Usually a PET scanner (positron emission tomography scanner) with radioactive glucose.
Note: following this test you will be slightly radioactive for about 10 to 12 hours.
the mixture of blood and fluids that suround the brain cause tis effect.
Jellyfish are extremely simple animals. They do not even have blood, a heart, or even a brain.
The chilly temperature slows blood flow. Less blood, less color.
Arteries flow away from the heart. That's a technical answer. Some blood tubes that look like arteries flow into the heat to nourish it. Of interest is the pulmonary artery, the only artery to carry un-oxygenated blood. It carries blood to the lungs where it is oxygenated.
When you get cold the body routes blood away from the skin and into the core of the body instead. With less red blood in the skin it will look paler.
A CAT scan is used to look for evidence of structural damage - reduced blood flow, changes in neural activity, etc.
Yes, you will have blood. Menstruation is the process in which your uterus lining sheds, the menstrual flow is made-up of blood and uterus tissue mixed with your discharge. When your period first starts it may be light so there will be less blood, this may look like brown or pink discharge, then as your flow becomes heavier you will see more blood.
Brain
collateral hyperemic venous blood flow in abdominal wall due to portal cirrhosis of liver for example
A explosion of nerves sending signals of pain to the brain, blood gushing, cry's of pain.
Your dog died in one of two ways. When the car hit your dog it broke the aorta lose from its heart. Instead of pumping blood throughout your dogs body, your heart pumped blood nowhere. Blood did not get to your dog's brain and your dog died. The second way your dog died was that when the car hit your dog, it broke a blood vessel in its brain. That shorted out some necessary circuits and its brain could not send a message to its heart to continue to beat. Without an autopsy, it is impossible to know the exact cause. The first thing to look for is the aorta. The second thing to look for is the brain.
Massage it. Get blood flow moving in that area. Sounds easy, but takes a while. And you might look silly doing it. ,