Abstract：
BACKGROUND: Parkinson\'s disease (PD) is associated with the loss of neuromelanin (NM) and increased iron in the substantia nigra (SN). Magnetization transfer contrast (MTC) is widely used for NM visualization but has limitations in brain coverage and scan time. This study aimed to develop a new approach called Proton-density Enhanced Neuromelanin Contrast in Low flip angle gradient echo (PENCIL) imaging to visualize NM in the SN.
METHODS: This study included 30 PD subjects and 50 healthy controls (HCs) scanned at 3T. PENCIL and MTC images were acquired. NM volume in the SN pars compacta (SNpc), normalized image contrast (Cnorm), and contrast-to-noise ratio (CNR) were calculated. The change of NM volume in the SNpc with age was analyzed using the HC data. A group analysis compared differences between PD subjects and HCs. Receiver operating characteristic (ROC) analysis and area under the curve (AUC) calculations were used to evaluate the diagnostic performance of NM volume and CNR in the SNpc.
RESULTS: PENCIL provided similar visualization and structural information of NM compared to MTC. In HCs, PENCIL showed higher NM volume in the SNpc than MTC, but this difference was not observed in PD subjects. PENCIL had higher CNR, while MTC had higher Cnorm. Both methods revealed a similar pattern of NM volume in SNpc changes with age. There were no significant differences in AUCs between NM volume in SNpc measured by PENCIL and MTC. Both methods exhibited comparable diagnostic performance in this regard.
CONCLUSIONS: PENCIL imaging provided improved CNR compared to MTC and showed similar diagnostic performance for differentiating PD subjects from HCs. The major advantage is PENCIL has rapid whole-brain coverage and, when using STAGE imaging, offers a one-stop quantitative assessment of tissue properties.
METHODS: This study included 30 PD subjects and 50 healthy controls (HCs) scanned at 3T. PENCIL and MTC images were acquired. NM volume in the SN pars compacta (SNpc), normalized image contrast (Cnorm), and contrast-to-noise ratio (CNR) were calculated. The change of NM volume in the SNpc with age was analyzed using the HC data. A group analysis compared differences between PD subjects and HCs. Receiver operating characteristic (ROC) analysis and area under the curve (AUC) calculations were used to evaluate the diagnostic performance of NM volume and CNR in the SNpc.
RESULTS: PENCIL provided similar visualization and structural information of NM compared to MTC. In HCs, PENCIL showed higher NM volume in the SNpc than MTC, but this difference was not observed in PD subjects. PENCIL had higher CNR, while MTC had higher Cnorm. Both methods revealed a similar pattern of NM volume in SNpc changes with age. There were no significant differences in AUCs between NM volume in SNpc measured by PENCIL and MTC. Both methods exhibited comparable diagnostic performance in this regard.
CONCLUSIONS: PENCIL imaging provided improved CNR compared to MTC and showed similar diagnostic performance for differentiating PD subjects from HCs. The major advantage is PENCIL has rapid whole-brain coverage and, when using STAGE imaging, offers a one-stop quantitative assessment of tissue properties.
摘要：
背景：帕金森病（PD）与神经黑色素（NM）的丧失和黑质（SN）中铁的增加有关。磁化传递对比(MTC)广泛用于NM可视化,但在脑覆盖和扫描时间方面具有局限性。这项研究旨在开发一种新方法，称为低翻转角梯度回波（PENCIL）成像中的质子密度增强神经黑色素对比度，以可视化SN中的NM。
方法：本研究包括30名PD受试者和50名在3T扫描的健康对照（HC）。采集PENCIL和MTC图像。SN中的NM卷（SNpc），归一化图像对比度(Cnorm)，并计算对比噪声比(CNR)。使用HC数据分析SNpc中NM体积随年龄的变化。组分析比较了PD受试者和HC之间的差异。使用受试者工作特性（ROC）分析和曲线下面积（AUC）计算来评估SNpc中NM体积和CNR的诊断性能。
结果：与MTC相比，PENCIL提供了类似的NM可视化和结构信息。在HC中，PENCIL在SNpc中显示出比MTC更高的NM体积，但在PD受试者中未观察到这种差异。PENCIL有更高的CNR，而MTC有较高的Cnorm。两种方法都揭示了SNpc随年龄变化的NM体积的相似模式。通过PENCIL和MTC测量的SNpc中的NM体积之间的AUC没有显着差异。两种方法在这方面表现出相当的诊断性能。
结论：与MTC相比，PENCIL成像提供了改善的CNR，并且在区分PD受试者和HC方面显示出相似的诊断性能。主要优势是PENCIL具有快速的全脑覆盖，当使用舞台成像时，提供了一个一站式的组织性能定量评估。
方法：本研究包括30名PD受试者和50名在3T扫描的健康对照（HC）。采集PENCIL和MTC图像。SN中的NM卷（SNpc），归一化图像对比度(Cnorm)，并计算对比噪声比(CNR)。使用HC数据分析SNpc中NM体积随年龄的变化。组分析比较了PD受试者和HC之间的差异。使用受试者工作特性（ROC）分析和曲线下面积（AUC）计算来评估SNpc中NM体积和CNR的诊断性能。
结果：与MTC相比，PENCIL提供了类似的NM可视化和结构信息。在HC中，PENCIL在SNpc中显示出比MTC更高的NM体积，但在PD受试者中未观察到这种差异。PENCIL有更高的CNR，而MTC有较高的Cnorm。两种方法都揭示了SNpc随年龄变化的NM体积的相似模式。通过PENCIL和MTC测量的SNpc中的NM体积之间的AUC没有显着差异。两种方法在这方面表现出相当的诊断性能。
结论：与MTC相比，PENCIL成像提供了改善的CNR，并且在区分PD受试者和HC方面显示出相似的诊断性能。主要优势是PENCIL具有快速的全脑覆盖，当使用舞台成像时，提供了一个一站式的组织性能定量评估。
