MRI Pattern Recognition in Multiple Sclerosis Normal-Appearing Brain Areas

Objective Here, we use pattern-classification to investigate diagnostic information for multiple sclerosis (MS; relapsing­remitting type) in lesioned areas, areas of normal­appearing grey matter (NAGM), and normal-appearing white matter (NAWM) as measured by standard MR techniques. Methods A lesion mapping was carried out by an experienced neurologist for Turbo Inversion Recovery Magnitude (TIRM) images of individual subjects. Combining this mapping with templates from a neuroanatomic atlas, the TIRM images were segmented into three areas of homogenous tissue types (Lesions, NAGM, and NAWM) after spatial standardization. For each area, a linear Support Vector Machine algorithm was used in multiple local classification analyses to determine the diagnostic accuracy in separating MS patients from healthy controls based on voxel tissue intensity patterns extracted from small spherical subregions of these larger areas. To control for covariates, we also excluded group-specific biases in deformation fields as a potential source of information. Results Among regions containing lesions a posterior parietal WM area was maximally informative about the clinical status (96% accuracy, p<10−13). Cerebellar regions were maximally informative among NAGM areas (84% accuracy, p<10−7). A posterior brain region was maximally informative among NAWM areas (91% accuracy, p<10−10). Interpretation We identified regions indicating MS in lesioned, but also NAGM, and NAWM areas. This complements the current perception that standard MR techniques mainly capture macroscopic tissue variations due to focal lesion processes. Compared to current diagnostic guidelines for MS that define areas of diagnostic information with moderate spatial specificity, we identified hotspots of MS associated tissue alterations with high specificity defined on a millimeter scale

Post mortem magnetic resonance imaging in the fetus, infant and child: A comparative study with conventional autopsy (MaRIAS Protocol)

<p>Abstract</p> <p>Background</p> <p>Minimally invasive autopsy by post mortem magnetic resonance (MR) imaging has been suggested as an alternative for conventional autopsy in view of the declining consented autopsy rates. However, large prospective studies rigorously evaluating the accuracy of such an approach are lacking. We intend to compare the accuracy of a minimally invasive autopsy approach using post mortem MR imaging with that of conventional autopsy in fetuses, newborns and children for detection of the major pathological abnormalities and/or determination of the cause of death.</p> <p>Methods/Design</p> <p>We recruited 400 consecutive fetuses, newborns and children referred for conventional autopsy to one of the two participating hospitals over a three-year period. We acquired whole body post mortem MR imaging using a 1.5 T MR scanner (Avanto, Siemens Medical Solutions, Enlargen, Germany) prior to autopsy. The total scan time varied between 90 to 120 minutes. Each MR image was reported by a team of four specialist radiologists (paediatric neuroradiology, paediatric cardiology, paediatric chest & abdominal imaging and musculoskeletal imaging), blinded to the autopsy data. Conventional autopsy was performed according to the guidelines set down by the Royal College of Pathologists (UK) by experienced paediatric or perinatal pathologists, blinded to the MR data. The MR and autopsy data were recorded using predefined categorical variables by an independent person.</p> <p>Discussion</p> <p>Using conventional post mortem as the gold standard comparator, the MR images will be assessed for accuracy of the anatomical morphology, associated lesions, clinical usefulness of information and determination of the cause of death. The sensitivities, specificities and predictive values of post mortem MR alone and MR imaging along with other minimally invasive post mortem investigations will be presented for the final diagnosis, broad diagnostic categories and for specific diagnosis of each system.</p> <p>Clinical Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT01417962">NCT01417962</a></p> <p><b>NIHR Portfolio Number: </b>6794</p

Functional expression of CXCR3 in cultured mouse and human astrocytes and microglia

It has been established recently that inflammation of the CNS is accompanied by an expression of chemokines within the CNS. Several lines of evidence suggest that chemokines within the CNS initiate and orchestrate the infiltration of the inflamed brain by blood leukocytes. It is also known that endogenous cells of the CNS express functional chemokine receptors, raising the possibility that chemokines may be involved in intercellular signalling between brain cells during brain inflammation. It was shown recently that two chemokine ligands for CXCR3 are induced rapidly in damaged neurons. Little is known yet on the function of neuronal chemokine expression. In order to investigate whether neuronal chemokines contribute to endogenous signalling within the CNS we investigated possible expression of CXCR3 in glial cells. Reverse transcription-polymerase chain reaction experiments and in situ hybridization analysis showed that cultured astrocytes and microglia from both mouse and human sources express CXCR3 mRNA. Protein expression of CXCR3 in both cell types was detected by immunocytochemistry. Moreover, stimulation of cultured glial cells with chemokine ligands for CXCR3 induced intracellular calcium transients and chemotaxis, indicating the functional expression of CXCR3. These results indicate that glial cells in culture functionally express the chemokine receptor CXCR3. Since it has been shown that brain damage rapidly induces expression of neuronal chemokines that activate CXCR3, we suggest that glial CXCR3 might contribute to an intercellular signalling system in the CNS related to pathological conditions. (C) 2002 IBRO. Published by Elsevier Science Ltd. All rights reserved