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Peng G, Zhu W, Zuo Z, Liu C, Zhang Z, Zhao Y, Zhang X, Wu Z, Tao L. Efficacy of modified time of flight magnetic resonance venography in diagnosis of iliac vein compression syndrome. Eur J Radiol 2023; 166:111020. [PMID: 37542815 DOI: 10.1016/j.ejrad.2023.111020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/21/2023] [Accepted: 07/30/2023] [Indexed: 08/07/2023]
Abstract
OBJECTIVE We investigated the diagnostic efficacy of modified time of flight magnetic resonance venography (mTOF-MRV) for iliac vein compression syndrome diagnosis by optimizing the scanning parameters and improving image quality. METHODS A retrospective study was conducted on 69 patients who underwent routine time of flight magnetic resonance venography (TOF-MRV) and 85 patients who received mTOF-MRV. Assessment of image quality of the two methods was performed by two radiologists using a four-point method. The sensitivity, specificity, positive and negative predictive values of TOF-MRV and mTOF-MRV in the diagnosis of significant iliac vein compression (stenosis >50%) were analyzed by calculating the iliac vein stenosis rates of the two methods and using digital subtraction angiography (DSA) as the gold standard. RESULTS Inter-observer assessment of objective data measurement revealed excellent agreement {ICC [95% confidence interval (CI)]: 0.972 (0.953 to 0.983) for TOF-MRV and 0.979 (0.965 to 0.988) for m-TOF MRV, 0.976 (0.960 to 0.986) for DSA}. The mean error of stenosis rate of mTOF-MRV was markedly smaller than that of TOF-MRV (p < 0.05). Sensitivity, specificity, positive and negative predictive values of TOF-MRV in the diagnosis of significant stenosis were 100%, 95%, 67% and 100%, respectively. The sensitivity, specificity, positive and negative predictive values of mTOF-MRV were 100%. The mean image score for the mTOF-MRV was 3.63 ± 0.59, which was significantly higher compared with that of TOF-MRV (2.19 ± 0.42). CONCLUSION mTOF-MRV has better image quality and can accurately diagnose venous stenosis. Therefore, it can be used for the detection of iliac vein compression syndrome and further assessment after endovascular interventions.
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Affiliation(s)
- Gang Peng
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Zhu
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ziyu Zuo
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Chuan Liu
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zhiwei Zhang
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yu Zhao
- Department of Vascular Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoyu Zhang
- Department of Radiology, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, China
| | - Zhiyi Wu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, China
| | - Li Tao
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Relaxation-Enhanced Angiography without Contrast and Triggering (REACT) for pelvic MR venography in comparison to balanced gradient-echo and T2-weighted spin-echo techniques. Clin Imaging 2021; 74:149-155. [PMID: 33607595 DOI: 10.1016/j.clinimag.2020.12.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 12/09/2020] [Accepted: 12/28/2020] [Indexed: 11/21/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate the imaging capabilities of the REACT pulse sequence in pelvic venous vessels compared to conventional non-contrast pulse sequences. MATERIALS AND METHODS In addition to routine MRI venography, non-contrast enhanced REACT pulse sequence was performed in 4 healthy volunteers and 21 patients with suspected or known deep venous thrombosis and post thrombotic syndrome. Acquired images were independently interpreted by two MRI radiologists. The sequence performance was subjectively evaluated on a four-point scale regarding the delineation of small peripheral, midsize and large proximal venous vessels, the imaging of vascular pathologies, and the degradation due to artifacts. To evaluate statistical differences in diagnostic accuracy Friedman's test with Dunn's correction was used. RESULTS REACT depicted the peripheral veins superior to bTFE and T2-TSE with an average score of 3.39 compared to 2.33 in bTFE and 1.77 in T2-TSE. In midsize vessels REACT performed significantly better than T2-TSE (1.94) and bTFE (2.68) with a score of 3.64. For the large proximal vessels REACT (3.39), bTFE (3.33) and T2-TSE (3.56) performed equally without statistical difference. Visibility of venous pathologies was found to be equal between REACT (3.62), bTFE (3.51) and T2-TSE (3.52). The image degradation due to artifacts was rated best in T2-TSE (3.56), followed by REACT (3.39) and bTFE (3.33). CONCLUSIONS REACT is a promising tool for the visualization of the pelvic venous system using magnetic resonance imaging.
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Colbert CM, Shao J, Hollowed JJ, Currier JW, Ajijola OA, Fishbein GA, Duarte-Vogel SM, Dharmakumar R, Hu P, Nguyen KL. 3D-Printed Coronary Implants Are Effective for Percutaneous Creation of Swine Models with Focal Coronary Stenosis. J Cardiovasc Transl Res 2020; 13:1033-1043. [PMID: 32394352 PMCID: PMC9667863 DOI: 10.1007/s12265-020-10018-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 04/28/2020] [Indexed: 01/17/2023]
Abstract
Reliable, closed-chest methods for creating large animal models of acute myocardial hypoperfusion are limited. We demonstrated the feasibility and efficacy of using magnetic resonance (MR)-compatible 3D-printed coronary implants for establishing swine models of myocardial hypoperfusion. We designed, manufactured, and percutaneously deployed implants in 13 swine to selectively create focal coronary stenosis. To test the efficacy of the implants to cause hypoperfusion or ischemia in the perfused territory, we evaluated regional wall motion, myocardial perfusion, and infarction using MR imaging. The overall swine survival rate was 85% (11 of 13). The implant retrieval rate was 92% (12 of 13). Fluoroscopic angiography confirmed focal stenosis. Cine and perfusion MRI showed regional wall motion abnormalities and inducible ischemia, respectively. Late gadolinium enhancement and histopathology showed no myocardial infarction. Our minimally invasive technique has promising applications for validation of new diagnostic methods in cardiac MR. Graphical abstract Our new minimally invasive, percutaneous method for creating swine models of acute focal coronary stenosis can be used for magnetic resonance imaging studies of myocardial ischemia. Comparable to existing methods in its efficacy and reliability, this rapid prototyping technique will allow researchers to more easily conduct translational cardiac imaging studies of coronary artery disease in large animal models.
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Affiliation(s)
- Caroline M Colbert
- Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Jiaxin Shao
- Diagnostic Cardiovascular Imaging Laboratory, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - John J Hollowed
- Division of Cardiology, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare System, 11301 Wilshire Blvd, MC 111E, Los Angeles, CA, 90073, USA
| | - Jesse W Currier
- Division of Cardiology, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare System, 11301 Wilshire Blvd, MC 111E, Los Angeles, CA, 90073, USA
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center and Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gregory A Fishbein
- Department of Pathology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sandra M Duarte-Vogel
- Division of Laboratory Animal Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Rohan Dharmakumar
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center and Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Peng Hu
- Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Diagnostic Cardiovascular Imaging Laboratory, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Kim-Lien Nguyen
- Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
- Diagnostic Cardiovascular Imaging Laboratory, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
- Division of Cardiology, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare System, 11301 Wilshire Blvd, MC 111E, Los Angeles, CA, 90073, USA.
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Michalska M, Kazimierczak W, Leszczyński W, Nadolska K, Bryl Ł. Contemporary follow-up imaging after endovascular repair of lower extremity atherosclerotic lesions. Pol J Radiol 2018; 83:e634-e642. [PMID: 30800203 PMCID: PMC6384408 DOI: 10.5114/pjr.2018.80348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 11/22/2018] [Indexed: 12/22/2022] Open
Abstract
Atherosclerotic disease is currently one of the most important problems of modern medicine because it is a leading cause of increased morbidity, morbidity and mortality, and disability in the Western World. Atherosclerosis of the lower limbs (peripheral arterial disease - PAD) significantly affects the quality of life and in a considerable proportion of patients is a cause of disability. Radical treatment of PAD, both surgical and endovascular, aims at revascularisation of ischaemic tissues distal to obstructed arteries. Surveillance imaging is an important part of patient management after endovascular repair of PAD. Apart from availability and contraindications, challenges of imaging include calcifications, flow dynamics, and stent-related artefacts. The aim of this paper was to review the current literature on imaging methods for follow-up after endovascular repair of atherosclerotic lesions, with special attention paid to novel techniques. As a non-invasive modality, ultrasound is still the first-line examination, but computed tomography angiography remains a current state-of-the art technique for follow-up. However, since current imaging recommendations seem not to adhere to contemporary imaging possibilities, more attention should be paid to recent improvements in magnetic resonance angiography technology.
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Fujimoto K, Angelone LM, Lucano E, Rajan SS, Iacono MI. Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging. Front Physiol 2018; 9:1439. [PMID: 30459628 PMCID: PMC6232906 DOI: 10.3389/fphys.2018.01439] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 09/21/2018] [Indexed: 01/03/2023] Open
Abstract
Purpose: The purpose of this study was to investigate the need for high-resolution detailed anatomical modeling to correctly estimate radio-frequency (RF) safety during magnetic resonance imaging (MRI). RF-induced heating near metallic implanted devices depends on the electric field tangential to the device (Etan). Etan and specific absorption rate (SAR) were analyzed in blood vessels of an anatomical model to understand if a standard gel phantom accurately represents the potential heating in tissues due to passive vascular implants such as stents. Methods: A numerical model of an RF birdcage body coil and an anatomically realistic virtual patient with a native spatial resolution of 1 mm3 were used to simulate the in vivo electric field at 64 MHz (1.5 T MRI system). Maximum values of SAR inside the blood vessels were calculated and compared with peaks in a numerical model of the ASTM gel phantom to see if the results from the simplified and homogeneous gel phantom were comparable to the results from the anatomical model. Etan values were also calculated in selected stent trajectories inside blood vessels and compared with the ASTM result. Results: Peak SAR values in blood vessels were up to ten times higher than those found in the ASTM standard gel phantom. Peaks were found in clinically significant anatomical locations, where stents are implanted as per intended use. Furthermore, Etan results showed that volume-averaged SAR values might not be sufficient to assess RF safety. Conclusion: Computational modeling with a high-resolution anatomical model indicated higher values of the incident electric field compared to the standard testing approach. Further investigation will help develop a robust safety testing method which reflects clinically realistic conditions.
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Affiliation(s)
- Kyoko Fujimoto
- Division of Biomedical Physics, Office of Science and Engineering Laboratory, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Leonardo M Angelone
- Division of Biomedical Physics, Office of Science and Engineering Laboratory, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Elena Lucano
- Division of Biomedical Physics, Office of Science and Engineering Laboratory, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Sunder S Rajan
- Division of Biomedical Physics, Office of Science and Engineering Laboratory, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Maria Ida Iacono
- Division of Biomedical Physics, Office of Science and Engineering Laboratory, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
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Abstract
Airway stent implantation is a highly effective treatment for airway stenosis. However, it is presently unclear whether patients with airway stents can safely undergo magnetic resonance imaging (MRI). Such stents may be metallic or non-metallic, and MRI may induce stent dislodgment or heating and may be associated with stent-induced artifacts. We thoroughly reviewed the literature, experimental data, and manufacturer information on non-metallic, stainless steel (SS) and nickel-titanium alloy stents. Non-metallic stents are made of non-ferromagnetic materials associated with no MRI concerns. SS stents may shift in a magnetic field, generating significant artifacts. Nickel-titanium alloy stents are not at risk of dislodgement or heating, but may create some artifacts affecting image quality. Both non-metallic and nickel-titanium alloy stents are safe for patients who must undergo MRI. However, the safety of SS stents depends on the type of steel used.
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Affiliation(s)
- Yang Xia
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Rui Jin
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Wen Li
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Huahao Shen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
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Gurney-Champion OJ, Bruins Slot T, Lens E, van der Horst A, Klaassen R, van Laarhoven HWM, van Tienhoven G, van Hooft JE, Nederveen AJ, Bel A. Quantitative assessment of biliary stent artifacts on MR images: Potential implications for target delineation in radiotherapy. Med Phys 2017; 43:5603. [PMID: 27782717 DOI: 10.1118/1.4962476] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
PURPOSE Biliary stents may cause susceptibility artifacts, gradient-induced artifacts, and radio frequency (RF) induced artifacts on magnetic resonance images, which can hinder accurate target volume delineation in radiotherapy. In this study, the authors investigated and quantified the magnitude of these artifacts for stents of different materials. METHODS Eight biliary stents made of nitinol, platinum-cored nitinol, stainless steel, or polyethylene from seven vendors, with different lengths (57-98 mm) and diameters (3.0-11.7 mm), were placed in a phantom. To quantify the susceptibility artifacts sequence-independently, ΔB0-maps and T2∗-maps were acquired at 1.5 and 3 T. To study the effect of the gradient-induced artifacts at 3 T, signal decay in images obtained with maximum readout gradient-induced artifacts was compared to signal decay in reference scans. To quantify the RF induced artifacts at 3 T, B1-maps were acquired. Finally, ΔB0-maps and T2∗-maps were acquired at 3 T of two pancreatic cancer patients who had received platinum-cored nitinol biliary stents. RESULTS Outside the stent, susceptibility artifacts dominated the other artifacts. The stainless steel stent produced the largest susceptibility artifacts. The other stents caused decreased T2∗ up to 5.1 mm (1.5 T) and 8.5 mm (3 T) from the edge of the stent. For sequences with a higher bandwidth per voxel (1.5 T: BWvox > 275 Hz/voxel; 3 T: BWvox > 500 Hz/voxel), the B0-related susceptibility artifacts were negligible (<0.2 voxels). The polyethylene stent showed no artifacts. In vivo, the changes in B0 and T2∗ induced by the stent were larger than typical variations in B0 and T2∗ induced by anatomy when the stent was at an angle of 30° with the main magnetic field. CONCLUSIONS Susceptibility artifacts were dominating over the other artifacts. The magnitudes of the susceptibility artifacts were determined sequence-independently. This method allows to include additional safety margins that ensure target irradiation.
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Affiliation(s)
- Oliver J Gurney-Champion
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands and Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Thijs Bruins Slot
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Eelco Lens
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Astrid van der Horst
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Remy Klaassen
- Department of Medical Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands and Laboratory for Experimental Oncology and Radiobiology, Center for Experimental Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Hanneke W M van Laarhoven
- Department of Medical Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Geertjan van Tienhoven
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Jeanin E van Hooft
- Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Aart J Nederveen
- Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Arjan Bel
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
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Design considerations for studies of the biomechanical environment of the femoropopliteal arteries. J Vasc Surg 2013; 58:804-13. [DOI: 10.1016/j.jvs.2013.03.052] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/14/2013] [Accepted: 03/24/2013] [Indexed: 11/18/2022]
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In vitro stent lumen visualisation of various common and newly developed femoral artery stents using MR angiography at 1.5 and 3 tesla. Eur Radiol 2012; 23:588-95. [PMID: 22898936 DOI: 10.1007/s00330-012-2625-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 10/28/2022]
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Brown R, Karmonik C, Brunner G, Lumsden A, Ballantyne C, Johnson S, Wang Y, Morrisett J. Simultaneous bilateral magnetic resonance imaging of the femoral arteries in peripheral arterial disease patients. J Magn Reson Imaging 2011; 34:150-6. [PMID: 21598344 DOI: 10.1002/jmri.22591] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 03/07/2011] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To image the femoral arteries in peripheral arterial disease (PAD) patients using a bilateral receive coil. MATERIALS AND METHODS An eight-channel surface coil array for bilateral MRI of the femoral arteries at 3T was constructed and evaluated. RESULTS The bilateral array enabled imaging of a 25-cm segment of the superficial femoral arteries (SFA) from the profunda to the popliteal. The array provided improved the signal-to-noise ratio (SNR) at the periphery and similar SNR in the middle of a phantom compared to three other commercially available coils (4-channel torso, quadrature head, whole body). Multicontrast bilateral images of the in vivo SFA with 1 mm in-plane resolution made it possible to directly compare lesions in the index SFA to the corresponding anatomical site in the contralateral vessel without repositioning the patient or coil. A set of bilateral time-of-flight, T1-weighted, T2-weighted, and proton density-weighted images was acquired in a clinically acceptable exam time of ≈45 minutes. CONCLUSION The developed bilateral coil is well suited for monitoring dimensional changes in atherosclerotic lesions of the SFA.
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Affiliation(s)
- Ryan Brown
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
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Abstract
In the biomedical field, palladium has primarily been used as a component of alloys for dental prostheses. However, recent research has shown the utility of palladium alloys for devices such as vascular stents that do not distort magnetic resonance images. Dental palladium alloys may contain minor or major percentages of palladium. As a minor constituent, palladium hardens, strengthens and increases the melting range of alloys. Alloys that contain palladium as the major component also contain copper, gallium and sometimes tin to produce strong alloys with high stiffness and relatively low corrosion rates. All current evidence suggests that palladium alloys are safe, despite fears about harmful effects of low-level corrosion products during biomedical use. Recent evidence suggests that palladium poses fewer biological risks than other elements, such as nickel or silver. Hypersensitivity to palladium alone is rare, but accompanies nickel hypersensitivity 90-100% of the time. The unstable price of palladium continues to influence the use of palladium alloys in biomedicine.
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Affiliation(s)
- John C Wataha
- University of Washington School of Dentistry, Seattle, WA, USA.
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Kenny D, Hamilton MCK, Martin RP. Stainless steel stents and magnetic resonance imaging looking into a black hole. J Am Coll Cardiol 2010; 54:2202-3; author reply 2203. [PMID: 19942095 DOI: 10.1016/j.jacc.2009.04.101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 04/16/2009] [Indexed: 11/19/2022]
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Reinhardt J, Nguyen-Trong TH, Hähnel S, Bellemann ME, Heiland S. [Magnetic resonance imaging of stents: quantitative in vitro examination at 3 Tesla]. Z Med Phys 2009; 19:278-87. [PMID: 19995528 DOI: 10.1016/j.zemedi.2009.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 06/02/2009] [Accepted: 06/11/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE The aim of this study was to qualitatively and quantitatively study MR artifacts of various stents on the basis of in vitro experiments. We were particularly interested whether sequence type and orientation of the stent with respect to the static magnetic field influences the artifact. MATERIAL AND METHODS We examined 18 stents of different material (nitinol, stainless steel, cobalt alloy), different design of the stent meshes (AccuLink, OmniLink, DynaLink, Xact, Protoge, Wallstent Monorail), different diameter (5-10mm) and different length (18-58 mm) with a turbo spin echo (TSE), a 2D-fast low angle shot (FLASH) and a 3D-FLASH sequence. The MR images were examined qualitatively with respect to possible artifacts. Furthermore we examined the MR data quantitatively: The contrast-noise-ratio (CNR) was determined both within the stent and outside (within the tube); based on these values we calculated the transparency factor P, furthermore we calculated the apparent vascular lumen within the tube and within the stent. RESULTS The stents made of stainless steel and cobalt alloy displayed severe susceptibility artifacts. Therefore the vessel lumen within the stent could not be assessed. The nitinol stents showed different artifact patterns: The AccuLink and DynaLink stents showed less artifacts compared to the Xact and Protoge stents. Besides the susceptibility artifacts we found artifacts due to RF shielding by the stent mesh, particularly in TSE sequences. CONCLUSION A MR control of patients after stenting is possible and may yield diagnostic information when using the AccuLink or DynaLink stents. However, it is important to make sure that the stent is MR safe for the field strength used for the examination.
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Affiliation(s)
- Julia Reinhardt
- Sektion Experimentelle Radiologie, Neurologische Universitätsklinik Heidelberg, Im Neuenheimer Feld 400, D-69120 Heidelberg, Germany
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Mani G, Feldman MD, Patel D, Agrawal CM. Coronary stents: a materials perspective. Biomaterials 2006; 28:1689-710. [PMID: 17188349 DOI: 10.1016/j.biomaterials.2006.11.042] [Citation(s) in RCA: 410] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 11/29/2006] [Indexed: 12/21/2022]
Abstract
The objective of this review is to describe the suitability of different biomaterials as coronary stents. This review focuses on the following topics: (1) different materials used for stents, (2) surface characteristics that influence stent-biology interactions, (3) the use of polymers in stents, and (4) drug-eluting stents, especially those that are commercially available.
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Affiliation(s)
- Gopinath Mani
- Department of Biomedical Engineering, College of Engineering, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 0619, USA
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