Detailing radio frequency heating induced by coronary stents: a 7.0 Tesla magnetic resonance study.
Detailing radio frequency heating induced by coronary stents: a 7.0 Tesla magnetic resonance study.
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DOI：
10.1371/journal.pone.0049963
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Niendorf T
中科院分区：
文献类型：
--
作者：
Santoro D;Winter L;Müller A;Vogt J;Renz W;Ozerdem C;Grässl A;Tkachenko V;Schulz-Menger J;Niendorf T
超高场磁共振（UHF-MR）的灵敏度增益有望提高空间和时间分辨率。然而，用于治疗冠状动脉疾病的冠状动脉内支架目前被认为是UHF-MR的禁忌症。支架诱导的天线效应和射频波长缩短会增加7.0 T下的局部射频（RF）功率沉积，并有可能引起局部加热，从而导致组织损伤。意识到这些限制，本研究使用电磁场（EMF）模拟和具有模拟心肌特性的模型来研究支架的射频加热效应。为此，使用专用鸟笼线圈诱导超过临床限制的射频功率沉积。利用含铜管或冠脉支架的琼脂糖模型，采用光纤探针和磁共振测温法进行温度监测。结果表明，射频加热诱导的温度变化源自EMF模拟与MR测温之间的一致。为射频加热量身定制的鸟笼线圈的辐射功率超过IEC指南规定的特定吸收率（SAR）限制的三倍。这种设置在参考模体中提供射频诱导温度变化高达+ 27k。铜管或冠状动脉支架引起的最大额外温度升高小于3 K。冠状动脉支架检查显示射频加热行为类似于铜管。我们的研究结果表明，如果遵循局部/全局SAR的IEC指南，支架在心肌组织中引起的额外射频加热可能与定制的心脏传输射频线圈在7.0 T下沉积的能量引起的基线加热相比并不显着，并且可能比在本研究中使用的情况下观察到的额外射频加热更小。
The sensitivity gain of ultrahigh field Magnetic Resonance (UHF-MR) holds the promise to enhance spatial and temporal resolution. Such improvements could be beneficial for cardiovascular MR. However, intracoronary stents used for treatment of coronary artery disease are currently considered to be contra-indications for UHF-MR. The antenna effect induced by a stent together with RF wavelength shortening could increase local radiofrequency (RF) power deposition at 7.0 T and bears the potential to induce local heating, which might cause tissue damage. Realizing these constraints, this work examines RF heating effects of stents using electro-magnetic field (EMF) simulations and phantoms with properties that mimic myocardium. For this purpose, RF power deposition that exceeds the clinical limits was induced by a dedicated birdcage coil. Fiber optic probes and MR thermometry were applied for temperature monitoring using agarose phantoms containing copper tubes or coronary stents. The results demonstrate an agreement between RF heating induced temperature changes derived from EMF simulations versus MR thermometry. The birdcage coil tailored for RF heating was capable of irradiating power exceeding the specific-absorption rate (SAR) limits defined by the IEC guidelines by a factor of three. This setup afforded RF induced temperature changes up to +27 K in a reference phantom. The maximum extra temperature increase, induced by a copper tube or a coronary stent was less than 3 K. The coronary stents examined showed an RF heating behavior similar to a copper tube. Our results suggest that, if IEC guidelines for local/global SAR are followed, the extra RF heating induced in myocardial tissue by stents may not be significant versus the baseline heating induced by the energy deposited by a tailored cardiac transmit RF coil at 7.0 T, and may be smaller if not insignificant than the extra RF heating observed under the circumstances used in this study.
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DOI：
10.1186/1532-429x-14-15
发表时间：
2012-02-06
期刊：
Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
影响因子：
--
作者：
Dall'Armellina E;Piechnik SK;Ferreira VM;Si QL;Robson MD;Francis JM;Cuculi F;Kharbanda RK;Banning AP;Choudhury RP;Karamitsos TD;Neubauer S
通讯作者：
Neubauer S
影响因子：
0.9
作者：
Huang, Shuning;Sosnovik, David E.
通讯作者：
Sosnovik, David E.
影响因子：
2.1
作者：
Rawson, Nigel S. B.;Chu, Rong;Terres, Jorge Alfonso Ross
通讯作者：
Terres, Jorge Alfonso Ross
影响因子：
37.8
作者：
Carpenter JP;He T;Kirk P;Roughton M;Anderson LJ;de Noronha SV;Sheppard MN;Porter JB;Walker JM;Wood JC;Galanello R;Forni G;Catani G;Matta G;Fucharoen S;Fleming A;House MJ;Black G;Firmin DN;St Pierre TG;Pennell DJ
通讯作者：
Pennell DJ
影响因子：
3.3
作者：
Nordbeck, Peter;Fidler, Florian;Quick, Harald H.
通讯作者：
Quick, Harald H.