CAT & PET Scans for Diagnosis Bipolar Disorder

CAT (sometimes referred to as CT, computer axial tomography) scans are a diagnostic tool for problems in the brain. It’s a painless procedure, takes less time than an MRI, and doesn’t have the risks from the magnetic fields. It is used mainly to rule out other disorders before a diagnosis of bipolar disorder can be made.(1) Generally if there is something found abnormal on the CT scan, an MRI is ordered.

 “Information gathered from a CT scan isn’t useful in making a bipolar diagnosis”

 PET (Positron Emission Technology) Scans work differently. It uses radiation (eek!) or nuclear medicine imaging to produce a 3-D picture of the human body.(2) The machine detects pairs of gamma rays emitted indirectly by a positron(3) emitting radionuclide, which is in the body on an active molecule. The images are constructed on a computer, and many machines take a CT scan and X-ray during the procedure. Again, this is a painless procedure, just boring.

 PET scans are used to diagnose health conditions, or find out how an existing condition is developing, to see how the treatment is working.

 And now onto the mental illness part.

Pharma companies have been saying mental disorders are chemically based for years, but actually, there isn’t really any proof.(4) A PET scan is changing that, they are finding interesting results comparing PET scans from the mentally interesting to the normals.


  • Depressed brains are more active

  • PTSD sufferer’s brains are less active

 The other side of the fence(5)

What Brain Scans Can Do

  • Show damage to brain tissue, the skull, or blood vessels in the brain

  • Be used with other medical tests to help doctors find the right diagnosis for mood and behavioral problems

  • Help researchers study healthy brain development, effects of mental illnesses or effects of mental health treatments on the brain.


What Brain Scans Cannot Do

  • Diagnose mental illness when used by themselves

  • Predict risk of getting a mental illness.

 There is a lot of controversy surrounding brain scans and mental illness. Some say yes, some say no. Specific scans can show the damage done by drug use, however. They are mostly used to rule out neurological disorders. Perhaps in future years, technology will allow us to see into the brain more carefully.








  3. Positively charged particles




Can EEG (Electroencephaolography) Be Used as a Diagnostic Tool?

Some say yes, some say no, many say maybe.

First, let’s examine what Electroencephaolography (I’m going to call it an EEG, its way easier to type that) is. Electrodes are painlessly stuck to your scalp (this sucks if you have long hair, washing the goop out later) to detect electrical activity in your brain(1). There are always active brain cells, even when you’re sleeping. This test is commonly used to rule out seizure disorders, or determine what part of the brain is causing the seizure.

However, an EEG is not for use to diagnose mental illness, but there are studies that show the electrical circuits in the brain that are different in the mentally interesting than the “normal population”.

The EEG was used to test schizophrenics, a condition similar to bipolar disorder that has a “hybrid” of schizoaffective disorder. The study of patients indicates a higher number of them with abnormal records decreased in alpha activity. There are left side abnormalities, and some coherence abnormalities. (2) Further testing needed.

This study(3) claims that schizophrenia can be diagnosed before major symptoms happen, using EEG technology.



“What we found, in terms of disease, was quite striking – defects in the genes that encode these human synapse proteins are really a major cause of disease,” he said. “There are over 135 nervous system diseases, psychiatric and neurological, that arise because of defects in these synaptic proteins. These are common and rare diseases – schizophrenia, bipolar disorder, autism.”

Although there are those doubting the EEG being used a diagnostic tool, it could help in the future as research continues, to decide on the best medications to use, and also to create new medications.


Diagnostic Tools Part 1 – MRI and fMRI

They’re always looking for a way to diagnose mental illness using the physical body, assuming the physical and mental are somehow interconnected. I’m going to go over popular diagnostic tools and sho how effective they are in diagnosing, or confirming a bipolar disorder diagnosis.




Magnetic resonance imaging is in the works of becoming a diagnostic tool for bipolar disorder, according to the researchers at the Royal College of Psychiatrists International Congress.(1)

A function MRI (or fMRI) can be used to scan the neural pathways and DTI (Diffusion Tension Imaging) can scan the brains white matter.

So far, scans of brains of those with depression or bipolar disorder have shown differences from the brains of those who do not have these conditions. “Functionally coupled” activity is shown in two parts of the brain: the amygdala(2) and the pre-frontal cortex(3).

Those with bipolar disorder had an increased right lateral ventricular(4), left temporal lobe(5) and right putamen(6) volume. If the patients were taking lithium, hippocampal(7) and amygdala(2) volume were significantly increased. Cerebral volume reduction was associated with illness duration in bipolar individuals.


In conclusion, there is hope out there for a fairly simple diagnostic test for bipolar disorder. It can even be used to predict bipolar disorder.




  2. The amygdala processes emotions.

  3. The pre-frontal cortex is important for emotional regulation.

  4. Protects the brain from trauma.

  5. Information retrieval, reading, emotional stability, memory, sensory processing

  6. Regulate movements and influence various types of learning.

  7. Plays a role in memory, spatial navigation and control of attention.