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Experimental Studies |
1 From the Department of Morphological-Biomedical Sciences, Institute of Anatomy and Histology, University of Verona, Medical Faculty, Strada Le Grazie 8, 37134 Verona, Italy. Received July 25, 2000; revision requested September 7; final revision received January 22, 2001; accepted February 12. F.O. supported by Ministero dellUniversità e della Ricerca Scientifica e Tecnologica grant 9805406803. Address correspondence to A.B. (e-mail: sbarbati@borgoroma.univr.it).
PURPOSE: To evaluate whether the vascular system resulting from an arterial lesion shows differences in permeability to a tracer with respect to the normal vascular system and whether eventual differences are maintained for long periods.
MATERIALS AND METHODS: Permanent ischemia was induced in rats with femoral arterial removal, and magnetic resonance (MR) imaging was performed after 1, 7, 14, and 90 days. Gadopentetate dimeglumine was injected, and the kinetics of its penetration in the leg were studied. Phosphorus 31 spectroscopy was performed to determine the bioenergetic characteristics of the gastrocnemius muscle at rest and stimulation. Ischemic muscles were then processed for electron microscopy.
RESULTS: After ischemia induction, a hyperintense area that progressively decreased was present on T2-weighted images. Gadopentetate dimeglumine improved the signal intensity of the area. Three months after arterial occlusion, the contrast-enhanced images still showed microvessels highly permeable to the tracers. Spectroscopic data revealed that 3 months after arterial removal, the bioenergetic reserve of the gastrocnemius muscle was reduced, suggesting that the contrast-enhanced MR imagingvisible area is functionally relevant. Ultrastructural examination revealed persistent muscle damage and signs of chronic microangiopathy.
CONCLUSION: After ischemia induction, the restitutio ad integrum is not complete, and delayed muscle injuries can result from arterial insufficiency.
Index terms: Animals Magnetic resonance (MR), experimental studies Magnetic resonance (MR), spectroscopy, 92.12945 Magnetic resonance (MR), vascular studies, 92.12943, 92.12945, 92.12949 Muscles, blood supply, 92.769 Muscles, gastrocnemius, 45.91
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