Perfusion MRI demonstrates crossed-cerebellar diaschisis in sickle cell disease.

Arterial spin labeling is a fully noninvasive magnetic resonance perfusion imaging method, ideally suited to pediatric perfusion imaging. We describe an 8-year-old boy with sickle cell disease, extensive right-hemispheric cerebral infarction, and crossed-cerebellar diaschisis apparent on arterial spin labeling perfusion magnetic resonance imaging. To our knowledge, this is the first case of crossed-cerebellar diaschisis demonstrated with arterial spin labeling, highlighting the potential value of perfusion magnetic resonance imaging in the clinical evaluation and follow-up of crossed-cerebellar diaschisis, and the suitability of arterial spin labeling methods for routine perfusion imaging in pediatric patients.

A longitudinal study of diffusion tensor MRI in ALS.

In this study, we investigated whether diffusion tensor MRI (DTI) could detect progressive corticospinal tract degeneration in amyotrophic lateral sclerosis (ALS) and whether changes in diffusion variables reflected clinical deterioration. Twenty-three ALS patients and 25 healthy volunteers underwent whole brain DTI. Patients and a subset (n = 12) of controls returned for a second scan. Clinical measures of disease severity were assessed in the ALS group. Changes in fractional anisotropy (FA) and mean diffusivity (MD) were measured along the corticospinal tract using a region of interest approach. Adequate DTI data were available in 11 ALS patients and 11 controls at two time points. FA and MD differed significantly between ALS patients and controls at both time points, but neither changed significantly over time, while global measures of disease severity in patients increased with time. Although we confirmed that DTI detects corticospinal tract damage in ALS, there were no significant changes in diffusion measures over time. The sensitivity of DTI may be improved by advanced data analysis techniques, although the high dropout rate suggests that use of MRI as a biomarker in ALS may be restricted to earlier stages of disease.

Interictal temporal delta activity in temporal lobe epilepsy: correlations with pathology and outcome.

PURPOSE: To determine the characteristics and the clinical significance of focal slow activity and its association with focal epileptogenesis in patients with temporal lobe epilepsy (TLE). METHODS: We analyzed the interictal EEGs of 141 patients who had temporal lobe resections for intractable focal seizures and correlated the findings with pathologic changes and outcome. The pathologic changes were categorized into medial temporal sclerosis, tumors, and nonspecific changes. RESULTS: Lateralized slow activity was found in 66% of the patients, and it was mainly temporal, of delta frequency and irregular morphology. None of its characteristics, including quantity and reactivity to eye opening, was substrate specific. It was highly concordant with temporal spiking (60%), without any difference across the three groups, but provided additional information in 19 (15%) patients who had no lateralizing spikes. The effect of sleep also was similar in all three groups and included transition of slow waves into spikes. Lateralized slow activity to the side of the operation was significantly associated with favorable outcome only in the group with nonspecific pathology (p = 0.008), regardless of the presence, laterality, or topography of spikes. CONCLUSIONS: Our findings suggest that in patients with TLE whose brain magnetic resonance imaging (MRI) is either normal or suggestive of medial temporal sclerosis, interictal temporal slow activity has a lateralizing value similar to that of temporal spiking. Its association with a favorable outcome in patients with nonspecific pathology also suggests that candidates with lateralizing temporal delta and normal MRI should not be barred from further preoperative assessment.

Registered computed tomography images as an alternative to postimplantation magnetic resonance imaging in the assessment of subthalamic electrode placement.

Magnetic resonance imaging (MRI) after implantation of electrodes in the subthalamic nuclei is currently performed at a number of sites, but a recent adverse incident and changes in MRI technology may heighten safety concerns. In this report, it is demonstrated that given whole-head image data, registration of postimplantation computed tomography to preimplantation MRI can enable verification of the position of electrodes to an accuracy of 2 mm. This registration technique can remove the need for potentially risky postoperative MRI.

Nonsyndromic mental retardation and cryptogenic epilepsy in women with doublecortin gene mutations.

DCX mutations cause mental retardation in male subjects with lissencephalypachygyria and in female subjects with subcortical band heterotopia (SBH). We observed four families in which carrier women had normal brain magnetic resonance imaging (MRI) and mild mental retardation, with or without epilepsy. Affected male subjects had SBH or pachygyria-SBH. In two families, the phenotype was mild in both genders. In the first family, we found a tyr138his mutation that is predicted to result in abnormal folding in the small hinge region. In the second family, we found an arg178cys mutation at the initial portion of R2, in the putative beta-sheet structure. Carrier female subjects with normal MRI showed no somatic mosaicism or altered X-inactivation in lymphocytes, suggesting a correlation between mild mutations and phenotypes. In the two other families, with severely affected boys, we found arg76ser and arg56gly mutations within the R1 region that are predicted to affect DCX folding, severely modifying its activity. Both carrier mothers showed skewed X-inactivation, possibly explaining their mild phenotypes. Missense DCX mutations may manifest as non-syndromic mental retardation with cryptogenic epilepsy in female subjects and SBH in boys. Mutation analysis in mothers of affected children is mandatory, even when brain MRI is normal.