Evolution of Apparent Diffusion Coefficient, Diffusion-weighted, and T2-weighted Signal Intensity of Acute Stroke
Maarten G. Lansberga,
Vincent N. Thijsa,
Michael W. O'Briena,
Juan O. Alia,
Alex J. de Crespignya,
David C. Tonga,
Michael E. Moseleya and
Gregory W. Albersa
a From the Stanford Stroke Center, Stanford University Medical Center, Palo Alto, CA (M.G.L., V.N.T., M.W.O., J.O.A., A.J.C., D.C.T., M.E.M. and G.W.A.); the Department of Neurology, UZ Gasthuisberg, Leuven, Belgium (V.N.T.); and the MGH-NMR Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA (A.J.C.).
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FIG 1. MR images (6000/210/1) at five subsequent time points in a 67-year-old woman with left hand weakness, left facial droop, and slurred speech. This example shows the typical evolution of the SIT2 (top row), SIFLAIR (second row), SIDWI (third row), ADCCONV (fourth row), and ADCFLAIR (bottom row) of an acute ischemic lesion (right hemisphere). On the ADC maps, the lesion is hypointense up to day 7 and hyperintense at 27 days, making it possible to differentiate the acute from the chronic lesion. On the DWI images, the lesion is hyperintense at all time points so that, by visual inspection, the signal intensity of the lesion on the acute scan cannot be differentiated from that on the chronic scan. On the T2-weighted and FLAIR images, lesion signal intensity increases up to day 4 and remains high thereafter. Note that at 27 days the lesion is more identifiable on the ADCFLAIR map than on the ADCCONV map
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FIG 2. Average relative lesion ADC values and signal intensities with 95% confidence intervals during five time intervals after onset of stroke symptoms.
A, rADCCONV, rADCFLAIR, and rSIDWI.
B, rSIT2 and rSIFLAIR (see Table 2 for the number of lesions included at each time interval).
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