It's not all that uncommon when someone does suffer a brain injury where the CT scan and the MRI scan come back normal. You go to the doctor and the doctor has diagnosed that you are having problems with motor function, speech function, memory or whatever area of the brain that has been affected is showing up in your life but not on the imaging tests. So what does the doctor do to try and locate the injury? They can use what is known as a SPECT scan.
A SPECT scan is about as expensive as an MRI but they produce a much more detailed look of how the fluid or blood moves or accumulates within the brain. When the doctor orders a SPECT scan of the brain, areas of the brain that have been damaged will show up a different color because damaged tissue doesn't have the same blood flow as healthy tissue. So it's going to look different on the SPECT scan. Then the doctor knows what you are complaining of in terms of your symptoms, what they call the "clinical symptoms", and they want to match up the loss of blood flow to that area of the brain that has been affected as confirmation or proof that that has been caused by damage to the neurons or brain tissue in that area of your brain.