Abstract：
Magnetic resonance thermometry (MRT) can measure in-vivo 3D-temperature changes in real-time and noninvasively. However, for the oropharynx region and the entire head and neck, motion potentially introduces large artifacts. Considering long treatment times of 60-90 min, this study aims to evaluate whether MRT around the oropharynx is clinically feasible for hyperthermia treatments and quantify the effects of breathing and swallowing on MRT performance. A 3D-ME-FGRE sequence was used in a phantom cooling down and around the oropharynx of five volunteers over ∼75 min. The imaging protocol consisted of imaging with acceleration (ARC = 2), number of image averages (NEX = 1,2 and 3). For volunteers, the acquisitions included a breath-hold scan and scans with deliberate swallowing. MRT performance was quantified in neck muscle, spinal cord and masseter muscle, using mean average error (MAE), mean error (ME) and spatial standard deviation (SD). In phantom, an increase in NEX leads to a significant decrease in SD, but MAE and ME were unchanged. No significant difference was found in volunteers between the different scans. There was a significant difference between the regions evaluated: neck muscle had the best MAE (=1.96 °C) and SD (=0.82 °C), followed by spinal cord (MAE = 3.17 °C, SD = 0.92 °C) and masseter muscle (MAE = 4.53 °C, SD = 1.16 °C). Concerning the ME, spinal cord did best, then neck muscle and masseter muscle, with values of -0.64 °C, 1.15 °C and -3.05 °C respectively. Breathing, swallowing, and different ways of imaging (acceleration and NEX) do not significantly influence the MRT performance in the oropharynx region. The ROI selected however, leads to significant differences.
摘要：
磁共振测温法（MRT）可以实时且无创地测量体内3D温度变化。然而,对于口咽区域和整个头部和颈部，运动可能会引入大的伪影。考虑到60-90分钟的长处理时间，本研究旨在评估口咽周围的MRT在热疗治疗中是否具有临床可行性,并量化呼吸和吞咽对MRT表现的影响.3D-ME-FGRE序列用于在约75分钟内冷却五名志愿者的口咽周围的幻影。成像协议包括加速成像（ARC=2），图像平均数(NEX=1、2和3)。对于志愿者来说,这些采集包括屏气扫描和故意吞咽扫描。对颈部肌肉的MRT性能进行了量化，脊髓和咬肌，使用平均平均误差(MAE)，平均误差(ME)和空间标准偏差(SD)。在幻影中，NEX的增加导致SD的显着降低，但MAE和我没有改变。在不同扫描之间的志愿者中没有发现显著差异。评估的区域之间存在显着差异：颈部肌肉具有最佳的MAE（=1.96°C）和SD（=0.82°C），其次是脊髓（MAE=3.17°C，SD=0.92°C）和咬肌（MAE=4.53°C，SD=1.16°C)。关于我，脊髓做得最好，然后是颈部肌肉和咬肌，值为-0.64°C，分别为1.15°C和-3.05°C。呼吸,吞咽,和不同的成像方式（加速度和NEX）不会显着影响口咽区域的MRT性能。然而，选择的ROI，导致显著差异。
