OCD Structural and Functional Connectivity Study

# OCD Structural and Functional Connectivity Study ## Overview This dataset contains structural (T1-weighted), resting-state functional (fMRI), and diffusion tensor imaging (DTI) data from patients diagnosed with Obsessive-Compulsive Disorder (OCD). ## Participants Patients (n = 41) meeting DSM-5 criteria for OCD, aged 18-50 years, with or without pharmacological treatment at the time of scanning. ### Inclusion criteria 1. Diagnosis of OCD according to DSM-5 criteria. 2. Age between 18 and 50 years, with or without pharmacological treatment. 3. Minimum educational level: primary school completed. 4. Intellectual coefficient within normal range (80-120, per standardized intelligence scale). 5. Signed informed consent. ### Exclusion criteria 1. Comorbidity with another psychiatric disorder. 2. Presence of a neurological disorder. 3. History of substance abuse. 4. Any contraindication for MRI examination. ### Elimination criteria (post-acquisition) 1. Structural brain abnormalities identified on MRI. 2. Voluntary withdrawal from the study. ## MRI Acquisition Images were acquired on a 3.0 T Discovery MR750 scanner (GE Healthcare) with a 32-channel head coil, at the Unidad de Resonancia Magnética (URM), Instituto de Neurobiología, UNAM. Participants were positioned supine with foam padding for head fixation and earplugs for auditory protection. ### T1-weighted (anat) - Sequence: 3D FSPGR (Fast Spoiled Gradient Recalled Echo) - Orientation: sagittal - TR/TE: 8.2/3.2 ms - Acquisition matrix: 256 x 256 - Field of view: 256 mm - Slice thickness: 1 mm, contiguous ### Resting-state fMRI (func) - Sequence: EPI GRE (Echo Planar Imaging Gradient Echo) - TR/TE: 2000/40 ms - Acquisition matrix: 64 x 64 - Slices: 35 axial, 4 mm - Duration: 10 minutes - Task: eyes open, central fixation cross, instructed to remain still and awake ### Diffusion tensor imaging (dwi) - Sequence: EPI2 (GE), 60 diffusion directions, 2 mm isotropic slices - TR/TE: 7000/60.5 ms - Flip angle: 90 degrees - Acquisition matrix (PE): 128, reconstructed to 256 - Parallel imaging reduction factor: 2 - Phase encoding direction: j ## Quality control Scans were visually inspected; runs with head motion greater than 2 mm or atypical structural findings were discarded. ## Data conversion Raw DICOM images were converted to NIfTI format using dcm2nii (version 1.0.20181125 for T1/func; dcm2niix v1.0.20210317 for dwi).