Huan Ma1, Jianzhong Yang2, Dewei Sun1, Dafu Zhang1, Yan Zhang2, Jing Yuan2, and Xiaoyong Zhang3
1Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China, 2Department of Psychiatry, The Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China, 3Clinical Science, Philips Healthcare, Chengdu, China, Chengdu, China
Synopsis
We
obtained sMRI data from unmedicated adolescents and young adults with MDD, StD
and well-matched healthy control subjects, and identified radiomics features
from gray and white matter, and establish classification models. The accuracies and AUC were 86.75%, 0.93
for distinguishing MDD from HC, 70.51%, 0.69 for discriminating StD from HC, and
59.15%, 0.66 for differentiating MDD from StD, respectively.
These findings provide
preliminary evidence that radiomics features of brain structure are valid for
discriminating MDD and StD from HCs. The MRI-based radiomics approach, with
further improvement and validation, is a potential facilitating method to
clinical diagnosis of mental illness.
Background
Previous evidence of conventional MRI studies suggested
the presence of neuroanatomical abnormalities in depression. However, the brain
structural relationship between major depressive disorder (MDD) and subthreshold
depression (StD) remains unclear. Radiomics is an emerging image
analysis framework that provides more details than conventional methods. In present study, we
aimed to identify structural radiomics features of gray matter (GM) and
white matter (WM), and
to develop and validate the classification model for MDD and StD diagnosis using
radiomics analysis.Materials and Methods
A consecutive cohort of 142 adolescents and young
adults, including 43 cases
with MDD, 49 cases with StD and 50 healthy controls (HC), were recruited and underwent the three-dimensional
T1 weighted imaging (3D-T1WI) and diffusion tensor imaging (DTI). We extracted radiomics features
representing the shape and diffusion properties of GM and WM from all participants.
Then, an all-relevant feature selection process embedded in a 10-fold
cross-validation framework was used to identify features with significant power
for discrimination. Random forest classifiers (RFC) were established and
evaluated successively using identified features.Results
The results showed that a total of 3030 features were
extracted after preprocessing, including 2262 shape-related features from each T1-weighted image
representing GM morphometry and 768 features from each DTI
representing the diffusion properties of WM. 25 features were selected
ultimately, including ten features for MDD versus HC, eight features for StD
versus HC, and seven features for MDD versus StD. The accuracies and area under
curve (AUC) the RFC achieved were 86.75%, 0.93 for distinguishing MDD from HC with
significant radiomics features located in the left medial orbitofrontal cortex, right superior and middle temporal
regions, right anterior cingulate, left cuneus and hippocampus, 70.51%, 0.69
for discriminating StD from HC within left cuneus, medial orbitofrontal cortex,
cerebellar vermis, hippocampus, anterior cingulate and amygdala, right superior
and middle temporal regions, and 59.15%, 0.66 for differentiating MDD from StD
within left medial orbitofrontal cortex, middle temporal and cuneus, right
superior frontal, superior temporal regions and hippocampus, anterior cingulate,
respectively.Discussion
Based on radiomics analysis, the major
finding of this study indicated that the radiomic-based classifiers could provide
moderate diagnostic value by using cerebral sMRI features in discriminating MDD
or StD from healthy controls, especially in distinguishing MDD from healthy
controls with excellent classification accuracy. The majority of gray matter
morphometry alteration that contributed to the discrimination was located
within left medial orbitofrontal lobe, right superior frontal gyrus, right
superior and middle temporal regions, bilateral anterior cingulate and
hippocampus, left cuneus, amygdala, and cerebellar vermis. Our results are
consistent with the previous MRI findings based on traditional data analysis 1,
2, 3. In our study, the AUC and accuracy the classifier achieved were 0.93 and 86.75%
respectively in classification of MDD and normal controls, which show the better
classification performance than voxel-based morphometry 4, 5, 6, 3. This also
suggested that structural changes of medial orbitofrontal cortex, temporal
lobe, hippocampus, and anterior cingulate gyrus could be potential imaging
features for quantitative diagnosis of MDD patients.
Our results revealed all three brain
regions including medial orbitofrontal cortex, superior temporal regions and
anterior cingulate were identified to be significantly different among the HC
versus StD and StD versus MDD. Previous neuroimaging studies have also showed
that patients with MDD and StD had relatively smaller GM volume in the temporal
gyrus and orbitofrontal cortex than healthy controls, and the
decreasing degree of StD subjects was less than that in the patients with
MDD 7, 8. These finding suggested that pathophysiological trajectory process in
these gyri might be involved in the transformation of brain structures from HC
to StD and to MDD which seems like a continuous spectrum of what is happening
in the brain structure, and depressive disorders should be better treated as a
spectrum disorder 8.
DTI characterizes the alterations in WM
microstructural properties that cannot be measured using conventional anatomical
MRI in vivo. Subtle, but widespread abnormalities of WM in MDD patients were
found within the corpus callosum, corona radiata, cingulum, internal capsule,
fronto-occipital fasciculus, and fornix. Furthermore, it seems that WM microstructural changes were
more common in adult MDD patients with an age of onset over 21 years and more
than one episode of MDD 9, 10. However, previous results have been inconsistent
in the pattern of deficits, and the degree of disruption across studies 9, 11,
12. Unfortunately, no significant WM radiomics features were found in our study
contributed to discriminating MDD and StD from controls. Therefore, we need to
increase the sample size for further research.Conclusion
In general, this study presented a
radiomic approach using structural radiomics features derived from gray and
white matter to discriminate MDD and StD individuals from healthy controls in
adolescents and young adults. Our preliminary results show that the MRI-based radiomics
analysis, with further improvement and validation, is a potential facilitating
method to clinical diagnosis of mental illness.Acknowledgements
No acknowledgement found.References
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