Canadian Expert Panel Recommendations for MRI Use in MS Diagnosis and Monitoring.

BACKGROUND: A definitive diagnosis of multiple sclerosis (MS), as distinct from a clinically isolated syndrome, requires one of two conditions: a second clinical attack or particular magnetic resonance imaging (MRI) findings as defined by the McDonald criteria. MRI is also important after a diagnosis is made as a means of monitoring subclinical disease activity. While a standardized protocol for diagnostic and follow-up MRI has been developed by the Consortium of Multiple Sclerosis Centres, acceptance and implementation in Canada have been suboptimal. METHODS: To improve diagnosis, monitoring, and management of a clinically isolated syndrome and MS, a Canadian expert panel created consensus recommendations about the appropriate application of the 2010 McDonald criteria in routine practice, strategies to improve adherence to the standardized Consortium of Multiple Sclerosis Centres MRI protocol, and methods for ensuring effective communication among health care practitioners, in particular referring physicians, neurologists, and radiologists. RESULTS: This article presents eight consensus statements developed by the expert panel, along with the rationale underlying the recommendations and commentaries on how to prioritize resource use within the Canadian healthcare system. CONCLUSIONS: The expert panel calls on neurologists and radiologists in Canada to incorporate the McDonald criteria, the Consortium of Multiple Sclerosis Centres MRI protocol, and other guidance given in this consensus presentation into their practices. By improving communication and general awareness of best practices for MRI use in MS diagnosis and monitoring, we can improve patient care across Canada by providing timely diagnosis, informed management decisions, and better continuity of care.

Teaching NeuroImages: neurodegeneration with brain iron accumulation in aceruloplasminemia.

A 55-year-old African Canadian man with insulin-dependent diabetes mellitus and alcohol abuse presented with diabetic ketoacidosis. Progressive cognitive decline over the previous 5 years resulted in long-term care placement. Aside from pigmentary retinopathy, general examination was unremarkable. MRI demonstrated iron accumulation in the brain (figure 1) and liver (figure 2A). Ceruloplasmin, a ferroxidase enzyme important in iron homeostasis, was undetectable and associated with low serum iron, low serum copper, and 10-fold increase in serum ferritin. Liver biopsy confirmed increased hepatocyte iron storage (figure 2B). Aceruloplasminemia was diagnosed.(1,2) Iron chelation was not administered given advanced dementia at presentation.

A longitudinal study on the effects of typical versus atypical antipsychotic drugs on hippocampal volume in schizophrenia.

BACKGROUND: Previous studies have reported that hippocampal volumes correlate with symptom severity in schizophrenia. This longitudinal study measured changes in symptoms and hippocampal volume in patients switched from typical antipsychotics to olanzapine. METHODS: MRI scans were acquired from patients with chronic schizophrenia (n=10) and healthy volunteers (n=20). At baseline, patients were treated with typical antipsychotics for at least one year, then switched to olanzapine, and rescanned approximately one year later. RESULTS: Olanzapine treatment resulted in no significant change in right or left hippocampal volume. Individual changes in right hippocampal volume correlated significantly with changes in symptoms. CONCLUSIONS: Hippocampal volume change may serve as a marker of symptom change in patients on olanzapine.

Reduced thalamic volume in patients with chronic schizophrenia after switching from typical antipsychotic medications to olanzapine.

OBJECTIVE: The authors performed a longitudinal study of the effects on thalamic volume of switching from typical to atypical antipsychotic medications. METHOD: Magnetic resonance imaging scans were acquired from 10 subjects with chronic schizophrenia taking typical antipsychotics and 20 healthy volunteers. Subjects with schizophrenia were switched to olanzapine; both groups were rescanned. RESULTS: At baseline, thalamic volumes in subjects with chronic schizophrenia were 5.8% greater than those of healthy volunteers. At follow-up, there was no significant difference between groups. Additional analysis revealed a significant positive correlation between baseline thalamic volume and dosage of typical antipsychotic medication. Higher dosages at baseline were correlated with larger reductions in volume after the switch to olanzapine. CONCLUSIONS: Antipsychotic medication effects may be a factor in the wide range of thalamic volume differences reported between subjects with schizophrenia and healthy volunteers.

Reduced basal ganglia volumes after switching to olanzapine in chronically treated patients with schizophrenia.

OBJECTIVE: A follow-up study of patients with schizophrenia was conducted to examine change in striatal volumes and extrapyramidal symptoms after a change in medication. METHOD: Thirty-seven patients with schizophrenia and 23 healthy volunteers were examined. Patients at baseline receiving typical antipsychotics (N=10) or risperidone but exhibiting limited response (N=13) were switched to treatment with olanzapine. Patients receiving risperidone and exhibiting a good response (N=14) continued treatment with risperidone. Caudate, putamen, and pallidal volumes were assessed with magnetic resonance imaging. The Extrapyramidal Symptoms Rating Scale was used to assess clinical signs and symptoms. RESULTS: At baseline, basal ganglia volumes in patients treated with typical antipsychotics were greater than in healthy subjects (putamen: 7.0% larger; globus pallidus: 20.7% larger). After the switch to olanzapine, putamen and globus pallidus volumes decreased (9.8% and 10.7%, respectively) and did not differ from those of healthy subjects at the follow-up evaluation. Akathisia was also reduced. In the patients receiving risperidone at baseline, basal ganglia volumes did not differ between those exhibiting good and poor response, and no significant volume changes were observed in subjects with poor risperidone response after the switch to olanzapine treatment. CONCLUSIONS: Olanzapine reversed putamen and globus pallidus enlargement induced by typical antipsychotics but did not alter volumes in patients previously treated with risperidone. Changes in striatal volumes related to typical and atypical antipsychotics may represent an interactive effect between individual medications and unique patient characteristics.

Gradients of detection in neglect: comparison of peripersonal and extrapersonal space.

Previous studies of target-cancellation performance in visuospatial neglect patients have reported lateral (left-right) and radial (near-far) gradients of attentional ability. The purpose of the present study was to replicate the reported attentional gradients in peripersonal space (within arms reach) and to examine whether lateral gradients of detection also appear in extrapersonal space (beyond arms reach), using equivalent tasks with no manual requirement. The relationship between radial gradients in peripersonal space and neglect severity (degree of lateral gradient) in extrapersonal space was also of interest. Right-hemisphere stroke subjects, with and without neglect, and healthy control subjects named visual targets on scanning sheets placed in peripersonal and extrapersonal space. The neglect group showed lateral gradients of increasing target detection from left to right in both peripersonal and extrapersonal space, which were not evident in the performance of either of the control groups. Double dissociations of neglect severity in peripersonal and extrapersonal space were also found in analyses of individual performance. Lesion analyses showed that peripersonal neglect was related to dorsal stream damage and extrapersonal neglect was related to ventral stream damage. Group analyses showed no significant radial gradients in peripersonal space in the three groups. In addition, while analyses of some individuals found significant near-far and far-near radial gradients, there was no correlation between radial gradients in peripersonal space and neglect severity in extrapersonal space. These results are discussed in terms of theorised hemispheric mechanisms of spatial attention and the relationship of neglect in the two co-ordinate spaces to the extent and location of damaged neurons in the right hemisphere.