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BIM Final Review 2
Lecture 5: Biomedical Imaging
Question | Answer |
---|---|
Imaging fundamentals Resolution | the detail an image holds. How close lines can be to each other and still be distinctly visible |
Imaging fundamentals Noise | random (not present in the object) variations of brightness or color information in images. Usually an aspect of electronic noise. |
Imaging fundamentals | Digital storage |
Imaging systems | ultrasound, x-ray, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), optical imaging |
Ultrasound | sound waves with frequencies higher than upper audible limit echo off tissues |
Different tissues reflect ultrasounds | differently |
Functional ultrasound | Doppler – blood flow Intravascular ultrasound (IVUS) Drug delivery Treatment of fibroids |
X-ray | electromagnetic radiation is absorbed by hard structures |
Produced first medical images inside the body | Wilhelm Rontgen in 1895 |
X-rays are best for imaging | dense tissue (bone and teeth) |
X-rays are also used for soft tissue | heart and lung conditions, mammography Used with contrast dye |
CT | tomographic images (3D image composed of slices of specific areas) are obtained from large series of x-rays taken in different directions Digital |
MRI | essentially map the location of water via hydrogen atoms. Hydrogen atoms generate radio frequencies. |
MRI resolution compared to CT | high |
MRI's do not use radiation | preferred to CT whenever it can be used |
fMRI | measures brain activity by detecting changes associated with blood flow – differences between oxygen-rich and oxygen-poor blood |
PET | patients emit radioactive waves |
PET | Radioactive components are targeted to specific functional aspects of a disease: cancer cells, inflammatory cells |
Classes that are important to biomedical imaging | Physics, math, computer programming, signal processing, image processing |