3D imaging has been a critical component in the clinical diagnostic process – especially when it comes to detecting brain tumors. In fact, more than 40 million units of MRI tests were performed in 2019 in the United States and 16% of the tests were head scans. Without posing radiation risks, MRI tests have been leveraged as a preferable means to visualize and localize brain tumors.
Let’s learn more about astrocytomas and take a look at an MRI scan of a grade-three astrocytoma.
Every year, 150,000 astrocytomas are diagnosed, making it one of the most common brain cancer types in the United States. Arising from a particular type of glial cells called astrocytes, astrocytomas are often detected in the brain and spinal cord. Based on the level of tumor growth and invasiveness, astrocytomas are classified into four grades.
- Grade I: Usually non-invasive and slow-growing, but can become very large.
- Grade II: Also called low-grade or diffuse astrocytoma. Usually invasive and relatively slow-growing with poorly defined borders.
- Grade III: Also called anaplastic (malignant) astrocytoma. It grows more quickly and is more invasive than a grade II astrocytoma.
- Grade IV: Also called glioblastoma, it is the most aggressive and destructive type of nervous system tumor. It accounts for 60% of astrocytomas and 23% of all primary brain tumors.
To diagnose astrocytomas, doctors often order a series of imaging tests such as MRI with contrasts.
During an MRI, the patient will be injected with an iodine-based colorless liquid into the body. After the liquid has been absorbed into the body, the patient will be placed on a table which will slide into a cylindrical machine where the magnetic waves will align the protons inside the body. When radio waves from the machine are sent, the protons will be dealigned.
Once the waves are off, the protons will return to their original position while sending radio signals to the computer, translating the data into cross-sectional images for diagnosing.