Cortical Local Gyrification Index Research Articles

Association between cortical gyrification and white matter integrity in spinocerebellar ataxia type 3.

Gray matter volume and thickness reductions have been reported in patients with spinocerebellar ataxia type 3 (SCA3), whereas cortical gyrification alterations of this disease remain largely unexplored. Using local gyrification index (LGI) and fractional anisotropy (FA) from structural and diffusion MRI data, this study investigated the cortical gyrification alterations as well as their relationship with white matter microstructural abnormalities in patients with SCA3 (n = 61) compared with healthy controls (n = 69). We found widespread reductions in cortical LGI and white matter FA in patients with SCA3 and that changes in these 2 features were also coupled. In the patient group, the LGI of the left middle frontal gyrus, bilateral insula, and superior temporal gyrus was negatively correlated with the severity of depressive symptoms, and the FA of a cluster in the left cerebellum was negatively correlated with the Scale for the Assessment and Rating of Ataxia scores. Our findings suggest that the gyrification abnormalities observed in this study may account for the clinical heterogeneity in SCA3 and are likely to be mediated by the underlying white matter microstructural abnormalities of this disease.

A magnetic resonance imaging study on brain surface morphology change in patients with first-episode obsessive compulsive disorder

Objective To analyze the brain structure changes of the first-episode obsessive compulsive disorder (OCD) patients who were scanned by three-dimensional structure magnetic resonance imaging. Methods According to the diagnostic criteria of OCD in American Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV), the fist-episode obsessive compulsive disorder patients as case group(OCD, n=26) and the adult healthy volunteers as control group (control group, n=25) were selected.All subjects were assessed with Yale-Brown obsessive-compulsive scale(Y-BOCS), Hamilton Anxiety rating Scale (HAMA) and Hamilton Depression Rating Scale(HAMD), and then, they received 3D-MRI scanning runs.All the data was processed with freesurfer software and analyzed about cerebral cortical volume, cortical thickness, cortical surface area, the local gyrification index and subcortical nuclei volume. Results Compared with control group, the cerebral cortical thickness of OCD group increased at the left postcentral gyrus((2.223±0.118)mm), left supramarginal gyrus((2.486±0.027)mm) and left parahippocampal gyrus((2.399±0.164)mm). The cerebral cortical surface area larged at the right inferior frontal gyrus((1.036±0.079)mm2), right paracentral lobule((0.827±0.048)mm2)and medial orbitofrontal((0.990±0.083)mm2), and decreased at right superior parietal lobule((0.779±0.040)mm2), right inferior parietal lobule((0.767±0.093)mm2)and right inferior temporal gyrus((0.888±0.070)mm2). The cerebral cortical volume increased at the right inferior frontal gyrus((2.330±0.223)mm3). The cerebral cortical local gyrification index decreased at right middle temporal gyrus(2.893±0.288)and left inferior temporal gyrus(2.589±0.100). Conclusion The first-episode OCD patients have multiple changes of brain structures, and this changes were priority for the frontal lobes, orbital frontal, parietal lobe, temporal lobe and hippocampus.The changes in these regions maybe have close relationship with symptoms of OCD. Key words: First-episode obsessive-compulsive disorder; Magnetic resonance imaging; Freesurfer scanning images software; The local gyrification index

Stage-dependent loss of cortical gyrification as Parkinson disease "unfolds".

Nigrostriatal terminal losses are known to progress most rapidly in early-stage Parkinson disease (PD) and then plateau, whereas cortical pathology continues and may provide a better marker of PD progression in later stages. We investigated cortical gyrification indices in patients with different durations of PD, since cortical folding may capture complex processes involving transverse forces of neuronal sheets or underlying axonal connectivity. Longitudinal cohort structural MRI were obtained at baseline, 18 months, and 36 months from 70 patients with PD without dementia and 70 control participants. Cortical local gyrification index (LGI) was compared between controls and PD subgroups based upon duration of illness (DOI, <1 year [PDE, n = 17], 1-5 years [PDM, n = 19], >5 years [PDL, n = 24]) and adjusted using false discovery rate. Associations between LGI and clinical measurements were assessed using multiple linear regression. Areas having significantly reduced LGI also were analyzed using baseline data from a newly established cohort (PD n = 87, control n = 66) to validate our findings. In the longitudinal cohort, PDL had significantly reduced overall gyrification, and bilaterally in the inferior parietal, postcentral, precentral, superior frontal, and supramarginal areas, compared to controls (p < 0.05). Longitudinally, loss of gyrification was accelerated in PDM participants, compared to controls. LGI showed robust correlations with DOI and also was correlated with PD-related clinical measurements. Similar results were obtained in the validation sample. Loss of cortical gyrification may be accelerated within the first few years after PD diagnosis, and become particularly prominent in later stages. Thus, it may provide a metric for monitoring progression in vivo.

Cortical thinning and caudate abnormalities in first episode psychosis and their association with clinical outcome

First episode psychosis (FEP) has been associated with structural brain changes, largely identified by volumetric analyses. Advances in neuroimaging processing have made it possible to measure geometric properties that may identify subtle structural changes not appreciated by a measure of volume alone. In this study we adopt complementary methods of assessing the structural integrity of grey matter in FEP patients and assess whether these relate to patient clinical and functional outcome at 3year follow-up.1.5Tesla T1-weighted Magnetic Resonance (MR) images were acquired for 46 patients experiencing their first episode of psychosis and 46 healthy controls. Cerebral cortical thickness and local gyrification index (LGI) were investigated using FreeSurfer software. Volume and shape of the hippocampus, caudate and lateral ventricles were assessed using manual tracing and spherical harmonics applied for shape description.A cluster of cortical thinning was identified in FEP compared to controls; this was located in the right superior temporal gyrus, sulcus, extended into the middle temporal gyrus (lateral temporal cortex — LTC). Bilateral caudate volumes were significantly lower in FEP relative to controls and the right caudate also displayed regions of shape deflation in the FEP group. No significant structural abnormalities were identified in cortical LGI or hippocampal or lateral ventricle volume/shape. Neither LTC nor caudate abnormalities were related to change in symptom severity or global functioning 3years later.LTC and caudate abnormalities are present at the first episode of psychosis but do not appear to directly affect clinical or functional outcome.