Stankovic M R, Maulik D, Rosenfeld W, Stubblefield P G, Kofinas A D, Gratton E, Franceschini M A, Fantini S, Hueber D M
Department of Obstetrics and Gynecology, Brooklyn Hospital Center, Cornell University School of Medicine, New York 11201, USA.
J Matern Fetal Med. 2000 Mar-Apr;9(2):142-9. doi: 10.1002/(SICI)1520-6661(200003/04)9:2<142::AID-MFM11>3.0.CO;2-O.
Inability of continuous wave (CW) optical spectroscopy to measure changes in scattering, and the use of an arbitrary rather than an actual baseline, makes the CW method highly susceptible to errors that can lead to a false-positive or false-negative diagnosis. Our objective was to assess whether, and to what extent, the use of quantitative frequency domain spectroscopy would improve our ability to detect and monitor the development of brain hemorrhage.
A dual-channel frequency-domain tissue spectrometer (Model 96208, ISS, Inc., Champaign, IL) was used to monitor the development of experimental subcortical and periventricular-intraventricular hemorrhage (IVH) in 10 newborn piglets (blood injection model). The multidistance approach was employed to calculate the absorption and reduced scattering coefficients and hemoglobin changes from the ac, dc, and phase values acquired at four different source-detector distances and at 752 nm and 830 nm.
There were significant absorption and scattering changes in the subcortical hematoma (n = 5) and the IVH groups (n = 5). The smallest detectable amount of blood in the brain was 0.04 ml. Changes associated with subcortical hematoma were several times higher than those associated with IVH, and correlated better with the estimated cross-sectional area of the hematoma than with the volume of the injected blood. As opposed to IVH, there was a significant absorption difference between the injured (subcortical hematoma) and normal side of the brain, probably because in case of IVH a significant volume of the injected blood had accumulated/spread beyond the reach of the probe.
Clearly, frequency-domain spectroscopy cannot increase our ability to quantify the volume (size) or the oxygenation of the injected blood, especially in the case of IVH. However, the ability to quantify the baseline tissue absorption and scattering would significantly improve diagnostic performance, and may allow for early identification and treatment of neonatal brain hemorrhage.
连续波（CW）光学光谱法无法测量散射变化，且使用的是任意基线而非实际基线，这使得CW方法极易出现误差，可能导致假阳性或假阴性诊断。我们的目的是评估使用定量频域光谱法能否以及在多大程度上提高我们检测和监测脑出血发展的能力。
使用双通道频域组织光谱仪（型号96208，ISS公司，伊利诺伊州尚佩恩）监测10只新生仔猪（注血模型）实验性皮质下和脑室周围-脑室内出血（IVH）的发展情况。采用多距离方法，根据在四个不同源-探测器距离以及752纳米和830纳米处获取的交流、直流和相位值，计算吸收系数、约化散射系数和血红蛋白变化。
皮质下血肿组（n = 5）和IVH组（n = 5）出现了显著的吸收和散射变化。大脑中可检测到的最小血量为0.04毫升。与皮质下血肿相关的变化比与IVH相关的变化高几倍，并且与血肿估计横截面积的相关性优于与注入血液体积的相关性。与IVH不同，大脑受伤侧（皮质下血肿）与正常侧之间存在显著的吸收差异，可能是因为在IVH情况下，大量注入的血液积聚/扩散到了探头无法触及的范围之外。
显然，频域光谱法无法提高我们量化注入血液体积（大小）或氧合的能力，尤其是在IVH的情况下。然而，量化基线组织吸收和散射的能力将显著提高诊断性能，并可能有助于早期识别和治疗新生儿脑出血。
