A quantitative study of magnetic susceptibility-weighted imaging of deep cerebral veins.

OBJECTIVE: To evaluate the value of magnetic susceptibility-weighted imaging (SWI) for measuring deep cerebral venous diameter. METHODS: The diameters of 150 deep cerebral veins were measured by SWI and digital subtraction angiography (DSA) in 50 patients. RESULTS: SWI showed whole cerebral veins as clear soft vessels, but with a crooked hypointense linear structure along the sulcus. Venous vessel diameter as measured by SWI was greater than that by DSA, but values from the two different techniques showed significant linear correlation (r=0.905). CONCLUSION: SWI is reliable and suitable for quantitative measurements of deep cerebral veins, and more sensitive for measuring smaller vessels deep within the brain.

[Motor cortex by real-time imaging process functional MRI during finger movements].

OBJECTIVE: To explore the techniques of RTIP-fMRI scanning and the correspondence between structure and functional changes of motor cortex during self-paced finger movements by RTIP-fMRI in normal volunteers. METHODS: The 15 healthy volunteers were studied by RTIP-fMRI, and the activation tasks consisted of self-paced finger movements performed with the right and the left hands. Image postprocessing was done on the workstation by "correlation coefficient" algorithm analysis method, IAC and SPM software. RESULTS: There was a good correspondence between the anatomical landmarks of the somatotopical organization of primary motor areas in the 15 volunteers; during the finger tasks, the functional changes occurred in the contralateral primary motor-somatosensory cortex (M1/S1), the supplementary motor area (SMA), and the ipsilateral primary motor cortex. CONCLUSION: RTIP, a promising new technique, can localize the motor cortex accurately. It is superior to any other fMRI techniques, and may be used widely in the function research of the brain.

Abnormal neural activity of brain regions in treatment-resistant and treatment-sensitive major depressive disorder: a resting-state fMRI study.

BACKGROUND: Patients with treatment-resistant depression (TRD) and those with treatment-sensitive depression (TSD) responded to antidepressants differently. Previous studies have commonly shown that patients with TRD or TSD had abnormal neural activity in different brain regions. In the present study, we used a coherence-based ReHo (Cohe-ReHo) approach to test the hypothesis that patients with TRD or TSD had abnormal neural activity in different brain regions. METHODS: Twenty-three patients with TRD, 22 with TSD, and 19 healthy subjects (HS) matched with gender, age, and education level participated in the study. RESULTS: ANOVA analysis revealed widespread differences in Cohe-ReHo values among the three groups in different brain regions which included bilateral superior frontal gyrus, bilateral cerebellum, left inferior temporal gyrus, left occipital cortex, and both sides of fusiform gyrus. Compared to HS, lower Cohe-ReHo values were observed in TRD group in bilateral superior frontal gyrus and left cerebellum; in contrast, in TSD group, lower Cohe-ReHo values were mainly found in bilateral superior frontal gyrus. Compared to TSD group, TRD group had lower Cohe-ReHo in bilateral cerebellum and higher Cohe-ReHo in left fusiform gyrus. There was a negative correlation between Cohe-ReHo values of the left fusiform gyrus and illness duration in the pooled patients (r = 0.480, p = 0.001). The sensitivity and specificity of cerebellar Cohe-ReHo values differentiating TRD from TSD were 83% and 86%, respectively. CONCLUSIONS: Compared to healthy controls, both TRD and TSD patients shared the majority of brain regions with abnormal neural activity. However, the lower Cohe-ReHo values in the cerebellum might be as a marker to differentiate TRD from TSD with high sensitivity and specificity.

Altered white matter integrity of forebrain in treatment-resistant depression: a diffusion tensor imaging study with tract-based spatial statistics.

BACKGROUND: The association between alterations of the white matter (WM) integrity in brain regions and mood dysregulation has been reported in major depressive disorder (MDD). However, there has never been a neuroimaging study in patients who have treatment-resistant depression (TRD) and are in a current treatment-resistant state. In the present study, we used diffusion tensor imaging (DTI) with tract-based spatial statistics (TBSS) method to investigate the WM integrity of different brain regions in patients who had TRD and were in a current treatment-resistant state. METHODS: Twenty-three patients with TRD and Hamilton Rating Scale total score of ≥18 and 19 healthy controls matched with age, gender, and education level to patients were scanned with DTI. Thirty 4 mm thick, no gap, contiguous axial slices were acquired and fractional anisotropy (FA) images were generated for each participant. An automated TBSS approach was used to analyze the data. RESULTS: Voxel-wise statistics revealed that patients with TRD had lower FA values in the right anterior limb of internal capsule, the body of corpus callosum, and bilateral external capsule compared to healthy subjects. Patients with TRD did not have increased FA values in any brain regions compared to healthy subjects. There was no correlation between the FA values in any brain region and patients' demographics and the severity of illness. CONCLUSIONS: Our findings suggest the abnormalities of the WM integrity of neuronal tracts connecting cortical and subcortical nuclei and two brain hemispheres may play a key role in the pathogenesis of TRD.

Alterations of the amplitude of low-frequency fluctuations in treatment-resistant and treatment-response depression: a resting-state fMRI study.

BACKGROUND: Patients with treatment-resistant depression (TRD) and those with treatment-response depression (TSD) respond to antidepressants differently and previous studies have commonly reported different brain networks in resistant and nonresistant patients. Using the amplitude of low-frequency fluctuations (ALFF) approach, we explored ALFF values of the brain regions in TRD and TSD patients at resting state to test the hypothesis of the different brain networks in TRD and TSD patients. METHODS: Eighteen TRD patients, 17 TSD patients and 17 gender-, age-, and education-matched healthy subjects participated in the resting-state fMRI scans. RESULTS: There are widespread differences in ALFF values among TRD patients, TSD patients and healthy subjects throughout the cerebellum, the visual recognition circuit (middle temporal gyrus, middle/inferior occipital gyrus and fusiform), the hate circuit (putamen), the default circuit (ACC and medial frontal gyrus) and the risk/action circuit (inferior frontal gyrus). The differences in brain circuits between the TRD and TSD patients are mainly in the cerebellum, the visual recognition circuit and the default circuit. CONCLUSIONS: The affected brain circuits of TRD patients might be partly different from those of TSD patients.

Disrupted regional homogeneity in treatment-resistant depression: a resting-state fMRI study.

BACKGROUND: Using a newly developed regional homogeneity (ReHo) approach, we were to explore the features of brain activity in patients with treatment-resistant depression (TRD) in resting state, and further to examine the relationship between abnormal brain activity in TRD patients and specific symptom factors derived from ratings on the Hamilton Rating Scale for Depression (HRSD). METHODS: 24 patients with TRD and 19 gender-, age-, and education-matched healthy subjects participated in the fMRI scans. RESULTS: 1. Compared with healthy controls, decreased ReHo were found in TRD patients in the left insula, superior temporal gyrus, inferior frontal gyrus, lingual gyrus and cerebellumanterior lobe (culmen) (p<0.05, corrected). 2. Compared with healthy controls, increased ReHo were found in the left superior temporal gyrus, cerebellum posterior lobe (tuber), cerebellum anterior lobe (culmen), the right cerebellar tonsil and bilateral fusiform gyrus (p<0.05, corrected). 3. There was no correlation between the ReHo values in any brain region detected in our study and the patients' age, years of education, illness duration, HRSD total score and its symptom factors. LIMITATION: The influence of antidepressants to the brain activity in TRD patients was not fully eliminated. CONCLUSIONS: The pathogenesis of TRD may be attributed to abnormal neural activity in multiple brain regions.

Abnormal neural activities in first-episode, treatment-naïve, short-illness-duration, and treatment-response patients with major depressive disorder: a resting-state fMRI study.

BACKGROUND: Abnormality of limbic-cortical networks was postulated in depression. Using a regional homogeneity (ReHo) approach, we explored the regional homogeneity (ReHo) of the brain regions in patients with first-episode, treatment-naïve, short-illness-duration, and treatment-response depression in resting state to test the abnormality hypothesis of limbic-cortical networks in major depressive disorder (MDD). METHODS: Seventeen patients with treatment-response MDD and 17 gender-, age-, and education-matched healthy subjects participated in the resting-state fMRI scans. CONCLUSIONS: Our findings suggested the abnormality of limbic-cortical networks in first-episode, treatment-naïve, short-illness-duration, and treatment-response MDD patients, and added an expanding literature to the abnormality hypothesis of limbic-cortical networks in MDD.