FIG 5. Images in a 63-year-old woman with an onset of left-sided weakness 26 days before imaging. Regions 1 and 2 indicate the lesion ROI and control ROI, respectively.
A, Ratio DW image was computed as the 1000 times the ratio of the image with b = 1000 s/mm2 image divided by the image with b = 0 s/mm2. Image shows an infarct in the right frontal lobe with signal intensity (-33%) lower than that of the contralateral control tissue. This finding indicates increased tissue water motion in the infarct.
B, Fluid-suppressed image (b = 0 s/mm2, TEeff =101 milliseconds, TI = 2200 milliseconds) shows substantially increased signal intensity (+93%).
C, Standard DW image (b = 1000 s/mm2, TEeff = 101 milliseconds, TI = 2200 milliseconds) with both ADC and T2 effects shows increased signal intensity within the infarct (+30%). This is an example of a patient in period 3 (10–57 days). For patients imaged during this time period, the small negative effect of ADC on infarct signal intensity on DW images more than made up for by larger contribution of the increase of T2 to infarct signal intensity.
D, ADC map shows that infarct ADC is increased 55% over that of the control tissue.