Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration
Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration
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DOI：
10.1088/0031-9155/52/1/010
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发表时间：
2007-01-07
影响因子：
3.5
通讯作者：
Beard, Paul
中科院分区：
文献类型：
--
作者：
Laufer, Jan;Delpy, Dave;Beard, Paul
开发了一种基于脉冲光声光谱的新方法，用于以高空间分辨率非侵入性量化组织发色团浓度。该技术适用于定量组织发色团，如氧合血红蛋白（HbO（2））和脱氧血红蛋白（HHb），用于测量生理参数，如血氧饱和度（SO2）和总血红蛋白浓度。它还可以用于量化在光声分子成像中使用的靶向造影剂的局部积累。该技术采用了基于模型的反演方案，以恢复从光声测量的生色团浓度。这包括检测到的时间相关的光声信号的数值前向模型，其结合了用于描述光传输的基于多波长扩散的有限元光传播模型和用于描述光声波的产生、传播和检测的时域声学模型。然后通过迭代地将其拟合到在不同波长处获取的光声信号的测量值来反演前向模型，以恢复发色团浓度。为了验证这种方法，使用740 nm和1040 nm之间的纳秒激光脉冲在组织模型中产生光声信号。该组织模型包括一个悬浮液的intraperoid，血液和近红外染料，其中三个管浸入。血液在生理血红蛋白浓度和氧饱和度范围为2%至100%的水平下通过管循环。将来自检测到的光声波形的不同时间段的信号幅度绘制为波长的函数，并且将前向模型拟合到这些数据以恢复HbO（2）和HHb的浓度、总血红蛋白浓度和SO2。其性能优于实验室一氧化碳血氧计，HbO（2）和HHb浓度的测量分辨率分别为+/- 3.8 g l（-1）（+/- 58 μ M）和+/- 4.4 g l（-1）（+/- 68 μ M），SO2的测量分辨率为+/- 4%，后者的准确度在-6%-+7%范围内。
A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin ( HbO(2)) and deoxyhaemoglobin ( HHb) for the measurement of physiological parameters such as blood oxygen saturation ( SO2) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO(2) and HHb, total haemoglobin concentration and SO2. The performance was found to compare favourably to that of a laboratory CO-oximeterwith measurement resolutions of +/- 3.8 g l(-1) ( +/- 58 mu M) and +/- 4.4 g l(-1) ( +/- 68 mu M) for the HbO(2) and HHb concentrations respectively and +/- 4% for SO2 with an accuracy in the latter in the range -6%-+7%.