For example:
* In traumatic brain injury (TBI): There are various CT grading scales used to classify the severity of hemorrhages (bleeding) or edema (swelling) in the brain. These scales often consider factors like the location and size of the bleed, the presence of midline shift (brain displacement), and the amount of edema. There isn't one single universally accepted scale, but rather several systems used by different clinicians and institutions. A radiologist will interpret the CT scan and use their institution's preferred grading system to communicate the findings to the treating physician.
* In other neurological conditions: Similar grading scales might exist for evaluating the severity of other conditions visible on brain CT scans, like stroke or tumors. Again, these scales would be specific to the condition and the institution's practice.
In short: There's no single "CT grading scale." The term refers to a range of grading systems used to describe the severity of findings on a brain CT scan depending on the specific clinical context. To understand the meaning of a specific CT grading, you need to know the context (the condition being assessed) and the specific grading system used by the radiologist.