X-ray micro-computed tomography of postmortem brain tissue using potassium dichromate as a contrast agent

Connections between the internal and the external capsules and the globus pallidus in the sheep: A dichromate stain X‐ray microtomographic study

“…Also, GP-EC fibre connections have been identified. For this purpose, the approach using the dichromate-staining protocol under a laboratory-based µ-CT (Herrera et al, 2018) allows the three-dimensional visualization of myelinated bundles in a non-destructive manner. Also, the differential contrast imparted to the grey and white matter compartments allows the identification of the putamen and the GP in the images, and their relationships with the IC and EC; it also and facilitates the observation of bundle trajectories.…”

“…After the staining period, the samples were washed in bidistilled water until they did not release any more DK, transferred to a cylindrical µ-CT sample holder and scanned in wet cotton. For a more detail description of the methods used, see Herrera et al, (2018).…”

“…In the last decade, important advances have been made visualization of the nervous system using contrast-enhanced techniques with an X-ray source (deCrespigny et al, 2008;Gignac & Kley, 2018;Metscher, 2009), permitting visualization of the grey and white matter compartments of the brain. However, the majority of the media used are non-specific for the white matter compartment, with the exception of osmium tetroxyde (Metscher, 2009) and potassium dichromate (Herrera, Notario, Barrio, Metscher, & Murillo, 2018). The use of µ-CT methods, using contrast-enhanced media, to facilitate study of the normal myeloarchitecture in animals can facilitate the extrapolation of experimental results to human studies.…”

Revealing the three-dimensional murine brain microstructure by contrast-enhanced computed tomography

“…According to existing literature, mainly inorganic CESAs have been explored for CECT imaging of brain tissue. These include simple, but rather toxic and invasive compounds (i.e., osmium tetroxide (OsO 4 ) ( Ribi et al, 2008 ; White and Brown, 2015 ; Parlanti et al, 2017 ; Chen et al, 2018 ; Masis et al, 2018 ; Pinto et al, 2022 ), potassium dichromate (K 2 Cr 2 O 7 ) ( Herrera et al, 2018 ), uranyl acetate (([UO 2 (CH 3 CO 2 ) 2 H 2 O)]H 2 O) n ) ( Smith et al, 2016 ; Parlanti et al, 2017 ), silver nitrate (AgNO 3 ) ( Mizutani et al, 2010 ), phosphotungstic acid (PTA) ( Buytaert et al, 2014 ; Smith et al, 2016 ; Zikmund et al, 2018 ; Rother et al, 2021 ) and alcoholic ( Buytaert et al, 2014 ; Smith et al, 2016 ; Zikmund et al, 2018 ; Kavkova et al, 2021 ; Pinto et al, 2022 ) or aqueous ( Buytaert et al, 2014 ; Anderson and Maga, 2015 ; Choi et al, 2017 ; Heimel et al, 2019 ; Lombardi et al, 2019 ; Llambrich et al, 2020 ; Feldman et al, 2022 ) iodine-based formulations). Furthermore, staining with Lugol’s iodine solution, alcoholic iodine solutions and PTA resulted in substantial tissue shrinkage and hence possible tissue deformation, which prevent correct and quantitative characterization of the tissue microstructure ( Vickerton et al, 2013 ; Wong et al, 2013 ; Buytaert et al, 2014 ; Balint et al, 2016 ; Koc et al, 2019 ; Dawood et al, 2022 ).…”

“…Multiple iodinated organic molecules have also been applied as CESAs, such as Hypaque ® -76 ( de Crespigny et al, 2008 ) and Iopamiron ® ( Saito and Murase, 2012 ; Udagawa et al, 2019 ). In many of the aforementioned cases where CESAs have been screened, the link between the chemical properties of the CESA, the solvent (e.g., aqueous buffer solution) and the observed affinity (i.e., the staining mechanisms) towards the different brain tissue constituents has not been thoroughly investigated, notwithstanding the fact that some studies do give well-substantiated hypotheses ( Saito and Murase, 2012 , 2013 ; Herrera et al, 2018 ).…”