title: BOLD fMRI and DTI in strabismic amblyopes following occlusion therapy.
abstract: 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.
authors.affiliation: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Shikha
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Department of Nuclear Magnetic Resonance & MRI Facility, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India. senthilnmr@gmail.com.
authors.forename: Senthil S
authors.initials: SS
authors.lastname: Kumaran
authors.affiliation: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Rohit
authors.initials: R
authors.lastname: Saxena
authors.affiliation: Department of Nuclear Magnetic Resonance & MRI Facility, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
authors.forename: Sunita
authors.initials: S
authors.lastname: Gudwani
authors.affiliation: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Vimala
authors.initials: V
authors.lastname: Menon
authors.affiliation: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Sharma
mesh_terms: D000293:Adolescent; D000550:Amblyopia / Q000503:physiopathology* / Q000628:therapy; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D002648:Child; D003430:Cross-Sectional Studies; D056324:Diffusion Tensor Imaging; D023882:Dominance, Ocular; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood*; D012029:Refraction, Ocular / Q000502:physiology; D012683:Sensory Deprivation; D013285:Strabismus / Q000503:physiopathology* / Q000628:therapy; D014792:Visual Acuity / Q000502:physiology
chemical_list: D010100:Oxygen
keywords: DTI; FMRI; Occlusion therapy; Strabismic amblyopes