TABLE 2.
A Review of Imaging Studies of OCD
| Structural Modality | Brain Area | Finding |
|---|---|---|
| CT | VBR, asymmetry, sulcal prominence | No significant differences between patients with OCD and healthy control subjects [113] |
| CT | Caudate, lenticular nuclei, third and lateral ventricles | Caudate volume lower in OCD patients compared to healthy control subjects [114] |
| CT | Ventricular-brain ratio | Patients with OCD had a higher ventricle-brain ratio [115] |
| MRI | Caudate | No structural difference in caudate between patients with OCD and healthy control subjects [116] |
| MRI | Caudate, cingulate gyrus, intracaudate/frontal horn ratio, corpus collosum | No significant differences between patients with OCD and healthy control subjects [117] |
| MRI | OFC, ACC, thalamus, caudate, putamen | Patients with OCD had a smaller left OFC volume compared to healthy control subjects [118] |
| MRI | Superior frontal gyrus, ACC, OFC, hippocampus, amygdala | Patients with OCD had decreased bilateral OFC and amygdala volume compared to healthy control subjects [119] |
| MRI | Grey matter | Increased gray matter regional density in multiple areas including left OFC and subcortical areas [120] |
| MRI | Frontal-striatal circuitry | Increase in volume of ventral PFC and striatum [121] |
| MRI | White matter | Spin-lattice relaxation time (T1) differences in right frontal white matter of OCD patients compared to control subjects [122] |
| MRI | Head of caudate | Increase in volume of right caudate head in OCD patients compared to healthy subjects [123] |
| MRI | Caudate, putamen, globus pallidus, ACC, superior frontal gyrus | OCD patients had smaller globus pallidus volumes and more total gray matter in the ACC compared to healthy control subjects [124] |
| MRI | PFC, caudate, lateral and third ventricles, and whole brain | Caudate volume lower in OCD patients [125] |
| MRI | PFC, striatum, lateral and third ventricles, and intracranial volume | Patients with OCD had smaller striatal, and larger third ventricle, volumes than control subjects [126] |
| MRI | Corpus callosum | Patients with OCD had increased size of the corpus callosum compared to healthy control subjects [127] |
| MRI | Whole brain volume | Decreased total white matter and greater total cortex and opercular volumes in patients with OCD compared to healthy control subjects [128] |
| MRI and 1H-MRS | Caudate and corpus striatum | No difference between volumes of caudate between patients with OCD and healthy control subjects. Decreased N-acetylaspartate levels in left corpus striatum [129] |
| MRI DTI | White matter | Lower fractional anisotropy in ACC white matter, partietal region, right posterior cingulate, and left occipital lobe compared to healthy control subjects [130] |
| MRI VBM | Regions defined a priori as likely to be involved in OCD | Increased grey matter in the OFC and parahippocampal regions, decreased grey matter in ACC in OCD patients compared to healthy control subjects [131] |
| Functional Modality | Finding | |
| 1H MRS | N-Acetylaspartate levels decreased in the left corpus striatum in patients with OCD compared to healthy control subjects [129] | |
| 1H MRS | N-Acetylaspartate levels decreased in the ACC and right striatum in patients with OCD compared to healthy control subjects [132] | |
| 1H MRS | N-Acetylaspartate levels decreased in the thalamus in patients with OCD compared to healthy control subjects [133] | |
| 1H MRS | Decreased thalamic choline in OCD patients compared to healthy control subjects and patients with major depressive disorder [134] | |
| 99mTc HMPAO SPECT | Hyperperfusion in right thalamus, left frontotemporal cortex, and bilateral OFC in patients with OCD compared to healthy control subjects [135] | |
| 99mTc HMPAO SPECT | Hyperperfusion in right superior and inferior frontal cortex and bilateral thalamus in OCD patients compared to healthy control subjects [136] | |
| 99mTc HMPAO SPECT | Hyperperfusion in OFC, dorsal parietal cortex, and left posterofrontal cortex [137] | |
| 99mTc HMPAO SPECT | Increase in metabolism of bilateral superior frontal cortices and right caudate in patients with OCD and PTSD compared to patients with panic disorder and healthy control subjects [138] | |
| 99mTc HMPAO SPECT | Higher ratio of medial/frontal to whole brain perfusion in patients with OCD compared to healthy control subjects [139] | |
| 99mTc HMPAO SPECT | Differences in regional brain perfusion between early-onset and late-onset OCD [140] | |
| 99mTc HMPAO SPECT | Decrease in right OFC perfusion in OCD patients without motor tics compared to healthy control subjects [141] | |
| FDG-PET | Metabolic rate increased in the left OFC and bilateral caudate nuclei compared to healthy control subjects and patients with unipolar depression [142] | |
| FDG-PET | Increased metabolic rate in left OFC, right sensorimotor, bilateral prefrontal and ACC regions in OCD patients compared to healthy control subjects [143] | |
| FDG-PET | Increased metabolic rate in cingulate cortex, thalamus, and pallidum/putamen complex. Successful SSRI treatment lowered metabolism in the cingulate [144] | |
| FDG-PET | Decreased metabolism in whole, and prefrontal lateral, cortex in patients with OCD compared to healthy control subjects [145] | |
| fMRI | Symptom induction was associated with activation of the OFC, superior frontal, and the DLPFC; the anterior, medial, and lateral temporal cortex; and the right anterior cingulate in patients with OCD [146] | |
| fMRI | Increased activation in OFC, lateral frontal, anterior temporal, ACC, insula, caudate, lenticulate, and amygdala in patients with OCD compared to healthy control subjects [147] | |
| fMRI | Patients with OCD showed greater error-related activation of the ACC than healthy control subjects [107] | |
| fMRI | Symptom improvement with successful SSRI treatment resulted in decreased symptom-provoked activation of OFC, dorsolateral prefrontal cortex, and ACC [148] | |
| O15 PET | Increased metabolism in OFC, premotor, and midfrontal cortex in patients with obsessional slowness compared to healthy control subjects [149] | |
| O15 PET | Symptom provocation resulted in increased blood flow to the right caudate, left ACC, and bilateral OFC in patients with OCD [150] | |
OCD = obsessive-compulsive disorder; VBR = ventricular brain ratio; OFC = orbitofrontal cortex; ACC = anterior cingulate cortex; PFC = prefrontal cortex; DLPFC = dorsolateral prefrontal cortex; SSRI = selective serotonin reuptake inhibator; fMRI = functional magnetic resonance imaging; MRI DTI = magnetic resonance imaging diffusion tensor imaging; MRI VBM = magnetic resonance imaging voxel-based morphometry; 1H-MRS = proton magnetic resonance spectroscopy; HMPAO = Tc-Hexamethylpropyleneamine Oxime; SPECT = single photon emission computed tomography; FDG-PET = 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography