Correlation of Diffusion-Weighted Magnetic Resonance Imaging Determined Infarct Volume with Clinically Assessed National Institutes of Health Stroke Scale in Patients of Acute Stroke: A Cross-sectional Study

Abstract

Introduction: Infarct volume is an essential factor in predicting patient prognosis. National Institutes of Health Stroke Scale (NIHS) allows consistent reporting of neurological deficits in stroke patients. Limited studies have been done in the Indian population correlating the volume of infarct and the NIHS Scale. Aim: To correlate the Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) assessed infarct volume with the clinically assessed NIHS to prognosticate clinical outcomes in patients of acute stroke. Materials and Methods: This was a cross-sectional study comprising 36 patients of acute stroke with a study duration from November 2017 to April 2019. Diffusion-Weighted MRI was obtained on Siemens Magnetom 3 Tesla, and diffusion restriction on b=1000 image was measured with a Region of Interest (ROI) tool using manual contouring in each slice. Assessment of the neurological deficit was done by NIHS scale at the time of admission and 7 days post admission for each patient. Correlation of the infarct volume with NIHS Scale was done with p<0.05 considered statistically significant. Receiver Operating Characteristic Curve (ROC) was used to predict cut-off of the volume of infarct and NIHS Scale to predict adverse patient outcome. Results: Present study consisted of 36 patients of acute stroke with a mean age of 52.05±18.53 years. The minimum age of the patient was one year, and the maximum age was 78 years. There was a statistically significant correlation between the volume of infarct and NIHS Scale at time of admission admission (p=0.001; r=0.807) and the NIHS Scale at one week (p=0.002; r=0.602).The Area Under the Curve (AUC) for a cut-off of 115 cc of the volume of infarct in predicting adverse patient outcomes was 0.931, whereas that for the NIHS scale of 20 was 0.998. Conclusion: Volume of infarct of 115 cc and NIHS Scale of 20 are excellent as prognostic tools in predicting patient outcome and have comparable efficacy.