BACKGROUND AND PURPOSE: Focal cerebral ischemia results in neuronal changes in remote areas that have fiber connections with the ischemic area. We reported previously that a high-signal-intensity lesion was observed in the substantia nigra after striatal infarction on T2-weighted MR images in both clinical and experimental cases. However, the origin of these changes in signal intensity remains unclear. The aim of this study was to investigate the nigral changes by examining the correlation between the apparent diffusion coefficient (ADC) and the tissue structure. METHODS: Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Four days after the occlusion, when T2-weighted images revealed the presence of an area of high signal intensity in the ipsilateral substantia nigra, diffusion-weighted imaging was performed using a 4.7-T superconductive MR unit, and the ADCs were calculated and imaged. Histopathologic examination by both light and electron microscopy was performed on day 4 after surgery. RESULTS: Diffusion-weighted images showed an area of high signal intensity in the ipsilateral substantia nigra, and the ADC map revealed uniform reduction of the ADC in this area. Swelling of astrocytic end-feet was observed, especially in the pars reticulata. CONCLUSION: These findings suggest that MR changes in the ipsilateral substantia nigra after striatal injury consist mainly of swelling in the astrocytic end-feet.
BACKGROUND AND PURPOSE: Focal cerebral ischemia results in neuronal changes in remote areas that have fiber connections with the ischemic area. We reported previously that a high-signal-intensity lesion was observed in the substantia nigra after striatal infarction on T2-weighted MR images in both clinical and experimental cases. However, the origin of these changes in signal intensity remains unclear. The aim of this study was to investigate the nigral changes by examining the correlation between the apparent diffusion coefficient (ADC) and the tissue structure. METHODS:Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Four days after the occlusion, when T2-weighted images revealed the presence of an area of high signal intensity in the ipsilateral substantia nigra, diffusion-weighted imaging was performed using a 4.7-T superconductive MR unit, and the ADCs were calculated and imaged. Histopathologic examination by both light and electron microscopy was performed on day 4 after surgery. RESULTS: Diffusion-weighted images showed an area of high signal intensity in the ipsilateral substantia nigra, and the ADC map revealed uniform reduction of the ADC in this area. Swelling of astrocytic end-feet was observed, especially in the pars reticulata. CONCLUSION: These findings suggest that MR changes in the ipsilateral substantia nigra after striatal injury consist mainly of swelling in the astrocytic end-feet.
Authors: R M Dijkhuizen; S Knollema; H B van der Worp; G J Ter Horst; D J De Wildt; J W Berkelbach van der Sprenkel; K A Tulleken; K Nicolay Journal: Stroke Date: 1998-03 Impact factor: 7.914
Authors: J Mintorovitch; G Y Yang; H Shimizu; J Kucharczyk; P H Chan; P R Weinstein Journal: J Cereb Blood Flow Metab Date: 1994-03 Impact factor: 6.200
Authors: D Hervé; N Molko; S Pappata; F Buffon; D LeBihan; M-G Bousser; H Chabriat Journal: J Neurol Neurosurg Psychiatry Date: 2005-02 Impact factor: 10.154
Authors: K Kamiya; N Sato; Y Nakata; K Ito; Y Kimura; M Ota; A Takahashi; H Mori; A Kunimatsu; K Ohtomo Journal: AJNR Am J Neuroradiol Date: 2012-08-16 Impact factor: 3.825
Authors: Benjamin Winter; Peter Brunecker; Jochen B Fiebach; Gerhard Jan Jungehulsing; Golo Kronenberg; Matthias Endres Journal: PLoS One Date: 2015-09-01 Impact factor: 3.240