The most common clinical methods to detect blood clots are ultrasound of the neck blood vessels, CT of the head blood vessels, and cerebral angiography with MRI, which can clearly observe whether the patient has blood clots and the site of blood clots. For example, angiography is an allergic test because of the contrast agent, and it is an invasive test, which may have a negative impact on the patient’s body. Therefore, the most common means of initial screening in clinical practice is through ultrasound of the cervical vessels and Doppler examination of the intracranial vessels. Generally, ultrasound is non-invasive and has precise localization of the thrombus, but for the deeper parts of the vessels, such as capillaries or the deeper parts of the brain, the thrombus is not visible and may require CTA for clarification. In summary, the common clinical methods are non-invasive: color ultrasound, enhanced CT (CTA) of blood vessels. The invasive one is angiography.