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The Need for Objective Assessment of the New Imaging Techniques and Understanding the Expanding Roles of Stroke Imaging

William T. C. YuhGo,a, Toshihiro Uedaa, Matthew Whitea, Michael E. Schustera and Toshiaki Taokaa

a From the Department of Radiology, University of Iowa Hospital, Iowa City.



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  		FIG 1. A, T2-weighted (top), diffusion-weighted (middle), and perfusion-weighted (TTP) (bottom) images obtained 2.5 hours after onset of symptoms. T2 and diffusion findings are negative, but profound perfusion abnormality (hyperintensity) of the right hemisphere is shown.

B, 3-day follow-up T2-weighted (top), diffusion-weighted (middle), and perfusion-weighted (bottom) images (rCBV, max {Delta}R2*, and TTP) show large right anterior and middle cerebral artery infarctions.

(Courtesy of Michael E. Moseley, Stanford University.)



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  		FIG 2. 72 hours after the onset of stroke symptoms in a patient with vasculitis.

A, T2-weighted MR image shows bilateral posterior watershed lesions (arrows).

B, The ADC map also shows bilateral posterior watershed lesions (arrowheads), but both lesions are larger than those seen on T2-weighted images (A).

C, The rMTT map shows hypoperfusion (hyperintensity) of both posterior watershed territories (arrowheads).

D, The rCBV map shows only a left-sided lesion (arrow), including posterior watershed and part of the posterior cerebral artery territory (arrowhead).

E, The 16-month follow-up T2-weighted image confirmed small left posterior watershed infarction (arrow) and new infarction at the territory of the left posterior cerebral artery (arrowhead), which was not apparent on initial T2-weighted image (A) or ADC map (B) but was partially visible on rCBV map (D). The abnormality of the right posterior watershed area initially demonstrated on the T2-weighted image (A) and ADC map (B) did not develop into infarction (E). It was accurately predicted by the rCBV map whereas the T2-weighted image and ADC map were falsely positive. The left posterior cerebral artery infarction (arrowhead) was partially diagnosed by the rCBV map, but the ADC map and T2-weighted images were falsely negative.

(Permission granted from the AJNR 20:983–989, June/July 1999.)



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  		FIG 3. A, T2-weighted (top) and diffusion-weighted (middle) as well as ADC map (bottom) obtained 11 hours after onset of symptoms show normal T2 and abnormal diffusion (hyperintensity). ADC findings (hypointensity) are in the left parietal lobe of the ADC map.

B, T2-weighted (top) and diffusion-weighted images (middle) and ADC map (bottom) obtained 35 hours after onset of symptoms show disappearance of the abnormality previously noted on diffusion-weighted image and ADC map obtained at 11 hours (A) and persistent normal T2. These imaging findings are consistent with the resolution of clinical symptoms.

(Courtesy of Michael E. Moseley, Stanford University.)





Copyright © 2009 by the American Society of Neuroradiology. Print ISSN: 0195-6108 Online ISSN: 1936-959X