A neurologist is a physician who diagnoses and treats disorders of the nervous system which is comprised of the brain, spinal cord and nerves. These doctors do not perform surgery, but refer patients to neurological surgeons when they determine that surgical intervention is necessary.
Some of the conditions that neurologists diagnose and treat are epilepsy, aneurysms, hydrocephalus, Parkinson's disease, multiple sclerosis, stroke, spinal disc herniation, and spinal disease.
In addition to using diagnostic tests like MRI, CT scans, EEG and EMG, neurologists also employ neurological testing to gauge muscle strength and movement, balance, reflexes, sensation, memory, speech, and other cognitive abilities.

Radiologists help doctors get a closer look at what’s happening inside your body. If your primary care doctor wants to investigate your symptoms further, they may refer you to a radiologist to get an ultrasound or x-ray. Some radiologists specialize in mammography and breast imaging, which is who you see when you need a mammogram. A Radiologist can also determine if bones are broken or fractured after any kind of accident.
Radiologists are trained to perform MRIs and CT scans, both of which are used to determine the presence of diseases or disorders and help your doctor properly diagnose you. They can detect anything from tumors, bleeding and infections to bone and muscle disorders.

A radiologist is a physician who specializes in the use of medical imaging to diagnose and treat illnesses or injuries in patients.
The different types of medical imaging are X-ray, computed tomography (CT) scans, magnetic resonance imaging (MRI), ultrasound, and nuclear medicine.
Radiologists are experts in these different types of tests and can advise a primary care doctor on which test is most appropriate in a specific case. These doctors also assist primary care doctors in analyzing the images produced by these tests in order to determine next steps necessary for treatment.

A psychiatrist is a doctor with specific training in the diagnosis and treatment of mental illness.
He or she can not only provide the counseling necessary to both diagnose and treat a patient, but can also prescribe medication when needed. In some cases, a psychiatrist will only provide the medication and the counseling will be provided by another healthcare specialist, like a certified counselor or psychologist.
Like other doctors, psychiatrists employ diagnostic tools like CT scans and MRI in order to observe the structure and function of a patient's brain.
Once a diagnosis is made, these specialists may use behavior or cognitive therapy in order to address the patient's condition, or a multitude of other types of therapy, in conjunction with or in place of medication.