Diffusion tensor imaging study of the fornix in first episode schizophrenia and in healthy controls.
BACKGROUND
The fornix is a compact bundle of white matter fibers that project from the hippocampus to the mamillary bodies and septal nuclei. Its association with memory, as well as with symptoms in schizophrenia, has been reported in chronic schizophrenia. The purpose of this study is to determine whether or not fornix abnormalities are evident at the onset of schizophrenia.


METHODS
Diffusion tensor imaging (DTI) and DT tractography were used to evaluate the fornix in 21 patients with first episode schizophrenia (16 males/5 females) and 22 healthy controls (13 males/9 females). Groups were matched on age, gender, parental socioeconomic status, education and handedness. Fractional anisotropy (FA), a measure of white matter integrity, radial diffusivity (RD), thought to reflect myelin integrity, trace, a possible marker of atrophy or cell loss, and axial diffusivity (AD), thought to reflect axonal integrity, were averaged over the entire tract extracted by means of DT tractography, and used to investigate fornix abnormalities in first episode schizophrenia compared with healthy controls.


RESULTS
Significant group differences were found between first episode patients and controls for FA (p=0.0001), RD (p=0.001) and trace (p=0.006).


CONCLUSIONS
These findings suggest abnormalities in the fornix in the early stages of schizophrenia, and further suggest that white matter abnormalities, which are apparent in the early course of the disease, may reflect myelin disturbances.
Psychiatry Neuroimaging Laboratory, Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States. Electronic address: jfitzsimmons@bwh.harvard.edu.
J
J
Fitzsimmons
Psychiatry Neuroimaging Laboratory, Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States; Department of Psychiatry, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States.
H M
HM
Hamoda
Psychiatry Neuroimaging Laboratory, Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
T
T
Swisher
Psychiatry Neuroimaging Laboratory, Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
D
D
Terry
Psychiatry Neuroimaging Laboratory, Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States; Department of General Psychiatry, Medical University Innsbruck, Innsbruck, Austria.
G
G
Rosenberger
Beth Israel Deaconess Medical Center, Massachusetts Mental Health Center, Public Psychiatry Division, Harvard Medical School, Boston, MA, United States; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
L J
LJ
Seidman
Beth Israel Deaconess Medical Center, Massachusetts Mental Health Center, Public Psychiatry Division, Harvard Medical School, Boston, MA, United States; Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
J
J
Goldstein
Beth Israel Deaconess Medical Center, Massachusetts Mental Health Center, Public Psychiatry Division, Harvard Medical School, Boston, MA, United States.
R
R
Mesholam-Gately
Stanley Center of Psychiatry Research, Broad Institute of MIT and Harvard, Boston, MA, United States; Psychiatry and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, United States.
T
T
Petryshen
Beth Israel Deaconess Medical Center, Massachusetts Mental Health Center, Public Psychiatry Division, Harvard Medical School, Boston, MA, United States.
J
J
Wojcik
Surgical Planning Laboratory, MRI Division, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
R
R
Kikinis
Surgical Planning Laboratory, MRI Division, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
M
M
Kubicki
D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D020712:Fornix, Brain / Q000473:pathology*; D006801:Humans; D008297:Male; D009186:Myelin Sheath / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D012559:Schizophrenia / Q000473:pathology*; D066127:White Matter / Q000473:pathology; D055815:Young Adult
Axial diffusivity; Diffusion tensor imaging; First episode schizophrenia; Fornix; Fractional anisotropy; Radial diffusivity; Trace