<s>[INST] How is Ischemic stroke diagnosed? [/INST] Ischemic stroke can be diagnosed by using various techniques such as CT Scan, MRI etc.

CT scan: X-ray pictures of skull and brain are taken using Computed Tomography (CT) Scan machine. Patient is made to lie on a table that slides down into a tunnel-like device. The inside of this machine rotates and takes several X-ray pictures of brain from different angles. This enables the doctor to detect the presence blockages or clot inside the brain.
MRI Scan: Unlike CT Scan, MRI (Magnetic Resonance Imaging) technique does not use X-rays for imaging purposes. It makes use of radio waves and magnetic field to get accurate pictures of brain anatomy. It is highly effective in taking soft issue images and can show minute differences between similar areas. Patient is made to lie on a table and slided into the opening of MRI machine. The images assist doctors in identifying clots, blockages and tumors.
Cerebral Angiogram: A thin, flexible tube called as catheter is inserted into groin through a small incision. It is further glided up to vertebral artery. A dye is injected into blood vessels for better view of arteries under X-ray imaging.
Carotid Ultrasound: Carotid ultrasound test helps in identifying plaque build up and flow of blood in carotid arteries. It uses sound waves.
Doctors may ask to do either single test or combination of tests for better analysis and interpretation. Source: MEDIFEE. Link: https://www.medifee.com/faq/stroke#9. Field: Neurology. Disease: Stroke </s>