New optical brain imaging in infants by using near-infrared diffuse optical tomography

发展了一种利用近红外漫反射光学层析成像(NIR DOT)来估计婴儿局部光散射和吸收特性的光学三维成像方法。近红外光点检测系统由16根源-探测器光纤、波长为759 nm和835 nm的脉冲半导体激光器和时间相关的单光子计数单元组成。图像重建算法是基于改进的广义脉冲光谱技术。用时间分辨数据估计氧合Hb和脱氧Hb的浓度。在人工呼吸器的辅助下，于出生后29天测量一名胎龄为23周、出生体重为658g的婴儿的DOT。这项研究获得了父母的书面知情同意，并得到了当地伦理委员会的批准。研究数据在两种不同状态下获得：(A)正常呼吸和(B)过度换气引起的低呼吸。点图像显示在状态(B)减去(A)时获得的Hb浓度。结果显示，脑内大部分部位的总Hb浓度降低，反映了脑血流量的减少，尤其是脑白质区域。结果表明，近红外斑点成像技术能够在床边重建出高空间分辨率的新生儿Hb浓度图像。

An optical 3D imaging method using near-infrared diffuse optical tomography (NIR DOT) to estimate the regional light scattering and absorption properties in infants has been developed. The NIR DOT system is consisted of 16 source-detector fibers, pulsed diode lasers operating at the wavelengths of 759 and 835 nm and time correlated single photon counting units. The image reconstruction algorithm is based on the modified generalized pulsed spectral technique. The time-resolved data were used to estimate for concentration of oxyHb and deoxyHb.DOT was measured in an infant on 29 days after birth, whose gestational age and birth weight was 23 weeks and 658g, assisted by an artificial respirator. Informed consent in writing was obtained from the parents, and the study was approved by the local ethics committee.The data under two different state, (A) normocapnea and (B) hypocapnea induced by hyperventilation, were obtained. DOT images showed the Hb concentrations obtained at the state (B) subtracted by (A). The results showed that the total Hb concentration in the most parts of the brain decreased, reflecting the decrease in cerebral blood flow, especially white matter regions. The results demonstrated that NIR DOT is capable of reconstructing the images of Hb concentration with a high spatial resolution in infants at the bedside.