- Email: [email protected]
Diffusion tensor imaging of white matter changes in schizophrenia
18
ABSTRACTS / Schizophrenia Research 98 (2008) 3–199
Acknowledgement: This work was funded by the Mental Illness and Neuroscience (MIND) Institute. doi:10.1016/j.schres.2007.12.033
DIFFUSION TENSOR IMAGING OF WHITE MATTER CHANGES IN SCHIZOPHRENIA I. Rasmussen, Jr 1, N.I. Hoven 1, R. Nesvåg 1, T.R. Vangberg 2, E. Jonsson 3, S. Skare 4, I. Agartz 1,3. 1
Institute of Psychiatry, Oslo University, Norway Radiological Department, Tromsø University Hospital, Norway 3 Human Brain Informatics, Stockholm, Sweden 4 Radiological Department, Stanford University, USA 2
Presenting Author details: [email protected] Forskningsveien 7, 0500 Oslo, Norway, Tel.: +47 00 45670829. Background: Diffusion tensor imaging provides a robust method of in vivo quantification of white matter integrity. The method was applied on a group of schizophrenic individuals. Methods: DT-MRI data was acquired from 37 chronic schizophrenic patients and 32 healthy control subjects using a Siemens 1.5-T scanner with the following parameters applied: Voxel size: 1.8 × 1.8 × 3 mm3, TE = 95 ms, cardiac-gated acquisition with TR = 22 heartbeats. An exploratory analysis using voxel-based morphometry was applied on fractional anisotropy (FA) and ADC-maps generated from the images to find group differences in white matter integrity. Supplementary ROI-based analysis and tractography was performed to confirm results from the statistical parametric mapping analysis. Results: The schizophrenia patient group exhibited reduced FA and increased ADC values in the corpus callosum and the posterior part of the temporal lobe white matter. This was also seen in the grey matter of the thalami. ROI analysis and tractography confirm and refine the results from the voxel-based morphometry analysis. Conclusions: DTI measurements in schizophrenic patients show signs of white matter deficits compared to healthy control subjects. These may both be ascribed to the disease process itself and/or to the prolonged use of therapeutics. Voxel-based morphometry should only be considered an exploratory procedure to define regions of interest for additional analysis.
2 Medical and Radiological Sciences (Medical Physics), University of Edinburgh, UK 3 Clinical Neurosciences, University of Edinburgh, UK
Presenting Author details: [email protected] Psychiatry, Leazes Wing, Royal Victotria Informary., NE1 4LP Newcastle upon Tyne, United Kingdom, Tel.: +44 191 2202203. Background: Euthymic bipolar subjects exhibit executive impairment. Intra-hemispheric fronto-subcortical circuits and inter-hemispheric communication via the corpus callosum are important in neuropsychological function. Increased MRI white matter hyperintensities, changes in the size and in T1 MRI intensity of the corpus callosum and alterations in diffusion tensor MRI in deep, periventricular and callosal white matter suggest microstructural abnormalities in bipolar disorder. We therefore aimed to investigate hemispheric and callosal white matter integrity and executive function in prospectively verified euthymic bipolar subjects. Methods: 28 bipolar subjects and 28 controls, all right-handed, matched for age, gender and pre-morbid IQ were compared. Exclusion criteria included dementia, alcohol/substance misuse, neurological disorders and hypertension. Subjects underwent neuropsychological assessment. Structural and diffusion tensor (apparent mean diffusivity (AMD) and fractional anisotropy (FA)) MRI data were obtained at 1.5 T and FA were measured bilaterally in callosal, periventricular, prefrontal, occipital and central white matter regions of interest. White matter hyperintensity loads were assessed. Results: Bipolar subjects had impaired executive function. Mean FA was significantly decreased in all callosal regions and, in the dominant occipital region, was significantly increased in some callosal regions and bilaterally in the periventricular and pre-frontal regions. In lithiumfree bipolar subjects, pre-frontal and periventricular regions were significantly increased, in contrast to lithium-treated subjects who did not differ form controls. Proportions of subjects with white matter hyperintensities did not differ between groups. Conclusions: Callosal, periventricular and pre-frontal white matter microstructural abnormalities are present in bipolar subjects with executive impairment. They may represent trait phenomena, products of the bipolar disease process or drug effects. They may underlie the neuropsychological impairment in bipolar disorder. Their anatomical location is consistent with the effects on executive processing within each hemisphere and on the integration of dominant and non-dominant hemisphere functions. doi:10.1016/j.schres.2007.12.035
doi:10.1016/j.schres.2007.12.034
DIFFUSION TENSOR MRI ABNORMALITIES OF HEMISPHERIC AND CALLOSAL WHITE MATTER IN EUTHYMIC BIPOLAR SUBJECTS WITH EXECUTIVE DYSFUNCTION
Symposium 12: Are Words and their Lateralisaton the Key? VERBAL MEMORY AS A PROMISING ENDOPHENOTYPE FOR SCHIZOPHRENIA
A.J. Lloyd 1, K.A.N. Macritchie 1, M. Bastin 1, R. Eyre 1, K. Vasudev 1, I. Marshall 2, J.M. Wardlaw 3, I.N. Ferrier 1, P.B. Moore 1, A.H. Young 1.
A.D. Pentaraki 1, N.K. Stefanis 1,4,5, T. Toulopoulou 1,3, D. Stahl 2, S.C. Kaliora 5, D. Roukas 5, C. Theleritis 5, I. Chatzimanolis5, N. Smyrnis 5, T. Russell 1, E. Kravariti 1, R. Murray 1.
1
1
School of Neurology, Neurobiology and Psychiatry, University of Newcastle upon Tyne, UK
Institute of Psychiatry, Kingʼs College London, Division of Psychological Medicine, London, United Kingdom
ABSTRACTS / Schizophrenia Research 98 (2008) 3–199
Acknowledgement: This work was funded by the Mental Illness and Neuroscience (MIND) Institute. doi:10.1016/j.schres.2007.12.033
DIFFUSION TENSOR IMAGING OF WHITE MATTER CHANGES IN SCHIZOPHRENIA I. Rasmussen, Jr 1, N.I. Hoven 1, R. Nesvåg 1, T.R. Vangberg 2, E. Jonsson 3, S. Skare 4, I. Agartz 1,3. 1
Institute of Psychiatry, Oslo University, Norway Radiological Department, Tromsø University Hospital, Norway 3 Human Brain Informatics, Stockholm, Sweden 4 Radiological Department, Stanford University, USA 2
Presenting Author details: [email protected] Forskningsveien 7, 0500 Oslo, Norway, Tel.: +47 00 45670829. Background: Diffusion tensor imaging provides a robust method of in vivo quantification of white matter integrity. The method was applied on a group of schizophrenic individuals. Methods: DT-MRI data was acquired from 37 chronic schizophrenic patients and 32 healthy control subjects using a Siemens 1.5-T scanner with the following parameters applied: Voxel size: 1.8 × 1.8 × 3 mm3, TE = 95 ms, cardiac-gated acquisition with TR = 22 heartbeats. An exploratory analysis using voxel-based morphometry was applied on fractional anisotropy (FA) and ADC-maps generated from the images to find group differences in white matter integrity. Supplementary ROI-based analysis and tractography was performed to confirm results from the statistical parametric mapping analysis. Results: The schizophrenia patient group exhibited reduced FA and increased ADC values in the corpus callosum and the posterior part of the temporal lobe white matter. This was also seen in the grey matter of the thalami. ROI analysis and tractography confirm and refine the results from the voxel-based morphometry analysis. Conclusions: DTI measurements in schizophrenic patients show signs of white matter deficits compared to healthy control subjects. These may both be ascribed to the disease process itself and/or to the prolonged use of therapeutics. Voxel-based morphometry should only be considered an exploratory procedure to define regions of interest for additional analysis.
2 Medical and Radiological Sciences (Medical Physics), University of Edinburgh, UK 3 Clinical Neurosciences, University of Edinburgh, UK
Presenting Author details: [email protected] Psychiatry, Leazes Wing, Royal Victotria Informary., NE1 4LP Newcastle upon Tyne, United Kingdom, Tel.: +44 191 2202203. Background: Euthymic bipolar subjects exhibit executive impairment. Intra-hemispheric fronto-subcortical circuits and inter-hemispheric communication via the corpus callosum are important in neuropsychological function. Increased MRI white matter hyperintensities, changes in the size and in T1 MRI intensity of the corpus callosum and alterations in diffusion tensor MRI in deep, periventricular and callosal white matter suggest microstructural abnormalities in bipolar disorder. We therefore aimed to investigate hemispheric and callosal white matter integrity and executive function in prospectively verified euthymic bipolar subjects. Methods: 28 bipolar subjects and 28 controls, all right-handed, matched for age, gender and pre-morbid IQ were compared. Exclusion criteria included dementia, alcohol/substance misuse, neurological disorders and hypertension. Subjects underwent neuropsychological assessment. Structural and diffusion tensor (apparent mean diffusivity (AMD) and fractional anisotropy (FA)) MRI data were obtained at 1.5 T and FA were measured bilaterally in callosal, periventricular, prefrontal, occipital and central white matter regions of interest. White matter hyperintensity loads were assessed. Results: Bipolar subjects had impaired executive function. Mean FA was significantly decreased in all callosal regions and, in the dominant occipital region, was significantly increased in some callosal regions and bilaterally in the periventricular and pre-frontal regions. In lithiumfree bipolar subjects, pre-frontal and periventricular regions were significantly increased, in contrast to lithium-treated subjects who did not differ form controls. Proportions of subjects with white matter hyperintensities did not differ between groups. Conclusions: Callosal, periventricular and pre-frontal white matter microstructural abnormalities are present in bipolar subjects with executive impairment. They may represent trait phenomena, products of the bipolar disease process or drug effects. They may underlie the neuropsychological impairment in bipolar disorder. Their anatomical location is consistent with the effects on executive processing within each hemisphere and on the integration of dominant and non-dominant hemisphere functions. doi:10.1016/j.schres.2007.12.035
doi:10.1016/j.schres.2007.12.034
DIFFUSION TENSOR MRI ABNORMALITIES OF HEMISPHERIC AND CALLOSAL WHITE MATTER IN EUTHYMIC BIPOLAR SUBJECTS WITH EXECUTIVE DYSFUNCTION
Symposium 12: Are Words and their Lateralisaton the Key? VERBAL MEMORY AS A PROMISING ENDOPHENOTYPE FOR SCHIZOPHRENIA
A.J. Lloyd 1, K.A.N. Macritchie 1, M. Bastin 1, R. Eyre 1, K. Vasudev 1, I. Marshall 2, J.M. Wardlaw 3, I.N. Ferrier 1, P.B. Moore 1, A.H. Young 1.
A.D. Pentaraki 1, N.K. Stefanis 1,4,5, T. Toulopoulou 1,3, D. Stahl 2, S.C. Kaliora 5, D. Roukas 5, C. Theleritis 5, I. Chatzimanolis5, N. Smyrnis 5, T. Russell 1, E. Kravariti 1, R. Murray 1.
1
1
School of Neurology, Neurobiology and Psychiatry, University of Newcastle upon Tyne, UK
Institute of Psychiatry, Kingʼs College London, Division of Psychological Medicine, London, United Kingdom