susceptibility (ferromagnetic) artifacts. We evaluated the patency of both stainless steel balloon-expandable and nitinol self-expandable stents using a new state of the art Magnetic Resonance Imaging (MRI) sequence that uses echo time (TE) in the order of tens of microseconds. Intraluminal signal was detected in both; giving the way, for the possibility of restenosis evlaution. Materials and MethodsExperiments were performed on a 3.0 Tesla MRI Scanner using a surface coil. Stainless steel balloon-expandable (Wavemax by Abbott Australasia Pty Ltd and Lifestent by Edwards Lifesciences Pty Ltd) and nitinol self-expandable (Luminex by Bard Australia Pty Ltd) were tested. IV tubing filled with Gadolinium chelate (concentration of 0.01 millimole/liter) was placed inside the stent. This phantom was imaged using two sequences: 1) ultra-short TE (UTE) sequence that uses radial readout and TE of 50 microseconds and 2) conventional 3D Spoiled Gradient Recalled Echo (SPGR) sequence. Experiments were performed on a 3.0 Tesla MRI Scanner using a surface coil. Stainless steel balloon-expandable (Wavemax by Abbott Australasia Pty Ltd and Lifestent by Edwards Lifesciences Pty Ltd) and nitinol self-expandable (Luminex by Bard Australia Pty Ltd) were tested. IV tubing filled with Gadolinium chelate (concentration of 0.01 millimole/liter) was placed inside the stent. This phantom was imaged using two sequences: 1) ultra-short TE (UTE) sequence that uses radial readout and TE of 50 microseconds and 2) conventional 3D Spoiled Gradient Recalled Echo (SPGR) sequence. Teaching Points1. Intraluminal signal was detected in the self-expandable stent using either the 3D SPGR or UTE. However, there was significant signal loss within the balloon-expandable stent using the 3D SPGR; however, this signal was largely reclaimed using the UTE Sequence. 2. Using the new UTE Sequence, it is possible to identify intraluminal signal in both balloon-expandable and self-expandable stents. 1. Intraluminal signal was detected in the self-expandable stent using either the 3D SPGR or UTE. However, there was significant signal loss within the balloon-expandable stent using the 3D SPGR; however, this signal was largely reclaimed using the UTE Sequence. 2. Using the new UTE Sequence, it is possible to identify intraluminal signal in both balloon-expandable and self-expandable stents.