First Week :CT and MRI

My first week at the hospital involved observing Doctors in the neuro reading room where they analyze images taken from patients. The images analyzed in this room are those taken on brain, neck, and spine.

These images are taken by

1.      MRI (Magnetic Resonance Imaging)

2.      CT (Computer Tomography)

3.      MRA (Magnetic Resonance Angiogram)

4.      CTA (Computer Tomography Angiogram)

CT works as a densitometer, where the images are formed based on densities that different brain features have, while MRI form images based on how atoms behave in different features of the brain under magnetic influence. MRA is used to image blood vessels just as CTA but CTA requires use of contrast agents while MRA doesn’t.  CT images tend to be coarse and they can be taken faster. So they can be used to analyze the situation of the brain quickly to know if there is anything that needs to be done immediately, then MRI can be taken to give more details.

In the above brain imaging technologies, images are taken as slices spaced at a fixed interval in the imaged organ. The images are taken in coronal, sagittal and axial directions. These stacks of images taken are then used to build a 3D view of the organ. Viewing the 3D image in coronal, sagittal and axial directions enables doctors to study and analyze any abnormalities in the organ under investigation.

For this week I observed doctors conduct analysis on images from patients.

I learned that the size of the ventricles in the brain contribute to stability during walking. Enlarged ventricles cause gait during walking. By observing the size of the brain ventricles we can tell whether gait symptoms are caused by the enlargement of the ventricles. Also brain becomes smaller as a person gets older/ages which may cause the ventricles to enlarge.

MRI/CT technologies are also used to see if there are any tumors or bleeding in the brain. In this case for example, images taken at different intervals of time from the same patient are compared to see if a tumor is shrinking or growing. In addition, images taken post-operation are used to see if there is any enhancement of a removed tumor.

MRI/CT are also used to view conditions of the neck and spine. Analyses of images taken may indicate causes of pain in these areas stated by patients. Other illnesses such as epilepsy are also analyzed using on MRI/CT.

Another interesting study I observed was on the correlation between weakening of limb functionality and accumulation of minerals such as iron, in the motor cortex area controlling that particular limb.