School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia.
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
Transfusion. 2020 Mar;60(3):588-597. doi: 10.1111/trf.15704. Epub 2020 Feb 14.
Umbilical cord blood has become an important source of hematopoietic stem and progenitor cells for therapeutic applications. However, cord blood banking (CBB) grapples with issues related to economic viability, partially due to high discard rates of cord blood units (CBUs) that lack sufficient total nucleated cells for storage or therapeutic use. Currently, there are no methods available to assess the likelihood of CBUs meeting storage criteria noninvasively at the collection site, which would improve CBB efficiency and economic viability.
To overcome this limitation, we apply a novel label-free optical imaging method, called quantitative oblique back-illumination microscopy (qOBM), which yields tomographic phase and absorption contrast to image blood inside collection bags. An automated segmentation algorithm was developed to count white blood cells and red blood cells (RBCs) and assess hematocrit. Fifteen CBUs were measured.
qOBM clearly differentiates between RBCs and nucleated cells. The cell-counting analysis shows an average error of 13% compared to hematology analysis, with a near-perfect, one-to-one relationship (slope = 0.94) and strong correlation coefficient (r = 0.86). Preliminary results to assess hematocrit also show excellent agreement with expected values. Acquisition times to image a statistically significant number of cells per CBU were approximately 1 minute.
qOBM exhibits robust performance for quantifying blood inside collection bags. Because the approach is automated and fast, it can potentially quantify CBUs within minutes of collection, without breaching the CBUs' sterile environment. qOBM can reduce costs in CBB by avoiding processing expenses of CBUs that ultimately do not meet storage criteria.
脐带血已成为治疗应用中造血干细胞和祖细胞的重要来源。然而，脐带血库（CBB）在经济可行性方面存在一些问题，部分原因是由于缺乏足够的总核细胞进行储存或治疗用途，导致脐带血单位（CBU）的高废弃率。目前，尚无方法可在采集现场非侵入性地评估 CBU 符合储存标准的可能性，这将提高 CBB 的效率和经济可行性。
为了克服这一限制，我们应用了一种新颖的无标记光学成像方法，称为定量斜向背面照明显微镜（qOBM），该方法可产生断层和吸收对比，以对采集袋内的血液进行成像。开发了一种自动分割算法来计数白细胞和红细胞（RBC）并评估红细胞压积。测量了 15 个 CBU。
qOBM 可清晰地区分 RBC 和有核细胞。细胞计数分析与血液学分析相比平均误差为 13%，具有近乎完美的一对一关系（斜率=0.94）和强相关性系数（r=0.86）。评估红细胞压积的初步结果也显示出与预期值非常吻合。每个 CBU 成像具有统计学意义的细胞数量的采集时间约为 1 分钟。
qOBM 表现出对采集袋内血液进行定量的强大性能。由于该方法是自动化和快速的，因此它可以在采集后几分钟内潜在地对 CBU 进行定量，而不会破坏 CBU 的无菌环境。qOBM 可以通过避免处理最终不符合储存标准的 CBU 来降低 CBB 的成本。
