Background: Imaging studies are an integral part of stroke evaluation and non-contrast head CT is the initial imaging modality. Although critical for assessing acute hemorrhage, ischemic changes may not be visible on CT for up to 24 hours. MRI brain detects ischemic changes within 20 minutes of symptom onset. It is an invaluable tool to confirm an ischemic stroke and determine its etiology. A focused workup for stroke etiology or evaluation for stroke mimics accelerates management strategies and reduces length of stay in the hospital. Early discharge facilitates early rehabilitation and better functional recovery of stroke patients. Current guidelines for management of acute stroke recommend head CT within 25 minutes of presentation. However, to date, a recommendation regarding timeline for MRI brain in stroke evaluation is lacking. Objective of this study was to investigate the correlation between time to MRI & length of hospital stay to functional outcome in stroke patients.
Methods: 648 patients (mean age 69±0.5 years; 50.4% women) admitted to Hartford Hospital (Comprehensive Stroke Center) with a focal neurological deficit in the year 2014 and got a CT head and MRI brain were enrolled in the study. Data collection was done via stroke database and retrospective chart review. Patients with any hemorrhage or age<18 years, were excluded from the study. We used Mann-Whitney U and Spearman’s correlation co-efficient to compare time from arrival to MRI and length of stay in the hospital.
Results: There was a significant effect of time from arrival to MRI on length of hospital stay (r=0.27, p<0.01). Subgroup analysis revealed a significant decrease in length of stay if MRI was done within 12 hours of admission (p<0.02) as compared to 24 hours or above (p<0.12). Based on MRI findings, 27% patients had a new diagnosis of stroke and in 24.1% patients stroke was ruled out. This change in diagnosis had a significant effect on length of stay (Z=-2.4, p<0.02).
Conclusions:Our study indicates that delay in MRI for a suspected stroke increases hospital length of stay. It suggests MRI within 12 hours of admission to be the new standard of care for stroke patients. Ongoing work will assess the correlation of timing to MRI to functional outcomes in stroke patients.