Specific absorption rate in neonates undergoing magnetic resonance procedures at 1.5 T and 3 T.
Specific absorption rate in neonates undergoing magnetic resonance procedures at 1.5 T and 3 T.
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DOI：
10.1002/nbm.3256
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发表时间：
2015-03
影响因子：
2.9
通讯作者：
Hajnal, Joseph V.
中科院分区：
文献类型：
--
作者：
Malik, Shaihan J.;Beqiri, Arian;Price, Anthony N.;Teixeira, Jose Nuno;Hand, Jeffrey W.;Hajnal, Joseph V.
MRI 发现新生儿人群的临床应用有所增加；商用 MRI 扫描仪用于量化比吸收率 (SAR) 的电磁模型在多大程度上准确反映了这种替代情况尚不清楚。本研究调查了使用 1.5T 和 3T MRI 扫描仪成像时，在不同条件下与成人相关的 SAR 预测如何与新生儿相关。在通用 MRI 身体发射设备内对不同体型和位置的新生儿受试者进行电磁模拟，该设备运行于 64MHz 和 128MHz，分别对应于 1.5T 和 3T MRI 扫描仪。还模拟了成人模型，以及球形盐水模型，该模型也用于量热实验。研究发现，在所有情况下，新生儿受试者的 SAR 均低于成人的 SAR；然而，高估因素是可变的。例如，3 T 身体扫描导致成人局部 10 g SAR 为 10.1 W kg−1，而新生儿则为 2.6 W kg−1：大约是四倍的差异。接受 MRI 的新生儿受试者所经历的 SAR 低于同等情况下的成人。如果使用适合成人的模型评估此类手术的安全性，那么结果是保守估计。 © 2015 作者。生物医学中的 NMR 由 John Wiley & Sons, Ltd 出版。
MRI is finding increased clinical use in neonatal populations; the extent to which electromagnetic models used for quantification of specific absorption rate (SAR) by commercial MRI scanners accurately reflect this alternative scenario is unclear. This study investigates how SAR predictions relating to adults can be related to neonates under differing conditions when imaged using 1.5 T and 3 T MRI scanners. Electromagnetic simulations were produced in neonatal subjects of different sizes and positions within a generic MRI body transmit device operating at both 64 MHz and 128 MHz, corresponding to 1.5 T and 3 T MRI scanners, respectively. An adult model was also simulated, as was a spherical salt‐water phantom, which was also used in a calorimetry experiment. The SAR in neonatal subjects was found to be less than that experienced in an adult in all scenarios; however, the overestimation factor was variable. For example a 3 T body scan resulting in local 10 g SAR of 10.1 W kg−1 in an adult would deposit 2.6 W kg−1 in a neonate: an approximately fourfold difference. The SAR experienced by neonatal subjects undergoing MRI is lower than that in adults in equivalent situations. If the safety of such procedures is assessed using adult‐appropriate models then the result is a conservative estimate. © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.
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