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Separating changes in the intra‐ and extracellular water apparent diffusion coefficient following focal cerebral ischemia in the rat brain
Author(s) -
Silva Matthew D.,
Omae Tsuyoshi,
Helmer Karl G.,
Li Fuhai,
Fisher Marc,
Sotak Christopher H.
Publication year - 2002
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.10296
Subject(s) - chemistry , effective diffusion coefficient , extracellular , ischemia , extracellular fluid , nuclear magnetic resonance , nuclear medicine , magnetic resonance imaging , medicine , biochemistry , physics , radiology
Selective intracellular (IC) and extracellular (EC) brain water apparent diffusion coefficient (ADC) values were measured in normal and ischemic rat brain. Selective T 1 ‐relaxation enhancement of the EC water, using intracerebroventricular (ICV) infusion of an NMR contrast reagent (CR), was used to separate the IC and EC signal contributions. In the CR‐infused, normal brain (n = 4), T 1 = 235 ± 10 ms and T 2 = 46 ± 2 ms for IC water (85%) and T 1 = 48 ± 8 ms and T 2 = 6 ± 2 ms for EC water (15%). Volume‐localized ADC z (z‐gradient axis) values were 0.90 ± 0.02 (EC+IC), 0.81 ± 0.05 (IC), 0.51 ± 0.02 (EC+IC), and 0.53 ± 0.07 (IC), for normal, CR‐infused, ischemic, and ischemic/CR‐infused groups, respectively (ADC values are ×10 ‐3 mm 2 /s; n = 5 for each group). Imaging ADC z values were 0.81 ± 0.03 (EC+IC), 0.75 ± 0.05 (IC), 0.51 ± 0.04 (EC+IC), and 0.52 ± 0.05 (IC), respectively, for the same groups. Imaging ADC av (average diffusivity) values for the same groups were 0.70 ± 0.05 (EC+IC), 0.69 ± 0.06 (IC), 0.45 ± 0.06 (EC+IC), and 0.44 ± 0.06 (IC), respectively. These results suggest that the IC water ADC determines the overall water ADC value in normal and ischemic rat brain. Magn Reson Med 48:826–837, 2002. © 2002 Wiley‐Liss, Inc.