Lixia Yang1 and Yu Cheng1
1Department of image center, Shanghai Xuhui central hospital,Shanghai, Shanghai, People's Republic of China
Synopsis
Both
Susceptibility Weighted Imaging (SWI) and T2 star (T2*) imaging can measure the
brain iron deposition. However, the two ways by which the brain iron is
measured are not compared. This study measured the brain iron of healthy
volunteers and Parkinson’s disease patients by SWI and T2* imaging. we found
that SWI and T2* imaging could estimate the brain iron, and the SWI radiant
values of SNr and RN were significance difference between healthy volunteers
and Parkinson’s disease patients, suggesting the SWI had better reliability to
diagnose the Parkinson’s disease than the T2* imaging.
Purpose
the
purpose of this study is to measure the brain iron contents of deep gray matter
nucleus using the SWI and T2* imaging, compare its differences and select a
better way to diagnose the Parkinson’s disease.Methods
Population: In
this study, sixty healthy volunteers (40 males, 20 females, mean age= 69.8±11.2
years, NC group) and thirty patients (20 males, 10 females, mean age=70.1±11.1
years, PD group) with Parkinson’s disease were recruited, the ratio between NC
group and PD group was two. We conducted a prospective study approved by the
local Institutional Ethics Committee. The written consent forms were obtained
from all subjects before data acquisition.
Image
acquisition: A 3.0T MRI system scanner (Magnetom Verio Tim,
Siemens, Germany) with a 32-channel head coil was used. The imaging pulse
sequences included conventional MR sequences (axial T2W, T2W FLAIR, T1W FLAIR, DWI) and a axial SWI/ T2* imaging. A group of
magnitude, phase, minimum intensity projection (MIP) and SWI images were
automatically online reconstructed. The detailed imaging parameters were
presented in Table 1.
Data Analysis: Regions of interest (ROIs)
were placed bilaterally in deep gray matter (GM) nucleus in putamen (PUT), globus
palidus (GP), cadudate nucleus (CN), thalamus (THA), substantia nigra
reticulate (SNr), substantica nigra compacta (SNr) and red nucleus (RN)(Fig 1).
Image J software (National institutes of Health, Bethesda, MD, http://rsbweb.nih.gov/ij/
) was used to evaluate the
brain iron content of ROIs. First, the ROIs were recognized and manually
outlined by the polygon tool of
Image J software in the SWI image of SWI and T2 image of T2* imaging,
and then copied to the phase image and T2* mapping image, which guaranteed that
the boundaries and regions were exactly the same in both images. The phase
value and T2* values of ROIs were measured in the phase image and T2* mapping
image, and the radiant value were
measured by the following formula, φ=π-π*ψ/2048, φ is radiant value, ψ is phase
value, and the R2* value were measured by the following formula, R2*=1/T2*.
During manually outlined these ROIs, we needed to avoided the cerebrospinal
fluid (CSF), calcification, vessels and cerebral infarction
in the selected lays.Results
As
shown in Table 2, both radiant values (r=0.862, P=0.027) and R2*
values (r=0.827, P=0.042) had a significant correlation with the
brain iron contents of ROIs, which were estimated from the empirical equations
reports by Hallgren and Sourander 6. As shown in Table 3 and 4,there
was significant difference in the radiant values of SNr (P=0.025) and RN (P=0.030)
areas between the NC group and PD group.Conclusions
In
this study, we found that SWI and T2* imaging could be applied to
non-invasive estimate the brain iron
contents for healthy volunteers. More importantly, the SWI radiant values of
SNr and RN areas was significant difference between the healthy volunteers and
patients with Parkinson’s disease. Thus, the non-invasion MRI, such as SWI and
T2 * imaging, is a good tool for quantitative assessment of the brain iron
contents, and the SWI had better reliability than the T2* imaging to
diagnose the Parkinson’s disease.Synopsis
Both
Susceptibility Weighted Imaging (SWI) and T2 star (T2*) imaging can measure the
brain iron deposition. However, the two ways by which the brain iron is
measured are not compared. This study measured the brain iron of healthy
volunteers and Parkinson’s disease patients by SWI and T2* imaging. we found
that SWI and T2* imaging could estimate the brain iron, and the SWI radiant
values of SNr and RN were significance difference between healthy volunteers
and Parkinson’s disease patients, suggesting the SWI had better reliability to
diagnose the Parkinson’s disease than the T2* imaging.Acknowledgements
There
was significant correlation between excessive brain iron deposition and the
central nervous system degenerative diseases, especially the Parkinson’s
disease. The excessive brain iron deposition was believed to participate in the
pathological process of the disease 1,2. Thus, assessment of the brain
iron is significant to diagnose the Parkinson’s disease in clinical practice. Brain
iron which is a common para-magnetic substance can shorten the T2* relaxation
time in T2* imaging. Brain iron also cause the difference in susceptibility
between tissues, and accurately reflect the phase change in the SWI 3-5.
However, traditional method to measure the brain iron just apply the SWI or T2*
imaging. But the two ways which one would be the better to measure the brain
iron contents. Thus, the purpose of this study is to measure the brain iron
contents of deep gray matter nucleus using the SWI and T2* imaging, compare its
differences and select a better way to diagnose the Parkinson’s disease.References
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QuyenQ. Hoang. PNAS, 2014.111(7): 2402-2403.
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Barbosa JH, Santos AC, et al . Magn Reson Imaging. 2015, 33 (5): 559-565.
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Haacke EM, AyazM, KhanA. JMRI 2007,26:256-264
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Kurz FT, Freitag M, Schlemmer HP, et al. Radiology.2016,56(2):124-136.
[6] Hallgren B, Sourander
P. 1958,3(1):41-51.