Validity of Computed Tomography in Evaluation of Acute Ischaemic Stroke in Comparison to Magnetic Resonance Imaging: A Cross-sectional study

Abstract

Introduction: Cerebrovascular disease represents a major reason for mortality and morbidity worldwide. Imaging plays a pivotal role in the management of stroke patients. Haemorrhagic stroke diagnosis is straightforward using a Computed Tomography (CT) scan whereas early ischaemic strokes are sometimes difficult to diagnose by imaging. The use of Magnetic Resonance Imaging (MRI) may diagnose ischaemic stroke more convincingly; however MRI remains less available, time consuming and complicated. Unenhanced CT can be performed quickly; can help to identify early signs of stroke. Aim: To determine the validity of CT in the evaluation of acute ischaemic stroke compared to MRI for early diagnosis. Materials and Methods: The study was a cross-sectional study conducted in the Department of Radiodiagnosis, Agartala Government Medical College and GB Pant Hospital, Agartala, Tripura, India. The study period was from December 2018 to December 2020 and included 70 patients. The instruments used were SIEMENS 128 slice CT-SOMATOM model definition AS and SIEMENS 3.0 Tesla MRI-SKYRA model. Statistical Package for Social Sciences (SPSS) for Windows, version 25.0 (SPSS Inc, Chicago, USA) was used for data analysis. Results: Out of all patients (n=70) 63 patients were ultimately found to have infarction. Out of these 63 cases of infarction 69.84%(n=44) were male and 30.16% (n=19) were female. Sensitivity of CT scan was 87.3%, specificity was 71.4%, positive predictive value was 96.4%, negative predictive value was 38.4% and accuracy was 85.7%. The p-value was 0.002. In all patients who presented before six hours (n=15) showed decreased creatinine value during Magnetic Resonance Spectroscopy (MRS) in the lesion area compared to the normal side of brain. None of the patients showed variation in the lactate value. Those presenting after 6 hours (n=48), creatinine was reduced in all the cases (100%), Choline was increased in 89.6%. Conclusion: Sensitivity and specificity of CT scan is lower than MRI. Diffusion-Weighted Imaging (DWI) has 100% sensitivity in diagnosing acute infarction.

Keywords

• diffusion-weighted imaging
• magnetic resonance spectroscopy
• time of flight imaging