Bézier curves and Raster vs Vector images

So I was really lucky today to have a tutorial from the head of vascular surgery about some basic imaging concepts.

Endovascular and vascular surgery requires careful planning beforehand using mainly CT scans. Since the aorta and many vessels can have tortuous paths, it can be difficult to to appreciate the true path of the vessel using only the traditional axial views or even sagittal/frontal reconstructions offered by the hopsital pacs system.

Horos is a free open source software (for macs only at the moment)  for medical imaging viewing. Pretty damn neat, download it and get involved!
Using an open source software like Horos or Osiris (another), you can do what's called multiplanar reconstructions which can enable you to take a slice of the body from any angle.
An incredibly valuable tool in surgical planning.
(as a medical student its actually worth playing around on)

Bézier curve
Is a curve that put simply can be generated from three simple points. You may have noticed it from powerpoint or photoshop programmes.
Youtube clip illustrating bézier curves
The maths is utilized when you trace a path aong the aorta in simply points. If you put the points in the centre of the lumen, the curve of the aorta can traced and you can generate an image that perfectly follows the curvature of the aorta.

The two kinds of images
Raster and vectorial images
Raster or bitmap images are your classic PC jpeg photo file. Every pixel colour is coded in the file and the location of each pixel is recorded. So a completely black square will still have lots of information coded as each pixel reports its location and colour (black).
Vectorial images are different, the file will simply state the size of square and all black for example. If you were to place a white circle over one corner of the image, the angle of the curvature would be coded by Bézier curve maths and then the colour behind simply coded white. With a vector/vectorial image, there is a lot less information to be coded and of course the file is significantly smaller.
CT scan slices are raster images. 
A raster image is of course better for images with lots of small details.
Helpful webpage

When using a CT scan to plan surgery pay attention to the thickness between slices. Optimal thickness is 0.2mm.

#CTscan #Vascularsurgery #Béziercurve #Imaging #MEDed #medicine