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- Henriksson, Karin, et al.
(författare)
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A morphometric magnetic resonance method for measuring cranial, facial and brain characteristics for application to schizophrenia : Part 1
- 2006
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Ingår i: Psychiatry Research. - : Elsevier BV. - 0925-4927 .- 1872-7506 .- 0165-1781. ; 147:2-3, s. 173-186
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Tidskriftsartikel (refereegranskat)abstract
- Serious psychopathology in adulthood may be associated with disturbed foetal brain development, which potentially shows lingering "fossil marks" in the cranial and facial regions. Several methods exist for assessing external craniofacial and internal brain distances but, to our knowledge, no method yet provides simultaneous measurement of cranial, facial and brain dimensions in live subjects. In this article we describe a method to identify landmarks on magnetic resonance images (MRI) for simultaneous measurement of cranial, facial and brain characteristics potentially associated with psychosis. To test the method itself, 30 patients with chronic schizophrenia and 31 healthy comparison subjects, mean age 41 years, were randomly selected from a larger cohort recruited at the Karolinska Hospital, Sweden. Participants were investigated with MRI, and 60 landmarks in the cranial, facial and brain regions were identified in the images. An independent anthropometric examination measured external craniofacial characteristics for study in relation to measurements produced through MRI. High inter-scorer and re-test reliabilities were obtained for two independent scorers of the landmarks in the MR images. Measurements of potentially comparable craniofacial distances showed high alignment with an established anthropometric method. This new method can provide simultaneous investigation of multiple aspects of cranial, facial and brain morphology in MR images originally collected for other purposes. In a second article we will use this method to compare 3D craniofacial measurements and shape between schizophrenia patients and healthy controls.
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| 6. |
- Hult, Roger, 1969-
(författare)
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Segmentation and Visualisation of Human Brain Structures
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis the focus is mainly on the development of segmentation techniques for human brain structures and of the visualisation of such structures. The images of the brain are both anatomical images (magnet resonance imaging (MRI) and autoradigraphy) and functional images that show blood flow (functional magnetic imaging (fMRI), positron emission tomography (PET), and single photon emission tomograpy (SPECT)). When working with anatomical images, the structures segmented are visible as different parts of the brain, e.g. the brain cortex, the hippocampus, or the amygdala. In functional images, the activity or the blood flow that be seen.Grey-level morphology methods are used in the segmentations to make tissue types in the images more homogenous and minimise difficulties with connections to outside tissue. A method for automatic histogram thresholding is also used. Furthermore, there are binary operations such as logic operation between masks and binary morphology operations.The visualisation of the segmented structures uses either surface rendering or volume rendering. For the visualisation of thin structures, surface rendering is the better choice since otherwise some voxels might be missed. It is possible to display activation from a functional image on the surface of a segmented cortex. A new method for autoradiographic images has been developed, which integrates registration, background compensation, and automatic thresholding to getfaster and more realible results than the standard techniques give.
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| 8. |
- Hult, Roger, et al.
(författare)
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Segmentation of the Brain in MRI Using Grey Level Morphology and Propagation of Information
- 1999
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Ingår i: Proceedings of SCIA'99. - : Pattern Recognition Society of Denmark, Lyngby. - 8788306429 ; , s. 367-373
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Konferensbidrag (refereegranskat)abstract
- An important step in the analysis of 3D MRI brain images is to segment the cortex from surrounding tissue. In this paper we present an algorithm for fully automatic segmentation of the cortex from T1-weighted MRI data. The automatic segmentation starts wi
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| 10. |
- Pircs, Karolina, et al.
(författare)
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Huntingtin Aggregation Impairs Autophagy, Leading to Argonaute-2 Accumulation and Global MicroRNA Dysregulation
- 2018
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 24:6, s. 1397-1406
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Tidskriftsartikel (refereegranskat)abstract
- Many neurodegenerative diseases are characterized by the presence of intracellular protein aggregates, resulting in alterations in autophagy. However, the consequences of impaired autophagy for neuronal function remain poorly understood. In this study, we used cell culture and mouse models of huntingtin protein aggregation as well as post-mortem material from patients with Huntington's disease to demonstrate that Argonaute-2 (AGO2) accumulates in the presence of neuronal protein aggregates and that this is due to impaired autophagy. Accumulation of AGO2, a key factor of the RNA-induced silencing complex that executes microRNA functions, results in global alterations of microRNA levels and activity. Together, these results demonstrate that impaired autophagy found in neurodegenerative diseases not only influences protein aggregation but also directly contributes to global alterations of intracellular post-transcriptional networks. Pircs et al. report that aggregation of the mutant huntingtin protein, a hallmark of Huntington's disease proteinopathy, impairs macroautophagy, leading to Argonaute-2 accumulation and global dysregulation of microRNAs. These results indicate that autophagy not only influences protein aggregation but also directly contributes to the global alterations of post-transcriptional networks in Huntington's disease.
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