This Article Full Text Full Text (PDF) All Versions of this Article: 33/12/2736    most recent 01.STR.0000041999.64363.B2v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lev, M. H. Articles by Tatlisumak, T. Search for Related Content PubMed PubMed Citation Articles by Lev, M. H. Articles by Tatlisumak, T.

(Stroke. 2002;33:2736.)
© 2002 American Heart Association, Inc.

Letters to the Editor

CT or MRI for Imaging Patients with Acute Stroke: Visualization of "Tissue at Risk"?

Department of Neuroradiology

Walter J. Koroshetz, MD Lee H. Schwamm, MD

Department of Neurology

R. Gilberto Gonzalez, MD, PhD

Department of Neuroradiology, Massachusetts General Hospital, Boston, Massachusetts

An extract of the first 250 words of the full text is provided, because this article has no abstract.

To the Editor:

In a recent Stroke editorial weighing the relative merits of CT versus MRI for imaging patients with acute stroke, Tatlisumak raises a number of important and compelling points.¹ Among these, however, is the statement—with regard to using MR perfusion-diffusion mismatch in order to identify treatable "tissue at risk"—that a "similar approach does not yet exist for CT imaging." We wish to call attention to preliminary results suggesting that such an approach may, indeed, currently exist using CT perfusion imaging.^2,3 Specifically, pilot studies in patients with middle cerebral artery stroke have revealed that, like diffusion-weighted imaging, CT cerebral blood volume maps may delineate ischemic regions with a high probability of being already infarcted by the time of image acquisition.^4–6 Quantitation of cerebral blood flow (CBF) and mean transit time with the bolus tracking technique should be more accurate using CT, rather than MR methodology, because signal change is linearly proportional to dye concentration with CT, but not with MR, and because CT images typically have higher spatial resolution. The poor specificity of MR perfusion maps has taught us that quantitative CBF thresholds are necessary to identify tissue that is still salvageable but destined for infarction without early reperfusion.² The restriction of CT CBF and mean transit time maps to a predetermined slab of tissue (typically 2 cm of coverage per contrast bolus) remains CT’s major limitation. Diffusion-weighted imaging also remains necessary to identify early brain stem and small infarcts.⁶ We would argue that, given the current published capability of a quick . . . [Full Text of this Article]

Turgut Tatlisumak, MD, PhD

Department of Neurology, Helsinki University Central Hospital, Helsinki, Finland

This article has been cited by other articles:

				E.S. Rosenthal, L.H. Schwamm, L. Roccatagliata, S.B. Coutts, A.M. Demchuk, P.W. Schaefer, R.G. Gonzalez, M.D. Hill, E.F. Halpern, and M.H. Lev Role of Recanalization in Acute Stroke Outcome: Rationale for a CT Angiogram-Based "Benefit of Recanalization" Model AJNR Am. J. Neuroradiol., September 1, 2008; 29(8): 1471 - 1475. [Abstract] [Full Text] [PDF]

				L. R. Caplan Stroke Thrombolysis: Slow Progress Circulation, July 18, 2006; 114(3): 187 - 190. [Full Text] [PDF]

				M. H. Lev CT versus MR for Acute Stroke Imaging: Is the "Obvious" Choice Necessarily the Correct One? AJNR Am. J. Neuroradiol., November 1, 2003; 24(10): 1930 - 1931. [Full Text] [PDF]