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首页> 外文期刊>Ultrasound in Medicine and Biology >Developmental changes in integrated ultrasound backscatter from embryonic blood in vivo in mice at high US frequency.
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Developmental changes in integrated ultrasound backscatter from embryonic blood in vivo in mice at high US frequency.

机译：高频率的小鼠体内来自胚胎血液的集成超声反向散射的发展变化。

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Mouse blood imaged using high-frequency ultrasound (US) is more echogenic in embryos than in adults. Studying changes in blood echogenicity in embryos may be of fundamental interest in studies on the genetic regulation of normal and abnormal blood development in mutant mice. Embryonic red blood cells (RBCs) are large and nucleated in midgestation but decrease in size and become enucleated as they mature. We therefore hypothesised that these structural alterations are responsible for variations in echogenicity of embryonic blood with gestational age and development. The objective of the current study was to quantify these structural changes in echogenicity (echo brightness) and apparent integrated backscatter (AIB) from embryonic blood at high US frequencies in vivo in mice. Results from anaesthetised pregnant mice studied using transcutaneous US showed that echogenicity of embryonic blood in the heart, aorta and umbilical cord and AIB within the heart chambers peaked at embryonic day (ED) 13.5 and thendecreased progressively toward term. Between EDs 13.5 and 17.5 (near term), RBC mean cell volume decreased from 133 to 109 fL, haematocrit increased from 12 to 34%, and the percentage of nucleated RBCs decreased from 59 to 2%. Relative to younger ages, RBC nuclei at ED 13.5 were small and dense (pyknotic) which may have contributed to the peak in echogenicity and AIB at this age. To calculate the AIB, radiofrequency (RF) signals with centre frequencies of 28 MHz and 35 MHz were integrated over the 16- to 35-MHz and 21- to 42-MHz frequency range, respectively. At 28 MHz, mean apparent integrated backscatter of blood in the embryonic heart increased significantly from 0.0023 +/- 0.0004 Sr.cm(-1) (mean +/- SEM) at ED 12.5 to peak at 0.0037 +/- 0.0005 Sr.cm(-1) at ED 13.5. The mean AIB then decreased progressively with advancing gestation to 0.0002 +/- 0.0001 Sr.cm(-1) at ED 17.5. At 35 MHz, the mean AIB changed similarly with gestational age, except that values were lower than at 28 MHz at all ages. Higher attenuation of US at 35 MHz than at 28 MHz in tissue likely accounted for the lower AIB of blood insonified at 35 MHz. We speculate that developmental changes in red cell morphology are responsible for the observed changes in echogenicity and AIB of embryonic blood with gestational age in mice. (E-mail: ).
机译：使用高频超声（US）成像的小鼠血液在胚胎中的回声比在成人中更明显。研究胚胎中血液回声性的变化可能对突变小鼠正常和异常血液发育的遗传调控研究具有根本意义。胚胎红细胞（RBC）较大，在妊娠中期有核，但尺寸减小并随着成熟而去核。因此，我们假设这些结构改变是造成胚胎血液回声性随胎龄和发育而变化的原因。当前研究的目的是在小鼠体内以高US频率量化来自胚胎血液的回声性（回声亮度）和表观整合背向散射（AIB）的这些结构变化。使用经皮超声检查对麻醉的怀孕小鼠进行的研究结果表明，心脏，主动脉和脐带中的胚胎血液以及心腔内的AIB的回声原性在胚胎天（ED）13.5达到峰值，然后朝足月期逐渐降低。在EDs 13.5和17.5（近期）之间，RBC平均细胞体积从133 fL下降到109 fL，血细胞比容从12％上升到34％，有核RBC的百分比从59％下降到2％。相对于较年轻的年龄，ED 13.5的RBC核小而密（致密），可能是这个年龄的回声和AIB峰值的原因。为了计算AIB，分别在16至35 MHz和21至42 MHz频率范围内对中心频率为28 MHz和35 MHz的射频（RF）信号进行了积分。在28 MHz时，胚胎心脏中血液的平均表观积分背向散射从ED 12.5处的0.0023 +/- 0.0004 Sr.cm（-1）（平均+/- SEM）显着增加到0.0037 +/- 0.0005 Sr.cm的峰值（-1）在ED 13.5。然后在ED 17.5时，随着妊娠的发展，平均AIB逐渐降低至0.0002 +/- 0.0001 Sr.cm（-1）。在35 MHz时，平均AIB随胎龄的变化类似，只是在所有年龄段其值均低于28 MHz。在组织中35 MHz处的US衰减高于组织在28 MHz处的衰减，可能是在35 MHz下声化的血液的AIB较低的原因。我们推测，在小鼠中，随着胚胎年龄的增长，胚胎细胞回声性和AIB的变化是造成红细胞形态发育变化的原因。 （电子邮件：）。

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