Brain imaging
The present disclosure relates generally to medical imaging and, more particularly, it relates to methods and systems for performing processing of magnetic resonance (MR) imaging of the brain which may be useful in the diagnosis of cognitive disorders. More specifically, the invention includes methods for processing cortical diffusion data from a region of a subject's brain, comprising determining values for the Axial Columnar Refraction (ACR) using values for AngleR and Axial Diffusivity.
1 . A computer-implemented method for determining an indication of a level of a cognitive disorder in a subject, or an indication of a number of microsegment breaks in a region of a subject's brain, the computer-implemented method comprising:
obtaining, at a magnetic resonance imaging device, at least one magnetic resonance image of the subject's brain;
receiving, at a computing device, diffusion data obtained from the at least one magnetic resonance image of the subject's brain;
pre-processing the diffusion data;
determining, from the pre-processed diffusion data, a principal diffusion direction in at least one first voxel in a region of grey matter in the subject's brain;
determining, from the pre-processed diffusion data, an average columnar direction of minicolumns in the at least one first voxel;
determining, from the pre-processed diffusion data, a value for an angle of deviation (AngleR) between the principal diffusion direction and the average columnar direction of minicolumns in the at least one first voxel;
determining, from the pre-processed diffusion data, a value for Axial Diffusivity in at least one second voxel in a region of white matter associated with underlying the region of grey matter;
determining a value for Axial Columnar Refraction (ACR) for each of the at least one first voxel and the at least one second voxel using the values for AngleR and Axial Diffusivity;
comparing the values of ACR with corresponding reference measurements derived from pre-obtained reference data; and
determining, based on the comparison, the indication of the level of a cognitive disorder in the subject, or the indication of the number of microsegment breaks in the region of the subject's brain.
2 . The computer-implemented method as claimed in claim 1 , wherein the magnitude of the values of ACR for the at least one first voxel and the at least one second voxel in comparison to the corresponding reference measurements provides an indication of the level of a cognitive disorder in the subject.
3 . The computer-implemented method as claimed in claim 1 , wherein the magnitude of the values of ACR for the at least one first voxels and the at least one second voxels provides an indication of the number of microsegment breaks in the region.
4 . The computer-implemented method as claimed in claim 1 , wherein the value for AngleR and/or Axial Diffusivity is obtained from or derived from one or more regions of the cortex of the brain.
5 . The computer-implemented method as claimed in claim 4 , wherein the region of the brain is selected from the group consisting of parahippocampal gyrus (PHG), fusiform gyrus (Fusi), dorsolateral prefrontal cortex area 9 (dlPFC), area 41, Heschl's gyrus (HG), planum temporale (PT), inferior parietal lobule (IPL), middle temporal gyrus (MTG), primary visual cortex (V1; area 17) and entorhinal cortex.
6 . The computer-implemented method as claimed in claim 1 , wherein the subject is one who has a cognitive disorder selected from the group consisting of Alzheimer's Disease (AD), cerebrovascular dementia (CVD), mild cognitive impairment (MCI), frontotemporal dementia (FTD), dementia with Lewy Bodies (DLB), autism, multiple sclerosis (MS), epilepsy, amyotrophic lateral sclerosis (ALS), Parkinson's disease, schizophrenia, bipolar disorder, dyslexia, Down's syndrome, Huntington's disease, prion disease, depression, obsessive-compulsive disorder or attention deficit hyperactivity disorder (ADHD), Subjective Cognitive Impairment, preMCI, and prodromal AD, Posterior Cortical Atrophy (subset of AD), behavioural, semantic, or progressive non-fluent aphasia (subsets of FTD), encephalopathy, hepatic encephalopathy, stroke, ischaemia, ischaemic hypoxia, neuro-inflammation, traumatic brain injury (TBI), mild TBI, chronic traumatic encephalopathy, concussion and delirium.
7 . A method of treatment of a subject, wherein the method comprises the computer-implemented method as claimed in claim 1 , wherein, if the subject is found have a level of a cognitive disorder beyond (above or below) a specified reference level or is found to have a value for ACR above a specified reference level, a cognitive-disorder treating medicament is administered to the subject.
8 . A method of treatment of a subject, wherein the method comprises obtaining or receiving results of the computer-implemented method for determining ACR as claimed in claim 1 , and if the ACR value is higher than a reference level, thereby providing an indication of the presence of a cognitive disorder in the subject, administering a treatment to the subject appropriate for treating the cognitive disorder.
9 . A system or apparatus comprising at least one processing means arranged to carry out the steps of the computer-implemented method as claimed in claim 1 .
10 . A non-transitory carrier bearing software comprising instructions for configuring a processor to carry out the steps of the computer-implemented method as claimed in claim 1 .
11 . A system for determining an indication of a level of a cognitive disorder in a subject, the system comprising:
a magnetic resonance imaging device configured to acquire diffusion data; and
processing means configured to:
pre-process the diffusion data;
determine, from the pre-processed diffusion data, a principal diffusion direction in at least one first voxel in a region of grey matter in the subject's brain;
determine, from the pre-processed diffusion data, an average columnar direction of minicolumns in the at least one first voxel;
determine, from the pre-processed diffusion data, a value for an angle of deviation (AngleR) between the principal diffusion direction and the average columnar direction of minicolumns in the at least one first voxel;
determine, from the pre-processed diffusion data, a value for Axial Diffusivity in at least one second voxel in a region of white matter associated with underlying the region of grey matter;
determine a value for Axial Columnar Refraction (ACR) for each of the at least one first voxel and the at least one second voxel using the values for AngleR and Axial Diffusivity;
compare the values of ACR with corresponding reference measurements derived from pre-obtained reference data; and
determine, based on the comparison, the indication of the level of a cognitive disorder in the subject.