Tissue window in stroke

INTRODUCTION: Stroke is known to human race since ancient time. The 7th century great Indian physician, Charaka described the stroke which he called “Pakshaghat” meaning hit one half of the body. The other synonyms are ardhang or lakwa. According to Charaka, stroke affects either right or left half of body leading to impaired movement and function of that half of the body (hemiparesis) and difficulty in speaking which may be inability to talk (aphasia) or slurred speech (dysarthria). He had also identified head as the vital organ, controlling the senses and nerve centers of the whole body. These meticulous observations of stroke symptoms are relevant till now. Stroke is one of the major causes of death and dependency among all the neurological disorders. According to World Health Organization (WHO) stroke is defined as rapidly developing clinical symptoms and / or signs of focal, at times global loss of cerebral function, with symptoms lasting more than 24 hours or leading to death, with no apparent cause other than of vascular origin. AIM OF THE STUDY: 1. To analyze the clinical profile of ischemic stroke. 2. To analyze the risk factors of ischemic stroke. 3. To study early imaging patterns in acute ischemic stroke. 4. To study the existence of ischemic penumbra in acute ischemic stroke up to 24 hours. MATERIALS AND METHOD: This study was conducted from May 2011 to January 2013. Patients were taken from Rajiv Gandhi Government General hospital. They were enrolled in this study after getting a written consent. INCLUSION CRITERIA: 1. Patients who presented with symptoms and signs of ischemic stroke. 2. Patients who presented only with anterior circulation stroke. 3. Patients who presented within 24 hours after the onset of stroke symptoms. EXCLUSION CRITERIA: 1. Patients who presented with symptoms and signs of hemorrhagic stroke. 2. Patients who presented with posterior circulation stroke. 3. Patients who presented more than 24 hours after the onset of stroke symptoms. 4. Patients who were not eligible for computed tomography (CT) perfusion study. 5. Patients who were having contraindications to Magnetic Resonance Imaging. Patients who presented with stroke symptoms and signs were subjected to plain CT Brain. If the CT Brain ruled out hemorrhagic stroke, then the patient was subjected to diffusion weighted image (DWI) sequence of Magnetic Resonance Imaging (MRI) and CT perfusion after analyzing the renal functions. In DWI MRI imaging ischemic core tissue was assessed. In CT perfusion imaging penumbra tissue was assessed. After doing Diffusion Perfusion mismatch, presence of potentially salvageable penumbra was assessed. CONCLUSION: 1. This study shows male preponderance in the acute ischemic stroke. 2. In this study commonest age group affected is >60 years (57.5%) followed by 40 to 60 years (30%) followed by <40 years (12.5%). 3. In this study there is slight predominance of left sided cerebral ischemia over right side (57.5% vs 42.5%) 4. In this study, middle cerebral artery (80%) is commonly affected than anterior cerebral artery (20%). 5. NIHSS score observed were, ≤4 - 10%, 5 to 10 – 47%, 11 TO 15 – 40% and 16 TO 20 – 3%. 6. All the patients with anterior circulation stroke were having NIHSS Score of less than 20. 7. Even though the cohort is too small for definitive conclusion, there is statistically significant correlation between penumbra and the risk factors such as age > 40 years, hypertension and diabetes mellitus. 8. In this study most of the individuals had early CT findings such as dense MCA sign, insular ribbon sign, loss of differentiation between grey and white matter and obscuration of lentiform nucleus. 9. Among the patients presented with acute ischemic stroke 22.5% patients had ischemic penumbra. 10. The occurrence of penumbra is common in female sex than in male sex. 11. The significant penumbra is present in middle cerebral artery strokes, and is persistent even upto 24 hours. Hence we propose that there could be a paradigm shift from time window to tissue window and from parenchymal imaging to physiological & penumbra imaging in acute ischemic stroke. 12. Aggressive measures to salvage the penumbra should continue even beyond the proposed time window