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Time course of diffusion imaging in acute brainstem infarcts
Author(s) -
Axer Hubertus,
Gräβel David,
Brämer Dirk,
Fitzek Sabine,
Kaiser Werner A.,
Witte Otto W.,
Fitzek Clemens
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21088
Subject(s) - brainstem , fractional anisotropy , diffusion mri , effective diffusion coefficient , medicine , lesion , ischemia , nuclear medicine , magnetic resonance imaging , radiology , cardiology , pathology
Purpose To study the time course of diffusion imaging at the lesion site in brainstem infarcts. Materials and Methods Sequential MR scans were acquired from 24 patients with brainstem infarcts. Diffusion‐weighted images (DWI), T 2 ‐weighted images ( T 2 w), maps of apparent diffusion coefficient, and maps of fractional anisotropy were generated from each MR scan. A trend function was fitted to these measurements to model an objective, general time course of the studied parameters. Results Apparent diffusion coefficient (ADC) continuously decreased over time until a transition time around 45 hours; afterwards a continuous increase took place. After the 14th day ADC reached values similar to the ADC of the intact contralateral side (pseudonormalization) and then further increased. Fractional anisotropy (FA) decreased continuously over 3 to 6 months. Conclusion Times of transition and pseudonormalization of ADC were longer than described for territorial hemispheric infarcts and describe the acute to subacute phase of brainstem ischemia. In contrast, the continuous decline of FA over 3 to 6 months indicates a chronic process of change of histological structures in brainstem ischemia, and may be regarded as an indicator of the chronic phase. J. Magn. Reson. Imaging 2007;26:905–912. © 2007 Wiley‐Liss, Inc.