Pathology: Blood or qi deficiency. This is seen in cases of deficiencies and failure of Qi and blood. It can also be seen in disharmonies of the even emotions, weakness in Yang Qi, internal damage to jing, and penetration of dampness.
Testing for venous blood clots. Venous blood clots may be detected in a variety of ways, though ultrasound is most commonly used. Occasionally, the patient's size and shape limit the ability for ultrasound to provide a definitive answer. Venography is an alternative test to look for a clot.
A soundwave of the heart (echocardiogram) may be done to look for a source of blood clots in the heart. Narrowing of the carotid artery (the main artery that supplies blood to each side of the brain) in the neck can be seen with a soundwave test called a carotid ultrasound.