ABSTRACT
Many brain disorders do not show visible lesions and most likely are resulted from abnormalities in regional brain activity or connectivity.Conventional diagnostic neuroimaging techniques are not capable of precisely localizing the abnormal brain activity,but the recently developed integrated PET/MR technology may have the potential to bridge this gap.Integrated PET/MR has been used in clinical practice.However,its primary application is still a combination of functional PET imaging and structural MRI.Simultaneous PET/fMRI,a "functional+functional" imaging technique,holds the advantages of high spatial and temporal resolution,high sensitivity and specificity,and non-invasiveness.Globally,simultaneous PET/fMRI research is still in its beginning stage,and a few initial PET/fMRI studies have shown that voxel-wise correlation between PET and fMRI metrics was not very high,indicating that they may reflect very different aspects of brain activity.To date more than 5 integrated PET/MR scanners have been set up in mainland China.China has the largest patient population,rapidly developing PET imaging techniques,and well-established capabilities in fMRI neuroimaging analytics.PET/fMRI studies require multi-disciplinary collaborations in nuclear medicine,radiology,chemistry,medical physics,computation science,and cognitive neuroscience.At the moment,the research management system in Chinese hospitals is not conducive to such collaborations and further improvement is needed to encourage multi-disciplinary research such as PET/fMRI.Given the known advantages in patient population and other resources,multi-center and multi-disciplinary studies hold the potential to put China at the leading edge of PET/fMRI research and produce high value results that will advance both neuroimaging sciences and future patient care in brain disorders.
ABSTRACT
Objective To explore the pattern of spontaneous neural activity in different frequency bands in Parkinson's disease(PD).Methods The blood oxygen level-dependent signals in 39 PD patients and 37 normal controls were acquired and the amplitude of low-frequency fluctuation ( ALFF) in five differ-ent frequecy bands ( slow-2:0.198-0.25 Hz;slow-3:0.073-0.198 Hz;slow-4:0.027-0.073 Hz;slow-5:0.01-0.027 Hz;slow-6:0-0.01Hz) was cacaulated.A repeated-measures analysis of variance and Post hoc t-test were performed to detect differences of spontaneous activity between two groups in different frequency bands. A correlation analysis was examined between Unified Parkinson’ s Disease Rating Scale ( UPDRS) motor score and ALFF in patients with PD in each frequency band to discover the relationship between disease se-verity and spontaneous neural activity.Results Compared with the normal controls,patients with PD had decreased ALFF in the putamen(-24,-3,-9) (-30,3,0) ( -21,9,6) in the slow-3,slow-4 and slow-5, and had decreased ALFF in the left precentral gyrus (-21,-24,75) (-21,-24,72) (-27,-21,72) (-15,-15,72) and right supplementary motor area (21,-24,75) (6,-3,72) (12,-6,60) (15,-24,72) in all frequency bands except for the slow-5.Increased ALFF in the cerebellum was found in all frequency bands.The ALFF in the putamen was negatively correlated with the UPDRS motor score in the slow-3,slow-5 and slow-6.Conclusion This study shows that the abnormal activities in the striatum are significant in the slow-3,slow-4and slow-5.Most frequency bands except slow-5 are helpful in detecting neural changes in mo-tor cortex.The increased activity in the cerebellum is the common findings in all frequency bands.Multiple frequency analysis may provide insight into the pathophysiological mechanisms of PD.
ABSTRACT
Anxiety and depression are common conditions among patients with irritable bowel syndrome(IBS)which may induce or aggravate intestinal symptoms. Psychological factors are considered to be involved in the pathogenesis of IBS via both central and peripheral pathways,and functional magnetic resonance imaging(fMRI)revealed that several brain areas,such as anterior cingulate cortex and prefrontal cortex,are associated with IBS,anxiety and depression. This article reviewed the use of fMRI for studying the correlation of IBS brain activity with anxiety and depression and its role in the central pathogenesis of IBS.
ABSTRACT
Objective:To study the differences of brain functions between children with attention deficit hyperactivity disorder(ADHD) predominantly inattentive (ADHD-I) and combined(ADHD-C) subtypes in resting state using functional magnetic resonance imaging(fMRI).Methods:A newly reported regional homogeneity(ReHo) approach was used to analyze blood oxygen level-dependent fMRI(BOLD-fMRI) data in resting state among 6 ADHD-C,9 ADHD-I and 15 normal control boys.Results:The brain regions showing differences among the three groups included bilateral frontal lobe,right cuneus and right inferior temporal gyrus.Compared with the normal controls,ADHD-C showed decreased ReHo in left frontal lobe and right inferior temporal gyrus,ADHD-I showed decreased ReHo in bilateral frontal and temporal lobe and right cerebellum and increased ReHo in bilateral occipital lobe and right inferior parietal gyrus.There were no brain regions showing different ReHo between ADHD-C and ADHD-I.Conclusion:Although both ADHD-C and ADHDI showed abnormal neural activity in resting state compared with the normal controls,there were no differences for brain functions in resting state between ADHD-C and ADHD-I.