Thursday 2 October 2008

Articles from Neurology

Link to journal
Astrakas, L G. ; Konitsiotis, S ; Margariti, P ; Tsouli, S ; Tzarouhi, L ; Argyropoulou, M I.
T2 relaxometry and fMRI of the brain in late-onset restless legs syndrome
Neurology. 71(12):911-916, September 16, 2008.
Abstract
Objective: To assess in patients with late-onset idiopathic restless legs syndrome (RLS) the brain iron content with magnetic resonance relaxometry, and brain activation during dorsiflexion and plantar flexion of both feet, using fMRI.Methods: The study was approved by the institutional review board, and informed consent was obtained. Twenty-five RLS patients (14 women, 11 men; age range 55-82 years; mean 66.5 +/- 8.9 years; disease duration 6.5 +/- 4.5 years) and 12 sex- and age-matched controls were studied. A T1-weighted high-resolution three-dimensional spoiled gradient echo sequence was used for structural imaging, a multislice spin echo [TAU]2-weighted sequence was used for T2 relaxometry, and a single-shot multislice gradient echo planar sequence was used for fMRI. The motor paradigm consisted of alternating periods of rest and movement, each 40 seconds in duration. Region of interest analysis was used on the T2 relaxometry maps. Statistical parametric mapping software was used for analysis of the functional data.Results: T2 relaxation time was significantly higher in patients than in controls in the substantia nigra pars compacta. Within-group analysis showed that both patients and controls activated the primary motor cortex, the primary somatosensory cortex, the somatosensory association cortex, and the middle cerebellar peduncles. Patients also activated the thalamus, putamen, middle frontal gyrus, and cingulate gyrus. Between-group analysis showed that patients had higher activation of the dorsolateral prefrontal cortex.Conclusion: Late-onset restless legs syndrome is associated with low iron content of the basal ganglia and increased activity of the dorsolateral prefrontal cortex


Xu, G ; Antuono, P G. ; Jones, J ; Xu, Y ; Wu, G ; Ward, D ; Li, S -J.
Perfusion fMRI detects deficits in regional CBF during memory-encoding tasks in MCI subjects
Publish Ahead of Print, POST COPYEDIT, 26 September 2007
Abstract
Objective: To determine how memory-encoding tasks elicit functional perfusion change in subjects with amnestic mild cognitive impairment (aMCI).Methods: Twelve subjects with aMCI and 14 age-matched cognitively normal (CN) subjects were recruited for this study. Arterial spin-labeling perfusion MRI (ASL-MRI) was employed to measure regional cerebral blood flow (CBF) during both control and encoding task conditions.Results: Experimental results demonstrated that hypoperfusion occurred in the right precuneus and cuneus in the aMCI group, and not the CN group, during the control state. During the memory-task performance, the difference in these regional hypoperfusion areas extended to the posterior cingulate. These regional perfusion rates correlated with the Mini-Mental State Examination and the Rey Auditory Verbal Learning Test scores. In addition, a CBF percentage increase (22.7%) occurred in the right parahippocampus region during the memory-encoding task performance in the CN group, with approximately no change in the aMCI group.Conclusion: Subjects with amnestic mild cognitive impairment had significant regional cerebral hypoperfusion and lacked the dynamic capability to modulate their regional cerebral blood flow responses to the challenge of the functional tasks.


Ludeman, N A. ; Berman, J I. ; Wu, Y W. ; Jeremy, R ; Kornak, J ; Bartha, A I. et al
Diffusion tensor imaging of the pyramidal tracts in infants with motor dysfunction
Publish Ahead of Print, POST COPYEDIT, 30 April 2008
Abstract
Objective: To determine if diffusion tensor imaging (DTI) metrics of the pyramidal tracts correlate with motor outcome in infants presenting with motor dysfunction.Methods: DTI tractography of the pyramidal tracts was performed in 21 patients with clinical motor dysfunction who were less than 30 months of age and in 22 age-matched controls. We plotted tract-specific DTI metrics (fractional anisotropy, parallel diffusivity, transverse diffusivity, and mean diffusivity) against age for the controls and generated normative curves. For each patient, we calculated the deviation from the normative curves. Patients returned for a neurodevelopmental evaluation when they were over 36 months of age, and motor outcome measures were performed. We analyzed the association between normative deviation in DTI metrics and motor outcome measures using linear and logistic regression models.Results: Normative deviation in fractional anisotropy and transverse diffusivity were significantly correlated with all measures of motor outcome. Lower fractional anisotropy and higher transverse diffusivity compared to controls were associated with worse motor outcome. Furthermore, children who were eventually diagnosed with permanent motor dysfunction had lower fractional anisotropy and higher transverse diffusivity compared with those whose motor dysfunction normalized.Conclusions: Diffusion tensor imaging metrics correlate with motor outcome in infants presenting with motor dysfunction. The identification of a quantitative imaging marker that can be applied to infants at the time of clinical presentation has implications for the evaluation of early motor dysfunction.

Sutherling, W W. ; Mamelak, A N. ; Thyerlei, D ; Maleeva, T ; Minazad, Y ; Philpott, L ; Lopez, N
Influence of magnetic source imaging for planning intracranial EEG in epilepsy
Neurology. 71(13):990-996, September 23, 2008.
Abstract
Background: Magnetic source imaging (MSI) is used routinely in epilepsy presurgical evaluation and in mapping eloquent cortex for surgery. Despite increasing use, the diagnostic yield of MSI is uncertain, with reports varying from 5% to 35%. To add benefit, a diagnostic technique should influence decisions made from other tests, and that influence should yield better outcomes. We report preliminary results of an ongoing, long-term clinical study in epilepsy, where MSI changed surgical decisions.Methods: We determined whether MSI changed the surgical decision in a prospective, blinded, crossover-controlled, single-treatment, observational case series. Sixty-nine sequential patients diagnosed with partial epilepsy of suspected neocortical origin had video-EEG and imaging. All met criteria for intracranial EEG (ICEEG). At a surgical conference, a decision was made before and after presentation of MSI. Cases where MSI altered the decision were noted.Results: MSI gave nonredundant information in 23 patients (33%). MSI added ICEEG electrodes in 9 (13%) and changed the surgical decision in another 14 (20%). Based on MSI, 16 patients (23%) were scheduled for different ICEEG coverage. Twenty-eight have gone to ICEEG, 29 to resection, and 14 to vagal nerve stimulation, including 17 where MSI changed the decision. Additional electrodes in 4 patients covered the correct: hemisphere in 3, lobe in 3, and sublobar ictal onset zone in 1. MSI avoided contralateral electrodes in 2, who both localized on ICEEG. MSI added information to ICEEG in 1.Conclusion: Magnetic source imaging (MSI) provided nonredundant information in 33% of patients. In those who have undergone surgery to date, MSI added useful information that changed treatment in 6 (9%), without increasing complications. MSI has benefited 21% who have gone to surgery.

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