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BIEN Final
| Question | Answer |
|---|---|
| Components of a digital grid | dots, picture elements (pixels) |
| Component of each pixel | color/tone of pixel |
| Bits in a byte | 8 |
| Formula for file size | (Dimensions of picture*bits per pixel)/8 bits per byte |
| Spatial Resolution | Ability to depict small details |
| Contrast | Difference in grey level value between anatomy of interest and background |
| Noise | Variance in grey level value |
| What does noise make it hard to do? | depict small structures |
| Examples of image artifacts | distortion, streaks |
| Phantoms | Measure image quality |
| Anthropomorphic | phantoms that model realistic anatomy |
| Pinhole camera | One of simplest imaging systems |
| Why are objects blurred in real pinhole camera systems | finite sized diameter |
| A | distance between object and pinhole |
| B | distance between pinhole and image |
| D | diameter |
| Connection between diameter and blurring | direct relationship as diameter increases blurring increases |
| Blurring formula | (D*(a+b))/a |
| Magnification factor | b/a |
| Why does distortion occur? | The rays at the edge of the object are too steep to fit through the pinhole |
| What we need to make image | waves/material that can penetrate and exit body, and interact with different tissues, safe, fast |
| Electromagnetic Wave spectrum | cosmic,gamma,x-rays,Ultraviolet,Infrared,Microwaves,TV,MRI,Radio,Electric Power |
| Ionizing radiation modalities | X-ray, CT, Nuclear Medicine/PET |
| Non-ionizing radiation | Ultrasound, MRI |
| Ionizing Radiation | created ions can damage RNA |
| How are the ions created? | Photons dislodging electrons |
| X-ray Radiography | Beam of x-rays travel through body, attenuation depends on density, resulting image is projection (shadow) of body |
| Only imaging modality that doesn’t use electromagnetic radiation | Ultrasound |
| Which type of radiation is safer | non-ionizing |
| Attenuation of x-ray depends on | tissue depth, density, atomic number |
| Clinical applications of x-rays | mammography, broken bones, GI tract, angiography( blood vessel injected with iodine) |
| Pros of x-rays | High spatial resolution(.1mm), cheap, fast(real time) |
| Cons of x-rays | ionizing radiation, 2D projection (shadow) imaging |
| 2D projection | 3D projection to 2D image, ex is the fork in the patient or on it |
| Tomosynthesis | Series of X-rays acquired over limited projection of angles, provides slices |
| Pros of tomosynthesis | relatively fast, cheaper than CT, partial 3D info, high spatial resolution (.5mm) |
| Cons of tomosynthesis | more ionizing radiation than x-ray, more expensive than x-ray, partial 3d info |
| Computed Tomography (CT) | reconstruct tomographic(cross sectional) images by acquiring x-ray projections at multiple view angles |
| Clinical applications of CT | looking at heart and arteries |
| Pros of CT | Fast, 3D, high spatial resolution (5mm) |
| Cons of CT | lots of ionizing radiation, only measures x-ray attenuation(density) ex)iodine and calcium may look same |
| Nuclear Medicine/Positron emission tomography (PET) | radioactive tracers injected into body and travel to specific organs and emit radiation |
| Type of radiation emitted in nuclear medicine imaging | gamma rays |
| Nuclear medicine provides these images rather than anatomical ones | functional |
| What Nuclear medicine/PET images are fused with this to provide functional and anatomical images | CT |
| Clinical applications of Nuclear Medicine/ PET | Oncology, looking at heart (coronary artery) |
| Pros of Nuclear Medicine/ PET | functional imaging, limitless applications |
| Chest CT has 200 times the radiation of | A chest X-ray |
| Radiation from 2 chest x-rays equal to | 2 round-trip flights from NY to LA |
| Risk induced fatal cancer fr 2 chest x-rays equal to | 1 in million, 6 min in canoe |
| Ultrasound is produced by sending | high frequency signals |
| Sound waves are not electromagnetic but | acoustic |
| transducer | transmits and receives sound waves |
| The longer it takes to hear an echo the | farther away the tissue is |
| Clinical applications of ultrasound | scan abdomen, obstetrics, breast imaging, liver imaging, cardiovascular imaging |
| How ultrasound makes a 3D image | moving transducer around |
| Pros of Ultrasound | safe, 3D, inexpensive, realtime |
| Cons of Ultrasound | limited spatial resolution, need acoustic window (can't see through bone or air) |
| MRI | most recently developed, hydrogen protons are small magnets that cause the magnetic field to precess |
| Presence of field effect on magnetization | in absence no net,in presence net |
| What protons do when placed in external magnetic field | precess about field at Lamour frequency |
| Clinical applications of MRI | brain imaging, knee and skeletal imaging, spine injuries, FMRI (Functional MRI sees what part of brain in doing most activity) |
| Pros of MRI | great soft tissue contrast, nonionizing radiation, limitless contrast possibilities |
| Cons of MRI | Slow, can't image people with magnetic material, claustrophobic, loud, expensive |
| How many shades can human eye perceive | 30 shades of grey |
| What do you need to see an image | a window |
| window width | range of CT numbers displayed |
| window level | center of CT numbers |
| Filter that increases blurring but reduces noise | low pass |
| high pass | filter that emphasizes edge of image |
| Traditional view that radiologists used | 2D axial (slices) |
| Total number of slices in 1980 | 25-35 |
| Total number of slices in 2005 | 600-4000 |
| New visualization methods | advanced 3D visualization, guided navigation, quantitative analysis, computer aided detection |
| z project | 2D image that displays at each pixel the brightest grey level from all the reconstructed slides |
| How 3D info is displayed on 2D image using 3D volume | rendering |
| Help radiologists find suspicious regions inn mamography and chest x rays | computer aided detection |
| Medical imaging is broken down into | Clinical need, acquiring data, reconstructing image, image processing, image display, clinical evaluation |
| Dr. Goldberg | Used imaging as design and planning tool, surgical planning and custom implants, can "rehearse" outside of patient |
| Dr. Ladisa | fluid dynamics, angiography, CT, MRI, Ultrasound, investigated cardiovascular disease, made valves as physiological as possible |
| Ryan McKindles | Neuromechanics,diffusion tensor imaging |
| Diffusion tensor imaging | Ryan McKindles, used to determine spinal injury location, aid in prognosis and monitor drug treatments |
| Relationship between bit depth and color | the greater the bit depth the more color in the image |
| Christian o Connor | WIFY, know importance of evaluating your skills, be open to opportunities and utilize them, embrace winded and varied career path |
| Obtained from converting customer needs into quantitative measurable design specifications | Target specifications |
| Things you need to know when solving BME challenge problem | customer needs, target specifications, |
| Concept generation | brainstorming and comparing ideas |
| phantom construction | final drawing, bill and test plan for validation |
| validation | Used imageJ, evaluate based on target specifications |
| 4 sections of resume | Personal contact info, education, experience, activities/interests |
| magnification (again) | aperture to screen distance/ aperture to object distance |
| Diameter formula | .047(f)^1/2 where f is optimal focal length |
| Field of View formula | di/do=hi/ho where o is object, i is image, d distance, h height |
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