The clinical-DWI mismatch -: A new diagnostic approach to the brain tissue at risk of infarction

Objective: To evaluate the usefulness of a mismatch between the severity of acute clinical manifestations and the diffusion-weighted imaging (DWI) lesion in predicting early stroke outcome and infarct volume. Methods: One hundred sixty-six patients with a hemispheric ischemic stroke of < 12 hours' duration were studied. The NIH Stroke Scale (NIHSS) score and the volume of DWI lesion were measured on admission and at 72 +/- 12 hours. Infarct volume was measured on T2-weighted or fluid-attenuated inversion recovery images at day 30. Early neurologic deterioration ( END) was defined as an increase of >= 4 points between the two NIHSS evaluations. Thirty-eight patients received IV thrombolysis or abciximab. Clinical - DWI mismatch (CDM) was defined as NIHSS score of >= 8 and ischemic volume on DWI of <= 25 mL on admission. The adjusted influence of CDM on END, DWI lesion enlargement at 72 hours, and infarct growth at day 30 was evaluated by logistic regression analysis and generalized linear models. Results: CDM was found in 87 patients (52.4%). Patients with CDM had a higher risk of END than patients without CDM because NIHSS < 8 ( odds ratio [ OR], 9.0; 95% CI, 1.9 to 42) or DWI lesion > 25 mL ( OR, 2.0; 95% CI, 0.8 to 4.9). CDM was associated with an increase of 46 to 68 mL in the mean volume of DWI lesion enlargement and infarct growth in comparison with non-CDM. All the effects were even greater and significant in patients not treated with reperfusion therapies. Conclusions: Acute stroke patients with an NIHSS score of greater than or equal to 8 and DWI volume of less than or equal to 25 mL have a higher probability of infarct growth and early neurologic deterioration. The new concept of CDM may identify patients with tissue at risk of infarction for thrombolytic or neuroprotective drugs.