Development of brain infarct volume as assessed by magnetic resonance imaging (MRI): Follow‐up of diffusion‐weighted MRI lesions
ABSTRACT PurposeTo investigate the development of ischemic brain lesions, as present in the acute stroke phase, by diffusion-weighted magnetic resonance imaging (DWI), and in the subacute and chronic phases until up to four months after stroke, in fluid-attenuated inversion recovery (FLAIR)- and T2-weighted (T2W) magnetic resonance (MR) images.Materials and Methods
Twelve consecutive patients with their first middle cerebral artery (MCA) infarction were included. Lesion volumes were assessed on T2W images recorded with a turbo spin echo (TSE) and on images recorded with the FLAIR sequence on average on day 8 and after about four months. They were compared with acute lesion volumes in perfusion and DWI images taken within 24 hours of stroke onset.ResultsOn day 8, lesion volumes in images obtained with FLAIR exceeded the acute infarct volumes in DWI. The chronic lesion volumes were almost identical in T2W and FLAIR images but significantly reduced compared with the acute DWI lesions. The lesion volumes assessed on DWI images correlated highly with the lesions in the images obtained with TSE or FLAIR, as did the lesions in the images obtained with FLAIR and TSE. The secondary lesion shrinkage was accompanied by ventricular enlargement and perilesional sulcal widening, as most clearly visible in the images obtained with FLAIR.Conclusion
Our results show that the acute DWI lesions are highly predictive for the infarct lesion in the chronic stage after stroke despite a dynamic lesion evolution most evident in MR images obtained with FLAIR. J. Magn. Reson. Imaging 2004;20:201–207. © 2004 Wiley-Liss, Inc.
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ABSTRACT: After cerebral ischemia, disruption and subsequent reorganization of functional connections occur both locally and remote to the lesion. However, the unpredictable timing and extent of sensorimotor recovery reflects a gap in understanding of these underlying neural mechanisms. We aimed to identify the plasticity of alpha-band functional neural connections within the perilesional area and the predictive value of functional connectivity with respect to motor recovery of the upper extremity after stroke. Our results show improvements in upper extremity motor recovery in relation to distributed changes in MEG-based alpha band functional connectivity, both in the perilesional area and contralesional cortex. Motor recovery was found to be predicted by increased connectivity at baseline in the ipsilesional somatosensory area, supplementary motor area, and cerebellum, contrasted with reduced connectivity of contralesional motor regions, after controlling for age, stroke onset-time and lesion size. These findings support plasticity within a widely distributed neural network and define brain regions in which the extent of network participation predicts post-stroke recovery potential.Experimental Neurology 06/2012; 237(1):160-9. · 4.65 Impact Factor
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ABSTRACT: By probing microscopic molecular motions, diffusion-weighted imaging (DWI) is the only method available today that provides noninvasively information on molecular displacements over distances comparable to cell dimensions. Since it measures a parameter different from those assessed by conventional MRI, DWI represents a new imaging technique that goes beyond depiction of neuroanatomy and evaluates function and physiopathology. Image contrast is related to differences in the diffusion rate of water molecules rather than to changes in total tissue water. DWI has proven its high sensitivity in early detection of acute infarction; it is reliable in differentiating acute stroke from other diseases that mimic acute stroke in clinical terms and on conventional MR images. By differentiating lesions with decreased diffusion from those with increased diffusion, DWI is useful in the evaluation of a wide variety of other disease processes including neoplasms, demyelization, traumatic brain injury, intracranial infections. In particular, DWI can distinguish between epidermoid and arachnoid cysts and provides key information for the diagnosis of cerebral abscess. In some clinical situations, DWI data have a prognostic value.EMC - Radiologie 01/2005; 2(2):133-164.
- Handbook of Clinical Neurology 01/2008; 94:1097-1117.