Detection of changes in the periaqueductal gray matter of patients with episodic migraine using quantitative diffusion kurtosis imaging: preliminary findings

Contralateral acupuncture for migraine without aura: a randomized trial protocol with multimodal MRI

Introduction

Migraine is a common clinical disorder, ranks as the second most disabling disease worldwide, and often manifests with unilateral onset. Contralateral acupuncture (CAT), as a classical acupuncture method, has been proven to be effective in the treatment of migraine without aura (MWoA). However, its neural mechanisms have not been investigated using multimodal magnetic resonance imaging (MRI).

Methods and analysis

In this multimodal neuroimaging randomized trial, a total of 96 female MWoA participants and 30 female healthy controls (HCs) will be recruited. The 96 female MWoA participants will be randomized into three groups: Group A (CAT group), Group B [ipsilateral acupuncture (IAT) group], and Group C (sham CAT group) in a 1:1:1 allocation ratio. Each group will receive 30 min of treatment every other day, three times a week, for 8 weeks, followed by an 8-week follow-up period. The primary outcome is the intensity of the migraine attack. Data will be collected at baseline (week 0), at the end of the 8-week treatment period (weeks 1-8), and during the 8-week follow-up (weeks 9-16). Adverse events will be recorded. Multimodal MRI scans will be conducted at baseline and after 8-week treatment.

Discussion

This study hypothesized that CAT may treat MWoA by restoring pathological alterations in brain neural activity, particularly by restoring cross-integrated functional connectivity with periaqueductal gray (PAG) as the core pathological brain region. The findings will provide scientific evidence for CAT in the treatment of MWoA.

Ethics and dissemination

The Medical Ethics Committee of the Second Affiliated Hospital of Yunnan University of Chinese Medicine has given study approval (approval no. 2022-006). This trial has been registered with the Chinese Clinical Trials Registry (registration no. ChiCTR2300069456). Peer-reviewed papers will be used to publicize the trial's findings.

Clinical trial registration

https://clinicaltrials.gov/, identifier ChiCTR2300069456.

Impact of truncating diffusion MRI scans on diffusional kurtosis imaging

OBJECTIVE

Diffusional kurtosis imaging (DKI) extends diffusion tensor imaging (DTI), characterizing non-Gaussian diffusion effects but requires longer acquisition times. To ensure the robustness of DKI parameters, data acquisition ordering should be optimized allowing for scan interruptions or shortening. Three methodologies were used to examine how reduced diffusion MRI scans impact DKI histogram-metrics: 1) the electrostatic repulsion model (OptEEM); 2) spherical codes (OptSC); 3) random (RandomTRUNC).

MATERIALS AND METHODS

Pre-acquired diffusion multi-shell data from 14 female healthy volunteers (29±5 years) were used to generate reordered data. For each strategy, subsets containing different amounts of the full dataset were generated. The subsampling effects were assessed on histogram-based DKI metrics from tract-based spatial statistics (TBSS) skeletonized maps. To evaluate each subsampling method on simulated data at different SNRs and the influence of subsampling on in vivo data, we used a 3-way and 2-way repeated measures ANOVA, respectively.

RESULTS

Simulations showed that subsampling had different effects depending on DKI parameter, with fractional anisotropy the most stable (up to 5% error) and radial kurtosis the least stable (up to 26% error). RandomTRUNC performed the worst while the others showed comparable results. Furthermore, the impact of subsampling varied across distinct histogram characteristics, the peak value the least affected (OptEEM: up to 5% error; OptSC: up to 7% error) and peak height (OptEEM: up to 8% error; OptSC: up to 11% error) the most affected.

CONCLUSION

The impact of truncation depends on specific histogram-based DKI metrics. The use of a strategy for optimizing the acquisition order is advisable to improve DKI robustness to exam interruptions.

Microstructural differences in migraine: A diffusion-tensor imaging study

BACKGROUND

Diffusion-tensor imaging can be applied to describe the microstructural integrity of the whole brain. As findings about microstructural alterations in migraine are inconsistent, we aimed to replicate the most frequent results and assess a relationship between migraine parameters and changes in microstructure.

METHODS

Diffusion-weighted MRI data of 37 migraine patients and 40 controls were collected. Two indices of diffusion of water molecules, fractional anisotropy and mean diffusivity were used in a voxel-wise analysis. Group comparisons were carried out in SPM12 using age and sex as covariates. Statistically significant results survived family-wise error correction (pFWE < 0.05). Migraine intensity, frequency, and duration were self-reported and correlated with mean fractional anisotropy and mean diffusivity values across clusters.

RESULTS

Migraine patients showed significantly lower fractional anisotropy in occipital regions, and significantly higher fractional anisotropy in thirteen clusters across the brain. Mean diffusivity of migraine patients was significantly decreased in the cerebellum and pons, but it was not increased in any area. Correlation between migraine duration and fractional anisotropy was significantly positive in the frontal cortex and significantly negative in the superior parietal lobule.

CONCLUSION

We suggest that microstructural integrity of the migraine brain is impaired in visual areas and shows duration-related alterations in regions of the default mode network.

Viability of AMURA biomarkers from single-shell diffusion MRI in clinical studies

Diffusion Tensor Imaging (DTI) is the most employed method to assess white matter properties using quantitative parameters derived from diffusion MRI, but it presents known limitations that restrict the evaluation of complex structures. The objective of this study was to validate the reliability and robustness of complementary diffusion measures extracted with a novel approach, Apparent Measures Using Reduced Acquisitions (AMURA), with a typical diffusion MRI acquisition from a clinical context in comparison with DTI with application to clinical studies. Fifty healthy controls, 51 episodic migraine and 56 chronic migraine patients underwent single-shell diffusion MRI. Four DTI-based and eight AMURA-based parameters were compared between groups with tract-based spatial statistics to establish reference results. On the other hand, following a region-based analysis, the measures were assessed for multiple subsamples with diverse reduced sample sizes and their stability was evaluated with the coefficient of quartile variation. To assess the discrimination power of the diffusion measures, we repeated the statistical comparisons with a region-based analysis employing reduced sample sizes with diverse subsets, decreasing 10 subjects per group for consecutive reductions, and using 5,001 different random subsamples. For each sample size, the stability of the diffusion descriptors was evaluated with the coefficient of quartile variation. AMURA measures showed a greater number of statistically significant differences in the reference comparisons between episodic migraine patients and controls compared to DTI. In contrast, a higher number of differences was found with DTI parameters compared to AMURA in the comparisons between both migraine groups. Regarding the assessments reducing the sample size, the AMURA parameters showed a more stable behavior than DTI, showing a lower decrease for each reduced sample size or a higher number of regions with significant differences. However, most AMURA parameters showed lower stability in relation to higher coefficient of quartile variation values than the DTI descriptors, although two AMURA measures showed similar values to DTI. For the synthetic signals, there were AMURA measures with similar quantification to DTI, while other showed similar behavior. These findings suggest that AMURA presents favorable characteristics to identify differences of specific microstructural properties between clinical groups in regions with complex fiber architecture and lower dependency on the sample size or assessing technique than DTI.

Abnormally Increased Effective Connectivity of the Periaqueductal Gray in Migraine Without Aura Patients

OBJECTIVES

The periaqueductal gray (PAG) is a key region in the descending pain modulatory system. We applied a Granger causality analysis-based approach to examine resting-state effective connectivity of the bilateral PAG regions in migraine patients without aura (MwoA).

MATERIALS AND METHODS

Resting-state functional magnetic resonance imaging data were obtained from 28 MwoA patients and 17 healthy controls. The effective connectivity of the bilateral PAG was characterized using a voxel-wised Granger causality analysis method. The resulting effective connectivity measurements were assessed for correlations with other clinical features.

RESULTS

Compared with the healthy controls, MwoA patients showed increased effective connectivity from the left PAG to the left anterior cingulate gyrus and right postcentral gyrus. Meanwhile, MwoA patients also showed increased effective connectivity from the right PAG to the left precentral gyrus and increased effective connectivity from the left caudate and right middle occipital gyrus to the right PAG.

DISCUSSION

Abnormally increased effective connectivity between PAG and limbic system, primary sensorimotor cortex, and visual cortex may play a key role in neuropathological features, perception, and affection of MwoA. The current study provides further insights into the complex scenario of MwoA mechanisms.

Headache-related circuits and high frequencies evaluated by EEG, MRI, PET as potential biomarkers to differentiate chronic and episodic migraine: Evidence from a systematic review

Background

The diagnosis of migraine is mainly clinical and self-reported, which makes additional examinations unnecessary in most cases. Migraine can be subtyped into chronic (CM) and episodic (EM). Despite the very high prevalence of migraine, there are no evidence-based guidelines for differentiating between these subtypes other than the number of days of migraine headache per month. Thus, we consider it timely to perform a systematic review to search for physiological evidence from functional activity (as opposed to anatomical structure) for the differentiation between CM and EM, as well as potential functional biomarkers. For this purpose, Web of Science (WoS), Scopus, and PubMed databases were screened.

Findings

Among the 24 studies included in this review, most of them (22) reported statistically significant differences between the groups of CM and EM. This finding is consistent regardless of brain activity acquisition modality, ictal stage, and recording condition for a wide variety of analyses. That speaks for a supramodal and domain-general differences between CM and EM that goes beyond a differentiation based on the days of migraine per month. Together, the reviewed studies demonstrates that electro- and magneto-physiological brain activity (M/EEG), as well as neurovascular and metabolic recordings from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), show characteristic patterns that allow to differentiate between CM and EM groups.

Conclusions

Although a clear brain activity-based biomarker has not yet been identified to distinguish these subtypes of migraine, research is approaching headache specialists to a migraine diagnosis based not only on symptoms and signs reported by patients. Future studies based on M/EEG should pay special attention to the brain activity in medium and fast frequency bands, mainly the beta band. On the other hand, fMRI and PET studies should focus on neural circuits and regions related to pain and emotional processing.

Microstructural white matter alterations associated with migraine headaches: a systematic review of diffusion tensor imaging studies

The pathophysiology of migraine as a headache disorder is still undetermined. Diffusion tensor imaging (DTI) has significantly improved our knowledge about brain microstructure in this disease. Here, we aimed to systematically review DTI studies in migraine and survey the sources of heterogeneity by investigating diffusion parameter changes associated with clinical characteristics and migraine subtypes. Microstructural changes, as revealed by widespread alteration of diffusion metrics in white matter (WM) tracts, subcortical and cortical regions, were reported by several migraine DTI studies. Specifically, we reported changes in the corpus callosum, thalamic radiations, corona radiata, and brain stem. These alterations showed high variability across migraine cycle phases. Additionally, migraine associated with depressive/anxiety symptoms revealed significant changes in the corpus callosum, internal capsule, and superior longitudinal fasciculus. No significant WM microstructural differences were observed between migraine patients with and without aura. Overall, differences between chronic and episodic migraine showed inconsistency across studies. Migraine is associated with microstructural changes in widespread regions including thalamic radiations, corpus callosum, and brain stem. These alterations can highlight neuronal damage and neuronal plasticity mechanisms either following pain stimulations occurring in migraine cycle or as a compensatory response to pain in chronic migraine. Longitudinal studies applying advanced modalities may shed new light on the underlying microstructural changes in migraine subtypes.

Overexpression of BDNF in the ventrolateral periaqueductal gray regulates the behavior of epilepsy-migraine comorbid rats

OBJECTIVE

To investigate the effects of brain-derived neurotrophic factor (BDNF) overexpression in the ventrolateral periaqueductal gray (vlPAG) on behavioral changes in epilepsy-migraine comorbid rats.

METHOD

We used an adeno-associated virus (AAV)-mediated vector to supplement BDNF in the vlPAG area prior to the establishment of a pilocarpine-nitroglycerin (Pilo-NTG) combination-induced comorbid model of epilepsy and migraine. Seizure- and migraine-related behaviors were analyzed. Cell loss and apoptosis in vlPAG were detected through hematoxylin-eosin (HE) and TUNEL staining. Immunofluorescence staining analyses were employed to detect expressions of BDNF and its receptor, tyrosine kinase B (TrkB), in vlPAG. Immunohistochemical staining was conducted to detect expressions of c-Fos and calcitonin gene-related peptide (CGRP) in the trigeminal nucleus caudalis (TNC) and trigeminal ganglion (TG).

RESULTS

Comparing to control group, AAV-BDNF injected comorbid group showed lower pain sensitivity, scratching head, and spontaneous seizures accompanied by the downregulation of c-Fos labeling neurons and CGRP immunoreactivity in the TNC and TG. However, these changes were still significantly higher in the comorbid group than those in both epilepsy and migraine groups under the same intervention.

CONCLUSION

These data demonstrated that supplying BDNF to vlPAG may protect structural and functional abnormalities in vlPAG and provide an antiepileptic and analgesic therapy.

Toward more robust and reproducible diffusion kurtosis imaging

PURPOSE

The general utility of diffusion kurtosis imaging (DKI) is challenged by its poor robustness to imaging artifacts and thermal noise that often lead to implausible kurtosis values.

THEORY AND METHODS

A robust scalar kurtosis index can be estimated from powder-averaged diffusion-weighted data. We introduce a novel DKI estimator that uses this scalar kurtosis index as a proxy for the mean kurtosis to regularize the fit.

RESULTS

The regularized DKI estimator improves the robustness and reproducibility of the kurtosis metrics and results in parameter maps with enhanced quality and contrast.

CONCLUSION

Our novel DKI estimator promotes the wider use of DKI in clinical research and potentially diagnostics by improving the reproducibility and precision of DKI fitting and, as such, enabling enhanced visual, quantitative, and statistical analyses of DKI parameters.

Decreased Resting-State Functional Connectivity of Periaqueductal Gray in Temporal Lobe Epilepsy Comorbid With Migraine

Objective: Patients with temporal lobe epilepsy (TLE) are at high risk for having a comorbid condition of migraine, and these two common diseases are proposed to have some shared pathophysiological mechanisms. Our recent study indicated the dysfunction of periaqueductal gray (PAG), a key pain-modulating structure, contributes to the development of pain hypersensitivity and epileptogenesis in epilepsy. This study is to investigate the functional connectivity of PAG network in epilepsy comorbid with migraine.

Methods: Thirty-two patients with TLE, including 16 epilepsy patients without migraine (EwoM) and 16 epilepsy patients with comorbid migraine (EwM), and 14 matched healthy controls (HCs) were recruited and underwent resting functional magnetic resonance imaging (fMRI) scans to measure the resting-state functional connectivity (RsFC) of PAG network. The frequency and severity of migraine attacks were assessed using the Migraine Disability Assessment Questionnaire (MIDAS) and Visual Analog Scale/Score (VAS). In animal experiments, FluoroGold (FG), a retrograde tracing agent, was injected into PPN and its fluorescence detected in vlPAG to trace the neuronal projection from vlPAG to PPN. FG traced neuron number was used to evaluate the neural transmission activity of vlPAG-PPN pathway. The data were processed and analyzed using DPARSF and SPSS17.0 software. Based on the RsFC finding, the excitatory transmission of PAG and the associated brain structure was studied via retrograde tracing in combination with immunohistochemical labeling of excitatory neurons.

Results: Compared to HCs group, the RsFC between PAG and the left pedunculopontine nucleus (PPN), between PAG and the corpus callosum (CC), was decreased both in EwoM and EwM group, while the RsFC between PAG and the right PPN was increased only in EwoM group but not in EwM group. Compared to EwoM group, the RsFC between PAG and the right PPN was decreased in EwM group. Furthermore, the RsFC between PAG and PPN was negatively correlated with the frequency and severity of migraine attacks. In animal study, a seizure stimulation induced excitatory transmission from PAG to PPN was decreased in rats with chronic epilepsy as compared to that in normal control rats.

Conclusion: The comorbidity of epilepsy and migraine is associated with the decreased RsFC between PAG and PPN.

Detection of microstructural white matter alterations in functional gastrointestinal disorders assessed by diffusion kurtosis imaging

BACKGROUND AND AIM

We evaluated whether diffusion kurtosis and tensor imaging (DKI/DTI) could reveal microstructural alterations in the brains of patients with functional gastrointestinal disorders (FGIDs), and whether imaging findings were correlated with health-related quality of life (HRQOL).

METHODS

Twelve patients with FGIDs fulfilling the Rome IV criteria, and seven healthy controls were examined using a 3 T magnetic resonance (MR) scanner. Tract-based spatial statistics and regions of interest analyses were performed to compare the mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD) between patients with FGIDs versus controls. HRQOL was assessed in patients with FGIDs using the eight-item short form of the Medical Outcome Study Questionnaire (SF-8) and the Gastrointestinal Symptom Rating Scale.

RESULTS

Patients with FGIDs had extensive, widespread regions of reduced MD in the white matter in comparison with healthy controls, whereas no significant differences were observed in MK and FA. No significant differences in deep gray matter for the MK, FA, and MD values were observed between patients with FGIDs and controls. In patients with FGIDs, the FA values in the globus pallidus had a significant and negative correlation with SF-8 (a mental component summary) (r = -0.797, P = 0.01 uncorrected for multiple comparisons).

CONCLUSIONS

DKI/DTI can help identify microstructural white matter alterations in patients with FGIDs. The FA values in the globus pallidus may be useful for a severity assessment of FGIDs.

Cerebral diffusion kurtosis imaging to assess the pathophysiology of postpartum depression

Postpartum depression (PPD), a main cause of maternal suicide, is an important issue in perinatal mental health. Recently, cerebral diffusion tensor imaging (DTI) studies have shown reduced fractional anisotropy (FA) in major depressive disorder (MDD) patients. There are, however, no reports using diffusion kurtosis imaging (DKI) for evaluation of PPD. This was a Japanese single-institutional prospective study from 2016 to 2019 to examine the pathophysiological changes in the brain of PPD patients using DKI. The DKI data from 3.0 T MRI of patients one month after delivery were analyzed; the patients were examined for PPD by a psychiatrist. The mean kurtosis (MK), FA and mean diffusivity (MD) were calculated from the DKI data and compared between PPD and non-PPD groups using tract-based spatial statistics analysis. Of the 75 patients analyzed, eight patients (10.7%) were diagnosed as having PPD. In the PPD group, FA values in the white matter and thalamus were significantly lower and MD values in the white matter and putamen were significantly higher. The area with significant differences in MD value was more extensive (40.8%) than the area with significant differences in FA value (6.5%). These findings may reflect pathophysiological differences of PPD compared with MDD.

Magnetic Resonance Imaging in Pediatric Migraine

This literature review provides an overview of the research using magnetic resonance imaging (MRI) in pediatric migraine and compares findings with the adult migraine literature. A literature search using PubMed was conducted using all relevant sources up to February 2019. Using MRI methods to categorize and explain pediatric migraine in comparison with adult migraine is important, in order to recognize and appreciate the differences between the two entities, both clinically and physiologically. We aim to demonstrate the differences and similarities between pediatric and adult migraine using data from white matter and gray matter structural studies, cerebral perfusion, metabolites, and functional MRI (fMRI) studies, including task-based and resting-state blood oxygen level-dependent studies. By doing this we identify areas that need further research, as well as possible areas where intervention could alter outcomes.

White matter changes in chronic and episodic migraine: a diffusion tensor imaging study

BACKGROUND

White matter alterations have been observed in patients with migraine. However, no microstructural white matter alterations have been found particularly in episodic or chronic migraine patients, and there is limited research focused on the comparison between these two groups of migraine patients.

METHODS

Fifty-one healthy controls, 55 episodic migraine patients and 57 chronic migraine patients were recruited and underwent brain T1-weighted and diffusion-weighted MRI acquisition. Using Tract-Based Spatial Statistics (TBSS), fractional anisotropy, mean diffusivity, radial diffusivity and axial diffusivity were compared between the different groups. On the one hand, all migraine patients were compared against healthy controls. On the other hand, patients from each migraine group were compared between them and also against healthy controls. Correlation analysis between clinical features (duration of migraine in years, time from onset of chronic migraine in months, where applicable, and headache and migraine frequency, where applicable) and Diffusion Tensor Imaging measures was performed.

RESULTS

Fifty healthy controls, 54 episodic migraine and 56 chronic migraine patients were finally included in the analysis. Significant decreased axial diffusivity (p < .05 false discovery rate and by number of contrasts corrected) was found in chronic migraine compared to episodic migraine in 38 white matter regions from the Johns Hopkins University ICBM-DTI-81 White-Matter Atlas. Significant positive correlation was found between time from onset of chronic migraine and mean fractional anisotropy in the bilateral external capsule, and negative correlation between time from onset of chronic migraine and mean radial diffusivity in the bilateral external capsule.

CONCLUSIONS

These findings suggest global white matter structural differences between episodic migraine and chronic migraine. Patients with chronic migraine could present axonal integrity impairment in the first months of chronic migraine with respect to episodic migraine patients. White matter changes after the onset of chronic migraine might reflect a set of maladaptive plastic changes.

Ventrolateral Periaqueductal Gray Matter Neurochemical Lesion Facilitates Epileptogenesis and Enhances Pain Sensitivity in Epileptic Rats

The ventrolateral periaqueductal gray matter (vlPAG) plays a critical role in the pathogenesis of migraine and few studies have shown that vlPAG might be involved in the pathophysiology of epilepsy. But its roles in epileptogenesis and comorbid relationship between migraine and epilepsy have never been reported. In this study, the impairments of vlPAG neuronal network during spontaneous recurrent seizure (SRS) development after status epilepticus (SE) were investigated, and the pain sensitivity as well as the SRS investigated after neurochemical lesion to vlPAG to determine the role of vlPAG in epileptogenesis and in migraine comorbidity with epilepsy. Neuronal loss and alterations of excitatory and inhibitory neural transmission within vlPAG accompanied the development of epileptogenesis induced by SE. On the other hand, neurochemical lesion to vlPAG enhanced frequency and duration of spontaneous seizure event and frequency of epileptiform inter-ictal spike discharges in electroencephalography (EEG), but decreased pain threshold in epileptic rats. This indicates an involvement of the pain regulating structure, vlPAG, in the pathogenesis of epilepsy. This may imply that vlPAG network alterations could be a possible underlying mechanism of the interactive comorbid relationship between epilepsy and migraine.

Decreased Mean Kurtosis in the Putamen is a Diagnostic Feature of Minimal Hepatic Encephalopathy in Patients with Cirrhosis

Objective To prevent the development of overt hepatic encephalopathy, the early intervention for minimal hepatic encephalopathy (MHE) based on an accurate diagnosis is essential. This study investigated whether or not magnetic resonance diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) could detect brain microstructure abnormalities in MHE. The aim was to confirm whether or not brain microstructure abnormalities detected by magnetic resonance (MR) imaging could be used for the diagnosis of MHE. Methods Thirty-two subjects were prospectively examined with a 3-T MR scanner. Tract-based spatial statistics and region of interest analyses of diffusion imaging were performed to compare the mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD) values between patients with and without minimal hepatic encephalopathy. The diagnostic performance for the detection of MHE was assessed with a receiver operating characteristic analysis. Results Ten subjects were diagnosed with MHE by neuropsychological testing. After the exclusion of unsuitable subjects, we analyzed 9 subjects with MHE and 14 without MHE. The patients with MHE had a reduced MK in the widespread white matter. We also found significant decreases in the MK in the caudate nucleus, putamen, globus pallidus, and/or thalamus in the subjects with MHE. The MK in the putamen showed the best diagnostic performance for differentiating the subjects with MHE from those without MHE (cut-off value, 0.74; sensitivity, 0.89; specificity, 0.86). Conclusion DKI detects changes in the cerebral white matter and basal ganglia regions of patients with MHE more sensitively than DTI. The MK values in the putamen can be a useful marker for diagnosing MHE from cirrhotic patients without MHE.

Alteration of gray matter texture features over the whole brain in medication-overuse headache using a 3-dimentional texture analysis

Background

Imaging studies have provided valuable information in understanding the headache neuromechanism for medication-overuse headache (MOH), and the aim of this study is to investigate altered texture features of MR structural images over the whole brain in MOH using a 3-dimentional texture analysis.

Methods

Brain three-dimensional T1-weighted structural images were obtained from 44 MOH patients and 32 normal controls (NC). The imaging processing included two steps: gray matter (gray images) segment and a 3-dimensional texture features mapping. Voxel-based gray-level co-occurrence matrix (VGLCM) was performed to measure the texture parameters mapping including Contrast, Correlation, Energy, Entropy and inverse difference moment (IDM).

Results

The texture parameters of increased Contrast and Entropy, decreased Energy and IDM were identified in cerebellar vermis of MOH patients compared to NCs. Increased Contrast and decreased Energy were found in left cerebellum. Increased Correlation located in left dorsolateral periaqueductal gray (L-dlPAG), right parahippocampal gyrus (R-PHG), and left middle frontal gyrus (L-MFG) and decreased Correlation located in right superior parietal lobule(R-SPL). Disease duration was positively correlated with Contrast of vermis and negatively correlated with Correlation of R-SPL.HAMD score was negatively correlated with Correlation of R-PHG. MoCA score was positively correlated with Correlation of R-SPL.

Conclusion

The altered textures in gray matter related to pain discrimination and modulation, affective and cognitive processing were helpful in understanding the pathogenesis of MOH. Texture analysis using VGLCM is a sensitive and efficient method to detect subtle gray matter changes in MOH.

Electronic supplementary material

The online version of this article (10.1186/s10194-017-0820-4) contains supplementary material, which is available to authorized users.

Differential diagnosis of parkinsonism by a combined use of diffusion kurtosis imaging and quantitative susceptibility mapping

PURPOSE

We investigated whether diffusion kurtosis imaging (DKI) and quantitative susceptibility mapping (QSM) could detect pathological changes that occur in Parkinson's disease (PD), multiple system atrophy with predominant parkinsonism (MSA-P) or predominant cerebellar ataxia (MSA-C), and progressive supranuclear palsy syndrome (PSPS) and thus be used for differential diagnosis that is often difficult.

METHODS

Seventy patients (41 with PD, 6 with MSA-P, 7 with MSA-C, 16 with PSPS) and 20 healthy controls were examined using a 3.0 T MRI scanner. From DKI and QSM data, we automatically obtained mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD) values of the midbrain tegmentum (MBT), pontine crossing tract (PCT), and superior/middle cerebellar peduncles (CPs), which were used to calculate diffusion MBT/PCT ratios (dMPRs) and diffusion superior/middle CP ratios (dCPRs), as well as MS (magnetic susceptibility) values of the anterior/posterior putamen (PUa and PUp) and globus pallidus (GP).

RESULTS

dMPRs of MK were significantly decreased in PSPS and increased in MSA-C compared with the other groups, while dCPRs of MK showed significant differences only between MSA-C and PD, PSPS, or control. MS values were significantly increased in the PUp of MSA-P and in the PUa and GP of PSPS compared with those in PD. The combined use of MK-dMPR and MS-PUp showed sensitivities of 83-100% and specificities of 81-100% for discriminating among the disease groups, respectively.

CONCLUSION

A quantitative assessment using DKI and QSM analyses, particularly MK-dMPR and MS-PUp values, can readily identify patients with parkinsonism.

Disrupted functional connectivity between the periaqueductal gray and other brain regions in a rat model of recurrent headache

Functional connectivity (FC) has been used to investigate the pathophysiology of migraine. We aimed to identify atypical FC between the periaqueductal gray (PAG) and other brain areas in rats induced by repeated meningeal nociception. The rat model was established by infusing an inflammatory soup (IS) through supradural catheters in conscious rats. Quiescent and face-grooming behaviors were observed to assess nociceptive behavior. FC analysis seeded on the PAG was performed on rats 21 days after IS infusion. The rats exhibited nociceptive behavior correlates of human behaviors associated with migraine after IS infusion. The PAG showed increased FC with the prefrontal cortex, cingulate gyrus, and motor cortex but decreased FC with the basal ganglia, dorsal lateral thalamus, internal capsule and prelimbic cortex in the rat model. The atypical FC of the PAG with brain regions in the rat model that are involved in nociception, somatosensory processing, emotional processing, and pain modulation are consistent with the clinical data from migraineurs, indicate that resting-state FC changes in migraine patients may be a consequence of headache attacks, and further validate this rat model of chronic migraine.

Resting state connectivity between default mode network and insula encodes acute migraine headache

Background

Previous functional MRI studies have revealed that ongoing clinical pain in different chronic pain syndromes is directly correlated to the connectivity strength of the resting default mode network (DMN) with the insula. Here, we investigated seed-based resting state DMN-insula connectivity during acute migraine headaches.

Methods

Thirteen migraine without aura patients (MI) underwent 3 T MRI scans during the initial six hours of a spontaneous migraine attack, and were compared to a group of 19 healthy volunteers (HV). We evaluated headache intensity with a visual analogue scale and collected seed-based MRI resting state data in the four core regions of the DMN: Medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC), and left and right inferior parietal lobules (IPLs), as well as in bilateral insula.

Results

Compared to HV, MI patients showed stronger functional connectivity between MPFC and PCC, and between MPFC and bilateral insula. During migraine attacks, the strength of MPFC-to-insula connectivity was negatively correlated with pain intensity.

Conclusion

We show that greater subjective intensity of pain during a migraine attack is associated with proportionally weaker DMN-insula connectivity. This is at variance with other chronic extra-cephalic pain disorders where the opposite was found, and may thus be a hallmark of acute migraine head pain.

Disrupted functional connectivity of periaqueductal gray subregions in episodic migraine

Background

The periaqueductal gray (PAG) dysfunction was recognized in migraine, and the altered dysfunction of PAG subregions were not totally detected up to now. The aim of this study is to investigate the altered functional connectivity of PAG subregions in EM patients.

Methods

The brain structural images and resting state functional MR imaging (rs-fMRI) data were obtained from 18 normal controls (NC) and 18 EM patients on 3.0 T MR system. Seven subregions of PAG were classified as bilateral ventrolateral PAG (vlPAG), lateral PAG (lPAG), dorsolateral PAG (dlPAG) and dorsomedial PAG (dmPAG). The functional connectivity maps of each PAG subregion were calculated, and Two sample t-test was applied with age and sex as covariables.

Results

Bilateral vlPAG and left dlPAG presented decreased functional connectivity, and the other subregions (bilateral lPAGs, right dlPAG and dmPAG) showed no significant altered functional connectivity in EM compared with NC. The brain regions with decreased functional connectivity mainly located in bilateral prefrontal cortex(PFC), middle temporal gyrus, primary motor area (PMA) and supplementary motor area (SMA) and right ventrolateral PFC (vlPFC) in EM patients in this study. Disease duration was positively related to the functional connectivity of bilateral vlPAG on the bilateral thalamus and putamen, left pallidum and right medial orbitofrontal gyrus in EM patients.

Conclusion

The present study suggested that the dysfunction of bilateral vlPAG and left dlPAG presented in EM, and functional evaluation of PAG subregions may be help for the diagnosis and understanding of EM pathogenesis.

Volume gain of periaqueductal gray in medication-overuse headache

BACKGROUND

Periaqueductal gray (PAG) is a substantial descending pain modulatory center, and previous voxel-based morphometry study confirmed the clusters with increased volume in PAG region in medication-overuse headache (MOH). The aim of this study is to investigate altered PAG volume in MOH using an automated PAG segment method to measure the true PAG volume.

METHODS

High resolution three-dimensional T1-weighted fast spoiled gradient recalled echo MR images were obtained from 22 patients with MOH and 22 normal controls (NC). PAG template was created based on ICBM 152 gray template, and the individual PAG was generated by applying the deformation field from structural image segment to the PAG template, and individual PAG volume was calculated.

RESULTS

There was a significant increased volume of PAG in MOH (0.366 ± 0.005 ml) than that in NC (0.341 ± 0.005 ml)(P < 0.05). There was no significant correlation between the PAG volume and the clinical variables in MOH patients (P > 0.05). The area of receiver operating characteristic (ROC) curve was 0.845, and the cut-off of PAG volume was 0.341 ml with sensitivity 95.5% and specificity 63.6%.

CONCLUSION

The present study demonstrated that the PAG volume gain was confirmed in MOH patients, and the automated individual PAG volume measure may be considered as a simple and effective imaging biomarker in MOH diagnosis.

Nonspecific periaqueductal gray lesions on T2WI in episodic migraine

Background

The specific periaqueductal gray (PAG) lesions with migraine-like headache were easily identified on conventional MR images in clinical practice, and the aim of this study is to investigate the nonspecific periaqueductal gray (PAG) lesions in episodic migraine (EM) patients based on T2 weighted imaging (T2WI).

Methods

T2WI images were obtained from 18 EM patients and 18 normal controls (NC) on 3.0 T MR system. The images were observed by two experienced radiologists, and the lesions were identified on T2WI by consensus by 2 experienced neuroradiologists blinded to the patient identity. Chi-Square test was performed for the significance test.

Results

Ring-like hyperintensity lesions (HILs) around the PAG region were observed in 14 EM patients and in 5 NCs on T2WI. Four EM patients and 13 NCs were normal in PAG region. The significance was revealed by Chi-Square test (P = 0.003).

Conclusion

HIL of PAG may be the direct evidence of the EM genesis, and the further structural and functional study should be performed to elucidate the neuromechanism of migraine pathogenesis.

Relation between injury of the periaqueductal gray and central pain in patients with mild traumatic brain injury: Observational study

The periaqueductal gray (PAG) plays a pivotal role in pain modulation. We attempted to examine the relation between injury of the PAG and central pain in patients with mild traumatic brain injury (TBI).Sixty-one patients with mild TBI with central pain and 31 healthy control subjects were recruited for this study. Visual analog scale (VAS) was used for evaluation of central pain. The region of interest was defined for the PAG and the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured.The FA value was significantly lower in the patient group than in the control group (P < 0.05). However, no significant difference in the ADC value was observed between the patient and control groups (P > 0.05). VAS score of the patient group showed significant moderate negative correlation with the FA (r = -0.38), while no significant correlation was observed between VAS score and the ADC value (P < 0.05).We demonstrated injury of the PAG in patients with central pain following mild TBI and the degree of injury of the PAG was closely related to the degree of central pain.