Large-scale longitudinal neuroimaging studies with diffusion imaging techniques are necessary to test and validate models of white matter neurophysiological processes that change in time, both in healthy and diseased brains. The predictive power of such longitudinal models will always be limited by the reproducibility of repeated measures acquired during different sessions. At present, there is limited quantitative knowledge about the across-session reproducibility of standard diffusion metrics in 3T multi-centric studies on subjects in stable conditions, in particular when using tract based spatial statistics and with elderly people. In this study we implemented a multi-site brain diffusion protocol in 10 clinical 3T MRI sites distributed across 4 countries in Europe (Italy, Germany, France and Greece) using vendor provided sequences from Siemens (Allegra, Trio Tim, Verio, Skyra, Biograph mMR), Philips (Achieva) and GE (HDxt) scanners. We acquired DTI data (2 × 2 × 2 mm(3), b = 700 s/mm(2), 5 b0 and 30 diffusion weighted volumes) of a group of healthy stable elderly subjects (5 subjects per site) in two separate sessions at least a week apart. For each subject and session four scalar diffusion metrics were considered: fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial (AD) diffusivity. The diffusion metrics from multiple subjects and sessions at each site were aligned to their common white matter skeleton using tract-based spatial statistics. The reproducibility at each MRI site was examined by looking at group averages of absolute changes relative to the mean (%) on various parameters: i) reproducibility of the signal-to-noise ratio (SNR) of the b0 images in centrum semiovale, ii) full brain test-retest differences of the diffusion metric maps on the white matter skeleton, iii) reproducibility of the diffusion metrics on atlas-based white matter ROIs on the white matter skeleton. Despite the differences of MRI scanner configurations across sites (vendors, models, RF coils and acquisition sequences) we found good and consistent test-retest reproducibility. White matter b0 SNR reproducibility was on average 7 ± 1% with no significant MRI site effects. Whole brain analysis resulted in no significant test-retest differences at any of the sites with any of the DTI metrics. The atlas-based ROI analysis showed that the mean reproducibility errors largely remained in the 2-4% range for FA and AD and 2-6% for MD and RD, averaged across ROIs. Our results show reproducibility values comparable to those reported in studies using a smaller number of MRI scanners, slightly different DTI protocols and mostly younger populations. We therefore show that the acquisition and analysis protocols used are appropriate for multi-site experimental scenarios.
Stroke due to brain vascular disease is a serious complication of tuberculous meningitis (TBM). This study evaluated the frequency, clinical characteristics, risk factors and outcomes of patients with TBM complicated by stroke admitted to the Infectious Disease Clinic, University of Perugia Hospital, Italy from 1971 to 2010. Over four decades, 419 patients were admitted with tuberculosis, of these 30 (7.1%) were diagnosed with TBM: 20 definite, one probable and nine possible. Twenty-six were evaluable for stroke and six (23%) had stroke. The latter six had advanced stages of meningitis, two tested HIV positive, three HIV negative and in one HIV was not performed. Of seven patients without stroke tested for HIV, only one resulted positive. No differences were found regarding CSF cell count, sugar, protein, microscopy or growth of Mycobacterium tuberculosis among patients with or without stroke. The overall survival rate at discharge was 83% in patients with stroke and 95% in those without stroke. It was found that stroke can be frequent among patients with TBM and the presence of HIV infection might be associated with a higher rate of stroke. Further research is needed on these findings, especially in low TB endemic countries.
Tuberculous meningitis (TBM) is a devastating disease. TBM occurs more commonly in HIV infected patients. The influence of HIV co-infection on clinical manifestations and outcome of TBM is not well defined. Yet, some differences have been observed and stroke has been recorded to occur more frequently. This study reports on an HIV infected Caucasian female with lung, meningeal tuberculosis and stroke due to a cortical sub-cortical ischemic lesion. TBM was documented in the absence of neurologic symptoms. At the same time, miliary lung TB caused by multi-susceptible Mycobacterium tuberculosis was diagnosed. Anti-TB therapy consisting of a combination of four drugs was administered. The patient improved and was discharged five weeks later. In conclusion, TBM and multiple underling pathologies including HIV infection, as well as other risk factors can lead to a greater risk of stroke. Moreover, drug interactions and their side effects add levels of complexity. TBM must be included in the differential diagnosis of HIV infected patients with stroke and TBM treatment needs be started as soon as possible before the onset of vasculopathy.
Motor impairment is the most relevant clinical feature in Parkinsons disease (PD). Functional imaging studies on motor impairment in PD have revealed changes in the cortical motor circuits, with particular involvement of the fronto-striatal network. The aim of this study was to assess brain activations during the performance of three different motor exercises, characterized by progressive complexity, using a functional fMRI multiple block paradigm, in PD patients and matched control subjects. Unlike from single-task comparisons, multi-task comparisons between similar exercises allowed to analyse brain areas involved in motor complexity planning and execution. Our results showed that in the single-task comparisons the involvement of primary and secondary motor areas was observed, consistent with previous findings based on similar paradigms. Most notably, in the multi-task comparisons a greater activation of supplementary motor area and posterior parietal cortex in PD patients, compared with controls, was observed. Furthermore, PD patients, compared with controls, had a lower activation of the basal ganglia and limbic structures, presumably leading to the impairment in the higher levels of motor control, including complexity planning and execution. The findings suggest that in PD patients occur both compensatory mechanisms and loss of efficiency and provide further insight into the pathophysiological role of distinct cortical and subcortical areas in motor dysfunction.
In patients with acute stroke, the hyperdense middle cerebral artery (MCA) and internal carotid artery (ICA) signs on CT scans are markers of early ischemia, but their prognostic implications remain unclear.The aims of this prospective study were to assess: (1) the occurrence rate of hyperdense MCA and/or ICA in patients admitted for acute ischemic stroke; (2) the risk factors for hyperdense MCA and/or ICA; (3) the correlation between hyperdense MCA and/or ICA and functional outcome at 3 months.
Kümmells disease is the current eponym of avascular osteonecrosis (AVN) of a vertebral body leading to a delayed non-healing vertebral compression fracture (VCF) and thus pseudo-arthrosis. AVN is characterized by production of gas that outlines a radiolucent zone in the vertebral body, called vacuum cleft sign (VCS) or "Kümmells sign". This sign has been observed in up to one-third of VCFs and is often associated with osteoporosis and never with malignant or inflammatory diseases. Generally, treatment strategies are conservative management and percutaneous vertebroplasty. Teriparatide (rhPTH [1-34]) is an osteoanabolic agent approved for treatment of osteoporosis and helpful in fractures healing too. Here, we describe the case of an 81-year-old osteoporotic woman presented with a 1-year history of persistent low back pain onset after a trauma. A lumbar spine Computer Tomography (CT) scan performed 2 months after the injury (November 2006) showed the VCS within a VCF of the first lumbar vertebra; a control CT scan 1 year later showed persistence of the finding. After 12 months of treatment with teriparatide 20 mcg/day, symptoms disappeared and vacuum was significantly reduced. In conclusion, Kümmells disease may be hypothesized in patients with chronic spinal symptoms, especially in the presence of osteoporosis. Moreover in this condition, osteoanabolic treatment may be used in patients with Kümmells disease to enhance vertebral fractures healing and contribute to back pain relief.
Here we report on two consecutive cases of tuberculosis in immunocompetent HIV-negative patients with lingual lesions. In both patients diagnosis was delayed. Disease progressed involving the lungs, lymph nodes and also the brain. Both patients are disease-free at 30 and 22 month follow-up respectively. Isolated Mycobacterium tuberculosis from these patients was multi-susceptible. Tuberculosis lesions of the oral cavity and brain are infrequently diagnosed in immunocompetent subjects from Western countries. Clinicians must take into greater consideration tuberculosis as a possible diagnosis when diagnosing chronic and/or recurrent lingual lesions even in the absence of pulmonary lesions.
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