BOLD fMRI and DTI in strabismic amblyopes following occlusion therapy
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Evaluation of brain cluster activation using the functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) was sought in strabismic amblyopes. In this hospital-based case–control cross-sectional study, fMRI and DTI were conducted in strabismic amblyopes before initiation of any therapy and after visual recovery following the administration of occlusion therapy. FMRI was performed in 10 strabismic amblyopic subjects (baseline group) and in 5 left strabismic amblyopic children post-occlusion therapy after two-line visual improvement. Ten age-matched healthy children with right ocular dominance formed control group. Structural and functional MRI was carried out on 1.5T MR scanner. The visual task consisted of 8 Hz flickering checkerboard with red dot and occasional green dot. Blood-oxygen-level-dependent (BOLD) fMRI was analyzed using statistical parametric mapping and DTI on NordicIce (NordicNeuroLab) softwares. Reduced occipital activation was elicited when viewing with the amblyopic eye in amblyopes. An ‘ipsilateral to viewing eye’ pattern of calcarine BOLD activation was observed in controls and left amblyopes. Activation of cortical areas associated with visual processing differed in relation to the viewing eye. Following visual recovery on occlusion therapy, enhanced activity in bilateral hemispheres in striate as well as extrastriate regions when viewing with either eye was seen. Improvement in visual acuity following occlusion therapy correlates with hemodynamic activity in amblyopes.
KeywordsFMRI Strabismic amblyopes DTI Occlusion therapy
Functional magnetic resonance imaging
Diffusion tensor imaging
Blood oxygen level dependent
Statistical parametric mapping
Lateral geniculate nucleus
Echo planar imaging
Flickering checkerboard with red dot and occasional green dot
Analysis of variance
Region of interest
Compliance with ethical standards
Conflict of interest
The authors disclose they have no potential conflicts of interest.
The study was approved by the institutional ethics committee and adheres to the tenets of declaration of Helsinki (1964) and its later amendments.
This article does not contain any studies with animals performed by any of the authors.
Informed consent was obtained from all individual participants/their parents included in this study.
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