MR imaging in the presence of vascular stents: A systematic assessment of artifacts for various stent orientations, sequence types, and field strengths

Klemm, Thomas; Duda, Stephan H.; Machann, Juergen; Seekamp-Rahn, K.; Schnieder, Ludger; Claussen, Claus D.; Schick, Fritz

doi:10.1002/1522-2586(200010)12:4<606::aid-jmri14>3.0.co;2-j

Cited by 115 publications

(93 citation statements)

References 20 publications

(21 reference statements)

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“…Klemm et al 14 and Graf et al 15 found stronger susceptibility artifacts at 1T compared with 0.2T, especially in stainless steel stents. Krämer et al 16 and Wall et al 5 described higher signal intensity-to-noise ratio (SNR) values within the stents at 3T compared with 1.5T, but the pattern of artifacts inside the stents evidently did not differ.…”

Section: Discussionmentioning

confidence: 99%

Carotid Artery Stents: In Vitro Comparison of Different Stent Designs and Sizes Using CT Angiography and Contrast-Enhanced MR Angiography at 1.5T and 3T

Lettau¹,

Sauer²,

Heiland³

et al. 2009

AJNR Am J Neuroradiol

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Section: Discussionmentioning

confidence: 99%

Carotid Artery Stents: In Vitro Comparison of Different Stent Designs and Sizes Using CT Angiography and Contrast-Enhanced MR Angiography at 1.5T and 3T

Lettau¹,

Sauer²,

Heiland³

et al. 2009

AJNR Am J Neuroradiol

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“…The reason for this is that most of these stents provoke relatively large susceptibility artifacts that degrade their visualization. This is not the case with stents made from low-artifact materials like nitinol or tantalum (7,20,21). For such implants the proposed scanning method may provide a tool for follow-up after stent placement.…”

Section: Discussionmentioning

confidence: 99%

“…Several authors have studied the artifacts caused by various commonly used stents in MRI and MRA (12)(13)(14)(15)(16)(17)(18)(19)(20)(21). The application of contrast enhanced (CE) MRA techniques has been shown to provide some improvement in stent visualization, but still it was found that the extent to which the images are distorted depends strongly on the type of stent used.…”

mentioning

confidence: 99%

Improved lumen visualization in metallic vascular implants by reducing RF artifacts

Bartels

Bakker

Viergever

2001

Magnetic Resonance in Med

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In this study, a method is proposed for MRI of the lumen of metallic vascular implants, like stents or vena cava filters. The method is based on the reduction of artifacts caused by flow, susceptibility, and RF eddy currents. Whereas both flow artifacts and susceptibility artifacts are well understood and documented, RF artifacts are not. Therefore, the present study comprises an in-depth theoretical explanation of the factors governing the severity of these RF artifacts. It is explained that the RF caging inside cage-like implants is caused by disturbances of the send and receive sensitivities due to coupling between the loops in the implant and the MR scanner's send and receive coils. A scaled excitation angle model describing the behavior of the signal intensity inside the implants as a function of the applied nominal excitation angle is introduced. This theoretical model was validated in phantom experiments. Reduced signal from within implants due to the caging problem could be restored by increasing the applied RF power in the excitation pulse, without exceeding the generally accepted SAR safety limits. For all these applications the imaging of regions of the body containing metallic vascular implants, like stents and vena cava filters, is troublesome because of the artifacts provoked by these implants. In particular, MRA of stented vessels is hampered inside and near the stent. Often signal void is seen at these locations, rendering evaluation of the stent lumen and detection of possible restenosis inside the stent impossible (9 -11).Several authors have studied the artifacts caused by various commonly used stents in . The application of contrast enhanced (CE) MRA techniques has been shown to provide some improvement in stent visualization, but still it was found that the extent to which the images are distorted depends strongly on the type of stent used. For older stent types, often made from stainless steel alloys, the artifacts are mainly due to local differences in magnetic volume susceptibility between the stent and its surroundings. For this reason, stents made of ferromagnetic materials show larger susceptibility artifacts than stents made of so-called MR-compatible materials like tantalum or nitinol. Recently however, it was observed that stents made from the same material, thereby having the same magnetic susceptibility, can provoke significantly different degrees of signal loss in their lumen (17,21,22). These differences were attributed to small variations in susceptibility (16) and to differences in the design of the wire mesh. RF caging of the stent lumen by the metallic cage-like construction of the implant plays an important role here. The extent to which this caging takes place is obviously different for different cage constructions, which accounts for the observed differences in signal disturbance inside the stents.Whereas both flow artifacts and susceptibility artifacts are well understood and documented, RF artifacts are not. Therefore, an in-depth study of the factors governing the seve...

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“…Furthermore, coronary arteries are in part oriented almost perpendicular to B o , which situation is known to cause the largest susceptibility artifacts. 4,16,29,31 Because coronary artery stent placement is frequently used for the treatment of stenosis [1][2][3]9 and in-stent restenosis or stent thrombosis is frequently seen in coronary stents, 9,12,32 a noninvasive imaging modality for assessment of the in-stent lumen (like coronary MRA) would be advantageous. In the present study, 3 prototype designs (hand woven, mechanically woven, and lasered) of a newly developed, metallic coronary MRI stent were investigated in vitro and in a swine model.…”

Section: Discussionmentioning

confidence: 84%

Artifact-Free Coronary Magnetic Resonance Angiography and Coronary Vessel Wall Imaging in the Presence of a New, Metallic, Coronary Magnetic Resonance Imaging Stent

et al. 2005

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Background-Coronary in-stent restenosis cannot be directly assessed by magnetic resonance angiography (MRA) because of the local signal void of currently used stainless steel stents. The aim of this study was to investigate the potential of a new, dedicated, coronary MR imaging (MRI) stent for artifact-free, coronary MRA and in-stent lumen and vessel wall visualization. Methods and Results-Fifteen prototype stents were deployed in coronary arteries of 15 healthy swine and investigated with a double-oblique, navigator-gated, free-breathing, T2-prepared, 3D cartesian gradient-echo sequence; a T2-prepared, 3D spiral gradient-echo sequence; and a T2-prepared, 3D steady-state, free-precession coronary MRA sequence. Furthermore, black-blood vessel wall imaging by a dual-inversion-recovery, turbo spin-echo sequence was performed. Artifacts of the stented vessel segment and signal intensities of the coronary vessel lumen inside and outside the stent were assessed. With all investigated sequences, the vessel lumen and wall could be visualized without artifacts, including the stented vessel segment. No signal intensity alterations inside the stent when compared with the vessel lumen outside the stent were found. Conclusions-The new, coronary MRI stent allows for completely artifact-free coronary MRA and vessel wall imaging.

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MR imaging in the presence of vascular stents: A systematic assessment of artifacts for various stent orientations, sequence types, and field strengths

Cited by 115 publications

References 20 publications

Carotid Artery Stents: In Vitro Comparison of Different Stent Designs and Sizes Using CT Angiography and Contrast-Enhanced MR Angiography at 1.5T and 3T

Carotid Artery Stents: In Vitro Comparison of Different Stent Designs and Sizes Using CT Angiography and Contrast-Enhanced MR Angiography at 1.5T and 3T

Improved lumen visualization in metallic vascular implants by reducing RF artifacts

Artifact-Free Coronary Magnetic Resonance Angiography and Coronary Vessel Wall Imaging in the Presence of a New, Metallic, Coronary Magnetic Resonance Imaging Stent

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