An in vivo probabilistic atlas of the human locus coeruleus at ultra-high field
Rong Ye,
Catarina Rua,
Claire O'Callaghan,
P. Simon Jones,
Frank H. Hezemans,
Sanne S. Kaalund,
Kamen A. Tsvetanov,
Christopher T. Rodgers,
Guy Williams,
Luca Passamonti,
James B. Rowe
Affiliations
Rong Ye
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK; Corresponding author.
Catarina Rua
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK; Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK
Claire O'Callaghan
Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine, University of Sydney, Sydney, Australia; Department of Psychiatry, University of Cambridge, Cambridge, UK
P. Simon Jones
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK
Frank H. Hezemans
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK; MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
Sanne S. Kaalund
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK
Kamen A. Tsvetanov
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK; Department of Psychology, University of Cambridge, Cambridge, UK
Christopher T. Rodgers
Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK
Guy Williams
Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK
Luca Passamonti
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK; Istituto di Bioimmagini e Fisiologia Molecolare (IBFM), Consiglio Nazionale delle Ricerche (CNR), Milano, Italy
James B. Rowe
Department of Clinical Neurosciences, University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK; MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
Early and profound pathological changes are evident in the locus coeruleus (LC) in dementia and Parkinson's disease, with effects on arousal, attention, cognitive and motor control. The LC can be identified in vivo using non-invasive magnetic resonance imaging techniques which have potential as biomarkers for detecting and monitoring disease progression. Technical limitations of existing imaging protocols have impaired the sensitivity to regional contrast variance or the spatial variability on the rostrocaudal extent of the LC, with spatial mapping consistent with post mortem findings. The current study employs a sensitive magnetisation transfer sequence using ultrahigh field 7T MRI to investigate the LC structure in vivo at high-resolution (0.4 × 0.4 × 0.5 mm). Magnetisation transfer images from 53 healthy older volunteers (52 - 84 years) clearly revealed the spatial features of the LC and were used to create a probabilistic LC atlas for older adults. This atlas may be especially relevant for studying disorders associated with older age. To use the atlas does not require use of the same MT sequence of 7T MRI, provided good co-registration and normalisation is achieved. Consistent rostrocaudal gradients of slice-wise volume, contrast and variance along the LC were observed, mirroring distinctive ex vivo spatial distributions of LC cells in its subregions. The contrast-to-noise ratios were calculated for the peak voxels, and for the averaged signals within the atlas, to accommodate the volumetric differences in estimated contrast. The probabilistic atlas is freely available, and the MRI dataset will be made available for non-commercial research, for replication or to facilitate accurate LC localisation and unbiased contrast extraction in future studies.
