Clinical utility of MRI in acute stroke beyond reperfusion therapy

Background: Stroke is primarily a clinical diagnosis. It can be hemorrhagic or ischemic in etiology. Computed tomography (CT) brain is usually the initial investigation in most patients with suspected stroke. Although it has excellent accuracy in diagnosing hemorrhage, ischemic changes may not be apparent in the first few hours. Some centers use focused magnetic resonance imaging (MRI) studies to help in selecting appropriate patients for reperfusion therapy. However, clinicians often use this investigation even when reperfusion therapy is not being considered. This study aims to find out whether doing an MRI in addition to a CT scan has any clinical utility in this situation. Primary Objective: To determine the proportion of patients who undergo a change in their management based on MRI findings. Secondary Objectives: 1. To determine the time duration from the onset of symptoms to presentation at the hospital. 2. To determine the time duration from presentation to the hospital to get CT performed. 3. To determine the proportion of patients who had MRI in addition to CT. 4. To determine the time duration from CT performed to MRI performed. Materials and Methods: Study Design: Retrospective, descriptive observational study. Inclusion Criteria: Patients above age 18 admitted at a tertiary hospital with a clinical diagnosis of stroke between 1/8/2018 and 30/7/2019. Exclusion Criteria: Patients who had already undergone MRI before presentation to the hospital and patients undergoing thrombolysis. Patients meeting the inclusion and exclusion criteria were identified from the hospital information system and the ward admission register and by manual examination of the patients' case notes. Relevant data were obtained from the case notes and collected on a google form and downloaded in Microsoft Excel 2019. SPSS version 22 was used for data analysis. Results: Out of the 106 patients, 54% (n = 57) were diagnosed as having ischemic stroke, whereas 46% (n = 49) were diagnosed with hemorrhagic stroke after initial assessment and CT scan. Only 2.8% (n = 3) of the patients presented within 4.5 hours of the onset of symptoms. 43.4% (n = 46) presented between 4.5 and 24 hours from the onset, whereas 53.8% (n = 57) presented more than 24 hours after the onset. Twenty-seven patients had their CT scan performed prior to their presentation at the center. For the remaining 79, the median time from presentation to CT scanning was 2 ± 1.5 hours. 24.5% (n = 26) of all patients had an MRI performed in addition to the CT scan. There was wide variation in the time from CT scanning to the MRI. Among the patients who had an MRI, additional information was obtained by the investigation in 58% (n = 15). However, this led to a change in management in only three (11.5%) of the patients. On review, it was found that the change was justified in only two patients. Furthermore, one patient who was diagnosed with tuberculoma had a long history of fever which was missed on initial evaluation. Considering these, MRI can be credited for a meaningful change in management in only 4% (n = 1) of the cases. Conclusion: The findings of this study do not support the routine use of MRI in patients who are not candidates for reperfusion therapy. Their use should be restricted to cases where some specific information is sought or where there is diagnostic uncertainty. Allocation of resources in developing integrated acute stroke pathways is likely to give a better value for money.