Published Online
on April 19, 2007

A more recent version of this article appeared on June 1, 2007

This Article Full Text (PDF) All Versions of this Article: 38/6/1820    most recent STROKEAHA.106.479154v1 Alert me when this article is cited Alert me if a correction is posted 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 Johnston, K. C. Search for Related Content PubMed PubMed Citation Articles by Johnston, K. C. Pubmed/NCBI databases Medline Plus Health Information Stroke Related Collections Health policy and outcome research CT and MRI Acute Cerebral Infarction

Submitted on November 30, 2006
Revised on January 10, 2007
Accepted on January 11, 2007

Validation of an Acute Ischemic Stroke Model. Does Diffusion-Weighted Imaging Lesion Volume Offer a Clinically Significant Improvement in Prediction of Outcome?

Karen C. Johnston MD, MSc^*; Douglas P. Wagner PhD; Xin-Qun Wang MS; George C. Newman MD; Vincent Thijs MD, PhD; Souvik Sen MD, MS; Steven Warach MD, PhD; for the GAIN, Citicoline, and ASAP Investigators

From the Departments of Neurology (K.C.J.) and Public Health Sciences (K.C.J., D.P.W., X.-Q.W.), University of Virginia, Charlottesville; the Department of Neurology (G.C.N.), Albert Einstein Medical Center, New York, NY; University Hospitals Leuven (V.T.), Leuven, Belgium; the Department of Neurology (S.S.), University of North Carolina at Chapel Hill; and the National Institute of Neurological Disorders and Stroke (S.W.), Bethesda, Md.

^* To whom correspondence should be addressed. E-mail: kj4v{at}virginia.edu.

Background and Purpose--Prediction models for ischemic stroke outcome have the potential to contribute prognostic information in the clinical and/or research setting. The importance of diffusion-weighted magnetic resonance imaging (DWI) in the prediction of clinical outcome, however, is unclear. The purpose of this study was to combine acute clinical data and DWI lesion volume for ischemic stroke patients to determine whether DWI improves the prediction of clinical outcome.

Methods--Patients (N=382) with baseline DWI data from the Glycine Antagonist In Neuroprotection and citicoline (010 and 018) trials were used to develop the prediction models by multivariable logistic regression. Data from prospectively collected patients (N=266) from the Acute Stroke Accurate Prediction Study were used to externally validate the model equations. The models predicted either full recovery or nursing home-level disability/death, as defined by the National Institutes of Health Stroke Scale, Barthel Index, or modified Rankin Scale.

Results--The full-recovery models with DWI lesion volume had areas under the receiver operating characteristic curves (AUCs) of 0.799 to 0.821, and those without DWI lesion volume had AUCs of 0.758 to 0.798. The nursing home-level disability/death models with DWI had AUCs of 0.832 to 0.882, and those without DWI had AUCs of 0.827 to 0.867. All models had mean absolute errors 0.4 for calibration.

Conclusions--All 12 models had excellent discrimination and calibration, with 8 of 12 meeting prespecified performance criteria (AUC 0.8, mean absolute error 0.4). Although DWI lesion volume significantly increased model explanatory power, the magnitude of increase was not large enough to be clinically important.

Key words: cerebral ischemia • prognosis • stroke outcome • models • statistical

This article has been cited by other articles:

				K. C. Johnston, C. E. Hall, B. M. Kissela, T. P. Bleck, M. R. Conaway, and for the GRASP Investigators Glucose Regulation in Acute Stroke Patients (GRASP) Trial: A Randomized Pilot Trial Stroke, December 1, 2009; 40(12): 3804 - 3809. [Abstract] [Full Text] [PDF]

				H. Ehrenreich, K. Weissenborn, H. Prange, D. Schneider, C. Weimar, K. Wartenberg, P. D. Schellinger, M. Bohn, H. Becker, M. Wegrzyn, et al. Recombinant Human Erythropoietin in the Treatment of Acute Ischemic Stroke Stroke, December 1, 2009; 40(12): e647 - e656. [Abstract] [Full Text] [PDF]

				K. M. Barrett, Y. H. Ding, D. P. Wagner, D. F. Kallmes, K. C. Johnston, and for the ASAP Investigators Change in Diffusion-Weighted Imaging Infarct Volume Predicts Neurologic Outcome at 90 Days: Results of the Acute Stroke Accurate Prediction (ASAP) Trial Serial Imaging Substudy Stroke, July 1, 2009; 40(7): 2422 - 2427. [Abstract] [Full Text] [PDF]

				J. L. Saver, G. W. Albers, B. Dunn, K. C. Johnston, M. Fisher, and for the STAIR VI Consortium Stroke Therapy Academic Industry Roundtable (STAIR) Recommendations for Extended Window Acute Stroke Therapy Trials Stroke, July 1, 2009; 40(7): 2594 - 2600. [Abstract] [Full Text] [PDF]

				K. C. Johnston, K. M. Barrett, Y. H. Ding, D. P. Wagner, and for the ASAP Investigators Clinical and Imaging Data at 5 Days as a Surrogate for 90-Day Outcome in Ischemic Stroke Stroke, April 1, 2009; 40(4): 1332 - 1333. [Abstract] [Full Text] [PDF]

				J. M. Wardlaw Surrogate Outcomes: A Cautionary Note Stroke, April 1, 2009; 40(4): 1029 - 1031. [Full Text] [PDF]

				M Uyttenboogaart, R E Stewart, P C Vroomen, G-J Luijckx, and J De Keyser Utility of the stroke-thrombolytic predictive instrument J. Neurol. Neurosurg. Psychiatry, September 1, 2008; 79(9): 1079 - 1081. [Abstract] [Full Text] [PDF]

				M. G. Lansberg, V. N. Thijs, R. Bammer, J.-M. Olivot, M. P. Marks, L. R. Wechsler, S. Kemp, and G. W. Albers The MRA-DWI Mismatch Identifies Patients With Stroke Who Are Likely to Benefit From Reperfusion Stroke, September 1, 2008; 39(9): 2491 - 2496. [Abstract] [Full Text] [PDF]