Imaging Tests for Sickle Cell Disease
Medical imaging is a technique that doctors use to create pictures of internal body parts. Different types of imaging tests help doctors make accurate diagnoses and treatment decisions. Doctors may use one or multiple tests to get the most information.
Some of the most common imaging tests are X-ray, MRI, CT scans, and ultrasound. Sickle cell disease (SCD) complications may be diagnosed or monitored using these and other imaging tests. This includes complications in the brain, lung, heart, bone, and abdomen.
How are strokes and other brain complications monitored?
Acute stroke episodes are common and a leading cause of death for people with SCD. The risk is highest for children under 5 years old.1,2
Children with SCD may be screened yearly using a transcranial Doppler (TCD) test. This test uses sound waves to measure the speed of blood flow through blood vessels in the brain. Children with high TCD measurements may have a higher risk of stroke. Doctors may then begin chronic blood transfusions to reduce the risk.3,4
TCD screening cannot detect silent stroke. This is a stroke that does not show any outward signs or symptoms. It can only be detected on magnetic resonance imaging (MRI) scans. Children showing infarctions (dead tissue from lack of blood) on MRI can then receive transfusion therapy.5,6
How are lung and heart functions checked?
Lung disease is another leading cause of death for people with SCD. Some common lung complications in SCD are acute chest syndrome, asthma, and pulmonary hypertension (high blood pressure in the lung).
Doctors often use an imaging test called Doppler echocardiography. This procedure uses soundwaves to measure the speed of blood flow from the heart. Adults with SCD may undergo echocardiography every couple years to detect pulmonary hypertension.4,7
Chest X-rays or computed tomography (CT) scans may also be used to diagnose pulmonary hypertension and acute chest syndrome. These tests generate images of your lungs so your doctor can identify abnormalities.8
How are bone complications diagnosed?
Osteonecrosis (also called avascular necrosis of the bone) is a common complication of SCD that causes chronic joint pain, especially in the hip and shoulder.9,10
In the early stages of osteonecrosis, your bones may look normal on X-ray and can only be detected on an MRI. Later stages can be seen on an X-ray.8,9
Dactylitis (swelling of the bones in the hands and feet) is also common in children with SCD. X-rays of hands and feet often show swelling of soft tissue. Osteomyelitis (bone and joint infection) can also happen because of a weakened immune system. Doctors usually use MRI to diagnose and monitor osteomyelitis.8,11
How are abdominal complications monitored?
The abdomen is the area between the chest and groin. SCD can cause complications in many organs in the abdomen, including the kidney, spleen, liver, and gallbladder. Doctors usually monitor liver and kidney function with blood and urine tests that measure the levels of certain metabolites.6,12
If these tests show issues, doctors may use ultrasound and CT to identify any structural issues with the liver or kidneys. Ultrasound and CT tests are also used to look at the gallbladder and spleen.8
What should I expect if I am getting an imaging test?
Imaging tests are usually painless and not invasive. It may be helpful to know how these tests work and what to expect during the procedure.
An X-ray is the most common imaging test. X-rays are a type of radiation that passes through your body. Bones and other dense objects that block radiation appear white on the film of the x-ray. Low exposure to X-rays is safe, but your doctor will take precautions if you are pregnant.13
The doctor may have you positioned at several angles during the procedure. Sessions usually last less than 10 minutes, and images are ready to view immediately on a computer.13
A CT scan is a more powerful and complex X-ray that takes a 360-degree image of your bones and internal organs. Doctors use it to diagnose problems with internal organs, while X-ray imaging is used more often for bones. A CT machine looks like a box with a tunnel through the center. You lie on a table slides into the tunnel, and the machine rotates around you.13
Ultrasound uses sound waves to create a live video view of the inside of the body. Real-time images show movement of the organs and blood flowing through blood vessels. Unlike X-rays or CT scans, there is no radiation exposure. During the procedure, doctors apply a layer of gel and place a probe directly on your skin.14
An MRI uses a strong magnet with radio waves. Unlike X-rays or CT scans, there is no radiation involved. The magnetic parts create detailed images of body structures. MRIs and CT scans may also be done after a dye is injected into the vein to help highlight organs and blood vessels.13
MRIs can take 30 minutes or more. MRI scans (and CT scans) may be difficult for people with claustrophobia. Discuss your options with your doctor if this is the case. They may be able to perform an open version of the scan or give anti-anxiety medications before the scan.13