Diffusion spectrum imaging tractography analysis of white matter integrity in patients with schizophrenia: Comparison between manual approach and template-base automatic approach
Date Issued
2012
Date
2012
Author(s)
He, Jhih-Wei
Abstract
Schizophrenia is a high-impact mental disorder that affects approximately 0.3~1% of the population in Taiwan, with ravaging effects on both psychological and economical resources. This serious mental illness not only affects our cognition but also contributes to chronic emotional problems. Disturbed communication of white matter within the brain region may be the possible pathology of schizophrenia, which was mentioned previously. Therefore, it’s important to investigate the white matter’s integrity. Also, the orbitofontal cortex (OFC) was linked to negative emotions and anxiety, which were the symptoms of schzophrenia. There are three white matter tracts which connected to the OFC chosen to be studied in the investigation of the difference between patients with schizophrenia and normal control patients in our research: bilateral anterior thalamic radiation (ATR), bilateral uncinate fasciculus (UF) and genu.
We recruited 20 patients with chronic schizophrenia and age- and gender-matched healthy controls to acquire diffusion spectrum images and T2-weighted structure images. The patients’ PANSS scores were measured in outpatients one week before the MRI scan or one week after the scan. The first, tractogrphy of ATR, UF and genu was rebuilt in a manual approach, and the general fractional anisotropy (GFA) was calculated. Then, we compared the difference between two groups and analyzed the correlation between GFA values and PANSS scores.
In the results, the GFA values were significantly reduced in all tracts except the right ATR in schizophrenia. And there was a negative correlation between GFA values in the genu of a factor of 5 (anxiety/depression).
Moreover, we used an automatic template-based approach to compare results to the manual approach. In this approach, we found that there was a trend that all GFA values of tracts in schizophrenia were lower than normal controls’ even though it was not significant. But we could compare the profiles between groups because the lengths of the GFA profiles were the same after normalization. We found the mean GFA value in schizophrenia was higher in the genu in the intersection with left superior longitudinal fasciculus (SLF). Also, there was a left-right asymmetry in thalamus in normal controls.
There was a significant positive correlation of GFA values between these two approaches. These two approaches were auxiliary to each other because they possessed different traits and could be explained together.
Our findings showed the usefulness of applying DSI and tractography to investigate white matter fiber tracts in vivo in schizophrenia, and thus extended our understanding of the pathophysiology of this disease. Also, we could investigate the different parts of the GFA profile by the automatic template-based approach.
In the future, we will combine these two approaches in order to find the neuroimage biomarker of schizophrenia or other diseases.
Subjects
schizophrenia
orbitofrontal cortex
anterior thalaic radiation
uncinate fasciculus
genu
PANSS
diffusion spectrum imaging
tractography
general fractional anisotropy
GFA profile
SDGs
Type
thesis
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