Sickle cell disease (SCD) is a genetic blood disorder that has profound effects on the brain. Chronic anemia combined with both macro- and microvascular perfusion abnormalities that arise from stenosis or occlusion of blood vessels increased blood viscosity, adherence of red blood cells to the vascular endothelium, and impaired autoregulatory mechanisms in SCD patients all culminate in susceptibility to cerebral infarction. Indeed, the risk of stroke is 250 times higher in children with SCD than in the general population. Unfortunately, while transcranial Doppler ultrasound (TCD) has been widely clinically adopted to longitudinally monitor macrovascular perfusion in these patients, routine clinical screening of microvascular perfusion abnormalities is challenging with current modalities (e.g., positron emission tomography and magnetic resonance imaging) given their high-cost, requirement for sedation in children < 6 year, and need for trained personnel. We assess the feasibility of a low-cost, noninvasive optical technique known as diffuse correlation spectroscopy (DCS) to quantify an index of resting-state cortical cerebral blood flow (BFI) in 11 children with SCD along with 11 sex- and age-matched healthy controls. As expected, BFI was significantly higher in SCD subjects compared to healthy controls ( p < 0.001 ). Within SCD subjects, BFI was inversely proportional to resting-state arterial hemoglobin levels ( p = 0.012 ), consistent with expected anemia-induced compensatory vasodilation that aims to maintain adequate oxygen delivery to the tissue. Further, in a subset of patients measured with TCD ( n = 7 ), DCS-measured blood flow was correlated with TCD-measured blood flow velocity in middle cerebral artery ( R s = 0.68 ), although the trend was not statistically significant ( p = 0.11 ). These results are consistent with those of several previous studies using traditional neuroimaging techniques, suggesting that DCS may be a promising low-cost tool for assessment of tissue-level CBF in pediatric SCD.

中文翻译：

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镰状细胞病患儿静息状态脑血流的无创光学评估。

镰状细胞病（SCD）是一种遗传性血液疾病，对大脑产生深远的影响。慢性贫血加上狭窄或闭塞血管引起的大血管和微血管灌注异常会增加血液粘度，SCD患者的红细胞对血管内皮的粘附以及自动调节机制受损，最终导致对脑梗死的敏感性上升。确实，患有SCD的儿童中风的风险比普通人群高250倍。不幸的是，尽管经颅多普勒超声（TCD）在临床上已广泛用于纵向监测这些患者的大血管灌注，但对微血管灌注异常的常规临床筛查对于当前的方式（例如，正电子发射断层扫描和磁共振成像），因为它们成本高昂，要求6岁以下儿童镇静，并且需要经过培训的人员。我们评估了一种低成本，无创性光学技术（称为弥散相关光谱法（DCS））的可行性，以量化11名SCD儿童以及11名性别和年龄相匹配的儿童的静息状态皮质脑血流量（BFI）的指数健康对照。正如预期的那样，与健康对照组相比，SCD受试者的BFI显着更高（p <0.001）。在SCD受试者中，BFI与静息状态的动脉血红蛋白水平成反比（p = 0.012），这与预期的贫血引起的代偿性血管舒张作用一致，后者旨在维持足够的氧向组织的输送。此外，在接受TCD测量的部分患者中（n = 7），DCS测得的血流与TCD测得的大脑中动脉血流速度相关（R s = 0.68），尽管趋势没有统计学意义（p = 0.11）。这些结果与以前使用传统的神经成像技术进行的几项研究结果一致，表明DCS可能是评估小儿SCD组织水平CBF的有前途的低成本工具。