Prevalence of Imaging Targets in Patients With Minor Stroke Selected for IV tPA Treatment Using MRI: The Treatment of Minor Stroke With MRI Evaluation Study (TIMES).

OBJECTIVE: To determine the IV tissue plasminogen activator (tPA) treatment rate of patients with minor acute ischemic stroke (mAIS) at our centers and compare the frequency of MRI targets by treatment stratification and clinical severity, we evaluated clinical characteristics and baseline MRIs for tPA-treated and untreated patients. METHODS: Patients with ischemic stroke from 2015 to 2017 with admit NIH Stroke Scale (NIHSS) <6 were considered. The treated cohort received standard IV tPA and was screened with baseline MRI. The untreated cohort received no acute intervention and baseline MRI was <4 hours from onset. Patients were stratified into "clearly" and "not clearly" disabling deficits by NIHSS elements. Baseline MRI was evaluated by independent raters for AIS targets, with frequencies compared between groups. RESULTS: Of 255 patients with mAIS ≤4.5 hours from onset, 140 (55%) received IV tPA, accounting for 46% of all IV tPA patients (n = 305). Eighty-five percent (n = 119) were screened with baseline MRI and had significantly more frequent imaging targets compared to those untreated (n = 90). Of this treated cohort, 75% (n = 89) were not clearly disabling. Except for perfusion-diffusion mismatch (81% clearly disabling vs 56% not clearly disabling [p = 0.036]), there were no significant differences in the frequency of imaging targets across the treated cohort stratified by clinical severity. CONCLUSIONS: In MRI-screened mAIS, imaging targets were more frequently seen in patients treated with IV tPA, with similar frequencies even in those without clearly disabling deficits. MRI targets could be used to guide thrombolytic therapy in patients with mAIS; however, a randomized trial is needed to demonstrate efficacy.

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.