BACKGROUND Transcranial B-mode sonography (TCS) can detect hyperechogenic speckles in the area of the substantia nigra (SN) in Parkinson's disease (PD). These speckles correlate with iron accumulation in the SN tissue, but an exact volumetric localization in and around the SN is still unknown. Areas of increased iron content in brain tissue can be detected in vivo with magnetic resonance imaging, using quantitative susceptibility mapping (QSM). METHODS In this work, we i) acquire, co-register and transform TCS and QSM imaging from a cohort of 23 PD patients and 27 healthy control subjects into a normalized atlas template space and ii) analyze and compare the 3D spatial distributions of iron accumulation in the midbrain, as detected by a signal increase (TCS+ and QSM+) in both modalities. RESULTS We achieved sufficiently accurate intra-modal target registration errors (TRE<1 mm) for all MRI volumes and multi-modal TCS-MRI co-localization (TRE<4 mm) for 66.7% of TCS scans. In the caudal part of the midbrain, enlarged TCS+ and QSM+ areas were located within the SN pars compacta in PD patients in comparison to healthy controls. More cranially, overlapping TCS+ and QSM+ areas in PD subjects were found in the area of the ventral tegmental area (VTA). CONCLUSION Our findings are concordant with several QSM-based studies on iron-related alterations in the area SN pars compacta. They substantiate that TCS+ is an indicator of iron accumulation in Parkinson's disease within and in the vicinity of the SN. Furthermore, they are in favor of an involvement of the VTA and thereby the mesolimbic system in Parkinson's disease.

中文翻译：

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分析帕金森氏病中黑质超强回声和铁蓄积的共定位：一项经颅超声和MRI的多模式图谱研究。

背景技术经颅B超检查（TCS）可以在帕金森氏病（PD）的黑质（SN）区域检测到高回声斑点。这些斑点与SN组织中的铁积累相关，但是尚不清楚SN中及其周围的确切体积定位。可以使用定量磁化图（QSM）通过磁共振成像在体内检测脑组织中铁含量增加的区域。方法在这项工作中，我们（i）从23名PD患者和27名健康对照受试者的队列中获取，共配准并将TCS和QSM成像转换为归一化的Atlas模板空间，并且ii）分析和比较铁蓄积的3D空间分布两种模式的信号增加（TCS +和QSM +）都可以检测到。结果对于所有MRI体积，我们均获得了足够准确的模态内目标配准错误（TRE <1 mm），对于66.7％的TCS扫描，实现了多模态TCS-MRI共定位（TRE <4 mm）。与健康对照组相比，在PD患者中，中脑的尾部部分TCS +和QSM +区域位于紧凑型SN pars内。更疯狂的是，在腹侧被盖区（VTA）的区域中发现了PD受试者中重叠的TCS +和QSM +区域。结论我们的发现与关于SN pars compacta地区铁相关蚀变的多项基于QSM的研究一致。他们证实TCS +是SN内及附近帕金森氏病中铁蓄积的指标。此外，他们赞成VTA的参与，从而支持帕金森氏病的中边缘系统。