Lesion volume change after treatment with tissue plasminogen activator can discriminate clinical responders from nonresponders.

BACKGROUND AND PURPOSE: A change in acute-to-chronic lesion volume has been proposed as a biomarker for stroke therapies. The objectives of this study were to determine the magnitude of lesion volume change after standard treatment with tissue plasminogen activator and to determine whether specific volume change thresholds can discriminate clinical responders from nonresponders. METHODS: We measured lesion volume on diffusion weighted at baseline and on 90-day fluid attenuated inversion recovery MRI and scored 3-month modified Rankin Scale in consecutive patients treated with tissue plasminogen activator. We identified variables associated with excellent (modified Rankin Scale 0 to 1) and independent (modified Rankin Scale 0 to 2) outcomes. RESULTS: We included 53 patients (mean age 69 years, median baseline National Institutes of Health Stroke Scale score 7). The mean acute-to-chronic lesion volume increase was 11.7 (+/-7.7) cm(3). In 23 patients, the chronic lesion was smaller than the baseline lesion. At 3 months, 32 patients had an excellent clinical outcome. Dichotomous volume change variables associated with outcome included decrease in volume >or=30% (P=0.004) and volume increase >or=5 cm(3) (P=0.002). CONCLUSIONS: In patients given standard tissue plasminogen activator therapy, changes in lesion volume are associated with clinical outcome, and threshold lesion volumes can differentiate excellent and poor outcome, suggesting these as a potential marker of outcome.

Comparison of MRI and CT for detection of acute intracerebral hemorrhage.

CONTEXT: Noncontrast computed tomography (CT) is the standard brain imaging study for the initial evaluation of patients with acute stroke symptoms. Multimodal magnetic resonance imaging (MRI) has been proposed as an alternative to CT in the emergency stroke setting. However, the accuracy of MRI relative to CT for the detection of hyperacute intracerebral hemorrhage has not been demonstrated. OBJECTIVE: To compare the accuracy of MRI and CT for detection of acute intracerebral hemorrhage in patients presenting with acute focal stroke symptoms. DESIGN, SETTING, AND PATIENTS: A prospective, multicenter study was performed at 2 stroke centers (UCLA Medical Center and Suburban Hospital, Bethesda, Md), between October 2000 and February 2003. Patients presenting with focal stroke symptoms within 6 hours of onset underwent brain MRI followed by noncontrast CT. MAIN OUTCOME MEASURES: Acute intracerebral hemorrhage and any intracerebral hemorrhage diagnosed on gradient recalled echo (GRE) MRI and CT scans by a consensus of 4 blinded readers. RESULTS: The study was stopped early, after 200 patients were enrolled, when it became apparent at the time of an unplanned interim analysis that MRI was detecting cases of hemorrhagic transformation not detected by CT. For the diagnosis of any hemorrhage, MRI was positive in 71 patients with CT positive in 29 (P<.001). For the diagnosis of acute hemorrhage, MRI and CT were equivalent (96% concordance). Acute hemorrhage was diagnosed in 25 patients on both MRI and CT. In 4 other patients, acute hemorrhage was present on MRI but not on the corresponding CT--each of these 4 cases was interpreted as hemorrhagic transformation of an ischemic infarct. In 3 patients, regions interpreted as acute hemorrhage on CT were interpreted as chronic hemorrhage on MRI. In 1 patient, subarachnoid hemorrhage was diagnosed on CT but not on MRI. In 49 patients, chronic hemorrhage, most often microbleeds, was visualized on MRI but not on CT. CONCLUSION: MRI may be as accurate as CT for the detection of acute hemorrhage in patients presenting with acute focal stroke symptoms and is more accurate than CT for the detection of chronic intracerebral hemorrhage.

Early magnetic resonance imaging findings in patients receiving tissue plasminogen activator predict outcome: Insights into the pathophysiology of acute stroke in the thrombolysis era.

We measured ischemic brain changes with diffusion and perfusion MRI in 42 ischemic stroke patients before and 2 hours (range approximately 1.5 to 4.5 hours) after standard intravenous tissue plasminogen activator (tPA) therapy. The median time from stroke onset to tPA was 131 minutes. Clinical and MRI variables (change in perfusion and/or diffusion weighted lesion volume) were compared between those with excellent outcome defined as 3-month modified Rankin score (mRS) of 0 to 1 and those with incomplete recovery (mRS >1). In multivariate logististic regression analysis, the most powerful independent predictor for excellent outcome was improved brain perfusion: hypoperfusion volume on mean transit time (MTT) map decrease >30% from baseline to 2-hour post tPA scan (p=0.009; odds ratio [95% confidence interval], 20.7 [2.1-203.9]). Except for age < 70 years, no other baseline clinical or imaging variable was an independent predictor of outcome. We propose MTT lesion volume decrease more than 30% 2 hours after tPA as an early marker of long-term clinical benefit of thrombolytic therapy.