Interpret the following CT brain carefully.
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Archive for the ‘Neuro-imaging’ Category
Case application of CT anatomy (3)
Wednesday, May 24th, 2017Case application for CT anatomy (2)
Wednesday, May 24th, 2017Interpret the following CT brain carefully. (more…)
Case application for CT anatomy (1)
Wednesday, May 24th, 2017Interpret the following CT brain carefully.
(more…)
Basic anatomy of CT brain
Wednesday, May 24th, 2017a) Various Densities in Axial Brain CT
The normal anatomy of brain is relatively easier to understand with CT than MRI, comparing to radiograph, it can better delineate different soft tissue density
– Structures appearing “white” in an unenhanced CT brain can only be the following high density structures :
1. Bone e.g. cranium ( calcium-containing )
2. Blood in acute bleeding ( later will become isodense and hypodense with time )
3. Metallic foreign bodies
– Structures appearing “grey” ( i.e. soft tissue density ) can be the brain parenchyma :
1. White matter
2. Grey matter
– Structures appearing “dark” could be :
1. CSF-filled spaces ( e.g. ventricles and cisterns )
2. Air-filled spaces ( e.g. paranasal sinuses or mastoid air cells )
Similar to any other axial CT of the body, left side of the image is in fact the right side of the patient’s body. Whenever learning the basics of interpretation of any imaging, it is always beneficial to integrate what you have already learnt in gross anatomy in pre-clinical years, especially cross-sectional imaging like CT and MRI. Some relevant disease conditions are also included briefly later.
Basic principles of CT brain
Wednesday, May 24th, 2017a) Principles of CT scan
Computed Tomography (CT) is an imaging modality that uses computer-generated analysis ( i.e. computed ) of the x-ray attenuation through a section of the body tissue to produce cross-sectional images ( i.e. tomography ) with great anatomical details.
Unlike plain X-ray images which are projected images of one plane, CT X-ray tubes produced a number of projections by rotation of the CT X-ray tube around the patient. Images are then produced by computer program which analyzes the sum of projections.
The basic principles of CT are identical to conventional x-ray, with greater x-ray attenuation results in regions of high density; whereas soft tissue structures that have weak attenuation of x-rays, such as organs and air-filled cavities, results in lower density.
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