Chunmei Li1, Guodong Song1, Yuhui Chen1, Xuna Zhao2, Jinyuan Zhou2, and Min Chen1
1Beijing Hospital, Beijing, China, People's Republic of, 2Johns Hopkins University, Baltimore, MD, United States
Synopsis
This study is to evaluate the
longitudinal Amide Proton Transfer-weighted (APTw) signal changes in patients
with stroke after treatment. APT weighted images of stroke patients was
acquired, including non-treatment and post treatment.
91.7% patients (22/24) showed gradual increased APT values with the
extension of time, accompanied with the clinical symptoms improvement. The
other 2 patients (8.3%) showed further decreased APT values in the second scan
(the first scan after treatment), accompanied with the clinical symptoms
aggravation. The increase of APT weighted signal may indicate the improvement
of clinical symptoms while the decrease may indicate the aggravating of
clinical symptoms. Purpose
To evaluate the longitudinal
Amide Proton Transfer-weighted (APTw) signal changes in patients with stroke
after treatment and compare the signal differences between
non-treatment and treatment.
Methods
Forty-two stroke
patients were recruited. All patients were
imaged on a 3 Tesla MR system, using an 8-channel head coil. APT weighted
imaging was acquired in the ischemic slices of the head, which were indicated
by diffusion weighted imaging. Each patient has underwent their first scan
before supportive treatment. Twenty-four patients continued to undergo APT
weighted scan after treatment, 1~3 times in different days. The
magnetization-transfer-ratio asymmetry of ischemic lesion and contralateral normal appearing
white matter (NAWM) at 3.5 ppm, MTRasym(3.5ppm)(l) and MTRasym(3.5ppm)(c), were measured. The
value differences between ischemic
lesion and contralateral NAWM, which named MTRasym(3.5ppm)(l-c) were calculated. The longitudinal
signal changes of stroke after treatment were analyzed. Independent t-test was
used to compare the APT signal differences between non-treatment and
post-treatment of stroke patients in the same onset
time group (4 groups: onset time ≤ 3days; 4~7 days; 8~21 days and ≥ 22days, respectively).
Results
For the 24 patients with follow-up scan, 22 of them (91.7%) showed
gradual increased MTRasym(3.5ppm)(l-c) with the extension of
time, accompanied with the clinical symptoms improvement. The
other 2 patients (8.3%) showed further decreased MTRasym(3.5ppm)(l-c)
in the second scan (the first scan after treatment), accompanied with the
clinical symptoms aggravation. The MTRasym(3.5ppm)(l-c) value of the non-treatment group were significantly lower
than the post-treatment group for onset time
≤ 3 days (-1.56±1.01 vs. -0.89±0.65, P= 0.031) and 4~7 days patients (-1.27±0.32 vs. -0.73±0.70,
P=0.019).
The data of onset time 8~21 days and ≥
22days group were not analyzed for only one and zero sample has collected in
the non-treatment group.
Discussion
Several previous
studies have evaluate the value of APT in stroke 1,2. This is the
first study to evaluate the longitudinal signal changes
of stroke after non thrombolysis treatment and compare the Amide Proton
Transfer (APT) signal differences between non-treatment and post-treatment of
stroke patients. The findings seemed to be promising.
From our result, most patients (over
90%) showed gradually increase tendency for APT-weighted values after treatment
while few patients showed obviously decreased APT-weighted values
after treatment. Moreover, the patients with increase APT-weighted values had
good prognosis while the other two with decrease changes had poor prognosis.
Though the patient number was not large enough to make a clear conclusion, such
result indeed indicated the potential of the longitudinal signal changes after
treatment, especially the changes on the first scan after treatment, in
predicting treatment effect. Decreased APT-weighted values may predict the poor
treatment effect at the early beginning of treatment and help neurologists to
make treatment adjustment.
In comparison of the APT-weighted
values between non- and post treatment groups, we divided the
patients in different phase according to their onset time (≤
3 days; 3~7 days; 8~21 days and ≥ 22days). The APT-weighted values of the
non-treatment group were significantly lower than the post treatment group for onset
time -treatment group were significant. Though the data
of onset time 8~21 days and ayse 8~2 group were not analyzed
for the small sample number of non-treatment group, we could still see the
lower tendency in non-treatment group for patients of onset time 8~21 days.
This may indicate the treatment influence in APT-weighted
values, which may be increased after treatment. Owing to the sample
limitation, we did not divide the data after treatment into different sub
groups according to the treatment effect (e.g., better or worse). The further
analysis with more samples and more detailed group division is needed in the
future.
Conclusion
The increase of APT weighted signal
may indicate
the improvement of clinical symptoms while the decrease may indicate
the aggravating of clinical symptoms. Significant differences can be found
between non-treatment and post-treatment patients at the same onset time.
Acknowledgements
This
study was supported by the National Natural Science Foundation of China (81401404 and 81361120392) and the National Institutes of Health
(R01EB009731, R01CA166171 and R01NS083425).
References
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2. Tietze A, Blicher J, Mikkelsen IK,
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