The objectives of this study were to measure the relative attenuation properties of the left and right ventricles in fetal pig hearts and to compare the spatial variation in attenuation measurements with those observed in previously published backscatter measurements. Approximately 1.0 mm thick, short-axis slices of excised, formalin-fixed heart were examined from 15 mid-gestational fetal pigs using a 50-MHz single-element transducer. Measurements of the attenuation properties demonstrate regional differences in the left and right ventricular myocardium that appear consistent with the previously reported regional differences in apparent integrated backscatter measurements of the same fetal pig hearts. For regions of perpendicular insonification relative to the myofiber orientation, the right ventricular free wall showed larger values for the slope of the attenuation coefficient from 30–60 MHz (1.48 ± 0.22 dB/(cm•MHz) (mean ± SD (standard deviation)) and attenuation coefficient at 45 MHz (46.3 ± 7.3 dB/cm (mean ± SD)) than the left ventricular free wall (1.18 ± 0.24 dB/(cm•MHz) and 37.0 ± 7.9 dB/cm (mean ± SD) for slope of attenuation coefficient and attenuation coefficient at 45 MHz, respectively). This attenuation study supports the hypothesis that intrinsic differences in the myocardium of the left and right ventricles exist in fetal pig hearts at mid-gestation.
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机译:这项研究的目的是测量胎儿猪心脏中左,右心室的相对衰减特性,并将衰减测量的空间变化与以前发表的反向散射测量结果进行比较。使用50 MHz单元件探头从15胎中期胎猪中检查了约1.0 mm厚的切除的福尔马林固定的心脏短轴切片。衰减特性的测量结果表明,左,右心室心肌的区域差异似乎与先前报道的同一胎猪心脏的表观综合背向散射测量结果中的区域差异一致。对于垂直于肌纤维方向的超声声区,右心室自由壁的衰减系数斜率在30–60 MHz处显示较大的值(1.48±0.22 dB /(cm•MHz)(平均值±SD(标准偏差)) )和45 MHz(46.3±7.3 dB / cm(平均值±SD))的衰减系数,比左心室游离壁(1.18±0.24 dB /(cm•MHz)和37.0±7.9 dB / cm(平均值±SD)衰减系数和45 MHz处的衰减系数的斜率)。该衰减研究支持以下假设,即胎猪心脏在妊娠中期左右心室的内在差异存在。
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