A novel Tungsten-based fiducial marker for multi-modal brain imaging

• Published in: Journal of neuroscience methods 2019-07, Vol.323, p.22-31
• Main Authors: Ose, Takayuki, Autio, Joonas A., Ohno, Masahiro, Nishigori, Kantaro, Tanki, Nobuyoshi, Igesaka, Ami, Mori, Tomoko, Doi, Hisashi, Wada, Yasuhiro, Nakajima, Iwao, Watabe, Hiroshi, Hayashi, Takuya
• Format: Article
• Language: English
• Subjects: Fiducial marker; MRI; Multi-modal registration; PET; Polytungstate; Tungsten
• ISSN: 0165-0270; 1872-678X
• DOI: 10.1016/j.jneumeth.2019.04.014

•A Tungsten-based fiducial marker was developed for multi-modal image registration.•The Tungsten solution has characteristics of high T1 and T2 contrasts and density.•The Tungsten-based marker allowed accurate registration and cortical functional mapping. Multi-modal brain image registration is a prerequisite for accurate mapping of brain structure and function in neuroscience. Image registration is commonly performed using automated software; however, its accuracy decreases when images differ in modality, contrast, uniformity, and resolution. This limitation could be overcome by using an external reference point; however, high-contrast agents in multi-modal imaging have not been previously reported. Here, we propose a novel multi-modal fiducial marker that contains Tungsten solution and provides high contrast in magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET). The basic characteristics of this multi-modal marker were investigated by assessing major sources of image contrast in the following modalities: density and T1-, T2-relaxivity in comparison with conventional contrast agents. Tungsten solution had lower T1- and T2-relaxivity and high solubility, and showed high contrast in T1- and T2-weighted MR and CT images at a high-density concentration (˜3.0 g/mL), whereas other conventional solutions did not show sufficient contrast in either CT or MRI. The use of this Tungsten-based multi-modal marker allowed more accurate registration than a software-only method in phantom and animal experiments. Application of this method demonstrated accurate cortical surface mapping of neurotransmitter function (dopamine transporter, DAT) using PET and MRI, and provided a neurobiologically relevant cortical distribution consistent with previous literature on histology-based DAT immunoreactivity. The Tungsten-based multi-modal fiducial marker is non-radioactive, easy to handle, and aids precise registration across different modalities of brain imaging.