Clinical history and physical examination form only part of the diagnostic skills of a Neurosurgeon. Imaging techniques such as CT scans, MRI scan and PET scan are essential tools for diagnosing brain and spinal problems. Nerve conduction study and electromyography (NCS/EMG) are critical ways of evaluating the peripheral nervous system.
Routine x-rays of the spine may be necessary for some patients to assess bone abnormalities or to assess alignment or abnormal movement.
CT Scans (X-ray computed tomography)
Computerised Axial Tomography (CAT scan or CT scan) was invented in 1972 by Godfrey Hounsfield and Alan Cormack. Pictures of structures within the body are created by a computer that takes data from multiple x-ray images and turns them into pictures. In the skull, CT scan is particularly useful in identifying bony anomalies and assessing trauma, but has been largely superseded by MRI for assessing the brain.
MRI Scans (Magnetic resonance imaging)
Magnetic Resonance Imaging (MRI) is a scan that uses a powerful magnetic field to align protons in water molecules and then release them. These magnetised protons send out an echo in response to the MRI’s radio waves. A computer then arranges these echoes to create images. MRI is particularly useful in imaging soft tissues such as the brain and any abnormalities within it. It is an integral part of the workup for patients with brain tumours, trigeminal neuralgia, hemifacial spasm or glossopharyngeal neuralgia, amongst other conditions.
PET Scans (Positron emission tomography)
A positron emission tomography scan is an imaging test using a radioactive substance called a tracer or isotope to look for disease in the body. The tracer is injected via a vein. The tracer travels through your blood and collects in organs and tissues variably according to activity. This helps the Doctor see certain areas more clearly.
You will need to wait about an hour as the tracer is absorbed into the tissues. This takes about 1 hour. Next, you will lie on a table that slides into a scanner. The PET detects signals from the tracer. A computer changes the signals into 3D pictures. The images are displayed on a monitor for the Doctor to read. You will need to lie still during the test as excess movement can blur the images.
Nerve Conduction Study (NCS) and Electromyography (EMG) are often used to assess nerve continuity and function. You will be referred to a Neurologist for this investigation. The purpose is to determine whether nerves and muscles are functioning properly. Small electrodes are placed on the skin for NCS and tiny needle in muscles for EMG to allow the neurologist to examine the electrical properties of both nerves and muscles. This test is invaluable for picking up damage and dysfunction that cannot necessarily be detected through routine neurological examination.