To assess the relative performance of MRI T₂ relaxation and ADC mapping as potential biomarkers of neurotoxicity, a model of 3-nitropropionic acid (NP)-induced neurodegeneration in rats was employed. Male Sprague-Dawley rats received NP (N = 20, 16–20 mg/kg, ip or sc) or saline (N = 6, 2 ml/kg, ip) daily for 3 days. MRI was performed using a 7 T system employing quantitative T₂ and ADC mapping based on spin echo pulse sequence. All maps were skull stripped and co-registered and the changes were quantified using baseline subtraction and anatomical segmentation. Following the in vivo portion of the study, rat brains were histologically examined. Four NP-treated rats were considered responders based on their MRI and histology data. T₂ values always increased in the presence of toxicity, while ADC changes were bidirectional, decreasing in some lesion areas and increasing in others. In contrast to T₂ in some cases, ADC did not change. The effect sizes of T₂ and ADC signals suggestive of neurotoxicity were 2.64 and 1.66, respectively, and the variability of averaged T₂ values among anatomical regions was consistently lower than that for ADC. The histopathology data confirmed the presence of neurotoxicity, however, a more detailed assessment of the correlation of MRI with histology is needed. T₂ mapping provides more sensitive and specific information than ADC about changes in the rat brain thought to be associated with neurotoxicity due to a higher signal-to-noise ratio, better resolution, and unidirectional changes, and presents a better opportunity for biomarker development.

为了评估MRI T ₂弛豫和ADC作图作为神经毒性潜在生物标志物的相对性能，采用了3-硝基丙酸（NP）诱导的大鼠神经变性模型。雄性Sprague-Dawley大鼠每天接受NP（N = 20、16–20 mg / kg，腹腔或皮下注射）或生理盐水（N = 6、2 ml / kg，腹膜内），持续3天。MRI使用7 T系统进行，该系统采用定量T ₂和基于自旋回波脉冲序列的ADC映射。所有地图都被剥去头骨并共同注册，并使用基线减法和解剖学分割对变化进行量化。在研究的体内部分之后，对大鼠的大脑进行了组织学检查。根据四只经NP处理的大鼠的MRI和组织学数据，将其视为反应者。Ť ₂当毒性存在时，数值总是会增加，而ADC的变化是双向的，在某些病变区域会降低，而在其他病变区域会增加。与T ₂相比，在某些情况下，ADC不变。提示神经毒性的T ₂和ADC信号的效应大小分别为2.64和1.66，并且解剖区域之间平均T ₂值的变异性始终低于ADC。组织病理学数据证实了神经毒性的存在，但是，需要对MRI与组织学的相关性进行更详细的评估。Ť ₂ 与更高的信噪比，更好的分辨率和单向变化相比，作图可提供比ADC更敏感，更具体的信息，有关老鼠大脑的变化被认为与神经毒性有关，并且为生物标记物的开发提供了更好的机会。