The Value of Apparent Diffusion Coefficient Maps in Early Cerebral Ischemia
Patricia M. Desmonda,
Amanda C. Lovella,
Andrew A. Rawlinsona,
Mark W. Parsonsa,
P. Alan Barbera,
Qing Yanga,
Ting Lia,
David G. Darbya,
Richard P. Gerratya,
Steven M. Davisa and
Brian M. Tressa
a From the Departments of Radiology (P.M.D., A.C.L., A.A.R., Q.Y., T.L., B.M.T.) and Neurology (M.W.P., P.A.B., D.G.D., R.P.G., S.M.D.), Royal Melbourne Hospital and University of Melbourne, Victoria, Australia.
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FIG 1. Regions of abnormality were identified on the TTP (A), T2 outcome (B), and the acute diffusion-weighted scans (C) using region-growing techniques. These were transferred on to the acute ADC map (D), and the region of expansion of the infarct was generated (black outline, right). The region was reflected about the midline axis and regrown to enclose just brain tissue (D, two black regions, left). The region of infarct expansion has reduced ADCs (D, white arrow) compared with the contralateral region and hazy, subtle change on the diffusion-weighted images (C, black arrow)
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FIG 2. Graph of mean rADC against region
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FIG 3. Infarct expansion. Patient 13 presented 1 hour 30 minutes, after stroke onset. Acute diffusion-weighted images (A) show small region of hyperintensity (black outline). There was a large area of altered perfusion on the TTP map (C). Extensive regions of lowered ADC values are seen on the colored ADC map (B, white arrow) in the regions that progress to infarction (D, subacute scan). (Outcome scan was not available for this patient.) In retrospect, hazy, ill-defined change is seen on the acute diffusion-weighted image (A, black arrowhead)
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FIG 4. Minor infarct expansion. Patient 10 presented 3 hours after stroke onset. The initial diffusion-weighted imaging lesion (A) was well defined and only minimally underestimated the final infarct size of the outcome scan (D). A large region of altered perfusion was present on the TTP (C). The larger regions of penumbral preservation show normal ADC values (B, white arrows)
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FIG 5. Histogram analysis of the region of infarct expansion (expansion) and the same region in the normal hemisphere (expansion flip) for patient 13. The curve is shifted to the left with a reduction in the mean ADC value.FIG 6. Histogram analysis of the region of penumbral preservation (no expansion) and the comparative region in the normal hemisphere (no expansion flip) for patient 10. The curves are similar
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FIG 7. Grouped data.
A, All regions. Only the region of infarct expansion shows a different distribution of ADC values.
B, The regions of infarct expansion have lowered ADC values compared with similar regions in the normal hemisphere.
C, The distribution of the ADC values in regions of penumbral preservation is the same as in the contralateral hemisphere.
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