finals Flashcards
(32 cards)
- high atomic number
- high fat solubility
- ability to cross the blood brain barrier (BBB)
- xenon contrast inhalation studies have demonstrated a wide variety of cerebral disorders
- particularly useful in evaluating regional perfusion in cerebrovascular disease & in studying brain metabolism
- may find significant clinical role in dementia, degenerative sleep disorders, migraines & epilepsy
xenon ct
in RTP, ___ are used to calculate physical & electron densities, which are then used in dose computation.
CT numbers
plot of the pixel values as a function of the frequency which each value occurs
CT histogram
allow for statistical calculations such as mean & standard deviation within ROI
ROI statistics
ROI can be transferred from slice to slice
ROI transfer
image n image can be split into 2 detailed thin slices
split imaging
in w/c 2 contiguous thin slices can be fused into a single thick slice
fused imaging
allow the user to render various 3D images from the axial data set
3D visualization tools
3D visualization tools three categories
- allow the user to render various 3D images from the axial data set
- volume rendering technique (VRT)
- maximum intensity projection (MIP)
application of 3D imaging & is used in the examination of the circulatory system
Computed tomography angiography (CTA)
- based on volume rendering technology
- changes in the opacity values of various tissues enable the observer to simultaneously visualize bone, soft tissues & vascular structures
- both foreground & background structures are visible
- useful & is preferred over conventional MIP techniques for visualization of:
- aortic aneurysms
- renal arteries
- stents
- carotid bifurcation
4D Angiography
Allows the user to render only a selected volume of data & does not require segmentation techniques
TARGET VOLUME MIP (TVMIP)
- allows the user to produce a set of MPR images including curved MPR images for the entire vessels
- skull removal tool facilitates the subtraction of the skull from the CTA image and allows the observer to visualize very detailed image of the vessels and soft tissues
vessel tracking tool
- display all types of MPR images from axial data set in the axial, coronal, sagittal
multiplanar reconstruction tools
- features in any 3D rendering mode:
- W/W level adjustment
- volume of interest adjustment
- scan information display
- movie creation & playback
- split screen presentation
- zoom
- measurements
Interactive visualization tools
allow user to view a large set of images very quickly
cine visualization tools
facilitate measurements such as distances, angles, areas, mean, standard deviation, maximum & minimum, voxel values, density value in HU, density histogram for a particular ROI & volume of 3D objects
Advance quantitative measurements tools
allow the user to combine images from a wide variety of imaging modalities such
as CT, MRI, PET & SPECT to facilitate diagnosis of tumor localization & qualification, surgical planning & oncology planning
Multimodality image fusion tools
- create 3D & 4D images of tubular structures such as the colon & bronchi & allow the user to “fly through” the images of hollow organs (CT virtual endoscopy)
voyager (picker) 3D navigator
usually CRTs or flat panel displays w/ at least ___ pixel resolution
2.5x2K
important feature of current workstations because of the current trend toward filmless radiology departments through the implementation of PACS, RIS & HIS
connectivity or networking
- continuous source rotation with patient transition through x-ray beam
- no interscan delay
- volumetric imaging within one breath hold at least 25s
- examination time is greatly reduced
spiral or helical
- relationship between patient couch movement & x-ray beam width
- expressed as a ration
pitch
formula of pitch
couch movement each 360 / beam width
